High Strength Steel

Domex and Supraform

High strength steels are steel which can be attained in various types, all which has a guaranteed value for yield strength as well as tensile strength.

Two of the main high strength steels available in South Africa are Domex and Supraform. Supraform is manufactured by Arcelor Mittal while the Domex range is manufactured by SSAB.

Both these high strength steels provide the end user, or the manufacturer of cold formed sections with steel that is weld able and improved toughness. Both these high strength steels are available from a 2mm minimum wall thickness. Supraform steel is available up to a 10mm while the Domex range is supplied up to 12mm wall thickness, depending on the strength of the material required.

The high strength steels are similar in comparison as is indicated in the table below:

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SSAB Arcelor Mittal Range
Product Name Yield Strength Product Name Yield Strength
DOMEX 315 M 315 TM 34 340-420
DOMEX 420 M 420 TM 38 380-46
DOMEX 460 M 460 TM 42 420-50
DOMEX 500 M 500 TM 46 460-560
DOMEX 550 M 550 TM 60 600
DOMEX 600 M 600 - -
DOMEX 650 M 650 - -
DOMEX 700 M 700 - -

One of the key factors for a steel tube or profile manufacturer when cold forming with high strength steel is to calculate the amount of spring-back that the material will have while being formed. As Domex and Supraform is a lot stronger than the normal steel in the market, such as S355 High Tensile, it has a wider spring-back range that should be accounted for. A potential way of countering the spring back when cold forming high strength steel as an open profile is to over form the material, then under form the material and in the last pass to re-form the material to the desired angle.

Tubecon have in the past cold formed open sections including lip channels and U-channels from Domex 700 as well as TM600 while rolling steel tubes and other welded sections from Domex 450.