E36钢光纤激光焊与光纤激光-MIG复合焊接头组织及性能分析

Microstructure and Properties of E36 Steel Joints Welded by Fiber Laser Welding and Fiber Laser-MIG Hybrid Welding

分别采用光纤激光焊接和激光-MIG复合焊接方法焊接6 mm厚E36钢板,研究焊接接头的显微组织、力学性能和腐蚀性能。结果表明:在不同的焊接方法下均可获得全熔透的接头,单激光焊接获得的接头呈现典型的"匙孔型"特征,激光-MIG电弧复合焊时获得的接头呈现复合焊特有的"高脚杯"特征。激光焊接时焊缝区组织主要由板条马氏体组成,激光-MIG复合焊接时,接头焊缝区有侧板条铁素体产生;激光焊接和激光-MIG复合焊接时,焊接接头热影响区组织的物相主要由铁素体、珠光体和少量粒状贝氏体组成。不同焊接方法下接头的抗拉强度和屈服强度变化不大,焊接接头最高硬度均出现在焊缝处。同一焊接方法下,焊接速度为2.1 m/min时焊接接头焊缝区的耐蚀性均比2.4m/min时焊接接头耐蚀性好。

6 mm thick E36 steel plate was welded by fiber laser welding and laser-MIG hybrid welding respectively.The microstructure,mechanical properties and corrosion resistance of the welded joints were studied.The results show that the welded joints with full penetration can be obtained by different welding methods.The laser welding joints show typical'keyhole'feature,however,the laser-MIG hybrid welding joints show unique'goblet'feature.The laser welding seam microstructure is mainly composed of lath martensite,and ferrite side plate is obtained in laser-MIG hybrid welding joints.The phase of the heat affected zone of the joint welded by laser welding and laser-MIG hybrid welding is mainly composed of ferrite,pearlite and a small amount of granular bainite.The tensile strength and yield strength of the joints welded by different welding methods change little,and the highest microhardness of the welded joints appears in the weld metal.Under the same welding method,the corrosion resistance of weld area of welded joint under 2.1 m/min is better than that under 2.4 m/min.