Cr对G520不锈钢焊缝组织及力学性能的影响

采用Cr含量分别为10%，18%，26%，34%(质量分数)的金属型药芯焊丝焊接G520沉淀硬化不锈钢，研究了药芯焊丝中Cr含量对G520沉淀硬化不锈钢焊接接头组织以及力学性能的影响. 结果表明，4组焊接接头焊缝区组织均为奥氏体和δ铁素体，随药芯焊丝中Cr含量的增加，δ铁素体由点块状转变为网状和条状. 固溶于基体组织中的Cr含量、δ铁素体及Cr₂₃C₆的含量、奥氏体晶粒平均尺寸的综合作用影响着焊接接头拉伸性能及室温冲击韧性. 焊丝中Cr含量为26%时，G520沉淀硬化不锈钢焊接接头的抗拉强度为969 MPa，断后伸长率为20.8%，冲击吸收能量为60.7 J，焊接接头力学性能最优.

Effect of Cr content on microstructures and mechanical properties of G520 stainless steel welded joints

The G520 precipitation hardening stainless steel was welded with metallic flux-cored wires with Cr content of 10 wt.%, 18 wt.%, 26 wt.%, and 34 wt.% respectively.The effect of Cr content in flux-cored wire on the microstructure and mechanical properties of G520 precipitation hardening stainless steel welded joints was studied.The results show that the microstructures of the weld zone of the four groups of welded joints are all austenite and δ-ferrite, and with the increase of the Cr content in the flux-cored wire, the δ-ferrite changes from a point block to a network and a strip.The combined effects of the content of Cr, the content of δ-ferrite and Cr₂₃C₆, and the average size of austenite grains in the microstructure affects the tensile properties and room temperature impact toughness of welded joints.When the Cr content in the welding wire is 26 wt.%, the Mechanical Properties of the G520 precipitation hardening stainless steel welded joint is the best, the tensile strength is 969 MPa, the elongation is 20.8%, the impact energy is 60.7 J.