| 摘要 |
PURPOSE:To assure prescribed characteristics without an annealing treatment and to reduce cost by subjecting a high-Cr ferritic steel contg. specific compsn. ratios of C, Cr, Mo, and W to specific final hot working, thereby forming a mixed structure composed of ferrite and carbide. CONSTITUTION:The high-Cr ferritic steel which contains 0.003-0.3wt.% C and 4-13% Cr and is further added with 1 or 2 kinds of Mo and W at 0.1-4% Mo+W is heated and held for >=1 minutes at 900-1300 deg.C, more preferably >=Ac3 point to solutionize the deposit, to uniformize segregation and to uniformize the nonuniformly worked structure at the time of subjecting the above-mentioned steel to final hot working. After the above mentioned steel is subjected to the final hot working, the steel is slowly cooled at a rate of <=200 deg.C/hour or held for >=1 minutes at 500 deg.C-Ac1 point. The mixed structure composed of the ferrite and carbide is thereby formed, by which the need for the annealing treatment after the final hot working is eliminated and the rationalization of the stage and the reduction of the cost are attained. The soln. strengthened high-Cr ferritic heat resisting steel product is thus obtd. |
