锰对高铬铸铁凝固组织和亚临界硬化行为的影响

采用电子探针、X射线衍射、磁性法和硬度测量等方法研究了两种不同含锰量高铬铸铁的凝固组织和在亚临界处理过程中的硬化行为。结果表明，含锰量分别为2．68％和1．98％的两种高铬铸铁的凝固组织都由奥氏体、马氏体和M7C3型碳化物组成。二者的共晶碳化物数量相当，前者和后者的奥氏体和马氏体含量分别为66．2％、13％和11．8％、68．2％。在亚临界处理中，高铬铸铁出现二次硬化，且前者的二次硬化更明显。这一现象归因于高铬铸铁在亚临界处理过程中所发生的马氏体相变。

Effect of Mn on the Solidification Structure and the Sub-Critical Hardening Behaviour of the High Chromium Cast Irons

In this paper,the solidification microstructure and the hardening behavior subjected to sub-critical treating for two kinds of high chromium cast irons with different content of Mn were investigated by using electron probe analyzer,X-ray diffraction,magnetic method and hardness test.The results show that the as-cast microstructures of two high chromium cast irons with 2.68% Mn and 1.98% Mn respectively consist of austenite,martensite and M_7C_3 carbide.And the amount of M_7C_3 carbide of them are almost equivalent.The former has 66.2% austenite,13% martensite and the later has 11.8% austenite,68.2% martensite respectively.In the process of the sub-critical treatment,the two high chromium cast irons both appear secondary hardening,and the former appears more obviously and attributed to the martensite transition of high chromium cast iron during sub-critical treating.