0Cr15Ni5Cu4Nb中厚板锁底结构大功率光纤激光焊接工艺特性

采用大功率光纤激光对7 mm厚度0Cr15Ni5Cu4Nb不锈钢锁底结构实施了焊接试验,通过对不同焊接工艺参数下的接头质量、力学性能、微观组织结构的分析,研究了其焊接工艺特性. 结果表明,焊缝中的主要缺陷是焊接气孔,采用负离焦、高速度的焊接参数能够有效抑制气孔的形成. 焊缝区域硬度有所增加,并且焊缝上部和下部的硬度要高于中部的硬度值,接头的力学性能稳定,焊缝平均抗拉强度为970 MPa,冲击韧性略有降低,为母材的89%. 焊缝组织主要由马氏体、残余奥氏体和δ-Fe组成,焊缝中部δ-Fe要多于上部,马氏体转变不充分,热影响区中主要由晶粒细小的淬火马氏体组成.

High power fiber laser welding of lock butt joint of medium 0Cr15Ni5Cu4Nb steel plate

The lock butt joint of 0Cr15Ni5Cu4Nb stainless steel of 7 mm in thickness was welded with high power fiber laser, the characterizations of welding process were studied by analyzing the influence of different welding parameters on the weld quality, mechanical properties and microstructure. Result shows that porosity is the main defect in the weld, and the negative defocus and high welding speed can prevent porosity from formation effectively. There is an increase in the hardness of the weld, and the top and bottom weld have higher hardness than the central weld does. The tensile strength of the joint is 970 MPa, and higher than that of base metal, but its impact toughness is slightly lower, is 89% of that the base metal. Weld microstructure consists of martensite, retained austenite and δ-Fe, and the central weld has more δ-Fe than the top weld. Martensitic transformation was not sufficient in the central weld, the microstructure of HAZ is mainly quenched martensite with small grain.