回火对药芯焊丝CHT71Ni熔敷金属组织与性能的影响

Effect of Tempering on the Organization and Properties of Flux Cored Wire CHT71Ni Deposited Metal

采用CHT71Ni型药芯焊丝进行焊接试验,熔敷金属样品于400,650℃回火1 h,应用金相显微镜、维氏硬度计、拉伸试验机、能谱仪等进行检测与分析。结果表明:经400℃回火的熔敷金属的综合力学性能最好。400℃回火显微组织是块状铁素体、珠光体及少量的贝氏体和第二相颗粒。650℃回火样品晶界处存在粗大的含有C、Si、Ni、Mn、Mo、Fe等元素的第二相颗粒。随回火温度提高,熔敷金属的屈服强度、维氏硬度值降低,断后伸长率相应增加。其中,熔敷金属的屈服强度由535 MPa下降到了413 MPa。650℃回火后,熔敷金属晶界的第二相颗粒长粗长大,破坏了晶界结构,-30℃低温冲击功由焊态的98 J下降为85 J。

Welding test using CHT71Ni flux-cored wire,molten metal samples tempered at 400,650℃for 1 h,the application of metallurgical microscopy,Vickers hardness tester,tensile testing machine,energy spectrometer,etc.for testing and analysis.The results show that:400℃tempered molten metal has the best overall mechanical properties.400℃tempering microstructure is massive ferrite,pearlite and a small amount of bainite and second-phase particles.650℃tempering samples at the grain boundary of the presence of coarse containing C,Si,Ni,Mn,Mo,Fe and other elements of the second phase particles.With the increase of tempering temperature,the yield strength and Vickers hardness values of the molten metal decreased and the elongation after break increased accordingly.Among them,the yield strength of the molten metal decreased from 535 MPa to 413 MPa.After tempering at 650℃,the second-phase particles at the grain boundary of the molten metal grew thicker and larger,destroying the grain boundary structure,and the low-temperature impact work at-30℃ decreased from 98 J to 85 J in the weld state.