한국주조공학회

A new approach of producing martensitic structure for guide-roll materials was developed using centrifugal casting instead of classic overlay welding process. Centrifugal casting offered a simpler process, fewer defects and even microstructures. Especially in terms of thermal fatigue cracking which usually occurs in the HAZ of welding beads of used continuous caster guide roll materials made by overlay welding process. A typical tensile strength of 1,600 MPa was obtained by this process and was higher than typical tensile strength(800~1,200 MPa) with overlay welding technique. Tempering at 400~550oC for 2 hrs was observed to have significant precipitate hardening effect which increases strength and elongation. Nitrogen content from the Cr-N input in the casting process was found to have positive contribution to decrease the volume fraction of δ-ferrite which directly corresponds to increasing strength of the roll materials.

Continuous casting roll, Roll hardfacing, Centrifugal casting, Martensitic stainless steel, Tempering.