Effects of welding speed and edge distance on solidification cracking length during laser welding at the narrow flange edge of austenitic stainless steel

Abstract

Although laser welding to the flange edge of a steel plate can contribute to weight reduction and productivity by reducing the flange width and by increasing the welding speed, solidification cracking tends to occur when welding near a flange edge. We have proposed a possible preventive measure, weld-periphery heating (WPH) and verified that WPH prevents or reduces the occurrence of the cracking. However, little is known about the welding parameters influencing the range of welding conditions under which WPH is applied, that is, the crack occurrence range during laser welding at a narrow flange of an austenitic stainless steel sheet. Therefore, in this research, the effects of crucial welding parameters such as the welding speed and the laser welding position relative to the flange edge (edge distance) on the solidification cracking length for type 310S stainless steel were investigated by experiment and finite element analysis using temperature-dependent interface elements. As a result, in the range of the welding speed of 10-40 mm/s and the edge distance of 3-6 mm, the cracking length became longer by reducing the welding speed and decreasing the edge distance. The plastic strain increment in the brittleness temperature range (BTR), the cracking index used for the FE analysis, correlated with the cracking length.Although laser welding to the flange edge of a steel plate can contribute to weight reduction and productivity by reducing the flange width and by increasing the welding speed, solidification cracking tends to occur when welding near a flange edge. We have proposed a possible preventive measure, weld-periphery heating (WPH) and verified that WPH prevents or reduces the occurrence of the cracking. However, little is known about the welding parameters influencing the range of welding conditions under which WPH is applied, that is, the crack occurrence range during laser welding at a narrow flange of an austenitic stainless steel sheet. Therefore, in this research, the effects of crucial welding parameters such as the welding speed and the laser welding position relative to the flange edge (edge distance) on the solidification cracking length for type 310S stainless steel were investigated by experiment and finite element analysis using temperature-dependent interface elements. As a result, in the range of t...