Patent ID: 7776162

Claim:
A steel prepared by casting liquid steel deoxidized with Al, including one or more rare-earth metals (REMs) selected from the group of Ce, La, Pr and Nd, characterized by, the steel containing alumina clusters and consisting essentially of C of 0.0005 to 1.5 mass %, Si of 0.005 to 1.2 mass %, Mn of 0.05 to 3.0 mass %, P of 0.001 to 0.1 mass %, S of 0.0001 to 0.05 mass %, Al of 0.005 to 1.5 mass %, and total oxygen T.O. of less than 80 ppm, with the remainder iron and unavoidable impurities, where the alumina clusters are oxide-based inclusions consisting essentially of alumina and REM-oxide, the inclusions containing Al 2 O 3 of not less than 78.6 mass % and REM-oxide of not less than 0.5 mass % and not more than 15 mass %, where the mass ratio of total REM to total oxygen REM/T.O. is not less than 0.05 and not more than 0.5, where total REM is not less than 0.1 ppm and less than 10 ppm and dissolved REM is less than 1 ppm.