| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing oxide dispersion-strengthened martensitic steel having excellent high temperature strength wherein the proportion of residualα-grains in which oxide particles are finely dispersed in high density is increased without causingα→γtransformation during hot extrusion. SOLUTION: The oxide dispersion-strengthened martensitic steel can be manufactured by a method comprising the steps of: mixing either element powder or alloy powder and Y<SB>2</SB>O<SB>3</SB>powder; subjecting the resulting mixed powder to mechanical alloying treatment; solidifying the resulting alloyed powder by hot extrusion; and subjecting the resulting extruded solidified material to final heat treatment involving normalizing and tempering heat treatment. The obtained oxide dispersion strengthened martensitic steel comprises, by weight, 0.05 to 0.25% C, 8.0 to 12.0% Cr, 0.1 to 4.0% W, 0.1 to 1.0% Ti, 0.1 to 0.5% Y<SB>2</SB>O<SB>3</SB>and the balance being Fe and unavoidable impurities, and Y<SB>2</SB>O<SB>3</SB>particles are dispersed in the steel. The blending of the powdery materials is performed for the mechanical alloying treatment so that an excess oxygen content in the steel (a value obtained by subtracting the oxygen content in Y<SB>2</SB>O<SB>3</SB>from the oxygen content in steel) satisfies a specified value. COPYRIGHT: (C)2005,JPO&NCIPI
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