Special PropertiesRound Bars

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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.

Size range SP bars can be delivered in round sizes from 14 to 47.5 mm and in lengths up to 12 m. Crack detected SP bars are limited to a length of 9.5 m.

Each case is specificNo customer case is similar to any other case. Each case is thoroughly reviewed in order to optimize

Special Properties

the material into customer's processing and our technical department is always involved in the review. Every inquiry is followed by a customer contract review in accordance with the ISO/TS 16949 requirements.

Tolerances

Mechanical properties Surface quality

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Replace peeled or cold drawn barIn many cases the tight SP tolerances are close enough to those generated in peeling or cold drawing process. 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 tonneThe 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.

Increased yieldBy using SP bars for cutting blanks in the forging operation the weight variation of the blanks is reduced which results in less burr and thus more efficient deburring after forging. The excellent roundness of SP bars can also be successfully utilized in the peeling operation. (There is not always a need for the peeling operation!) The amount of material removed from the surface becomes less when using SP bars in the peeling operation. We

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.

can also offer a combination of SP bars and our SBMTM steel for improved machinability, this will make peeling or any other machining operation much more efficient.

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

A combination of SP bars and our SBMTM steel for improved machinability.

RepeatabilityUsing SP bars with tight tolerances improves the repeat-ability in the customer process and, e.g. in the bending operation variation of spring back is reduced. You get more uniform properties on finished product when dimensional variations are reduced compared to con-ventional hot rolled bars.

Impact strength of boron steel Q&T for 10.9 bolt.

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Fatigue LifeFatigue Life is a very important property in applications with cyclic loading like spring applications. By apply-ing SP bars fatigue strength can be improved in both quenched and tempered and the as rolled condition. This will result in longer fatigue life and gives our cus-tomers the opportunity to downsize dimension or to replace peeled bars.

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.

Low temperature properties (Impact Strength)In low temperature applications, such as high strength bolts for wind mills, it becomes very important to secure high impact strength levels to avoid brittleness of the steel. By using SP bars, superior impact strength levels can be reached combined with high tensile strength in the quench and tempered condition. See figure below.

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Optimizing Steel ChemistryThe improved tensile strength and toughness in SP bars make it possible to either replace more expensive alloyed steel grades or to reduce the alloy content in the existing steel grade which would also improve weldability.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.

Avoid annealingCertain steel grades require an extra annealing operation, because of the high alloy content, in order to meet the specified hardness requirements. This is a costly opera-tion and can possibly be avoided by using SP bars.

Comparing conventional 42MnV7 and SP.

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Accurate control of reheating of billets prior to hot roll-ing ensures low level of decarburizing of bars which is important for mechanical properties.

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.

To ensure the surface quality the bars can be NDT in-spected in a state-of-the-art flux leakage crack detection equipment. The equipment works with high frequency alternating current which doesn’t cause any residual magnetism.

SP bars on Cooling bed.

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Some SP Applications

Railway clips Bolts for Wind power mills

Automotive applications

Steering racks Stabilizer bars

SALES UNITS

Finland

Ovako Bar Oy Ab

Teollisuuskuja 1

FI-14200 Turenki

Telephone: +358 (0)5 680 21

Telefax: +358 (0)3 633 4032

France

Ovako France S.A.S.

14, rue de Mirande

FR-21000 Dijon

Telephone: +33 (0)3 8054 1515

Telefax: +33 (0)3 8050 1467

Germany / Austria

Ovako GmbH

Postfach 1255

D-40672 Erkrath

Telephone: +49 (0)211 25 040

Telefax: +49 (0)211 250 4244

Netherlands

Ovako Bar Benelux

Bedrijvenpark Twente 295

NL-7602 KK Almelo

Telephone: +31 (0)546 588 360

Telefax: +31 (0)546 588 366

Poland

Ovako Polska Sp. Z.o.o.

Ilmet

Al. Jana Pawla II 15

PL-00-828 Warzawa

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

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Sweden

Ovako Bar AB

Box 5

SE-59010 Boxholm

Telephone: +46 (0)142 293 600

Telefax: +46 (0)142 293 702

Ovako Bar AB

Box 429

SE-69127 Karlskoga

Telephone: +46 (0)591 60 000

Telefax: +46 (0)591 60 441

Ovako Bar AB

SE-777 80 Smedjebacken

Telephone: +46 (0)240 668 000

Telefax: +46 (0)240 74 362

United Kingdom

Ovako Ltd.

Unit 2 York’s Park

Blowers Green Road, Dudley

DY2 8UL, United Kingdom

Telephone: +44 (0)138 421 3940

Telefax: +44 (0)138 424 3662

USA

Ovako North America Inc.

1096 Assembly Drive

Suite 312

Fort Mill, SC 29708

Telephone: + 1 803 802 1500

Telefax: + 1 803 802 1501

Ovako is a leading European producer of special long

steel products for the heavy vehicle, automotive and

engineering industries. Our production covers low-

alloy steels and carbon steels in the form of bars,

tubes, rings and pre-components. The company has

14 production units and several sales companies in

Europe and the US. Net sales are EUR 1,100 million

and the company employs 3,000 people. Total steel

production capacity is 1.3 million tonnes per year.

www.ovako.com