Special Properties Round Bars
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Special Properties Round Bars
Special Properties
Special Properties on round bar, more known as SP bars are the result of our never ending
efforts in our process development. SP Bars are not limited to any specific steel grade which
opens great possibilities for customers to use our advanced technology. They can benefit from
increased added value and substantial cost savings in manufacturing operations by optimizing
the properties of the material.
Simply, SP is a hot rolled bar with enhanced properties into customer’s processing and their
final product.
Tolerances
Mechanical properties Surface quality
Size range
SP bars can be delivered in round sizes from 14 to 47.5 the material into customer's processing and our technical
mm and in lengths up to 12 m. Crack detected SP bars department is always involved in the review. Every inquiry
are limited to a length of 9.5 m. is followed by a customer contract review in accordance
with the ISO/TS 16949 requirements.
Each case is specific
No customer case is similar to any other case.
Each case is thoroughly reviewed in order to optimize
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Tolerances
SP bars can offer extremely tight tolerances and the strive towards even tighter tolerances is
safeguarded by our continuous process development. In the information below you will find
some ideas of the benefits you can get from the tight tolerances shown in the table.
Available tolerances (¼ DIN 1013)
ø 14 – 20 ± 0.08
ø 20 – 30 ± 0.10
ø 30 – 42 ± 0.15
ø 42 – 47.5 ± 0.25
Replace peeled or cold drawn bar can also offer a combination of SP bars and our SBMTM
In many cases the tight SP tolerances are close enough steel for improved machinability, this will make peeling
to those generated in peeling or cold drawing process. or any other machining operation much more efficient.
This means in practice that these operations can be
eliminated thus enabling the customer to save manufac-
turing costs.
Residual surface stress levels in SP bars are lower than in
cold drawn bars as a result of lower degree of deformation
in the straightening process. SP bars can also be deliv-
ered non-straightened.
More out of tonne
The tight SP bar tolerances allows customers to decrease
the nominal size and more manufactured pieces are
obtained per tonne of purchased SP bar. This represents
a vital cost reduction.
A combination of SP bars and our SBMTM steel for improved
Increased yield machinability.
By using SP bars for cutting blanks in the forging operation
the weight variation of the blanks is reduced which Repeatability
results in less burr and thus more efficient deburring after Using SP bars with tight tolerances improves the repeat-
forging. The excellent roundness of SP bars can also ability in the customer process and, e.g. in the bending
be successfully utilized in the peeling operation. (There operation variation of spring back is reduced. You get
is not always a need for the peeling operation!) The more uniform properties on finished product when
amount of material removed from the surface becomes dimensional variations are reduced compared to con-
less when using SP bars in the peeling operation. We ventional hot rolled bars.
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Mechanical Properties
Steel is one of the world’s most used construction materials thanks to its excellent properties
and cost effectiveness in many different applications. Like any other material steel has its lim-
itations which we are pushing further with SP by continuously developing our process. How-
ever, the benefits on mechanical properties that can be reached depends on the steel grade
and the alloying elements.
Presented below are a few examples of how the use of SP bars can enhance the mechanical
properties and reduce customer manufacturing costs.
Fatigue Life Low temperature properties (Impact Strength)
Fatigue Life is a very important property in applications In low temperature applications, such as high strength
with cyclic loading like spring applications. By apply- bolts for wind mills, it becomes very important to secure
ing SP bars fatigue strength can be improved in both high impact strength levels to avoid brittleness of the
quenched and tempered and the as rolled condition. steel. By using SP bars, superior impact strength levels
This will result in longer fatigue life and gives our cus- can be reached combined with high tensile strength in
tomers the opportunity to downsize dimension or to the quench and tempered condition. See figure below.
replace peeled bars.
Impact strength of boron steel Q&T for 10.9 bolt.
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Optimizing Steel Chemistry Avoid annealing
The improved tensile strength and toughness in SP bars Certain steel grades require an extra annealing operation,
make it possible to either replace more expensive alloyed because of the high alloy content, in order to meet the
steel grades or to reduce the alloy content in the existing specified hardness requirements. This is a costly opera-
steel grade which would also improve weldability. tion and can possibly be avoided by using SP bars.
As mentioned earlier, it is also possible to reduce weight
in the construction by decreasing the size of SP bars. Or
just increase the security level of your construction.
Comparing conventional 42MnV7 and SP.
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Surface Quality
Thickness of the scale is generally reduced on SP bars. The amount of the reduction can be up
to 50% compared to conventional hot rolling. The reduced scale thickness on SP bars gives a
cleaner environment in subsequent operations such as cold forming or heat treatment, i.e. in
the quenching bath.
SP bars on Cooling bed.
Accurate control of reheating of billets prior to hot roll- To ensure the surface quality the bars can be NDT in-
ing ensures low level of decarburizing of bars which is spected in a state-of-the-art flux leakage crack detection
important for mechanical properties. equipment. The equipment works with high frequency
alternating current which doesn’t cause any residual
magnetism.
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Some SP Applications
Automotive applications
Steering racks Stabilizer bars
Railway clips Bolts for Wind power mills
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Ovako is a leading European producer of special long SALES UNITS
steel products for the heavy vehicle, automotive and
Finland Sweden
engineering industries. Our production covers low- Ovako Bar Oy Ab Ovako Bar AB
alloy steels and carbon steels in the form of bars, Teollisuuskuja 1 Box 5
FI-14200 Turenki SE-59010 Boxholm
tubes, rings and pre-components. The company has
Telephone: +358 (0)5 680 21 Telephone: +46 (0)142 293 600
14 production units and several sales companies in Telefax: +358 (0)3 633 4032 Telefax: +46 (0)142 293 702
Europe and the US. Net sales are EUR 1,100 million
France Ovako Bar AB
and the company employs 3,000 people. Total steel
Ovako France S.A.S. Box 429
production capacity is 1.3 million tonnes per year. 14, rue de Mirande SE-69127 Karlskoga
FR-21000 Dijon Telephone: +46 (0)591 60 000
Telephone: +33 (0)3 8054 1515 Telefax: +46 (0)591 60 441
Telefax: +33 (0)3 8050 1467
Ovako Bar AB
Germany / Austria SE-777 80 Smedjebacken
Ovako GmbH Telephone: +46 (0)240 668 000
Postfach 1255 Telefax: +46 (0)240 74 362
D-40672 Erkrath
Telephone: +49 (0)211 25 040 United Kingdom
Telefax: +49 (0)211 250 4244 Ovako Ltd.
Unit 2 York’s Park
Netherlands Blowers Green Road, Dudley
Ovako Bar Benelux DY2 8UL, United Kingdom
Bedrijvenpark Twente 295 Telephone: +44 (0)138 421 3940
NL-7602 KK Almelo Telefax: +44 (0)138 424 3662
Telephone: +31 (0)546 588 360
Telefax: +31 (0)546 588 366 USA
Ovako North America Inc.
Poland 1096 Assembly Drive
Ovako Polska Sp. Z.o.o. Suite 312
Ilmet Fort Mill, SC 29708
Al. Jana Pawla II 15 Telephone: + 1 803 802 1500
PL-00-828 Warzawa Telefax: + 1 803 802 1501
Telephone +48 (0)22 697 6464
Telefax +48 (0)22 697 6467
Russia
OOO Ovako
Business Center “Zeleniy Grad”
Office 1812, Savelkinskiy proezd, 4
124482 Zelenograd, Moscow
Telephone: +7 (0)495 228 0780
Telefax: +7 (0)495 228 0781
Ovako Bar AB SP ©Ovako 2011.
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