考虑固相变的钛合金焊接残余应力数值仿真方法

Numerical simulation method of welding residual stress of titanium alloy considering solid-state phase transformation

钛合金焊接结构广泛应用于深海耐压结构中,对焊接处残余应力分布规律的研究具有现实意义。本文采用JMAK方程和K-M方程来表达钛合金相变过程中的扩散转变和非扩散转变,建立Ti-6Al-4V焊接过程中固态相变的数学模型,确定数学模型中的参数求解方法,并基于ABAQUS软件开发考虑固态相变的热-冶金-力学耦合的有限元计算方法,该方法可以考虑温度与组织变化对焊接残余应力的影响。通过一个对接接头的激光焊接的有限元算例,验证所建立的固态相变的Ti-6Al-4V焊接模型的可行性。该工作对于定量分析Ti-6Al-4V焊接残余应力的影响因素具有参考意义。

Titanium alloy welded structures are widely used in deep-sea pressure structures.It is of practi⁃cal significance to study the residual stress distribution.In this paper,JMAK equation and K-M equation were used to express the diffusion transformation and no-diffusion transformation in the process of Ti-6Al 4V welding.The mathematical model of solid-state phase transformation in Ti-6Al-4V welding process was established,and the parameter calculation method in the mathematical model was determined.Based on ABAQUS software,a coupled thermo metallurgical mechanical finite element method considering solid phase transformation was developed,capable of considering the influence of temperature and microstructure on welding residual stress.The feasibility of the established Ti-6Al-4V welding model with solid phase transfor⁃mation was verified by a finite element example of laser welding of a butt joint.This work is of reference sig⁃nificance for the quantitative analysis of the influence factors of welding residual stress in Ti-6Al-4V.