Effects of Grain Size on Carbon Diffusion in an Ultra-Low Carbon Steel for Hot Press Forming

摘要

Carbon diffusion of ultra low carbon steel treated at 880°C and 930°C for 10, 30, 60 and 120 minutes was investigated using optical microscopy, SAM, EPMA, and Micro Vickers. The martensite patterns of the specimens treated at 880 °C and 930 °C were different. Martensite in the ferrite region was found in the specimen treated at 880 °C because of grain boundary diffusion. Such phenomena is explained by a carbon diffusion model.