Prior austenite grains in steels laser surface alloyed with carbon

Prior austenite grain size is known to affect the hardness of martensite in conventional martensitic hardening of steels. These grains develop in solid state during austenitizing treatment. In the present study, however, it is pointed out that the prior austenite grains that form as a result of solidification in laser surface hardening of steels by alloying with carbon should have similar effects on the resultant martensite in the alloyed layer. A low alloy steel and a commercial pure iron have been laser surface alloyed with carbon to show the solidified austenite grains in the alloyed layer.