Patent ID: 7037464
Filing Date: 2006-05-02
Classification: C21D,C22C

Abstract:
1. A method of manufacturing an oxide dispersion strengthened martensitic steel excellent in high-temperature strength, said method comprising mixing either element powders or alloy powders and a Y subjecting the resulting powder mixture to mechanical alloying treatment in an Ar atmosphere, subjecting the resulting alloyed powder to hot extrusion to solidify the alloyed powder, and subjecting the resulting solidified material to final heat treatment involving normalizing and tempering to manufacture an oxide dispersion strengthened martensitic steel which comprises, as expressed by % 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 wherein the oxide particles are finely dispersed and highly densified by adjusting the Ti content within the range of 0.1 to 1.0% so that an excess oxygen content Ex.O in the steel satisfies 0.22×Ti (% by weight)<Ex.O (% by weight)<0.46×Ti (% by weight), and the excess oxygen content Ex.O being a value obtained by subtracting an oxygen content in Y