Although the cost of the heat treatment process is only a minor portion of the total production cost, it is arguably the most important and crucial stage on the determination of material
quality. In the study of the carbon diffusion in H13 steel during austenitization, a series of
heat treatment experiments had been conducted under different atmospheric conditions
and length of treatment. Four austenitization atmospheric conditions were studied, i.e., heat
treatment without atmospheric control, heat treatment with stainless steel foil wrapping,
pack carburization heat treatment and vacuum heat treatment. The results showed that
stainless steel foil wrapping could restrict decarburization process, resulting in a constant
hardness profile as vacuum heat treatment does. However, the tempering characteristic
between these two heat treatment methods is different. Results from the gas nitrided samples showed that the thickness and the hardness of the nitrided layer is independent of the
carbon content in H13 steel.