灰口铸铁低温气体多元共渗后力学性能的变化研究

Study on Change of Mechanical Properties for Grey Cast Iron After Multielement Gas Penetration at Low Temperature

利用一种转化装置,实现了多种元素以气体方式进入炉体,对灰口铸铁表面进行低温气体氮、碳、氧多元共渗试验;利用SEM对共渗层进行成分分析,并对渗层的硬度和力学性能进行测试。结果表明:灰口铸铁表面形成的渗层由钝化层和白亮层组成,厚约50μm。最外层钝化层中氧含量显著高于基体,且渗层中氮元素的含量明显提高,在试样表面形成了弥散分布的氮化物;灰口铸铁表面显微硬度显著提高,达到750 HV。

Using a kind of transforming device to realize that multielements entered into the furnace as gases, the experiment of multielement penetration of the low temperature gases N-C-O on the grey cast iron was carried out. The phase microstrncture and the composition of the modified layer were analyzed by SEM. The hardness and the mechanical property of the layer were tested. The results show that the modified layer is composed of the passivation layer and the bright layer and the thickness is about 50 μm. The relative content of element O in the passivation layer is more than that in the base, and there is such an outstanding increase of the element N in the layer that nitride dispersed on the surface of test sample. The microhardness on the grey cast iron outstandingly increases to 750 HV.