| 摘要 |
PROBLEM TO BE SOLVED: To improve strength as well as to obtain good twisting property by adding elements with a specified composition by an appropriate quantity, giving a strain with cold working, etc., and allowing it to generate strain induced transformation to an austenitic phase as a base phase. SOLUTION: An alloy, which has a composition consisting of 30-45% Ni, 6-20% Co, 0.1-5.0% Al, 0.1-5.0% Ti, preferably satisfies a relationship between Al and Ti 1.5%<=(Al+Ti)<=5.0%, and a relationship among Ni, Co, Al 15%<=Ni-Co-2×(Al+Ti)<=23%, and further, if necessary, contains <=5% in total of one or two or more kinds among Mo, W, V, B, Si, Mn, Cr, Cu, Mg and the balance Fe with inevitable impurities, is subjected to aging treatment at a temp. of 630-750 deg.C for 40-50 hr, and then martensite is produced by cold working at a working rate of about 50-95%.
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