12Cr2Ni4A钢高温真空低压脉冲渗碳工艺

与传统气氛渗碳相比，高温真空渗碳在提高渗碳效率、产品质量和节约能源方面均表现出明显优势.本文分析了12Cr2Ni4A钢的奥氏体晶粒长大行为、扩散系数及奥氏体饱和碳质量分数等关键参数的影响，结合真空低压脉冲渗碳工艺原理，对高温真空低压脉冲渗碳工艺进行实验验证.结果表明:实验钢在930，950，980℃渗碳温度下，渗碳层的硬度梯度曲线和碳质量分数梯度曲线的实测值与预期值吻合较好.此外，随着渗碳温度的升高，碳的扩散系数和奥氏体饱和碳质量分数增加，高温真空渗碳可显著提高渗碳速率，温度每提高10℃约使渗碳效率提高14%~17%.

High Temperature Vacuum Low-Pressure Pulse Carburizing Process of 12Cr2Ni4A Steel

Compared with traditional atmosphere carburizing， the high temperature vacuum carburizing has great advantages in improving carburizing efficiency， product quality and saving energy. The critical parameters of austenite grain growth behavior， diffusion coefficient， and saturation carbon concentration of austenite in 12Cr2Ni4A steel were investigated in this work. Combined with the principle of vacuum low-pressure pulse carburization， the high temperature vacuum low-pressure pulse carburizing process was verified experimentally and the parameters of carburized layer depth and surface carbon concentration were further specified. The results show that under carburizing temperatures of 930， 950 and 980℃， the measured values from the hardness gradient curve and carbon concentration gradient curve of the carburized layer are in good agreement with the expected ones. In additional， the carbon diffusion coefficient and austenite saturation carbon concentration increases with the carburizing temperature， and the carburizing efficiency is increased by 14%~17% when the temperature is increased by every 10℃.