稀土软氮化工艺及应用的研究

Investigation on the Processes of RE-Carbonitriding and it's Application

研究了渗剂成分、共渗温度和时间对稀土软氮化渗层厚度、表面硬度及其分布的影响。结果表明，稀土的加入能明显加快共渗速度，缩短共渗时间；能提高渗层，特别是扩散层的硬度，使硬度梯度下降；渗层组织致密，过渡层中的碳化物和氮化物细小、弥散。生产应用效果表明，利用该工艺可改善模具的热疲劳性和耐冲蚀性，使铝合金压铸模使用寿命提高３倍以上。最佳工艺为５６０℃×４ｈ。

The effect of ingredient,temperature and time on the case depth,surface hardness and it's distributionwas investigated. Research shown that rare earth can faciliate the carbonitriding rate greatly,and increase case hardness,espically that of the diffusion layer,thus decrease hardness gradient,The structure is consistent,carbid and nitridate in diffusion layer are dispersed. Production experiment shown that RE-carbonitriding can improve the heatfatiuge Performeance,corrosion-and abrasion-resistance,prolong the life span of the die casting die for aluminumalloy by three times. The best processes is 560℃×4 h.