数值模拟技术在激光焊接过程中的应用及发展

激光焊接以其高效率、高精度成为材料高质量连接的先进方法.激光焊接过程涉及材料对激光能量的吸收与反射、熔化与蒸发、熔池的流动、匙孔的波动等多个物理场问题,建立反映激光焊接热过程特点的数值模型,进而定量描述并澄清影响材料激光焊接质量的关键因素及演变过程,为材料高品质激光焊接制造提供理论支撑和科学思路.文中从影响激光焊缝成形质量及服役性能的焊接缺陷、组织演变、残余应力几个方面入手,阐述数值模拟技术在激光焊接基础问题方面的应用及发展.

Influences of external restraint on welding distortion in low carbon steel bead-on thin plate joints

The out-of-plane deformation is a serious problem in thin-plate welded joint,and it is difficult to reduce or control the distortion during welding process. External restraint is regarded as an effective method to mitigate the distortion,and it is widely used in the actual manufacturing process. In order to investigate the influence of external restraint on welding deformation in thin plate joints,a thermo-elastic-plastic finite element method based on ABAQUS software was developed to calculate welding-induced deformation. Meanwhile,welding deformation in the thin-plate joints was measured by experiments.Through comparing the numerical results with the measured data,the effectiveness of the developed computational approach was verified. Based on the simulated and experimental results,the generation mechanism of the out-of-plane deformation in thin plate bead-on joint was discussed,and the influence of external restraint on the final welding deformation was clarified.

SUS310S不锈钢局部真空电子束焊接接头残余应力及变形研究

作为一种新型焊接方法,局部真空电子束焊接常被用于制造厚大的奥氏体不锈钢焊接接头,而该类接头的焊接残余应力和变形问题受到广泛关注。对板厚40mm的SUS310S不锈钢局部真空电子束焊接的对接接头进行了研究,并利用光学显微镜表征接头的组织形貌,利用显微硬度计测量接头的硬度分布,采用盲孔法装置和三坐标测量仪测量了接头的残余应力与面外变形。同时,基于ABAQUS有限元软件平台,通过编写用户子程序开发了一种复合热源模型来模拟局部真空电子束焊接过程中的热输入。采用所开发的"热-弹-塑性有限元"计算方法,模拟了接头在局部真空电子束焊条件下的残余应力与变形,模拟结果与试验结果吻合良好,验证了所开发的"热-弹-塑性有限元方法"的有效性。同时基于数值模拟结果,还详细讨论了局部真空电子束焊厚板对接接头的残余应力分布与焊接变形特征。