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利用OM、SEM、XRD、TEM、冲击力学测试和动电位极化研究了3.6 mass%和8.0 mass%两种Mn含量下19 mass%Cr节Ni型双相不锈钢800℃时效析出相的形成、韧性、耐点蚀性能。结果表明:Mn含量较低时,σ相析出较慢,54 h后呈细小颗粒弥散于铁素体奥氏体相界;由于Mn参与了σ相的形成,Mn含量较高时,σ相析出速度快,54 h后呈层片状覆盖在铁素体上;Mn含量的增加使奥氏体相比例增加,时效初期有助于提高实验钢的冲击性能,但时效后期大量σ相的析出加速了冲击性能的下降;低Mn含量实验钢点蚀电位在时效初期保持350 m V左右,比高Mn含量的电位高出约200 m V,54 h后两者耐点蚀性能均降低。较高的Mn含量在时效初期有助于提高实验钢的再钝化性能,54 h后两者再钝化性能趋于一致。
The formation and toughness of precipitated phases of 19% Cr Ni Ni duplex stainless steel at 800 ℃ under 3.6mass% and 8.0mass% Mn contents were investigated by OM, SEM, XRD, TEM, impact mechanics and potentiodynamic polarization. , Pitting corrosion resistance. The results show that when the content of Mn is low, the precipitation of sigma phase is slow, and fine particles disperse in the ferrite austenite phase after 54 h. Because Mn is involved in the formation of σ phase, the σ phase precipitates when Mn content is high After 54 h, the lamellar coating was covered on the ferrite. The increase of Mn content increased the austenite phase ratio, and the initial aging was helpful to improve the impact properties of experimental steel. However, the precipitation of a large amount of σ phase accelerated in the late aging The pitting corrosion resistance of the steel with low Mn content is about 350 mV at the initial aging stage and about 200 mV higher than that at the high Mn content. The pitting corrosion resistance of the steel decreases after 54 h. The higher Mn content in the early aging will help to improve the passivation of the experimental steel, and the reactivation performance of the two will be consistent after 54 h.