Surface Hardening of Medium Carbon Steels by Aluminization

摘要

Solid state surface aluminization of a medium carbon steel for roll applications is investigated. The processing temperatures range between 500 deg C and 700 deg C, and the diffusion time varies from 2 to 6 hours. The structures, phases, and mechanical properties of the coating layers are studied. The thickness of the coating layers are formed in the range of 20~90um. The activation energy for growth of coating layer is approximately 30.1 KJ/mole. The coating layer consists of two major phases. The Fe_2Al_5 phase is formed on the surface, while a solid solution with Fe_3Al structure is formed at the interface between surface Fe_2Al_5 layer and the substrate. The coating's hardness is as high as Hv826 while keeping the substrate hardness at relatively high level.