Cui Shuwan, Pang Shuwen, Zhang Suojun, Liao Yong, Cai Hongfeng
Dongfeng Liuzhou Automobile Co., Ltd., Liuzhou 545005, China.
School of Mechanical and Automotive Engineering, Guangxi University of Science and Technology, Liuzhou 545006, China.
Materials (Basel). 2022 May 19;15(10):3627. doi: 10.3390/ma15103627.
This paper attempted to establish a relationship between the morphology, microstructure and mechanical properties of a laser lap welded joint (WJ) of 780 duplex-phase (DP) steel under different welding parameters. The experimental results showed that the microstructure of the heat-affected zone (HAZ) of all the WJs were tempered martensite and equiaxed ferrite. The microstructure at the fusion zone (FZ) in all the WJs was dominated by lath martensite and ferrite, and the grain size of the FZ was larger than that in the base materials (BMs). The mechanical properties of the welded joints were tested by a universal testing machine, and the changing law of lap tensile resistance with the laser-welding parameters was analyzed. The results show that there was a linear relationship between the width of the weld and the tensile-shear forces of the weld, and the penetration of the weld had no obvious effect on the tensile-shear forces of the weld. A binary linear-regression equation was established to reveal the degree of influence of welding speed and laser power on the mechanical properties of WJs. It was found that the laser power had a greater influence on the mechanical properties of WJs than the welding speed.
本文试图建立780双相（DP）钢激光搭接焊接接头（WJ）在不同焊接参数下的形态、微观结构与力学性能之间的关系。实验结果表明，所有焊接接头热影响区（HAZ）的微观结构均为回火马氏体和等轴铁素体。所有焊接接头熔合区（FZ）的微观结构以板条马氏体和铁素体为主，且熔合区的晶粒尺寸大于母材（BM）中的晶粒尺寸。采用万能试验机对接头的力学性能进行测试，并分析了搭接抗拉强度随激光焊接参数的变化规律。结果表明，焊缝宽度与焊缝的拉伸剪切力之间存在线性关系，焊缝熔深对焊缝的拉伸剪切力没有明显影响。建立了二元线性回归方程以揭示焊接速度和激光功率对焊接接头力学性能的影响程度。结果发现，激光功率对焊接接头力学性能的影响大于焊接速度。
