铁路货车用高强度耐候钢Q450NQR1焊接工艺

Welding Process of High-Strength Weathering Steel Q450NQR1 for Railway Vehicle

通过选择焊接材料及焊接工艺参数,对新型耐候钢Q450NQR1进行了焊接工艺、焊接接头的显微组织和力学性能等研究.试验结果表明:用的S-8018焊条及BH550-NQ-A焊丝焊接Q450NQR1耐候钢时接头各项力学性能满足规定的技术要求,焊缝金属的显微组织基本相同,均以针状铁素体为主+少量的先共析铁素体,过热区组织均为粒状贝氏体,焊接热影响区正火及不完全正火区的组织均为铁素体+珠光体;焊接线能量变化对焊接接头焊缝及热影响区显微组织有一定的影响,但影响不大.

Weldability of a high-strength weathering steel Q450NQR1 was studied by selecting welding consumables and methods, welding technology and microstructure mechanical property of the welds is also studied. The results show that the mechanical properties of the welding joints meet technical requirements when using S- 8018 electrode and BH550-NQ-A wire. The weld microstructure of the two process methods are basically the same, consisted of mainly needle-like ferrite plus a small amount of proeutectoid ferrite. The microstructure of overheated zone are both granular bainite. The microstructures of normalized and not fully normalized zones are both ferrite plus perlite. The changes of welding heat input have little effect on microstrueture of the weld joints and heat affected zone.