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Welding handbook 11.0 Cutting of Weldox and Hardox

11.0 Cutting of Hardox and Strenx
©SSAB

The Hardox and Strenx grades are designed to 11.1 Oxy-fuel Cutting
facilitate all thermal cutting methods, including
oxy-fuel cutting, plasma cutting and laser cutting. Hardox and Strenx are easily cut by the oxy-fuel
Of course, it is also possible to use many common cutting process. Oxy-fuel cutting has almost no
cold cutting processes like abrasive water jet cutting limitations when it comes to material thickness, i.e.
and sawing. The enhanced thermal cutting material thicknesses up to 1000 mm can be cut.
performance of the Hardox and Strenx grades are Although it is possible to cut relatively thin materials,
primarily derived from their low alloy content to- the main thickness is above 20 mm. General
gether with their very low levels of impurities. features for oxy-fuel cutting can be seen in table 11.1.
Additionally, favorable properties that can be
Dim.
Kerf
Cutting
utilized for laser cutting are the narrow thickness method width HAZ tolerances
tolerances and smooth plate surfaces of the steel.
Many of the Hardox and Strenx grades, can at Oxy-fuel 2-5 mm 4-10 mm ± 2.0 mm
cutting
moderate thicknesses, be thermally cut using the Table 11.1: General features for oxy-fuel cutting.
same parameters as for mild steels without
additional consideration. However, in some cases, A common misunderstanding is that you need higher
it is necessary to adapt parameters to minimize the cutting oxygen pressure to cut hard steels. Oxy-fuel
risk for hydrogen cracking. Other issues that relate cutting is a thermal process where the hardness of
to the characteristics of the steel are:
the steel has no influence on the cutting performance.
Both Hardox and Strenx have a low alloying con-
4 The change of the mechanical properties in the cept which together with the cleanness of the steel
thermally affected part of the steel due to cutting. makes them easy to cut. Oxy-fuel cutting of primed
This section is called the heat-affected zone (HAZ). steel surfaces does not significantly affect the cutting
4 The distortions caused by thermal cutting. Due to parameters.
the higher levels of stresses, Hardox and Strenx
plates are prone to more movement during thermal 11.2 Plasma Cutting
cutting than ordinary steels.
Hardox and Strenx are easily cut by the plasma
The gases for the different thermal cutting methods are cutting process. Plasma cutting has a limitation
selected according to the manufacturer of the cutting when it comes to material thickness and the main
equipment. SSAB does not have any further stated thickness to be cut is below 50 mm (machine de-
recommendations in this respect for the Hardox and pendent). Generally features for plasma cutting
can be seen in table 11.2.
Strenx grades. The cold cutting methods, shearing and
punching, are limited to the Strenx grades, Hardox Cutting Kerf HAZ Dim. tolerances
400 and Hardox 450 up to 10 mm in plate thickness. method width
Abrasive water jet (AWJ) cutting is a cold cutting Plasma cutting 2 - 6,5 mm 2 - 5 mm ± 1.0 mm
method that provides advantageous mechanical prop- Table 11.2: General features for plasma cutting.
erties in the HAZ of the Hardox and Strenx grades.

This handbook contains general suggestions and information without any expressed or implied warranty of any kind. SSAB hereby expressly disclaims
all liability of any kind, including any damages, in connection with the use of the information and for their suitability for individual applications. 59
It is the responsibility of the user of this brochure to adapt the recommendations contained therein to the requirements of individual applications.