冷处理对超级马氏体不锈钢组织及逆变奥氏体的影响

Effect of cold treatment on microstructure and reversed austenite of super martensitic stainless steel

研究了淬火+回火(No.1钢)及淬火+冷处理+回火(No.2钢)两种处理工艺下,超级马氏体不锈钢组织和性能的差异。结果表明:两钢中基体组织均为回火马氏体,但经过冷处理的No.2钢马氏体板条更平直,尺寸更小。在No.1、No.2钢中,随回火温度的升高,逆变奥氏体含量的变化趋势都为先增高后降低。在No.1、No.2钢中逆变奥氏体达到最大值的回火温度分别为650℃,700℃。No.2钢中Ni元素富集点含量比No.1钢低,但Ni富集点数比No.1钢多。No.1、No.2钢的硬度变化趋势都为先快速降低后缓慢回升,但在相同回火温度下,No.2钢的硬度值更低。

The differences of microstructure and properties of super martensitic stainless steel heat treated by quenching and tempering( steel No. 1) and quenching plus cold treatment and then tempering( steel No. 2) were studied. The results show that the matrix is martensite in the steels treated by the two processes,but the martensitic laths are straighter and the size is smaller in steel No. 2. The amount of the reversed austenite increases first and then decreases for the differently heat-treated steels with the increasing of tempering temperature. The maximum reversed austenite amount occurs at tempering temperature of 650 ℃ and 700 ℃ for the steel No. 1 and steel No. 2,respectively. The number of Ni enriched fields in steel No. 2 is more than that in steel No. 1,but its concentration of Ni in the fields is lower than steel No. 1. The hardness decreases first and then increases both in steel No. 1 and steel No. 2 with the increase of tempering temperature. However,the hardness of steel No. 2 is lower than that of steel No. 1 at the same tempering temperature.