深冷处理对13Cr-2Mn-2V高铬白口铸铁显微组织和硬化行为的影响

Effects of Cryogenic Treatment on Microstructure and Hardening Behaviour of 13Cr-2Mn-2V High Chromium Cast Iron

采用X射线衍射、磁性法和硬度测量等方法研究了深冷处理对高铬白口铸铁显微组织和硬化行为的影响。结果表明,在去稳加空冷处理过程中,随着加热温度(90 0 115 0℃)的升高,高铬铸铁的硬度先升高并在10 0 0℃时达到最高值,然后开始下降。去稳加深冷处理过程中,高铬铸铁硬度的变化与前者相似,但其硬度显著高于未加深冷处理的高铬铸铁。深冷处理使高铬铸铁的残余奥氏体的含量大大下降,并且有二次碳化物的析出。尽管马氏体含量升高,但其含碳量降低,硬度降低。因此,在高铬铸铁硬度强化机制中,二次碳化物(Fe ,Cr) 2 3 C6,所起的作用要强于马氏体。当硬度达到最高时其组织中仍残留少量奥氏体。

The effects of deep cryogenic treatment on the microstructure and the hardening behavior for the 13Cr 2Mn 2V high chromium cast iron were investigated by X ray diffraction, magnetic method and hardness test. The results show that in the course of destabilized treatment without cryogenic, with increasing the heating temperature (from 900℃to 1150℃), the hardness of high chromium cast iron increase until the temperature reaches 1 000℃, and then the hardness begin to fall. In deep cryogenic treatment, there is similar disciplinarian, but the hardness are higher than that of the treatment without cryogenic. After deep cryogenic treatment, the content of retained austenite decreases greatly, and many tiny secondary carbide precipitate from matrix. Although the content of the martensite increases, the content of carbide decreases. The secondary carbide plays a greater role than the martensite for increasing bulk hardness. But there are still retained austenites in microstructures when the hardness reaches the maximum.