不锈钢焊接凝固裂纹的三维数值模拟

焊接凝固裂纹的产生与否取决于两个方面的因素,材料凝固裂纹阻力和凝固裂纹驱动力,凝固裂纹阻力可以通过实验方法来获得,而凝固裂纹驱动力主要采用有限元计算方法得到.本文通过对SUS310不锈钢,在裂纹敏感温度区间内,焊缝金属动态应力应变场演变过程三维模拟计算的研究,得到了10 mm厚板的凝固裂纹驱动力曲线.利用动态单元再生技术,解决了焊接凝固过程的三个因素-焊接熔池的变形、初始温度的变化和凝固收缩的影响.并且模拟计算得到的驱动力与实验测量的凝固裂纹阻力曲线进行了比较,预测了焊缝金属的凝固裂纹.

Three dimensional numerical simulation of weld solidification cracking in stainless steel

The formation of weld metal solidification cracking results from the competition between the material resistance to cracking and the driving force to cracking during the course of solidification of weld metal. The material resistance to cracking was obtained by measuring local strain at the trail of weld molten pool with test. The driving force to cracking was modeled with finite element method. This paper presents the development of a three dimensional finite element analysis procedure and the calculated dynamic stress/strain evolutions that contribute to the formation of solidification cracking in the cracking susceptible temperature range. In the mechanical model, three solidification effects - deformation in weld pool, change of initial temperature for thermal strain calculation, and solidification shrinkage-are treated by means of a dynamic element rebirth technique. The results of comparison between the calculated driving force and the experimental measurements of the material resistance predict the susceptibility of solidification cracking.