能量控制方式对不锈钢与钽激光焊接头裂纹倾向性的影响规律  

Influence of energy control method on the crack tendency of stainless steel and tantalum laser welding joints

作　　者：宋凡 孟祥毅 李思贝 许博 王心笛 Song Fan;Meng Xiangyi;Li Sibei;Xu Bo;Wang Xindi(ShangHai Institute of Space Propulsion,Shanghai 201112,China;Harbin Institue of Technology,Harbin 150001,China)

机构地区：[1]上海空间推进研究所,上海201112 [2]哈尔滨工业大学,哈尔滨150001

出　　处：《焊接》2024年第4期40-46,共7页Welding & Joining

摘　　要：为满足电推进系统阴极组件中不锈钢与钽的高质量连接需求,对两者进行了激光焊试验研究。结果表明,在激光焊常用的偏移量范围内,接头截面为熔钎焊成形模式,焊缝由固溶体和共晶组织构成。若光束大部辐照钽,或光束不偏钽但功率较高,钽母材的熔化量增多,其熔入焊缝会生成明显的脆性金属间化合物层,层间和层内各处难以避免出现裂纹,因此最佳的能量模式为,激光光束中心不向钽偏移,同时在保证焊透壁厚的熔深前提下尽可能降低激光功率,以及相应配套减小焊接速度。界面层是多种化合物大体分层分布的结构,厚层接头的纵向裂纹多诞生于结合力最差的化合物分层面,测试结果证明最薄弱的分层面是μ(FeTa)和ε(Fe_(2)Ta)之间,薄层接头的裂纹多萌生于化合物层和共晶组织之间,但扩展方向各有不同。In order to meet the high-quality connection requirements of stainless steel and tantalum in the cathode assembly of the electric propulsion system,a laser welding experimental study was carried out.The result shows that within the range of offsets commonly used in laser welding,the cross-section of the joint is in the brazing forming mode,and the weld is composed of solid solution and eutectic structure.If most of the beam irradiates tantalum,or the beam is not biased towards tantalum but the power is high,the amount of melting of the tantalum base metal will increase,and its fusion into the weld will generate a clear brittle intermetallic compound layer,which is unavoidable between layers and in layers.Therefore,the optimal energy mode is:the center of the laser beam does not shift to tantalum,and at the same time,the laser power is reduced as much as possible under the premise of ensuring the penetration depth,and the welding speed is correspondingly reduced.The interface layer is a structure in which a variety of compounds are generally distributed in layers.The longitudinal cracks of thick-layer joints are mostly born in the compound layer with the worst bonding force.The test results show that the weakest layer is betweenμ(FeTa)andε(Fe_(2)Ta).The cracks of thin-layer joints mostly originate between the compound layer and the eutectic structure,but the propagation directions are different.

关 键 词：不锈钢 钽 激光焊 热输入 裂纹 

分 类 号：TG456.7[金属学及工艺—焊接]