硼微合金化对6Mo超级奥氏体不锈钢微观组织及耐蚀性影响

摘要：综述了6Mo超级奥氏体不锈钢凝固、热加工和热处理阶段的微观组织演化规律，并分析了合金元素对Mo偏析和σ相析出及耐蚀性能的影响规律。结合作者前期工作，重点分析了微合金化元素硼对其凝固阶段Mo偏析、热加工和热处理阶段σ相析出以及耐蚀性能的影响。硼抑制热加工过程中σ相的析出，减小析出相数量和尺寸，有利于热塑性提高；同时还可促使钝化膜表面形成富铬和富Mo氧化物，加速基体表面钝化膜致密化，且减缓晶界处贫Cr和贫Mo区，提高耐蚀性。

Effect of boron microalloying on microstructure and corrosion resistance of 6Mo super austenitic stainless steel

The microstructural evolution of 6Mo super austenitic stainless steel during solidification, hot working and heat treatment was reviewed, and the effects of alloying elements on Mo segregation, σ phase precipitation and corrosion resistance were analyzed. Combined with the author's previous work, the effects of boron addition on Mo segregation in solidification stage, evolution of σ phase segregation in heat processing and heat treatment stage, and corrosion resistance were analyzed. As the results show, the boron element has a certain effect on Mo segregation in the solidification stage. B can effectively inhibit the segregation of σ phase at the grain boundary and reduce the number and size of precipitation phase, which is conducive to the improvement of hot ductility. Meanwhile, B can promote the formation of Cr and Mo rich oxides in the outer layer of passivation film, which makes the surface of passivation film and the interface of substrate more compact, and the corrosion resistance is improved significantly by reducing the Cr and Mo depleted zones at the grain boundary.