激光焊接速度对焊缝组织和硬度分布的影响

Effect of welding speed on the microstructure and hardness distribution of laser beam welding joints

利用激光焊接工艺焊接核级不锈钢,通过改变激光焊接速度得到不同的焊接接头.采用金相显微镜、扫描电子显微镜等手段研究了熔深比、δ/γ比、组织形貌以及焊缝中各相的成分.通过显微硬度测试了焊缝接头上硬度分布.随着焊接速度的增加,焊缝熔深比线性增加,焊缝中δ-铁素体含量增加,岛状组织增多,板条状组织增多,蠕虫状组织减少,焊缝区的平均硬度值增加.

Nuclear grade stainless steel welding joints were prepared by laser beam welding （LBW） at different welding speeds. Optical microscopy and scanning electron microscopy were subsequently used to study the weld penetration ratio, δ/γ ratio, micro structure, and phase composition. The hardness distribution was examined with a micro-Vickers hardness tester. When this welding speeds up, the weld penetration ratio and δ-ferrite content within the welding seam increase, the island and lath-shaped microstruc- tures enlarge at the cost of the worm-like one, and the average hardness value in the weld area becomes greater.