PURPOSE: To provide the title steel with superior thermal fatigue resistance and high temp. wear resistance by adding a specified amt. of Nb to an alloy steel contg. Ni, Cr, Mo, V, etc.
CONSTITUTION: A steel of the following compsn. is used as a material for various rolls for rolling a high temp. continuous-cast ingot in continuous casting facilities: the steel contains C 0.05W0.020%, Si 0.10W1.5%, Mn 0.10W1.5%, Ni 0.20W 3.0%, Cr 7W12%, Mo 0.10W2.0%, V 0.10W1.0% and Nb 0.03W1.0% or further contains one or more out of Ti 0.05W0.50%, Zr 0.01W0.30%, Ta 0.01W0.50% and B<0.01%, The coexistence of Ni and Cr provides superior thermal fatigue resistance and high temp. wear resistance, and the addn. of Nb results in grain refining. The steel is suitable for use as a material for a support roll, a guide roll, a pinch roll, etc. to which a high temp. continuous-cast ingot contacts.
SAKAMOTO YOSHIAKI
ITOU YUKIO
