Effect Of Heat Treatment And Nitrogen Content On The Performance Of254SMO Stainless Steel

254SMO super austenitic stainless steel was widely used in the industry of high requirements on chloride ion, such as paper and maritime industry, owing to its high corrosion resistance properties (e.g. resistance to pitting corrosion, crevice corrosion and stress corrosion). But this steel contains a high content of alloy elements, the production of hot rolled plate is difficult, prone to segregation phenomenon. The performance of254SMO stainless steel in domestic production fell far short of international standards. In order to optimize the production process and provide guidance to the smelting and rolling of steel production process, then we studied and discussed the hot rolled plate of254SMO super austenitic stainless steel(nitrogen content of No.l, No.2and No.3steel is0.096%,0.146%and0.262%, respectively) from the following aspects:Solid solution treatment results show that, with the increase of temperature, grain size becomes larger, the corrosion resistance turns to be worse. The structure of solid solution at1180℃is the best form of austenitic organization, composition is uniform and grain size is moderate.When ageing temperature is700℃to1000℃, with the increase of temperature, the precipitation and the hardness increase gradually, the corrosion resistance decreases. The main component of the precipitation is σ phase, σ phase is the main reason of hardness increasing and corrosion resistance worsening. Ageing temperature of recrystallization is800to1000℃. In the process of production and use, the steel should be avoided staying at1000℃, so as not to cause the failure of materials.Test results of different nitrogen content steel show that, with the increase of nitrogen content, the strength increases gradually, while the plasticity does not decrease. It is ductile fracture, the tensile fracture is dimple, and the mechanism is microvoid accumulation fracture.Test results of the same component steel show that, the strength and the plasticity of hot rolling plate are higher than the solid solution plate, while the strength and plasticity of solid solution at1200℃is similar to that of1250℃; the corrosion resistance of hot rolling steel is the worst, and the corrosion resistance of the steel solid solution at1200℃is the best.