Effects of Multi-Scale Microstructure on Pitting Corrosion and Mechanical Properties of High-Mn-N Low-Ni Superduplex Stainless Steel

摘要:

研究了一种包含有多尺度微结构的高MnN低Ni超级双相不锈钢25Cr-2Ni-3Mo-10Mn-0.5N经过冷轧和退火后，多尺度晶粒度对点腐蚀和力学性能的影响。结果表明：多尺度微结构与退火时间密切相关，在1050 oC，奥氏体与铁素体平均晶粒大小随着时效时间的增加而增加，时效1 min后，奥氏体和铁素体的晶粒大小分别为1.5和7.18 μm。随着多尺度晶粒的长大，样品的抗拉强度，屈服强度和断面收缩率下降，而样品的耐腐蚀性能增强。多尺度微结构对该双相钢25Cr-2Ni-3Mo-10Mn-0.5N的点腐蚀性能和力学性能起着重要作用

Abstract:

A high-Mn-N low-Ni superduplex stainless steel 25Cr-2Ni-3Mo-10Mn-0.5N with multi-scale microstructures has been prepared through severe cold rolling and annealing, and the effects of multi-scale grains on the pitting corrosion and mechanical properties have been investigated. The results show that the multi-scale microstructures have a strong relation with the annealing time, that is, the average grain sizes of austenite and ferrite increase with prolonging of the annealing time at 1050 oC, they have the minimum values of 1.5 and 7.18 μm, respectively, when the alloy is annealed for 1 min. The tensile strength, yield strength and reduction in area of the sample decrease with the growth of multi-scale grains, whereas the pitting corrosion resistance of the specimen is enhanced. The multi-scale microstructures play an important role on the pitting corrosion and the mechanical properties of superduplex stainless steel 25Cr-2Ni-3Mo-10Mn-0.5N.