氩气流量对304不锈钢激光焊接接头组织性能的影响

Effect of Ar Gas Flow Rate on Microstructure and Mechanical Properties of 304 Stainless Steel Laser Welded Joint

使用ND:YAG激光焊接对板厚为1 mm的304不锈钢进行对接焊接试验,利用金相显微镜、万能试验机等分析测试手段,研究了不同氩气流量对其焊接接头组织性能的影响。结果表明:以脉冲激光为加载热源在焊接电流170 A、脉宽13 ms、频率3 Hz、焊接速度50 mm/min、离焦量-1 mm、氩气流量11 L/min的焊接工艺参数下,焊接接头可获得最佳表面外观和综合力学性能。焊接接头近缝区主要是细小柱状晶体,焊缝中心区主要是细小的树枝晶和微量的胞状晶,氩气保护使焊缝中心区的等轴晶区增大;焊接接头抗拉强度均高于母材抗拉强度的85%;焊缝中心区显微硬度<母材显微硬度<热影响区显微硬度。

The 1mm thickness 304 stainless steel butt welded test was conducted using ND： YAG laser welding. Using optical microscopy, universal testing machines and other analytical tools, the effects of Ar gas flow rate on the welded joint microstructure and mechanical properties were studied. The results show that： using pulsed laser heat source load, in the welding process parameters of welding current 170 A, pulse width 13 ms, frequency 3Hz, welding speed 50 mm / min, defocus amount-1mm, argon gas flow 11 L / min, welded joints for optimum surface appearance and mechanical properties were obtained. There is mainly fine columnar crystals near the weld area in welded joints. There is mainly fine dendrite and trace cellular crystals in the center of the weld area, weld center equiaxed grains zone increases under argon protection. The tensile strength of the welded joints is higher 85% than that of the tensile strength of the base material. The hardness from small to large is weld center microhardness, base metal microhardness, and HAZ microhardness.