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使用不同氧气含量的保护气体对低合金高强钢HSLA-65进行了实心焊丝和药芯焊丝的熔化极气体保护焊。通过拉伸试验、冲击试验等力学性能检测,结合光学显微镜、扫描电镜、透射电镜和能谱分析等,研究了保护气体中氧气含量的变化对熔敷金属组织和力学性能的影响。结果表明:实心焊丝和药芯焊丝的熔敷金属显微组织均由针状铁素体和晶界铁素体组成。在相同保护气体成分下,药芯焊丝熔敷金属中针状铁素体比例大于实心焊丝熔敷金属,药芯焊丝熔敷金属的综合力学性能优于实心焊丝熔敷金属。随着保护气体中氧气比例的增加,实心焊丝熔敷金属中针状铁素体的含量先增加后减少;而药芯焊丝熔敷金属中针状铁素体含量一直在减少。两者熔敷金属的综合力学性能随针状铁素体比例的变化呈现出相同的变化规律。
Low-alloy high-strength steel HSLA-65 was welded with solid wire and flux-cored wire by using shielding gas with different oxygen content. The effects of oxygen content in the protective gas on the microstructure and mechanical properties of the deposited metal were studied by mechanical tests such as tensile test and impact test, combined with optical microscope, scanning electron microscope, transmission electron microscope and energy spectrum analysis. The results show that the deposited metal microstructure of solid wire and flux cored wire consists of acicular ferrite and grain boundary ferrite. Under the same shielding gas composition, the proportion of acicular ferrite in the flux-cored wire deposited metal is larger than that of the solid wire, and the mechanical properties of the flux-cored metal are better than the solid wire deposited metal. With the increase of the oxygen content in the shielding gas, the content of acicular ferrite in the solidified wire first increases and then decreases, while the acicular ferrite content in the deposited metal of the cored wire has been decreasing. The mechanical properties of both the deposited metal with acicular ferrite ratio showed the same changes in the law.