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.
At the time when element powder or alloy powder and Y2O3 powder 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 Ac3 transformation 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% Y2O3, and the balance Fe with inevitable impurities, and in which Y2O3 particles are dispersed, by adding Fe2O3 powder 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.
UKAI SHIGEHARU
MINAFUJI TAKEJI
FUJIWARA MASAYUKI
KOBELCO KAKEN KK