金属粉化失效及其控制

Metal Dusting Failure and Its Control

金属粉化失效是指铁、镍基合金在高碳活度（ac〉1）气氛中由于渗碳导致其分解为石墨和金属颗粒而发生的灾难性破坏。综述了金属粉化失效的特征及机理，阐述了金属粉化失效的影响因素，并提出了相应的应对措施。结果表明：金属粉化失效一般发生在400-800℃，400℃以下便不再发生金属粉化失效；镍基合金的抗粉化失效能力明显优于铁基合金，足够的铬含量会在金属表面形成Cr2O3保护层，提高合金的抗粉化失效能力；同时硅元素和铝元素的加入对于抑制金属粉化失效的发生十分有利；表面硬化处理和晶粒细化同样能够明显提高合金的抗粉化失效能力。

Metal dusting failure is a disintegration of Fe-base and Ni-base alloys to a dust of graphite and metal particles, occurring in carburizing atmospheres with ac 〉 1. An overview of the characteristics and mechanisms of metal dusting failure were undertaken. Influencing factors were expounded and corresponding protection measurements were propounded. The results show that metal dusting failure was mostly occurred at temperatures of 400-800℃, and there would no metal dusting failure happening below 400℃. The metal dusting failure resistance of Ni-base alloys was superior to that of Fe-base alloys. Protective Cr2O3, film would form with sufficient Cr content to enhance the metal dusting failure resistance. Si and Al elements were also beneficial to anti metal dusting failure. Surface hardening and grain fining could improve the metal dusting failure resistance too.