Microstructure and heat treatment effect on transformation strain in steels: Part1 experiment

Anisotropic strain is observed during phase transformation even though no external stress is applied when band structure is formed. The anisotropic strain can result in a change in shape and dimension or residual stress after heat treatment process and thus it achieved much attention. In this paper, three steel grades with different carbon content were prepared to explore the effect of carbon amount and resulting pearlite band thickness as well as heat treatment condition on anisotropic dilatation behaviour during phase transformation. Steel grades containing 0.05 and 0.15 wt-% carbon exhibit a pronounced anisotropy during reverse transformation, whereas 0.44 wt-% carbon shows more isotropic transformation strain. During cooling, transformation strain is anisotropic but less pronounced than that during heating.