Introduction For many years, fusion welding has been employed for the welding of Domex Advanced High Strength Steels. Compared with the fusion welding of mild steels, the process does not differ significantly. However, in order to maximize the benefits of these high strength steels, the welding process must still be controlled in a suitable manner. The following pages offer useful information about welding with Domex from SSAB. The advice and information here can help you to achieve optimal welding results, which allow you to experience the full potential of your choice in Domex from SSAB.
Contents Domex Joint preparation Welding Welding methods for Domex Hot cracks and lamellar tearing Hydrogen cracking Carbon equivalent EN 1011-2 Filler metals for Domex Static Strength of welded joints Heat input Interpass temperature Soft zones Results of mechanical testing Impact toughness of welded joint Recommendations in order to minimize distortion Stress relief annealing Hot straightening
4 6 7 7 7 8 8 8 9 11 11 11 12 13 14 14 15 15
3
Domex 1200 1100 1000 Yield strength, N/mm2
Domex is the brand name for hot-rolled sheet steels from SSAB. These steels are supplied in the thickness range 2–16 mm, and due to their exceptional formability in a cold state, they are also known as cold-forming steels. Domex steels are characterized by high yield strength, excellent formability and good weldability. These qualities make them optimal for use in the transportation industry (trailers, trucks, tippers, automotive, trains and cranes). Domex steels are available in the yield strength levels shown in figure 1. Their mechanical properties and chemical composition can be seen in tables 1 and 2.
900 800 700 600 500 400
460
500
355
300
Figure 1 Strength of Domex.
4
550
MC
600
650
700
Table 1 Mechanical properties of Domex. Mechanical Properties Steel grade
Domex 355 MC
Yield strengt Reh (MPa)
Tensile strength Rm (MPa)
Elongation Min. (%)
Bending radius, minimum in 90° bend.
minimum
minimum
A80 t15 ml/100 g weld metal) of the weld metal and an extremely low heat input (
