In this paper, the stability of low-temperature-gaseous-carburization (LTGC) layer in AISI316L stainless steel was investigated by exposing at temperature between 100 ℃ to 400 ℃ from 150 h to 3000 h in air. Test results show that, after carburization, a carburized layer with high carbon content, hardness and huge compressive residual stress form on the surface of 316L. The carburized layer is phase stable at the temperature not exceeding 400 ℃ that there are no undesired Cr carbides (such as M₂₃C₆) precipitate after heat exposure for 3000 h. The carburized layer thickness and hardness is basically stable at the temperature not exceeding 300 ℃. While for the stability of beneficial huge surface compressive residual stress, the highest service temperature should not exceed 200 ℃. Test results also showed that thickness reduction of carburized layer due to oxidation is also an important factor that affecting the stability of carburized layer. Because of high carbon atmosphere in the carburizing progress, a soot layer also forms on the surface of carburized layer and carbon atoms in the soot layer will diffuse in the carburized layer in the early stage of heat exposure progress.

本文通过将AISI316L不锈钢中的低温气态渗碳（LTGC）层在150到3000 h的空气中暴露于100℃至400℃的温度下，研究其稳定性。试验结果表明，渗碳后，在316L的表面上形成了碳含量高，硬度高和巨大残余压应力的渗碳层。渗碳层在不超过400℃的温度下是相稳定的，没有不希望的Cr碳化物（例如M ₂₃ C ₆）暴露3000小时后沉淀。渗碳层厚度和硬度在不超过300℃的温度下基本稳定。为了获得有益的巨大表面压缩残余应力的稳定性，最高使用温度不应超过200℃。试验结果还表明，氧化引起的渗碳层厚度减小也是影响渗碳层稳定性的重要因素。由于渗碳过程中的碳气氛高，因此在渗碳层的表面上也会形成烟灰层，并且在热暴露过程的早期，烟灰层中的碳原子会在渗碳层中扩散。