双相不锈钢及其焊接接头腐蚀研究进展

双相不锈钢耐点蚀、耐晶间腐蚀和耐氯化物应力腐蚀性能优良,是优良的海洋用金属材料,但其焊接接头常成为薄弱区而发生腐蚀问题.从材料因素综述了双相不锈钢腐蚀研究的进展.首先,总结了合金元素和热处理对双相不锈钢耐腐蚀性能的影响.合金元素分配及其引起的二次相析出及产生的元素贫化区、铁素体/奥氏体相比例的变化决定双相不锈钢的耐腐蚀...

Research Progress on Corrosion of Duplex Stainless Steel and Its Welded Joint

Duplex stainless steels (DSS) are the good materials for marine application because of their well resistance to pitting corrosion, intergranular corrosion and chloride stress corrosion. But the welded joint is usually the weakest zone of DSS which often causes various corrosion problems. The research progress of DSS corrosion has been reviewed from the perspective of material factors. Firstly, the effects of alloy element and heat treatment on the resistance of DSS corrosion were summarized. The corrosion resistance is determined by the distribution of alloy elements, the precipitation of secondary phase and the ratio of ferrite to austenite. The solution treatment can eliminate the secondary phases and the Cr-depleted zones adjacent to the secondary phases, mend the ratio of ferrite to austenite, and improve the corrosion resistance of DSS. Secondly, the corrosion characteristics of DSS welded joints were analyzed, and the effects of welding method, heat input, shielding gas and post-weld heat treatment on the corrosion resistance of welded joints were summarized. The resistance to localized corrosion of tungsten inert gas welding (TIG) joint is well. The corrosion resistance of welded joint can be improved by adopting multi pass welding with suitable heat input and controlling over interlayer temperature. Although the solution treatment can improve the corrosion resistance of the joint, it is difficult to be applied to the welded joint of pipeline and other engineering components. Finally, the current problems of DSS corrosion research are discussed, and the future research trends are pointed out.