不锈钢中厚板激光全熔透焊的有限元模拟

运用有限元计算软件ABAQUS对16mm厚不锈钢板的激光全熔透焊的温度场和应力场进行了模拟.采用一体两面的复合焊接热源模型来刻画激光全熔透焊过程中的热输入特征,以柱状体热源代表焊接小孔传热模式,以2个超高斯面热源代表等离子体/金属蒸气云对熔池的辐射传热模式.结果表明:温度场模拟结果得到了与实验结果相一致的"沙漏状"焊缝;钢板内纵向残余应力最大,横向应力次之,板厚方向横向应力最小;纵向拉应力主要分布在焊缝两侧约25mm的区域内,最大值已超过材料的屈服强度;经测算,钢板焊后的角变形量仅为0.35°,这是由于激光焊接能量输入高且集中、可不用开坡口而一次性将钢板焊透.

Numerical Simulation on Laser Full-penetration Welding of Medium-thickness Stainless Steel Plates

The temperature and stress field of laser full-penetration welding process for 16 mm-thick stain- less steel plates were numerically simulated using commercial software ABAQUS, during which the heat source model was described by a combination of one volume heat source and two super-Gaussian surface sources, respectively representing the keyhole thermal conduction and plasma/metal vapor thermal radia- tion. Results show that the weld joint with hourglass cross section obtained by simulation agrees well with that of experiments~ the longitudinal residual stress in the plate is the largest, followed by the transverse stress, and finally the transverse through-thickness stress~ longitudinal tensile stress exists mainly in the zone 25 mm away from the center line of weld, and the maximum value has already exceeded the yield strength; an angular distortion of 0.35° after welding is predicted, and such small distortion could be at- tributed to the high and dense energy input by the laser, which can fully penetrate the plate by one pass without weld groove.