18Ni不锈钢电阻点焊接头力学性能有限元仿真  

Finite element simulation of mechanical property of 18Ni stainless steel resistance spot-welded joint

作　　者：余海松 余闪闪 李婷 尹彦平 吕晓刚[1] Yu Haisong;Yu Shanshan;Li Ting;Yin Yanping;LüXiaogang(China Airborne Missile Academy,Luoyang 471009,Henan,China;Yunnan Agricultural University,Kunming 650201,China)

机构地区：[1]中国空空导弹研究院,河南洛阳471009 [2]云南农业大学,昆明650201

出　　处：《焊接》2023年第5期24-28,共5页Welding & Joining

摘　　要：为了研究航空用18Ni马氏体不锈钢电阻点焊接头的剪切性能和微观组织,开展了18Ni马氏体不锈钢的电阻点焊试验和点焊接头的剪切试验,并采用有限元分析软件,仿真了点焊接头在剪切过程中的应力分布。结果表明,18Ni不锈钢电阻点焊接头的最大抗剪力为45.01 kN,最小抗剪力为36.87 kN;仿真结果显示,剪切过程中的应力主要集中分布在焊点处,尤其是两块试板中间的焊点位置应力最大;观察金相组织后发现,点焊接头的微观组织类似于铸造组织,粗大的柱状晶从焊缝边缘向焊缝中心生长,最终在焊缝中心形成一条明显的晶界线,同时发现,晶粒内部的组织为针状马氏体组织和残余奥氏体组织,热影响区的晶粒为等轴晶,且等轴晶的晶粒尺寸小于焊缝柱状晶的晶粒尺寸,还发现焊缝内部存在有微裂纹缺陷。In order to study the shear properties and microstructure of 18Ni martensitic stainless steel resistance spot-welded joints for aerospace applications.In this paper,the resistance spot-welding experiment and shear experiment of 18Ni martensitic stainless steel were carried out.Besides,the finite element analysis software was used to simulate the stress distribution of spot-welded joint in shearing process.The results show that the maximum shear resistance of 18Ni stainless steel resistance spot-welded joint is 45.01 kN,and the minimum shear resistance is 36.87 kN.The simulation results show that the stress is mainly concentrated on the spot-welding seam.Especially,the spotwelding seam between the two steel sheets has the maximum stress.After metallographic structure observation,it is found that the microstructure of spot-welded joint is similar to that of casting.The coarse columnar crystals grow from the edge of the weld seam to the center of the weld seam,and a clear grain boundary line is formed in the center of the weld seam finally.It is also found that the internal structure of the grain is acicular martensite and residual austenite.The grains in the heat affected zone are isometric crystals and the size of isometric crystal is smaller than that of weld columnar crystal.It is also found that there is micro-crack in the weld seam.

关 键 词：18Ni不锈钢 电阻点焊 有限元仿真 剪切性能 微观组织 

分 类 号：TG453[金属学及工艺—焊接]