螺母凸焊焊点断口形貌分析

摘要

分析常规螺母材料10B21与H260PD+Z镀锌钢板凸焊焊点的断裂方式.对工件进行破坏性试验,通过SEM观察焊点的断口形貌,结合焊点内部金相组织,发现螺母凸焊焊点的断裂方式分为两种:当断裂发生在熔合区时,断裂为脆性断裂;当断裂发生在板材的热影响区时,为韧性断裂和脆性断裂的混合断裂方式.结合理论分析和实际生产发现,当断裂发生在板材的热影响区时,断口具有一定的韧性,这样的断裂方式对螺母凸焊更为安全.%In this paper,the fracture modes of projection welding weld of both conventional nut 10B21 and galvanized steel sheets are analyzed.After destructive test,through observing the weld's fracture morphology by SEM and considering its internal microstructure,it is found that there are two kinds of weld fracture modes of projection welding weld for nut:Brittle fracture in fusion zone and mixed fracture of brittle fracture and ductile fracture in sheet HAZ.Theoretical analysis and practical experience reveals that fracture shows some toughness when fracture occurs in sheet HAZ,and this fracture mode is safer for nut projection welding.