焊后热处理对钛合金对接板疲劳寿命影响的数值模拟  

Numerical simulation of the effect of post-welding heat treatment on fatigue life of titanium alloy butt plate

作　　者：罗家元[1] 张宇翔 吕晨轲 Luo Jiayuan;Zhang Yuxiang;LüChenke(School of Mechatronics and Vehicle Engineering,Chongqing Jiaotong University,Chongqing 400074,China)

机构地区：[1]重庆交通大学机电与车辆工程学院,重庆400074

出　　处：《钢铁钒钛》2023年第5期76-83,共8页Iron Steel Vanadium Titanium

基　　金：重庆市技术创新与应用发展专项重点项目(cstc2021jscx-dxwtBX0022);国家重点研发计划项目(2020YFF0404209);重庆市博士后特别资助项目(Xm2017034)。

摘　　要：基于有限元软件建立了考虑蠕变应力松弛效应的30 mm厚TC4钛合金对接板的热—弹—塑性有限元模型,采用该模型模拟了TC4钛合金对接板电子束焊接过程中的温度场与应力场,对比了3种焊后热处理工艺下对接板内部残余应力分布情况,得出最优的焊后热处理工艺。通过疲劳分析软件fe-safe分析了焊后热处理对于对接板疲劳性能的影响。结果表明,数值模拟得到的残余应力分布情况较为准确。对接板经过700℃×2 h焊后热处理,其内部横向、纵向残余应力基本完全消除,峰值分别为28、46.3 MPa。蠕变效应在焊后热处理消除残余应力的过程中起重要作用,经过焊后热处理,对接板焊缝与热影响区的疲劳安全系数由0.192提升至0.7左右。Based on the finite element software,a thermo-elastic-plastic finite element model of 30 mm thick TC4 titanium alloy butt plate considering the creep stress relaxation effect was established.The temperature field and stress field in the electron beam welding process of TC4 titanium alloy butt plate were simulated by this model,and the distribution of residual stress in the butt plate under three postwelding heat treatment processes was compared.The optimal post-welding heat treatment process is obtained.Fatigue analysis software fe-safe was used to analyze the influence of heat treatment on the fatigue properties of butt plate.The results show that the residual stress distribution obtained by numerical simulation is accurate.After 700℃×2 h post-welding heat treatment,the internal transverse and longitudinal residual stresses of the butt plate were completely eliminated,and the peak values are 28 MPa and 46.3 MPa,respectively.The creep effect plays an important role in the process of post-welding heat treatment to eliminate the residual stress,and the fatigue safety factor of welding seam and heat-affected zone of the butt plate can be increased from 0.192 to about 0.7.

关 键 词：钛合金 焊后热处理 数值模拟 组合热源 残余应力 疲劳寿命 

分 类 号：TF823[冶金工程—有色金属冶金] TG405[金属学及工艺—焊接]