摘要
本文通过杯突试验、拉伸试验和显微硬度试验对退火前冷硬态HC550/980DP双相高强钢窄搭接电阻焊焊接接头进行了力学性能检测,并采用金相显微镜和扫描电镜对焊接接头进行了微观组织表征。研究结果表明,搭接量1.04mm、补偿量1.15mm、焊接速度12.8m/min、焊接压力18kN、焊接温度1150℃、焊接电流15.9A的焊接参数条件下,冷硬双相钢具有良好的宏观形貌,焊缝中心微观组织主要由板条马氏体组成,受焊接热循环过程的影响,焊缝热影响区主要划分为粗晶区、细晶区和两相区,粗晶区的组织主要由粗大的板条马氏体和贝氏体构成,而细晶区和两相区的组织则出现了少量的铁素体。焊缝中心表现出较高硬度,平均值约452HV,而热影响区硬度出现软化现象;拉伸试样断裂于焊接热影响区,抗拉强度低于母材约80MPa,延伸率相差不大,断裂方式为脆性断裂和韧性断裂。
In this paper,the mechanical properties of narrow lap resistance welding joint of cold-rolled HC550/980DP dual-phase high-strength steel before annealing was tested by means of cupping testing,tensile testing,microhardness tester,and the microstructure of the welded joints was characterized by metallography and scanning electron microscopy.The results showed that the cool-rolled dual-phase steel has satisfactory macroscopic weldability under the welding parameters of lap amount 1.04mm,compensation amount 1.15mm,welding speed 12.8m/min,welding pressure 18KN,welding temperature 1150℃,and welding current 15.9A.The microstructure of the weld center was mainly composed of lath martensite.Affected by the welding thermal cycle,the weld heat affected zone was divided into coarse-grained zone,fine-grained zone and two-phase zone.The microstructure of the coarsegrained zone was mainly composed of coarse lath martensite and bainite,while a small amount of ferrite occurs in the microstructure of fine-grained zone and two-phase zone.The center of the weld showed high hardness,with an average of 452HV,while the hardness of the heat-affected zone softened.The tensile specimen fracture in the weld heat affected zone,and the tensile strength was about 80MPa lower than the base metal.Moreover,the fracture modes included brittle fracture and ductile fracture.
作者
杜天宇
张才华
史根豪
白瑞召
DU Tianyu;ZHANG Caihua;SHI Genhao;BAI Ruizhao(HBIS Group Hansteel Company Production and Manufacturing Department,Handan 056000,Hebei,China;HBIS GroupHansteel Company Technology Center,Handan 056000,Hebei,China;HBIS GroupHansteel Company Hanbao Cold Rolling Plant Handan 056000,Hebei,China)
出处
《四川冶金》
CAS
2022年第4期1-6,共6页
Sichuan Metallurgy
