对5 mm厚T91马氏体耐热钢板激光填丝焊工艺进行研究, 分析了热输入对焊缝成型、微观组织、内部气孔数量的影响规律, 并对最佳参数焊缝的力学性能进行了检测。结果表明, 采用同质焊丝焊接T91钢, 焊后对焊缝进行热处理, 随着热输入的增加, 焊缝宽度变大, 焊缝内部气孔数量减少, 晶粒度变化不明显, 焊缝区与热影响区组织均为回火马氏体; 采用功率5 600W、速度1.2 m/min、送丝速度1.2 m/min的参数焊接可获得内部基本无气孔的焊缝, 焊缝显微硬度300 HV, 抗拉强度697 MPa, 断裂在母材, 180°正弯与背弯曲均未出现裂纹, 20/0/-20℃下冲击性能均高于母材。

The research on laser welding 5 mm thick T91 martensite heat-resistant steel with filler wires is conducted, and the effects on weld appearance,microstructures,and porosity are studied, also the weld mechanical properties of the optimal parameters are tested. The results show that when welding heat input increased by using same material wire to weld T91 steel, after heat treated, weld seam width increased, porosity decreased, and grain size changed a little, microstructure of weld zone and HAZ are tempered martensite. The weld seam can be pore-free with the parameters of power 5 600 W, speed 1.2 m/min, feeding speed 1.2 m/min, its microhardness is 300 HV, tensile strength is 697 MPa, no cracks appear by 180° bending and back bending, and the impact properties are better than base metal at 20/0/-20 ℃.