Patent ID: 6358336
Filing Date: 2002-03-19
Classification: C21D,C22C

Abstract:
A Crâ€”Mo alloy steel consisting essentially of, on a mass % basis,C: 0.01-0.25%,Si: 0.01-0.7%Mn: 0.01-1%,P: 0.03% or less,S: 0.015% or less,Cr: 0.1-3%,Nb: 0.005-0.2%,Mo: 0.01-2.5%,Ca: 0.0001-0.01%,N: 0.0005-0.01%,B: 0.0001-0.01%,with the balance being Fe and impurities, andwhich satisfies the following expression:0.1 < Nb + Moâ€ƒwherein each element symbol denotes content thereof (mass %), wherein MX complex precipitates are formed inside microcrystalline grains of the steel, the M in the MX complex precipitates representing the above metallic elements, the X in the MX complex precipitates representing C and N, and the total amount of Mo in the MX complex precipitates is 30 mass % or more, and the total amount of Nb in the MX complex precipitates is 7 mass % or more.