Behaviour of domex S355 laser welds under stress

Abstract

The stresses in welds are the result of phase transformations and thermal expansion. Both mechanisms are connected with the heat input which is less in laser welding than arc welding methods. The paper describes laser welding of high-strength steel with the yield strength of 355 MPa without and with filler material. As expected, laser welds show a lower level and lower concentrations of internal stresses at critical points. The result is a higher level of mechanical properties and a tensile strength close to that of the base material. Cracks in parts laser welded with filler material propagate in the base metal, while cracks in parts welded without filler material occur in the heat affected zone. The filler material also leads to improved impact strengths when compared to plain laser welds.The stresses in welds are the result of phase transformations and thermal expansion. Both mechanisms are connected with the heat input which is less in laser welding than arc welding methods. The paper describes laser welding of high-strength steel with the yield strength of 355 MPa without and with filler material. As expected, laser welds show a lower level and lower concentrations of internal stresses at critical points. The result is a higher level of mechanical properties and a tensile strength close to that of the base material. Cracks in parts laser welded with filler material propagate in the base metal, while cracks in parts welded without filler material occur in the heat affected zone. The filler material also leads to improved impact strengths when compared to plain laser welds.