18CrNiMo7-6齿轮钢真空渗碳工艺研究

在轨道交通重载机车主动齿轮生产工艺中引入真空渗碳油淬工艺。研究主动齿轮18CrNiMo7-6材料的真空渗碳工艺，并与该齿轮常用的传统可控气氛渗碳工艺进行对比，对热处理后试样的碳浓度、硬度、有效硬化层深度、金相组织等进行检测分析。结果表明:该主动齿轮真空渗碳比传统可控气氛渗碳节约18%的工艺时间，且真空渗碳后的组织无内氧化、非马氏体等不良组织，马氏体、碳化物等组织级别均符合该机车主动齿轮技术条件。

Study on Vacuum Carburizing Process of 18CrNiMo7-6 Gear Steel

The vacuum carburizing oil quenching process was employed in the production process of the driving gear of a heavy haul locomotive in rail transit. The vacuum carburizing process of 18CrNiMo7-6 material for driving gear was studied and compared with the conventional controlled atmosphere carburizing process. After the treatment, the carbon concentration, hardness, effective hardening depth and metallographic structure of the sample wereanalyzed. The vacuum carburizing process can save 18% of treatment time compared with the traditional controlled seven-minute carburizing process. There are no bad microstructure such as inner oxidation and non-martensite after vacuum carburizing. The grade of martensite and carbide meet the technical requirement of the locomotive driving gear.