METHOD FOR PRODUCING FERRITIC OXIDE DISPERSION STRENGTHENED STEEL HAVING COARSE CRYSTAL GRAIN STRUCTURE AND HAVING EXCELLENT HIGH TEMPERATURE CREEP STRENGTH

摘要

PPROBLEM TO BE SOLVED: To provide a method for producing a Ti-containing ferritic oxide dispersion strengthened steel having a coarsened, equi-axed crystal grain structure effective for improving high temperature creep strength. PSOLUTION: At the time when element powder or alloy powder and YSB2/SBOSB3/SBpowder are mixed, and the powdery mixture is subjected to mechanical alloying treatment, is solidified by hot extrusion, and is thereafter subjected to holding under heating to an AcSB3/SBtransformation point or higher and the subsequent annealing heat treatment at a ferrite forming critical rate or lower as final heat treatment, so as to produce a ferritic oxide dispersion strengthened steel containing, by mass, 0.05 to 0.25% C, 8.0 to 12.0% Cr, 0.1 to 4.0% W, 0.1 to 1.0% Ti and 0.1 to 0.5% YSB2/SBOSB3/SB, and the balance Fe with inevitable impurities, and in which YSB2/SBOSB3/SBparticles are dispersed, by adding FeSB2/SBOSB3/SBpowder to the raw material to be mixed by the mechanical alloying treatment, the bond of Ti and C is suppressed, thus the reduction of the C concentration in the matrix is prevented. PCOPYRIGHT: (C)2006,JPO&NCIPI