冷轧DP590双相钢板脉冲激光焊接接头的组织及性能

摘要

采用脉冲激光对接焊接1．0 mm厚冷轧DP590双相钢板,研究了焊接接头的显微组织、力学性能及成形性能.结果表明：焊缝区、热影响区、母材区的显微组织分别为板条马氏体,铁素体和板条马氏体、铁素体和马氏体；焊缝区、热影响区、母材的平均硬度分别为344,275,205 HV；焊接接头拉伸断裂位置出现在母材区,为韧性断裂；杯突试验过程中裂纹在焊缝中心处形成后垂直于焊缝向热影响区和母材扩展,裂纹在焊缝区切断马氏体板条扩展,而在热影响区和母材区则沿着铁素体和马氏体界面扩展；焊接接头具有良好的成形性能,其杯突值为母材的81．9％,可满足实际生产要求.%The cold-rolled DP590 dual phase steel sheets with 1 mm thickness were butt-welded by the pulsed laser welding and the microstructure,mechanical properties and formability of the welded joint were studied.The results show that the microstructure of fusion zone (FZ),heat affected zone (HAZ)and base material (BM) consisted with lath martensite,ferrite and lath martensite,ferrite and martensite respectively.The average micro-hardness of FZ,HAZ and BM was 344,275,205 HV respectively.The tensile fracture position of the welded joint was in BM,which showed a ductile fracture.During the Erichsen test,the cracks formed at the center of FZ and then propagated into HAZ and BM perpendicular to FZ.The cracks propagated in FZ by cutting the lath martensite and in HAZ and BM along the ferrite and martensite interface.The formability of welded joint was good and the Erichsen value reached 81.9% that of BM,meeting the requirements for production.