1Cr21Ni5Ti锁底结构光纤激光焊接工艺特性

Fiber laser welding procedure characteristics of 1Cr21Ni5Ti lock butt joint

对3 mm厚的1Cr21Ni5Ti不锈钢锁底结构进行激光焊接试验,分析不同焊接工艺参数对接头成形、力学性能以及微观组织的影响,研究了其焊接工艺特性。结果表明,主要焊接缺陷为焊缝中的气孔以及收焊处凹坑,采用缓降功率的方法可减小焊缝收焊处凹坑深度,采用负离焦以及提高焊接速度有利于控制焊缝中的气孔缺陷。相比母材,焊缝硬度有所下降且不均匀,沿焊缝中心,焊缝中部区域硬度最高;在一定参数范围内,接头力学性能波动较小,焊缝平均抗拉强度达到816 MPa。焊缝内部晶粒呈等轴晶形式,主要由铁素体和奥氏体组成,焊缝中部奥氏体数量多于上部和下部,因此硬度较高;热影响区在焊接热循环作用下晶粒相对粗化,为焊缝的薄弱区域。

The 3 mm thick 1Cr21Ni5Ti stainless steel lock butt joint was welded with fiber laser,the welding procedure characteristics are studied by analyzing the effect of different welding parameter on the joint quality,mechanical properties and microstructure.The results show that the main weld defects are porosity and weld pit in the weld,slow power reduction can reduce the depth of pit in weld,and negative defocus and high speed welding can effectively prevent the formation of porosity.The hardness of the weld decreases,along the weld center,the hardness of the middle area of the weld is the highest.Within a certain range of parameters,the mechanical properties of the joint are stable,and the average tensile strength of the weld reaches 816 MPa.The grain in the weld is equiaxed crystal,mainly is composed of ferrite and austenite.The amount of austenite in the middle of the weld is greater than that in the top and bottom of the weld,thus showing a higher hardness.Under the action of welding thermal cycle,the grain in the heat affected zone becomes relatively coarse,and is the weak area of weld.