预抽真空可控气氛渗碳炉的工艺优化研究

Research on Process Optimization of Pre-vacuum-pumping Controlled Atmosphere Carburizing Furnace

建立渗碳过程中淬火前降温段不同的气氛组合,寻求预抽真空可控气氛渗碳炉(BBH)的热处理优化方案。采用硬度仪、光学显微镜对渗碳后试样进行分析。结果表明:在降温段使用氮气替代空气和甲醇,可以减轻试样的表面氧化程度,并且随着氮气用量的增加,试样的表面马氏体等级越高。当氮气和甲醇裂解气体比例控制在1:1.86时,试样的内氧化和非马氏体组织层深最浅。

The different atmosphere combinations during the cooling before quenching in the carburizing process were established,to find the heat treatment optimization scheme of pre-vacuum-pumping controlled atmosphere carburizing furnace(BBH).The samples after carburizing were studied by hardness tester and optical microscope.The results showed that the surface oxidation degree of sample could be reduced by using nitrogen instead of air and methanol during cooling,and the surface martensite grade of sample was higher with the increase of the amount of nitrogen.When the ratio of nitrogen to methanol decomposition gas was controlled at 1:1.86,the depth of internal oxidation and non-martensitic structure was the shallowest.