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本文研究了双相不锈钢在氮、氩混合气中和在真空中进行渗氮和脱氮热处理,以及含铝及13wt％Cr的不锈钢在氮基气氛中进行渗氮热处理。双相不锈钢在1250C于氮、氩混合气中进行热处理时,若混合气中氮气含量高于80％,则表层中得到γ单相,而当混合气中氮气含量低于20％时,表层中得到α单相。双相不锈钢在氮气中于1050℃处理,在表面得到γ相,其硬度比心部高出40HV,而脱氮使硬度下降,故在真空中处理之试样,其表面和心部的硬度几乎相同。含铝及13wt％Cr的不锈钢,在氮分压为0.5kg/cm~2的气氛中处理时,铝、氮之间的强亲合力使氮能渗入钢的内部。获得高层深和高硬度的最佳条件是,控制铝含量使在渗氮温度下基体中含有α+γ(马氏体)相,而表层则为含氯化物的γ相。能满足这种条件的最佳铝含量为1.65wt％。
In this paper, the nitriding and denitrification heat treatment of duplex stainless steel in nitrogen and argon mixed gas and in vacuum, and nitriding heat treatment of stainless steel containing aluminum and 13wt% Cr in nitrogen atmosphere were studied. When the duplex stainless steel is heat-treated at 1250C in a mixture of nitrogen and argon, if the content of nitrogen in the mixture is higher than 80%, the γ single phase is obtained in the surface layer, and when the content of nitrogen in the mixture is less than 20% Obtain α single phase. Duplex stainless steel is treated at 1050 ° C in nitrogen to obtain γ phase on the surface. Its hardness is 40HV higher than that of the core, and the hardness is decreased by denitrification. Therefore, the hardness of the sample treated in vacuum is nearly the same. When stainless steel containing aluminum and 13 wt% Cr is treated in an atmosphere having a nitrogen partial pressure of 0.5 kg / cm 2, the strong affinity between aluminum and nitrogen allows nitrogen to penetrate into the steel. The best conditions for attaining high depth and high hardness are to control the aluminum content such that the matrix contains the α + γ (martensite) phase at the nitriding temperature and the chloride phase of the γ phase. The optimum aluminum content to satisfy this condition is 1.65% by weight.