摘要
采用正交实验确定了锌铝镁镀层钢板HC340LAD+ZM的最佳点焊工艺,利用拉剪实验、显微镜、SEM、硬度计等方法研究了焊接接头组织、性能的变化。结果表明,焊接参数对拉剪力影响的顺序分别为焊接电流、电极压力、焊接时间,最优点焊工艺为焊接电流10 kA、电极压力2.6 kN、焊接时间14 cycles;此工艺下焊接接头组织清晰,呈现母材、相变、细晶、粗晶和熔核5个区域,各部分组织均匀过渡,未出现混晶,并且越靠近熔核区域马氏体含量越高,晶粒越粗大;焊接接头拉剪断口由C型韧窝组成,断裂形式为韧性断裂;焊接接头横向硬度呈“W”型分布,熔核区显微硬度值最高,为350 HV;垂直方向硬度变化不大,中心区域硬度值稍稍偏高。
The optimum spot welding process of zinc aluminum magnesium coated steel plate HC340LAD+ZM was determined by orthogonal experiment.The changes of microstructure and properties of welded joints were studied by tensile shear test,microscope,SEM and hardness tester.The results show that the influence order of welding parameters on tensile and shear force is welding current,electrode pressure and welding time.The best welding process is welding current 10 kA,electrode pressure 2.6 kN and welding time 14 cycles.Under this process,the microstructure of the welded joint is clear,showing five areas:base metal,phase transformation,fine grain,coarse grain and nugget.The microstructure of each part is uniform and there is no mixed crystal.The closer to the nugget area,the higher the martensite content and the coarser the grain.The tensile shear fracture of welded joint is composed of C-type dimple,and the fracture form is ductile fracture.The transverse hardness of welded joint presents a"W"distribution,and the microhardness value of the nugget zone is 350 HV,which is the highest.The hardness changes little in the vertical direction,and the hardness value in the central area is slightly higher.
作者
熊自柳
齐建军
孙力
侯金海
卢岳
Xiong Ziliu;Qi Jianjun;Sun Li;Hou Jinhai;Lu Yue(HBIS Group Technology Research Institute, Shijiazhuang 050023,Hebei;College of Materials Science and Engineering, Chongqing University, Chongqing, 400044)
出处
《河北冶金》
2022年第1期34-38,52,共6页
Hebei Metallurgy
基金
河北省自然科学基金(E2018318013)。