X70管线钢焊接用自保护药芯焊丝研制

制备了3种不同合金成分的TiO_2-MgO-Al_2O_3熔渣体系自保护药芯焊丝,研究焊缝熔敷金属性能,得到工艺性能较好的T50SS-3药芯焊丝。采用X射线探伤、金相显微镜、SEM等测试方法,研究药芯焊丝的焊缝宏观、微观组织、断口形貌及夹杂物分布、尺寸和成分。结果表明,焊缝无未焊透、咬边、气孔、夹渣等缺陷,微观组织主要为低分散型贝氏体+少量铁素体,中间为奥氏体颗粒,非金属夹杂为锆的氧化物为形核中心形成铝的氮化物,弥散均匀分布。

Research on the self-shielded flux-cored wire for welding of X70 pipeline steel

Three kinds of TiO2-MgO-Al2O3 slag system self-shielded flux-cored wires with different components are used to study the properties of the depositedmetal,and the T50SS-3 flux-cored wire is obtained.The X ray inspection,metallographic microscope,SEM are used to study the properties of the welded joints,including the macrostructure,microstructure and fracture appearance of the welds,and the distribution,size and composition of the inclusions.The results show that there are no defects such as lack of penetration,undercut,pores,slag and so on in the welds.The microstructure belongs to low dispersion bainite + a small amount of ferrite,intermediates are austenite grains,non-metallic inclusions are aluminum nitride,whose the nucleation occurs with zirconia,and distribute uniformly.