| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive steel excellent in stress corrosion resistance, strength and toughness and also to provide a method of manufacture of this steel by using the existing stainless steel strip manufacturing line. SOLUTION: A 13%Cr ferritic stainless steel, having a chemical composition which contains, by weight, <=0.06% C and <=0.6% Ni and in which the value of Cr equivalent, represented by equation (Cr equivalent) = %Cr+1.5%Si+2.5% Al-80(%C+%N)-3%Ni-2%Mn, is regulated to 6.0-8.5, is subjected to a first hardening treatment, to cold rolling, to second hardening treatment, to cold working, and then to annealing treatment at 200 to 500 deg.C. By this procedure, a metallic structure, having 25 to 50%, by volume ratio, of ferritic phase in a matrix of martensitic phase and also having <=10μm average crystalline grain size, can be formed.
|
