14Cr 1Mo 15V高铬白口铸铁的深冷硬化机理

 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，去稳+深冷处理铸铁的硬度比未深冷处理铸铁明显提高，从HRC 641提高到HRC 670。这是因为深冷处理使高铬白口铸铁的残余奥氏体量大大下降，马氏体的大量形成和细微二次碳化物的析出强化作用显著提高了高铬白口铸铁的硬度。深冷处理后铸铁组织中仍存在少量残余奥氏体。

Hardening Mechanism for 14Cr-1Mo-1.5V Cast Iron Subjected to Cryogenic Treatment

The effects of cryogenic treatment on the microstructure and the hardening behavior for high chromium cast iron were investigated by X ray diffraction, magnetic method and hardness test. The results show that after cryogenic treatment, the sample bulk hardness has a great increase, from HRC 641 for air cooling treatment to HRC 670 for cryogenic treatment after holding half an hour at 1 000 ℃. The analysis of microstructure reveals that the retained austenite content of sample after cryogenics treatment decreases greatly and much fine secondary carbide precipitates from matrix. Martensite transformation and the secondary carbide precipitation are the cause of bulk hardness increase. The matrix has few retained austenites even after cryogenic treatment.