Method of manufacturing oxide dispersion strengthened martensitic steel excellent in high-temperature strength having residual alpha-grains

摘要

An oxide dispersion strengthened martensitic steel excellent in high-temperature strength having residual alpha-grains can be manufactured by a method comprising mixing either element powders or alloy powders and a Y₂O₃ 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 to thereby manufacture an oxide dispersion strengthened martensitic steel in which Y₂O₃ particles are dispersed in the steel, wherein alphato gammatransformation is not allowed to occur during the described hot extrusion and the proportion of residual alpha-grains in which oxide particles are finely dispersed in high density is increased by controlling the mixture ratio of the powders for the mechanical alloying treatment.