B950CF高强钢超窄间隙激光焊接头组织对残余应力的影响  

Effect of Microstructures of Ultranarrow Gap Laser Welded B950CF Steel Joints on Residual Stress Distribution

作　　者：张成竹 陈辉[1] Zhang Chengzhu;Chen Hui(Welding Research Institute,School of Materials Science and Engineering,Southwest Jiaotong University,Chengdu,Sichuan 610031,China)

机构地区：[1]西南交通大学材料科学与工程学院焊接研究所,四川成都610031

出　　处：《中国激光》2021年第6期37-48,共12页Chinese Journal of Lasers

基　　金：科技部重点研发计划(2016YFB1102100);四川省重点研发项目(2019YFG0288)。

摘　　要：超窄间隙激光填丝焊(Ultra-narrow gap laser welding,Ultra-NGLW)是一种先进的厚贝氏体钢焊接技术。通过数值模拟和X射线衍射法,分析了超窄间隙激光填丝焊接头残余应力的分布和变化,结果表明:在不同厚度(20,50,70 mm)的超窄间隙激光填丝焊接头的表面,残余应力均呈"W"形分布。利用微型剪切试验,分析了显微组织对接头残余应力的影响:熔合线处形成的马氏体脆硬组织使接头形成了"软-硬-软"的夹心组织,导致接头的应力分布与一般的焊接接头不同,而多层填丝焊的特殊工艺导致接头中间层的应力增加。Objective Ultra-narrow gap laser welding(ultra-NGLW)is a type of advanced welding technology for high-strength thick steel plates that use a laser as the heat source in an ultranarrow groove.It has the advantages of high welding accessibility and efficiency,low heat input and residual stress,and low deformation.Ultra-NGLW is suitable for welding thick high-strength steel plates in pressure vessels,ships,pipes,and hydropower equipment.Different from the common arc welded joints,in the process of multilayer filler wire welding,the complex thermal process differently changes the microstructure of each filling layer,resulting in different mechanical properties of each micro-zone.Therefore,the residual stress distribution in the ultranarrow gap laser welded high-strength steel joint is related to its special microstructure.Methods In this paper,the B950 CF bainitic high-strength steel and XK-01 wire with diameter of 1.2 mm were considered the research objects.Ultra-NGLW joints with three different thicknesses of 20,50,and 70 mm were welded using the laser welding system comprising a TRUMPF-10002 high power laser and a Fronius automatic wire feeder.Considering the complex microstructure and highly uneven mechanical properties of the ultra-NGLW joint,the micro-shear test was adopted to study the relationship between the mechanical properties and microstructures of the joint.The micro-shear specimen with a dimension of 1.5 mm×1.5 mm×40 mm,including weld metal(WM),heataffected zone(HAZ),and base metal(BM),was cut from the different filling layers of the joint.The surface residual stress of the joints with different thicknesses was measured using theμX360 n X-ray residual stress tester.Considering the variance of the thermal-physical and mechanical properties of the B950 CF high-strength steel with temperature,the properties of the B950 CF steel at different temperatures were calculated using the JMat Pro simulation software.Based on the ABAQUS simulation software,a simulation model of the70-mm-thick ultraNGLW joint was

关 键 词：激光技术 超窄间隙激光填丝焊接 残余应力 X射线衍射法 微型剪切试验 高强度贝氏体钢 

分 类 号：TN249[电子电信—物理电子学]