热处理对B1500HS钢激光拼焊板力学性能的影响

利用单轴拉伸试验机、扫描电子显微镜、能量色散谱仪、光学显微镜、维氏硬度仪等研究了热处理前后B1500HS钢激光拼焊板的淬火性能.结果表明:热处理前B1500HS钢拼焊板焊缝强度远高于母材区，硬度分布极不均匀；热处理后，B1500HS钢拼焊板的元素分布几乎没有变化，整体强度有了大幅的提高，但塑性下降程度较大，其中横向塑性最差，经维氏硬度测试，发现焊缝至母材区的硬度过渡平滑.硬度值平滑过渡使得应力和应变分布更加均匀，保证了母材和焊缝力学性能的良好连续性，可以显著提高B1500HS钢拼焊板的成形性能. 

Effect of heat treatment on the mechanical properties of B1500HS steel laser tailor welded blanks

The microstructure and mechanical properties of B1500HS laser tailor welded blanks before and after hardening heat treatment were studied by optical microscopy, scanning electron microscopy, energy dispersive spectrometry, uniaxial tensile testing, and Vickers hardness testing. Before the heat treatment, the strength of the laser tailor welded blanks is much higher than that of the base metal, and the hardness is very unevenly distributed. After the heat treatment, the element distribution of the laser tailor welded blanks has almost no change, the overall strength is greatly improved, the plasticity greatly declines, the lateral plastic is the worst, and the hardness from the weld to base metal smoothly changes. This smooth transition of hardness makes the stress and strain distribution more uniform, ensures the good continuity of mechanical properties between the base material and the weld, and can significantly improve the formability of the laser tailor welded blanks.