Hastelloy C-276薄板脉冲激光焊接残余应力和变形的数值模拟和实验研究(英文)

Numerical Simulation and Experimental Investigation of Residual Stresses and Distortions in Pulsed Laser Welding of Hastelloy C-276 Thin Sheets

为了揭示0.5 mm厚度Hastelloy C-276薄板脉冲激光拘束焊接的热力学行为,借助ANSYS软件建立了三维有限元模型。实验测量了焊接温度历程和残余变形,验证了所建立有限元模型的可靠性。基于该有限元模型,采用改变夹具拘束条件的方法,进一步研究了拘束距离对Hastelloy C-276薄板焊接瞬态应力和塑性应变、残余应力及变形的影响规律。结果表明,温度历程和残余变形的模拟结果与实验结果吻合较好;拘束距离对瞬态塑性应变的大小有显著影响,进而改变了残余应力及变形的分布和大小。随着夹具拘束距离从20 mm减小到4 mm,除了纵向残余拉伸应力外,横向残余拉伸应力和位移的峰值以及角变形的大小都呈减小的趋势。相对较小的拘束距离可以作为抑制横向残余拉伸应力和角变形的高效低成本方法,但对纵向残余拉伸应力有不利影响。

A three-dimensional finite element model （FEM） was developed by using ANSYS software to reveal the ther- mal-mechanical behaviors during the pulsed laser welding （PLW） for the fixture restraint in a Hastelloy C-276 butt-welded joint with 0.5 mm thickness. The welding temperature histories and residual distortions were measured to validate the FEM. Based on the FEM, the effects of the restraint distance on transient stresses and plastic strains, residual stresses and distortions were investigated by changing the fixture restraint conditions. The results show that the simulated temperature histories and residual distortions agree well with the experimental results; the restraint distance has a great influence on the magnitude of transient plastic strains, and then the distribution and the magnitude of residual stresses and distortions are changed. Except for the longitudinal residual tensile stresses, the peak values of the transverse residual tensile stresses and displacements and the magnitudes of the angular distortions decrease as the restraint distance decreases from 20 mm to 4 mm. A relatively smaller restraint distance can be used as a cost-effective method for mitigating the transverse residual tensile stresses and the angular distortions, but has an adverse influence on the longitudinal residual tensile stresses.