异厚板激光拼焊接头动态拉伸性能数值仿真方法研究

Research on numerical simulation method for dynamic tensile performance of laser tailor-welded joints of different thickness

研究了异厚板HC340LA和HC260LA低合金高强钢激光拼焊工艺,对焊接接头进行了X射线探伤、静态拉伸、金相组织和显微硬度检测与分析。结果表明,异厚低合金高强钢通过激光拼焊工艺可以得到成形良好的焊缝,焊缝组织以柱状马氏体为主。焊缝经探伤无明显可见气孔、夹渣等缺陷,拉伸试样断裂位置位于薄板母材一侧上,且焊缝融合区硬度明显高于母材。针对激光拼焊接头进行了动态拉伸试验和数值仿真分析,研究了共节点模型与试验的差异性、区域效应和厚度效应对应力应变的影响规律。研究表明,采用共节点数值模型进行动态拉伸仿真,其应变值远大于试验测得的应变值。焊缝相关联的母材区域可直接调控应力应变的分布情况,可通过区域效应调控应变的大小,厚度效应调控应力的大小。

The laser tailored welding process of HC340 LA and HC260 LA low-alloy high-strength steels with different thicknesses was studied,and the welded joints were tested and analyzed by X-ray flaw detection,static tensile,metallographic structure and microhardness.The results show that the low-alloy high-strength steel with different thickness can get well-formed welds through the laser tailor welding process,and the weld structure is mainly columnar martensite.After flaw detection,the welds showed no obvious defects such as pores and slag inclusions.The fracture position of the tensile specimen was on the side of the base material of the thin blank,and the hardness of the weld fusion zone was significantly higher than that of the base material.For laser tailor-welded joints,dynamic tensile test and numerical simulation analysis are carried out,and the difference between common node model and test,regional effect and thickness effect on stress and strain are studied.The research shows that the strain values of the dynamic tensile simulation using the common node numerical model are much higher than those measured in the experiment.The area of the base metal associated with the weld can directly affect the distribution of stress and strain,the strain can be regulated by the regional effect,and the stress can be regulated by the thickness effect.