| 摘要 |
PROBLEM TO BE SOLVED: To form the structure of a ferromagnetic part into a structure of ferrite and carbide and to improve corrosion resistance by forming a stock, having a specific composition consisting of C, Cr, Ni, N, Si, Mn, Al, and Fe, into a ferromagnetic material and then applying local heating and rapid cooling to a part of this ferromagnetic material to form a nonmagnetic part. SOLUTION: A stock having a composition consisting of, by weight, 0.30-0.80% C, >16.0-25.0% Cr, 0.1-4.0% Ni, 0.01-0.06% N, further <=2.0% of one or more elements among Si, Mn, and Al, and the balance Fe with inevitable impurities, is hot worked, annealed at a temperature not higher than the A3 transformation point, cold worked, annealed at a temperature not higher than the A3 transformation point so as to be formed into a ferromagnetic material. Subsequently, a part of this ferromagnetic material is locally heated to about 1050 to 1300 deg.C to undergo solution heat treatment and then cooled rapidly to undergo austenitizing, by which a non-magnetic part of <=2 magnetic permeability (μ) is formed. By this method, the composite magnetic member, which has a ferromagnetic part having >=200 maximum permeability (μmax) and 0.1-20 μm maximum diameter of carbide and composed of ferrite and carbide and excellent in corrosion resistance, can be obtained. |
