Hot-dip galvanized steel strip - Technical Terms of Delivery

 
Hot-dip galvanized steel strip
Technical Terms of Delivery

voestalpine Stahl GmbH
www.voestalpine.com/stahl
Contents

                                                        T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Introduction                                       5

Hot-dip galvanized steel strip with zinc coating   6

   Steel grades                                     6
   Mild steels for cold forming                     6
   Structural steels                               12

High-strength steels for cold forming              16

   Micro-alloyed steels                            17
   Bake-hardening steels                           22
   High-strength IF steels                         24

                                                        2
   Dual-phase steels                               28
   Complex-phase steels                            33
   TRIP steels                                     35

Zinc coating groups                                38

Surface                                            39

   Surface of the zinc coating                     39
   Surface quality                                 39
   Surface type                                    40
   Subsequent surface treatment                    41

Available dimensions                               42

Inspection and Testing                             43

   Test unit                                       43
   Sample-taking                                   43
   Performance of tests                            43
   Repeat tests                                    44
Processing information                           45

                                                      T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
   Forming                                       45
   Joining                                       45
   Thermal rating                                46
   Suitability for the application of coatings   46

General notes                                    47

   Fretting corrosion                            47
   Darkening                                     47
   Formation of white rust                       47
   Flatness                                      48

Hot-dip galvanized steel strip with
zinc/iron-coating (Galvannealed)                 49

                                                      3
   Steel grades                                  49

ZF coating groups                                50

Surface                                          51

   Surface quality                               51
   Surface type                                  51
   Subsequent surface treatment                  52

Available dimensions                             53

Inspection and Testing                           54

Processing information                           55

   Joining                                       55
   Forming                                       55
   Suitability for the application of coatings   55
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
General notes                             56

   Fretting corrosion                     56
   Formation of white rust                56

Hot-dip galvanized steel strip with
zinc magnesium coating                    57

   Steel grades                           57

ZM coating groups                         58

Terms of delivery                         59

                                               4
Surface                                   72

   Subsequent surface treatment           72

Application and processing instructions   73

Appendix                                  74

   Pertinent standards                    74
Introduction

                                                                                                             T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Hot-dip galvanized steel strip is a hot-dip refined product with Zn, ZnMg or ZnFe coating on both
sides. The corresponding short forms are Z, ZM and ZF.

Hot-dip refining is based on a modified Sendzimir process. This is a high-integration manufacturing
process that consists of the following main process steps: Cleaning the full-hard strip (dry cleaning
and/or cleaning with easy reducing furnace atmosphere), recrystallizing annealing, coating by dip-
ping into a fusion-liquid bath and adjustment of the thickness with air or nitrogen blow-off, finishing
and/or straightening by stretching for the adjustment of mechanical properties, surface and flatness,
post-treatment, inspection and marking. All these processes run in continuous operation mode with
a continuous steel strip.
These Technical Terms of Delivery apply to hot-dip galvanized strip made of

p Mild steels for cold forming,
p Structural steels and
p High-strength steels suitable for cold forming.

                                                                                                             5
These terms of delivery are to provide information to the customer on the production program of our
hot-dip galvanizing lines at the Linz site and serve as a guideline for ordering and processing. In accor-
dance with these Technical Terms of Delivery, hot-dip coated and galvanized steel strip complies with
generally applicable guidelines as described in the pertinent standards. You will find a comparison of
the standards in the Appendix.

Market requirements have reached a degree of complexity with regard to applications that would far
exceed the limitations of these Terms of Delivery if every detail were taken into account. For this rea-
son we ask that you address any questions to your respective commercial or technical contact partner.
They will ensure that you receive an adequate answer.
Hot-dip galvanized steel strip

                                                                                                         T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
with zinc coating
Steel grades

The following contains a general description of the available steel grades and their respective areas
of application.The chemical constitution depends on the selected steel grade and is available upon
request. The mechanical properties, the available coatings and surfaces can be found in the respec-
tive tables.

Mild steels for cold forming

DX51D (machine crimping quality)
is suitable for the production of simple shapes such as trapezoid shapes and corrugated iron sheets as
well as for simple manual forming procedures.

                                                                                                         6
DX52D (drawing quality)
can be considered for complex sections, embossing and drawn components.

DX53D (deep-drawing quality)
is used for medium requirements on formability such as deep drawing.

DX54D (special deep-drawing quality)
is designed for the special requirements of formability and deep drawability.

DX56D (special deep-drawing quality)
is designed for the most demanding forming requirements.

DX57D (extra special deep-drawing quality)
was developed for extremely high forming behavior requirements, in particular for extreme deep-
drawing strain and for the manufacturing of complicated press parts in rapid processing and highly
automated press lines.

The DX51D, DX52D, DX53D, DX54D, DX56D and DX57D steel grades are delivered according to
their mechanical properties. The values for the mechanical properties apply for a period of

p One month for steel grades DX51D and DX52D from the time they are made ready for dispatch
p Six months for steel grades DX53D, DX54D, DX56D and DX57D from the time they are made ready
  for dispatch

Alternatively, agreement can be made on specific material properties for the manufacture of a parti-
cular component.
Mechanical properties 1)

                                                                                                                                             T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Mild steels for cold forming

     Steel grade         0.2% Yield         Tensile strength Fracture elongation 4)      Vertical        Work hardening    Zinc coating
                           point 2)                Rm                 A80             anisotropy 5) 6)    exponent 5)         group
                            Rp 0.2               [MPa]                [%]                   r              n10 – 20 (UE)
                           [MPa]                                     min.                 min.                min.

     DX51D                     -               270 – 500               22                    -                  -          Z 70 – Z 600 7)

     DX52D                 140 – 300   3)
                                               270 – 420               26                    -                  -          Z 70 – Z 600 7)

     DX53D                 140 – 260           270 – 380               30                    -                  -          Z 70 – Z 600 7)

     DX54D                 120 – 220           260 – 350               36                   1.6               0.18         Z 70 – Z 275

     DX56D                 120 – 180           260 – 350              39                   1.9 5)             0.21         Z 70 – Z 275

     DX57D                 120 – 170           260 – 350              41                   2.1    5)
                                                                                                              0.22         Z 70 – Z 275

1)
     Values transverse to rolling direction.
2)
     If the yield point is pronounced, the lower yield point ReL applies.
3)
     This value applies only to re-rolled products (MB and MC surfaces).
4)
     Minimum fracture elongation values are minimized by 2 units for product thicknesses of ≤ 0.7 mm.

                                                                                                                                             7
5)
     Warranty values for r are minimized by 0.2 for product thicknesses of > 1.5 mm and for product thicknesses of > 2.0 mm by 0.4.
6)
     Values for r are minimized by 0.2 for product thicknesses of > 0.7 mm and n by 0.01.
7)
     Coating profiles above Z 275 available upon request.
Available dimensions

                                                                                                                         T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
DX51D, DX52D
Available dimensions mild steels for cold forming

             Ordered strip thickness (mm)

               4.00

               3.50
                                              MC surface for automotive
                                              industry not possible.

               3.00

                                                                                                                         8
               2.50

               2.00

               1.50

               1.00

               0.50

               0.00

                       700       800        900     1000     1100      1200      1300     1400       1500     1600

                                                      Ordered strip width (mm)

                        The graphics refer to thickness values with symmetrical thickness tolerances.
                        The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
                        Please contact our sales departments for widths below 900 mm (production scheduling for
                        center slitting and longitudinal slitting lines).
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
DX53D
Available dimensions mild steels for cold forming

             Ordered strip thickness (mm)

               4.00

               3.50

               3.00

                                                                                                                         9
               2.50

               2.00

               1.50

                                              MC surface up to a maximum of 1.2 mm in
               1.00
                                              thickness not possible for automotive industry.

               0.50

               0.00

                       700       800        900     1000     1100      1200      1300     1400       1500     1600

                                                      Ordered strip width (mm)

                        The graphics refer to thickness values with symmetrical thickness tolerances.
                        The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
                        Please contact our sales departments for widths below 900 mm (production scheduling for
                        center slitting and longitudinal slitting lines).
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
DX54D, DX56D, DX57D
Available dimensions mild steels for cold forming

             Ordered strip thickness (mm)

               4.00

               3.50

               3.00

                                                                                                                         10
               2.50

               2.00

               1.50
                                              MC surface up to a maximum of 1.5 mm in
                                              thickness not possible for automotive industry.

               1.00

               0.50

               0.00

                       700       800        900     1000     1100      1200      1300     1400       1500     1600

                                                      Ordered strip width (mm)

                        The graphics refer to thickness values with symmetrical thickness tolerances.
                        The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
                        Please contact our sales departments for widths below 900 mm (production scheduling for
                        center slitting and longitudinal slitting lines).
Freedom of flow lines

                                                                                                         T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
It may be necessary to reroll the products in order to avoid the formation of flow lines during cold
rolling. The tendency toward the formation of flow lines can occur once again after some time, for
which reason it is in the interest of the user to process the products as soon as possible. Freedom of
flowing figures on MB and MC surfaces is maintained for the following duration after the material
has been made ready for dispatch:

p One month for steel grades DX51D and DX52D
p Six months for steel grades DX53D, DX54D, DX56D and DX57D

Coil break freedom

Rerolling or straightening through product stretching may be necessary for specific coil break freedom
requirements. The order must specify any coil break freedom requirement.

                                                                                                         11
Structural steels

                                                                                                                          T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Structural steels are supplied with guaranteed minimum yield strengths in steel grades S220GD
through S350GD. These steel grades are suitable for all easy forming procedures such as crimping,
edging and profiling. They are not, however, intended for stresses such as those caused by deep
drawing. Depending on the strength class, the increased tendency toward elastic recovery during
the adjustment of machinery must be taken into consideration. Formability may be diminished
when these grades are stored for a longer period of time. Prompt processing after the material has
been made ready for dispatch is in the interest of the customer. The order must specify any coil
break freedom requirement.

Mechanical properties 1)
Structural steels

     Steel grade            0.2% Yield point 2)      Tensile strength 3)     Fracture elongation 4)     Zinc coating
                                  Rp 0.2                     Rm                       A80                  group
                                 [MPa]                     [MPa]                      [%]
                                                            min.                     min.

                                                                                                                          12
     S220GD                        ≥ 220                      300                      20               Z 70 – Z 600 5)

     S250GD                        ≥ 250                      330                      19               Z 70 – Z 600 5)

     S280GD                        ≥ 280                      360                      18               Z 70 – Z 600 5)

     S320GD                        ≥ 320                      390                      17               Z 70 – Z 600 5)

     S350GD                        ≥ 350                      420                      16               Z 70 – Z 600 5)

1)
     Values longitudinal to rolling direction.
2)
     The upper yield point ReH applies when the yield point is pronounced.
3)
     A maximum range of 140 MPa can be calculated for the upper limit of tensile strength.
4)
     Minimum fracture elongation values are minimized by 2 units for product thicknesses of ≤ 0.7 mm.
5)
     Coating profiles above Z 275 available upon request.
Available dimensions

                                                                                                                         T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
S220GD, S250GD, S280GD
Available dimensions structural steels

             Ordered strip thickness (mm)

               4.00

               3.50
                                              MC surface for automotive
                                              industry not possible.

               3.00

                                                                                                                         13
               2.50

               2.00

               1.50

               1.00

               0.50

               0.00

                       700       800        900    1000      1100      1200      1300     1400       1500     1600

                                                      Ordered strip width (mm)

                        The graphics refer to thickness values with symmetrical thickness tolerances.
                        The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
                        Please contact our sales departments for widths below 900 mm (production scheduling for
                        center slitting and longitudinal slitting lines).
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
S320GD
Available dimensions structural steels

             Ordered strip thickness (mm)

               4.00

               3.50
                                              MC surface for automotive
                                              industry not possible.

               3.00

                                                                                                                         14
               2.50

               2.00

               1.50

               1.00

               0.50

               0.00

                       700       800        900    1000      1100      1200      1300     1400       1500     1600

                                                      Ordered strip width (mm)

                        The graphics refer to thickness values with symmetrical thickness tolerances.
                        The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
                        Please contact our sales departments for widths below 900 mm (production scheduling for
                        center slitting and longitudinal slitting lines).
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
S350GD
Available dimensions structural steels

             Ordered strip thickness (mm)

               4.00

               3.50
                                              MC surface for automotive
                                              industry not possible.

               3.00

                                                                                                                         15
               2.50

               2.00

               1.50

               1.00

               0.50

               0.00

                       700       800        900    1000      1100      1200      1300     1400       1500     1600

                                                      Ordered strip width (mm)

                        The graphics refer to thickness values with symmetrical thickness tolerances.
                        The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
                        Please contact our sales departments for widths below 900 mm (production scheduling for
                        center slitting and longitudinal slitting lines).
High-strength steels for cold forming

                                                                                                             T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
In addition to the mild steels, high-strength steel grades with yield strengths ranging from 160 to 500
MPa are available and are suitable for cold forming with less forming stress as well as for very difficult
forming procedures. Based on specifically coordinated steel analyses and production conditions, vari-
ous series of steel grades are available that lend themselves, depending on the steel grade, to specific
applications, particularly in the automotive industry. The higher yield point and the excellent forming
properties provide a significant potential for weight reduction.

The chemical composition of the substrate is adapted to the welding properties and is available
upon request. The maximum concentrations of base material elements correspond to the limit
values determined in EN 10346 for the respective grades (tables available in the Appendix).

The guaranteed mechanical parameters listed in the following sections are applicable to tests in
transverse direction to rolling. The mechanical parameters apply for a time period of three months
for all steels with guaranteed bake-hardening effect and six months for all other high-strength steel
grades from the time they are made ready for dispatch. Freedom of flow lines is guaranteed for this
period of time for Surface Type C orders. This does not apply to micro-alloyed steels.

                                                                                                             16
The yield strength increased by the heat effect (so-called bake-hardening effect) is determined in
accordance with DIN EN 10325.

It can generally be assumed that increasing yield stress and decreasing sheet thickness lead to a
tendency towards necking, wrinkling and tears as a consequence of forming, which also leads to
form inaccuracy as a result of elastic recovery. In contrast with mild steels, the forming conditions
must be adjusted to the respective steel grade.

If the steel grades listed in the following sections do not fulfill customer requirements, please send a
material inquiry. Many high-strength steel grades are still being developed. More innovative develop-
ments will make additional steel grades available that have not yet been included in these Technical
Terms of Delivery.

Some of these steel grades have already been included in these Technical Terms of Delivery for infor-
mation purposes only. Such products are delivered following technical review upon request.
Micro-alloyed steels

                                                                                                                        T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Refined micro-alloyed steels with a guaranteed yield strength of between 260 and 500 MPa cover
the upper range of the conventional high-strength steel grade series and are suitable for moderate to
medium forming stress.

Steel grades HX260LAD through HX500LAD are generally based on the stability-increasing effect
of micro-alloyed additions (niobium or niobium with titanium). Grain refinement, age hardening and
the alloying of further strength-increasing elements, essentially manganese, are implemented in or-
der to achieve the desired strength.

The main areas of application for micro-alloyed steels are structural components in the automotive
industry such as safety-related elements in the passenger compartment, side members or bumpers.

Micro-alloyed steels are also excellently suited for the manufacturing of high-strength special
sections. Upon special request, micro-alloyed hot-dip galvanized steel grades can be used as an
alternative in guaranteeing the mechanical parameters in longitudinal direction. In this case the
guaranteed range of yield strength correspondingly shifts to a lower range by around 20 MPa. The
tensile strength values also change to lower values for longitudinal samples by around 10 MPa. The

                                                                                                                        17
guaranteed value for fracture elongation is correspondingly raised by 1%.

Mechanical properties 1)
Micro-alloyed steels

     Steel grade           0.2% Yield point 2)        Tensile strength 3)    Fracture elongation 4)   Zinc coating
                                 Rp 0.2                       Rm                      A80                group
                                [MPa]                       [MPa]                     [%]
                                                             min.                    min.

     HX260LAD                   260 – 330                   350 – 430                  26             Z 70 – Z 600 4)

     HX300LAD                   300 – 380                   380 – 480                  23             Z 70 – Z 600 4)

     HX340LAD                   340 – 420                   410 – 510                  21             Z 70 – Z 600 4)

     HX380LAD                   380 – 480                   440 – 560                  19             Z 70 – Z 600 4)

     HX420LAD                   420 – 520                   470 – 590                  17             Z 70 – Z 600 4)

     HX460LAD                   460 – 560                   500 – 640                  15              Z 70 – Z 275

     HX500LAD                   500 – 620                   530 – 690                  13              Z 70 – Z 275

1)
     Values transverse to rolling direction.
2)
     The lower yield point ReL applies when the yield point is pronounced.
3)
     Lower minimum values by two percent are permissible for thicknesses of ≤ 0.7 mm
4)
     Coating profiles above Z 275 available upon request.
Available dimensions

                                                                                                                         T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HX260LAD, HX300LAD, HX340LAD
Available dimensions micro-alloyed steels

             Ordered strip thickness (mm)

               4.00

               3.50
                                              MC surface for automotive
                                              industry not possible.

               3.00

                                                                                                                         18
               2.50

               2.00

               1.50

               1.00

               0.50

               0.00

                       700       800        900    1000      1100      1200      1300     1400       1500     1600

                                                      Ordered strip width (mm)

                        The graphics refer to thickness values with symmetrical thickness tolerances.
                        The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
                        Please contact our sales departments for widths below 900 mm (production scheduling for
                        center slitting and longitudinal slitting lines).
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HX380LAD, HX420LAD
Available dimensions micro-alloyed steels

             Ordered strip thickness (mm)

               4.00

               3.50
                                              MC surface for automotive
                                              industry not possible.

               3.00

                                                                                                                         19
               2.50

               2.00

               1.50

               1.00

               0.50

               0.00

                       700       800        900    1000      1100      1200      1300     1400       1500     1600

                                                      Ordered strip width (mm)

                        The graphics refer to thickness values with symmetrical thickness tolerances.
                        The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
                        Please contact our sales departments for widths below 900 mm (production scheduling for
                        center slitting and longitudinal slitting lines).
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HX460LAD
Available dimensions micro-alloyed steels

             Ordered strip thickness (mm)

               4.00

               3.50

               3.00

                                                                                                                         20
               2.50

               2.00
                                                  MC surface for automotive industry not possible.

               1.50

               1.00

               0.50

               0.00

                       700       800        900       1000      1100      1200      1300   1400      1500     1600

                                                         Ordered strip width (mm)

                        The graphics refer to thickness values with symmetrical thickness tolerances.
                        The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
                        Please contact our sales departments for widths below 900 mm (production scheduling for
                        center slitting and longitudinal slitting lines).
HX500LAD
                                                                                                   Available dimensions micro-alloyed steels

                                                              Available dimensions upon request.

21   T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Bake-hardening steels

                                                                                                                                T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
By fine-tuning alloy compositions and adapting process parameters it is possible to produce hot-dip
coated bake-hardening steels that are characterized by their significant increase in yield strength
in the course of paint baking (bake-hardening effect). This increase in yield strength in the series of
steels from HX180BD to HX300BD is achieved by ensuring that a defined amount of carbon remains
dissolved in the steel.This carbon is released during heat treatment in the course of paint baking,
which leads to an increase in strength.
The hot-dip coated bake-hardening steels are also characterized by a very high degree of forma-
bility, which makes possible a wide range of applications in the manufacture of bodies in white.
Depending on the forming stress, the entire range of yield strengths can be used in interior compo-
nents for bodies in white. The HX180BD and HX220BD steel grades are also especially suitable for
exterior bodies in white because the bake-hardening effect in these steels when compared to mild
steels yields significantly improved dent resistance.

Mechanical properties 1)
Bake-hardening steels

                                                                                                                                22
     Steel grade         0.2% Yield         Tensile      Fracture       Vertical       Work            Bake-     Zinc coating
                           point 2)        strength    elongation 3)   anisotropy   hardening        hardening      group
                            Rp 0.2            Rm         A80 min.           r       exponent         value BH2
                           [MPa]            [MPa]          [%]            min.      n10 – 20 (UE)   [MPa] min.
                                                                                        min.

     HX180BD              180 – 240        290 – 360        34               1.5        0.16           35        Z 70 – Z 200

     HX220BD              220 – 280        320 – 400        32               1.2        0.15           35        Z 70 – Z 200

     HX260BD              260 – 320        360 – 440        28                -          -             35        Z 70 – Z 200

     HX300BD              300 – 360        400 – 480        26                -          -             35        Z 70 – Z 200

1)
     Values transverse to rolling direction.
2)
     The lower yield point ReL applies when the yield point is pronounced.
3)
     Lower minimum values by two percent are permissible for thicknesses of ≤ 0.7 mm.
Available dimensions

                                                                                                                         T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HX180BD, HX220BD, HX260BD, HX300BD
Available dimensions bake-hardening steels

             Ordered strip thickness (mm)

               4.00

               3.50

               3.00

                                                                                                                         23
               2.50

               2.00

               1.50

               1.00
                                              MC surface up to a maximum of 1.0 mm in
                                              thickness not possible for automotive industry.

              0.50

               0.00

                       700       800        900    1000      1100      1200      1300     1400       1500     1600

                                                      Ordered strip width (mm)

                        The graphics refer to thickness values with symmetrical thickness tolerances.
                        The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
                        Please contact our sales departments for widths below 900 mm (production scheduling for
                        center slitting and longitudinal slitting lines).
High-strength IF steels

                                                                                                                              T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Hot-dip coated, higher-strength, interstitial-free steels are based on a vacuum-decarburized IF base
material stabilized with Ti and/or Nb, which leads to an ideal condition for extremely difficult forming
procedures with deep-drawing stresses. The adjustment of the required ranges of strength is carried
out by alloying P and Mn in the course of solid-solution strengthening. This basic IF analysis lends
this group of steel grades higher values of vertical anisotropy (r value) when compared to other steel
grades of similar strength. This vertical anisotropy value is an important parameter for deep-drawing
strain. The high r values in diagonal direction lead to a certain degree of isotropic behavior during the
forming of this series of steel grades.
The main area of application for high-strength interstitial-free steels is found in formed automotive
components, such as in the interior wheel arch, side members that are difficult to form, or in bottom
plates in the area of the tunnel. For this reason, profiling applications seem to be less sensible because
no deep-drawing stress occurs.

Mechanical properties 1)
High-strength IF steels

                                                                                                                              24
     Steel grade       0.2% Yield point Tensile strength     Fracture          Vertical      Work hardening    Zinc coating
                            Rp 0.2             Rm          elongation 2)     anisotropy 3)     exponent           group
                           [MPa]             [MPa]              A80               r            n10 – 20 (UE)
                                                               [%]               min.              min.
                                                               min.

     HX160YD               160 – 220           300 – 360        37               1.9              0.20         Z 70 – Z 200

     HX180YD               180 – 240           330 – 390        34               1.7              0.18         Z 70 – Z 200

     HX220YD               220 – 280           340 – 420        32               1.5              0.17         Z 70 – Z 200

     HX260YD               260 – 320           380 – 440        30               1.4              0.16         Z 70 – Z 200
     HX300YD               300 – 360           390 – 470        27               1.3              0.15         Z 70 – Z 200

1)
     Values transverse to rolling direction.
2)
     Lower minimum values by two percent are permissible for thicknesses of ≤ 0.7 mm.
3)
     The guaranteed value is minimized by 0.2 units for product thicknesses > 1.5 mm.
Available dimensions

                                                                                                                         T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HX160YD, HX180YD, HX220YD
Available dimensions higher-strength IF steels

             Ordered strip thickness (mm)

               4.00

               3.50

               3.00

                                                                                                                         25
               2.50

               2.00

               1.50

               1.00
                                              MC surface up to a maximum of 1.0 mm in
                                              thickness not possible for automotive industry.

               0.50

               0.00

                       700       800        900    1000      1100      1200      1300     1400       1500     1600

                                                      Ordered strip width (mm)

                        The graphics refer to thickness values with symmetrical thickness tolerances.
                        The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
                        Please contact our sales departments for widths below 900 mm (production scheduling for
                        center slitting and longitudinal slitting lines).
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HX260YD
Available dimensions higher-strength IF steels

             Ordered strip thickness (mm)

               4.00

               3.50

               3.00

                                                                                                                         26
               2.50

               2.00

               1.50

               1.00
                                              MC surface up to a maximum of 1.0 mm in
                                              thickness not possible for automotive industry.

               0.50

               0.00

                       700       800        900    1000      1100      1200      1300     1400       1500     1600

                                                      Ordered strip width (mm)

                        The graphics refer to thickness values with symmetrical thickness tolerances.
                        The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
                        Please contact our sales departments for widths below 900 mm (production scheduling for
                        center slitting and longitudinal slitting lines).
HX300YD
                                                                                                   Available dimensions higher-strength IF steels

                                                              Available dimensions upon request.

27   T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Dual-phase steels

                                                                                                                                 T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Dual-phase steels consist of a multi-phase base material microstructure of which the main com-
ponents are ferrite (80–90%) and martensite (10–20%). Other phases may be included in smaller
amounts.
The special characteristic of dual-phase steels is that particularly low yield ultimate ratios can be ob-
tained with high ultimate tensile strengths. As related to the high level of tensile strength, high de-
grees of fracture elongation and hardening exponents can also be achieved. Because of pronounced
offset strain hardening, particularly at the beginning of forming, dual-phase steels are especially
predestined for forming stress in the stretch forming area. An additional positive characteristic is the
achievable bake-hardening effect, which leads to an additional increase in the yield strength after
forming during paint baking.
Based on the characteristic property profile of dual-phase steels, this series of steel grades is especially
suitable for crash-relevant structural parts such as side members, crossmembers, and stiffeners for A,
B or C columns. Dual-phase steels demonstrate special potential in significantly contributing to weight
reduction as well as increased passive safety in automotive structures.

Mechanical properties 1)

                                                                                                                                 28
Dual-phase steels

     Steel grade          0.2% Yield       Tensile strength     Fracture      Work hardening    Bake-hardening   Zinc coating
                            point 2)              Rm          elongation 3)     exponent            value           group
                             Rp 0.2             [MPa]              A80          n10 – 20 (UE)     BH2 [MPa]
                            [MPa]                min.             [%]               min.             min.
                                                                  min.

     HCT450X               260 – 340             450               27              0.16              30           Z 70 – Z 200

     HCT500X               300 – 380             500               23              0.15              30           Z 70 – Z 200

     HCT600X               340 – 420             600               20              0.14              30          Z 70 – Z 200

     HCT780X               450 – 560             780               14                -               30          Z 70 – Z 200

     HCT980X 4)            600 – 750             980               10                -               30           Z 70 – Z 200

1)
     Values transverse to rolling direction.
2)
     The lower yield point ReL applies when the yield point is pronounced.
3)
     Lower minimum values by two percent are permissible for thicknesses of ≤ 0.7 mm.
4)
     Available dimensions upon request.
Available dimensions

                                                                                                                         T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HCT450X
Available dimensions dual-phase steels

             Ordered strip thickness (mm)

               4.00

               3.50

               3.00

                                                                                                                         29
               2.50

               2.00
                                                  MC surface for automotive industry available
                                                  upon request.

               1.50

               1.00

              0.50

               0.00

                       700       800        900       1000      1100      1200      1300   1400      1500     1600

                                                         Ordered strip width (mm)

                        The graphics refer to thickness values with symmetrical thickness tolerances.
                        The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
                        Please contact our sales departments for widths below 900 mm (production scheduling for
                        center slitting and longitudinal slitting lines).
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HCT500X
Available dimensions dual-phase steels

             Ordered strip thickness (mm)

               4.00

               3.50

               3.00

                                                                                                                         30
               2.50

               2.00
                                                  MC surface for automotive industry available
                                                  upon request.

               1.50

               1.00

              0.50

               0.00

                       700       800        900       1000      1100      1200      1300   1400      1500     1600

                                                         Ordered strip width (mm)

                        The graphics refer to thickness values with symmetrical thickness tolerances.
                        The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
                        Please contact our sales departments for widths below 900 mm (production scheduling for
                        center slitting and longitudinal slitting lines).
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HCT600X
Available dimensions dual-phase steels

             Ordered strip thickness (mm)

               4.00

               3.50

               3.00

                                                                                                                         31
               2.50

               2.00
                                                  MC surface for automotive industry available
                                                  upon request.

               1.50

               1.00

              0.50

               0.00

                       700       800        900       1000      1100      1200      1300   1400      1500     1600

                                                         Ordered strip width (mm)

                        The graphics refer to thickness values with symmetrical thickness tolerances.
                        The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
                        Please contact our sales departments for widths below 900 mm (production scheduling for
                        center slitting and longitudinal slitting lines).
HCT780X, HCT980X
                                                                                                   Available dimensions dual-phase steels

                                                              Available dimensions upon request.

32   T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Complex-phase steels

                                                                                                                         T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
The availability of complex-phase steel grades with increased yield point and minimum tensile
strength is a meaningful addition to the dual-phase range of steels. These steel grades are defined
with minimum yield strengths from 780 to 980 MPa. The microstructure of these advanced high-
strength steels is characterized by the fact that the martensite particles are distributed in the soft
ferrite matrix, whereas bainite phases can also occur in addition to the martensite.

In comparison to the dual-phase steels, this series of steel grades is characterized by a higher yield
strength at the same tensile strength and thus a higher yield-strength ratio and a somewhat lower
possibility of guaranteeing certain levels of fracture elongation. The complex-phase steels are also
characterized by pronounced work-hardening behavior, even though this is not as noticeable as it is
with the dual-phase steels. The additional benefit that strength increases in the course of heat treat-
ment during paint baking, remains as it does in dual phase steels.

Structural parts with lower forming stress show higher yield strengths with this series of steel grades
in comparison to the dual-phase grades. This can be compensated through a simpler component
design aimed at increasing strength resulting from stronger deformation. Partially martensitic steels
are predestined for high-strength special sections and safety-related structural components with lo-

                                                                                                                         33
wer forming stresses.

This grade also lends itself well to the manufacture of foldable parts and roll-formed components.

Mechanical properties 1)
Complex-phase steels

     Steel grade         0.2% Yield point      Tensile strength   Fracture elongation   Bake-hardening   Zinc coating
                              Rp 0.2                  Rm                  A80               value           group
                             [MPa]                  [MPa]                 [%]             BH2 [MPa]
                                                     min.                min.                min.

     HCT780C 2)              600 – 750               780                  10                 30          Z 70 – Z 200

     HCT980C   2)
                             800 – 950               980                  6                  30           Z 70 – Z 200

1)
     Values transverse to rolling direction.
2)
     Available dimensions upon request.
Available dimensions

                                            T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HCT780C, HCT980C
Available dimensions complex-phase steels

Available dimensions upon request.

                                            34
TRIP steel

                                                                                                                                 T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
TRIP (transformation-induced plasticity) steels are comprised of a ferritic matrix (roughly 75%), bainite
(approximately 10%) and metastable residual austenite (up to 15%). The hard phase (bainite) and stabi-
lity of the austenite during forming influence the spectrum of mechanical properties.
Transformation-induced plasticity means that the metastable “soft” austenite is transformed into “hard”
martensite during plastic forming (deep drawing). This makes local constriction difficult and increases
the values for uniform elongation. This is the basis for the well-known excellent formability of TRIP
steels with high initial tensile strength of the respective basic strength. The increased bake-hardening
effect achieved by temperature treatment additionally increases the potential weight savings. This se-
ries of steel grades is available in two classes with minimum tensile strengths of 690 MPa and 780 MPa.
TRIP steels with 980 MPa are currently under development and can be delivered upon request. TRIP
steels are particularly suited to crash-relevant applications or safety parts with increased forming stress
in the manufacturing process.

Mechanical properties 1)
TRIP steels

                                                                                                                                 35
     Steel grade       0.2% Yield point    Tensile strength    Fracture    Work hardening        Bake-hardening   Zinc coating
                            Rp 0.2                Rm          elongation        exponent            value BH2        group
                           [MPa]                [MPa]           A80 min.   n10 – 20 (UE) [MPa]     [MPa] min.
                                                 min.             [%]                min.

     HCT600T               400 – 520             600             25                 -                 40          Z 70 – Z 200

     HCT690T               430 – 550             690             23               0.18                40          Z 70 – Z 200

     HCT780T               470 – 600             780             21               0.16                40          Z 70 – Z 200

1)
     Values transverse to rolling direction.
Available dimensions

                                                                                                                         T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HCT600T, HCT690T
Available dimensions TRIP steels

             Ordered strip thickness (mm)

               4.00

               3.50

               3.00

                                                                                                                         36
               2.50

               2.00
                                                  MC surface for automotive industry
                                                  not possible.

               1.50

               1.00

              0.50

               0.00

                       700       800        900       1000     1100      1200      1300   1400       1500     1600

                                                        Ordered strip width (mm)

                        The graphics refer to thickness values with symmetrical thickness tolerances.
                        The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
                        Please contact our sales departments for widths below 900 mm (production scheduling for
                        center slitting and longitudinal slitting lines).
HCT780T
                                                                                                   Available dimensions TRIP steels

                                                              Available dimensions upon request.

37   T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Zinc coating groups

                                                                                                                        T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
The available zinc coatings and their respective minimum values are shown in the following table.
The desired zinc coating group (corresponds to the zinc coating in g/m 2 on both sides) is specified in
the order.

Coating groups

                                    Zinc coating in g/m2 on both sides min.     Zinc coating thickness in µm per side
         Zinc coating group
                                    Triple surface test   Single surface test    Typical value            Area

               Z 100                       100                    85                   7                  5 – 12

               Z 140                       140                   120                  10                  7 – 15

               Z 200                       200                   170                  14                10 – 20

               Z 225                       225                   195                  16                11 – 22

               Z 275                       275                   235                  20                15 – 27

               Z 350                       350                   300                  25                19 – 33

                                                                                                                        38
               Z 450                       450                   385                  32                24 – 42

               Z 600                       600                   510                  42                32 – 55

A zinc coating of 100 g/m 2 (on both sides) corresponds to a zinc layer thickness of approximately
7 µm per side. The respective possibilities for delivery, depending on the steel grade, are shown in
the steel grade tables.

The Z350–Z600 zinc coating group can only be delivered with an NA surface.
Special coatings are available upon request in special cases only.

Different zinc coating for each side (different degree of galvanization) can be delivered upon reque-
st. In the event of differential galvanizing, in consequence of production, the surface of the side with
the lesser amount of zinc coating may have a different appearance than the side with the greater
amount of zinc coating.

The zinc coating is monitored continuously by means of an x-ray fluorescent technique.
Surface

                                                                                                             T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Zinc coating surface

The surface of the zinc coating is determined by the design, type and surface treatment. Hot-dip
galvanized steel strip Zn with surface NA and chemically passivated is delivered in the event the
order does not contain any additional information on the desired surface. Possible dimension-related
limitations with respect to the surface can be found in the limit curves.

The zinc coating does not include intentionally added lead concentrations (lead-free hot-dip galva-
nized strip). Finally, with respect to the environmental compatibility of the product, this measure was
implemented by voestalpine Stahl GmbH and excludes the delivery of hot-dip galvanized strip with
distinctive spangle formation (large spangles).

                                                                                                             39
Surface quality

Normal quality (N)
Zinc crystals occur in varying brightness and size, depending on prevalent galvanizing conditions.
The usability of the product is not influenced by these crystals. The grade is delivered even if no pre-
ferences regarding surface quality are specified. We reserve the right to ship rerolled material.

Small spangle (M)
The surface shows small to macroscopic non-visible spangles caused by targeted influence on soli-
dification. The products may show a slightly different body structure on the surface from coil to coil
and as well as in one coil. Delivery of slightly rerolled strip in surface type MA (explicitly not desired
by the customer) must be specified in the order.
Surface type

                                                                                                           T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
There are three different surface types.

Typical surface A
Small pits, different spangle sizes, dark spots, stripe-shaped marks, and small passivation defects are
acceptable on this type of surface. Straightening and bending fractures and zinc runoff waves may
be visible.

Improved surface B
This type of surface is attained by rerolling. A small number of fractures in stretch forming direction,
finishing imprints, scratches, impressions, spangle structures, zinc runoff waves and slight passiva-
tion errors may occur on the inspected side. The uninspected side of the material must at least meet
the requirements of Surface Type A.

Best surface C
This type of surface is also attained by rerolling. The inspected side does not negatively impact the
uniform appearance of a paint coat. The other side of the material must at least meet the require-
ments of Surface Type B. Surface Type C is available for delivery up to a maximum of 1.5 mm.

                                                                                                           40
Roughness
As a standard, Surface Types B and C are delivered with a medium roughness value ranging bet-
ween 0.6 and 1.9 µm. Determination of the mean Ra roughness value is subject to a wavelength limit
of 2.5 mm in accordance with EN 10049 (standard length of 12.5 mm).

Where specially required, the delivery of limited roughness values may be specified. Special qualities
include smooth, half mat or mat.

Roughness

                 Design                                           Median roughness value Ra (µm)

                 Standard                                                  0.6 – 1.9

                 Special design: smooth                                    0.9 max.

                 Special design: half-mat                                  0.6 – 1.4

                 Special design: mat                                       1.0 – 1.9

The desired quality must be specified in the order. Discussion of requirements with regard to surface
appearance is recommended when a smooth surface has been selected. Smooth surface with glossy
appearance (especially smooth) is subject to specification in the order.
Subsequent surface treatment

                                                                                                            T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Hot-dip galvanized steel strip is delivered only with surface protection on account of the increased pro-
pensity toward white rust. The following surface treatment procedures are usual:

p Chromium-free passivated (C)
p Oiled (O)
p Chromium-free passivated and oiled (CO)

Chromium-free passivated (C)
To the extent not specifically agreed, hot-dip galvanized steel strip is delivered with normal sur-
faces (NA) with small spangles (MA) and chromium-free passivated. Local discoloration caused by
chromium-free passivation is permitted and does not negatively influence other quality properties.
Chromium-free passivation may influence further surface treatments carried out by the customer, for
example phosphating. Another surface treatment is recommended in such cases.

Oiled (O)
Surfaces MB and MC are usually delivered in oiled condition. The oil layer can be removed with
suitable zinc-sparing degreasing agents. Depending on the intended treatment stress, two different

                                                                                                            41
standard coatings can be ordered: slightly oiled as a temporary form of corrosion protection and as
a forming aid for medium forming stress, oiled for very heavy forming stress. Although the oil is
distributed evenly, a certain degree of oil will invariably spread across the length and width of the
strip and some oil from heavily oiled strip will be shed from the surface during transportation and
storage. This is technically unavoidable.

Oil amounts

                      Slightly oiled                                approx. 0.7 g/m2 per side

                      Oiled                                         approx. 1.2 g/m2 per side

Chromium-free passivated and oiled (CO)
This combination of surface treatment can be agreed upon where increased protection against white
rust or oiling as a means to aid in forming is required.
Available dimensions

                                                                                                                  T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Hot-dip galvanized steel strip in coils

          Thickness                   Width            Maximum outside diameter   Inner diameter    Coil weight
            [mm]                      [mm]                      [mm]              roughly [mm] 3)    [t] max.

      ≥ 0.45      ≤ 3.5      ≥ 600        ≤ 800                 2000                   600               -

      ≥ 0.45      ≤ 3.5      > 800   1)
                                          < 900   1)
                                                                2000                   600               -

      ≥ 0.45      ≤ 3.5      ≥ 900        ≤ 1600 2)             2000                   600              32

1)
     Width range between > 800 and < 900 mm only upon request.
2)
     With limited width tolerance of 1,580 mm max.
3)
     Inner diameter of 500 mm upon request.

                                                                                                                  42
Inspection and Testing

                                                                                                                  T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
The products can be delivered with or without any test of compliance with the requirements of these
Technical Terms of Delivery and/or ordering standards.

Material test certificates
In the event a certificate is desired, one of the test certificates defined in EN 10204 is subject to agree-
ment at the time of the order.

Test unit

Specific tests are restricted to a test unit of 20 tons or a portion of 20 tons of hot-dip galvanized steel
strip of the same rolling unit. In the case of strip, a coil of more than 20 tons is considered as a test unit.

Scope of testing:
For each test unit, a series of tests is conducted to determine the following:

                                                                                                                  43
p Mechanical properties
p Coating adhesion
p Coating weight

Sample taking

Rolls from which samples are taken remain a constituent of the order. The right to select samples from
sheets is reserved by the employee responsible for the delivery certificate.

Performance of tests

Substrate testing
The tensile test is conducted in accordance with EN 10002-1 with samples of Form 2 (sample width
w = 20 mm, initial measured length L0 = 80 mm). Samples of mild steels, high-strength steels suita-
ble for cold forming and advanced high-strength steels are taken crosswise with respect to the di-
rection of rolling at a distance of at least 50 mm from the product edges. Structural steel samples are
taken in the longitudinal direction of rolling.
Zinc coating test

                                                                                                           T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
The zinc coating is generally determined in the course of a continuous and non-destructive test.

The zinc coating is generally determined in the course of a continuous and non-destructive test.
The following procedure is followed for special tests and in cases of arbitration. The samples for the
gravimetric test of the zinc coating are taken across the width of the strip (see Figure 1). The samples
can be round or square and must have a surface of at least 50 cm 2. The gravimetric test is carried
out in accordance with the methods described in EN 10292, EN 10326, EN 10327 and EN 10336. The
weight of the zinc coating is determined during this test by chemical dissolution of three samples ta-
ken from an area of distribution across the width of the strip. The final value is the arithmetic mean
derived from the three surface samples. The lowest value from the three surface samples is the value
for the single surface sample.

Figure 1: Gravimetric test

                                                                                                           44
                                                                                 50

                    50                                                    50
                                 b/                         b/
                                   2                          2
                                        Strip width B

Zinc adhesion test
Zinc coating adhesion is determined in a drop-ball impact test in accordance with SEP 1931/version
1991. Judgment is made based on a qualitative standard series, whereas the criterion of quality is
based on proper workability according to the respective application.

In cases of arbitration the zinc test is carried out by means of a bending test in accordance with
EURONORM 12. The diameter of the bending block or bending roll is applied in accordance with
Table 5. The bending angle is always 180°. The sample legs are pressed together in such a manner
that the coating is not damaged.

Repeat tests

EN 10021 applies. Repeat tests on coils are carried out at a distance of at least one coil turn, however
from 20 meters at the most from the end of the strip.
Processing information

                                                                                                          T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
The following brief instructions are intended to provide assistance in processing hot-dip galvanized
steel strip. Our technical staff members are at your disposal to answer any of your questions.

Forming

Depending on the particular grade of hot-dip galvanized strip, it can be used for conventional for-
ming processes such as edging, bending, curling, flanging, stamping, crimping, roll-profiling, stretch
forming and deep drawing. The selection of materials depends on the demands on formability as well
as the final geometry and function of the work piece. The zinc coating and the surface are adapted to
the processing parameters. The properties of the zinc require that the drawing gap and the retraction
radius are enlarged in certain cases as compared to uncoated thin sheet. Altered flow behavior ma-
kes it necessary in some cases to adapt the hold-down force in forming processes.

Joining

                                                                                                          45
Conventional thermal and mechanical joining and gluing processes are used as connecting tech-
niques, some of which, however, require adaptation of the processing parameters in order to take
into account special physical and chemical properties of the coatings. Hot-dip galvanized steel strip
is suitable for welding with common welding techniques. Special adjustment of the welding para-
meters and electrodes is necessary for this material when resistance welding (spot, projection or
stitch welding) is used. Thin zinc coatings simplify the welding process. The fumes generated during
welding should be exhausted. Corrosion protection in the welding area is optimized by means of a
suitable post-treatment process (such as zinc dust paint coating). Hot-dip galvanized sheet can be
soft-soldered or brazed. A metallically clean surface is a precondition that can be achieved with sui-
table fluxing agents. Proper filling of the joint is achieved with respective brazing metals. Corrosive
fluxing agents are to be carefully washed off after soldering. Mechanical joining techniques such as
screwing, riveting, crimping, flanging and clinching are not problematic and have the advantage that
they preserve the surface and maintain the anticorrosive properties. It is necessary to consider possi-
ble problems of contact corrosion when different materials are combined.
The significance of metal gluing is increasing in combination with other methods of joining. High-
strength connections are achievable with modern adhesives, even between oiled sheets. An examina-
tion of the surface systems, possible treatment processes and the adhesives themselves is advisable.
Thermal rating

                                                                                                              T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Structural parts made of hot-dip galvanized steel strip can undergo long-term heat treatment up to
roughly 200–250 °C. Temperature stress that lasts longer than this can lead to negative effects in the
substrate and surface materials because of the diffusion reaction between the zinc coating and the
substrate.

Suitability for the application of coatings

Hot-dip galvanized steel strip in all of its surface grades lends itself well to the application of organic
coatings (such as paints or films). Surface MB or MC is the correct selection in the event of high or
higher demands on a uniform surface appearance after coating. Proper pretreatment is required in
order to achieve perfect adhesion. Surface phosphating pretreatment in the works provides an excel-
lent base for the adhesion of conventional organic coatings as long as the surfaces are clean.

                                                                                                              46
General notes

                                                                                                            T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Fretting corrosion

Mutual friction between strips of hot-dip galvanized steel during transportation can cause dark spots
on the zinc surface. These affect the appearance but do not adversely affect the quality of the corrosion
protection. The tendency toward fretting corrosion can be minimized by oiling the hot-dip-galvanized
steel strip.

Darkening

Hot-dip galvanized steel strip is generally intended for short-term processing. The degree of surface
darkening may vary when these grades are stored for a longer period of time. This affects the appea-
rance of the surface but does not adversely affect corrosion protection.

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Formation of white rust

When hot-dip galvanized steel strip is subjected to humidity for a longer period of time with reduced
ventilation, a loose, mat gray to reddish material called white rust forms on the surface. Wide areas of
the material are attacked particularly when condensation water forms and wetness occurs between the
sheets or the coil layers.
There is no danger of white rust forming as long as the coils are stored properly. Temperature changes
during transportation and storage are critical.
Diagram used to determine danger of white rust caused by condensation

                                                                                                                    T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Example 1: Strip temperature of 8 °C, room temperature of 21 °C, relative humidity of 55%   danger of white rust.
Example 2: Storage area of 19 °C, relative humidity of 50%   minimum strip temperature of 11 °C required.

                      Temperature (°C)                                  Relative air humidity
                                                 40%     50%    60%    70%                    100%
                 25

                                     1
                 20
                               2

                 15

                 10

                                                                                                                    48
                                                             Area of condensation

                  5

                  0

                 -5

Flatness

The strip is placed under tension when it is coiled. This tension causes deviations in the flatness of the
strip when it is downcoiled. A suitable straightening machine must be used to achieve flat condition of
the strip when delivered in coils. In some cases it improves the flatness of the material when paper in-
serts are applied during coiling. These are marked by flags placed on the end face. If paper inserts are
not desired or permitted, please specify this in the order.
Hot-dip galvanized steel strip with

                                                                                                           T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
zinc/iron-coating (Galvannealed)
Hot-dip galvanized steel strip is a hot-dip refined product with Zn or ZnFe coating on both sides.
The strip is subjected to heat treatment immediately after being galvanized. The zinc coating reacts
with the substrate material and forms a ZnFe coating with approximately 8–12% Fe.
This manufacturing process was the forerunner of the generally known product name
GALVANNEALED (= GALVanized and ANNEALED).

Steel grades

All steel grades described in the section entitled Hot-dip galvanized steel strip are available with the
exception of complex-phase and TRIP steels.
The same guarantees apply to mechanical parameters, with the following exceptions:

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p Statistical values lower by two units apply to the minimums for mild steels from grade DX54D and
  high-strength steels.
p The guaranteed r values are decreased for all steel grades by 0.2.
p The guaranteed n90 value for steel grades DX56D and DX57D is decreased by 0.01.

The available dimensions are limited to a thickness range of 0.5 to 2.0 mm.
ZF coating groups

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Coating groups

                                  Zinc Coating in g/m2 on both sides min.      Zinc coating thickness in µm per side
            ZF coating group
                                   Triple surface test   Single surface test    Typical value            Area

                ZF 80                      80                    70                  5.5                4 – 10

                ZF 100                    100                    85                  7.0                5 – 12

                ZF 120                    120                   100                  8.0                6 – 13

A ZF coating of 100 g/m2 (on both sides) corresponds to a ZF layer thickness of approximately 7 µm
per side.

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Surface

                                                                                                         T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Hot-dip galvanized steel strip with a zinc/iron coating is delivered in Surface RA, RB and RC.

Surface quality

Surface quality R
Hot-dip galvanized steel strip with a zinc/iron coating is characterized by a mat gray surface that is
free of spangles.

Surface type

Typical surface A
Small pits, dark spots, stripe-shaped marks, and small passivation defects are acceptable on this type
of surface. Straightening and bending fractures and runoff waves may be visible.

Improved surface B

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This type of surface is attained by rerolling. The inspected side may be characterized by a small
number of occurrences of fractures in stretch forming direction, finishing imprints, scratches, im-
pressions and slight passivation errors. The uninspected side of the material must at least meet the
requirements of Surface Type A.

Best surface C
This type of surface is also attained by rerolling. The inspected side does not negatively impact the
uniform appearance of a paint coat. The other side of the material must at least meet the requirements
of Surface Type B. Surface Type C is available for delivery up to 1.5 mm.

Roughness
As a standard, Surface types B and C are delivered with a medium roughness value ranging bet-
ween 1.0 and 1.9 µm. Determination of the mean Ra roughness value is subject to a wavelength limit
of 2.5 mm in accordance with EN 10049 (standard length of 12.5 mm).
Subsequent surface treatment

                                                                                                        T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Hot-dip galvanized steel strip with a zinc/iron coating is normally delivered with an oiled (O) zinc/
iron coating. Galvannealed can be delivered upon request in chromium-free passivated (C) or chro-
mium-free passivated and oiled (CO). Depending on the defined micro-topography, difficult forming
stresses may make it necessary to increase the oil coating.

Oil amounts

                     Oiled                                        approx. 1.2 g/m2 per side

                     Heavily oiled                                approx. 1.6 g/m2 per side

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Available dimensions

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Hot-dip galvanized ZF hot-rolled strip in coils

          Thickness                   Width            Maximum outside diameter   Inner diameter   Coil weight
            [mm]                      [mm]                      [mm]               roughly [mm]     [t] max.

     ≥ 0.50 1)     ≤ 2.0     ≥ 600        ≤ 800                 2000                   600              -

     ≥ 0.50   1)
                   ≤ 2.0     > 800   2)
                                          < 900   2)
                                                                2000                   600              -

     ≥ 0.50 1)     ≤ 2.0     ≥ 900        ≤ 1600 3)             2000                   600             32

1
    ) Thicknesses below 0.5 mm only upon request.
2)
     Width range between > 800 and < 900 mm only upon request.
3)
     With limited width tolerance of 1,580 mm max.

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