wear resistance of b is better than that of a since the desired wear resistance is not attained by a strain induced content of less than 60 its weight percentage is specified to be 60 or more a preferred amount of the strain induced martensite is 70 or more the strain induced martensite herein indicates that a complete austenitic structure is once formed and is then subjected to working to induce the martensitic transformation in order to convert the gamma phase to an alpha phase the complete austenitic structure means that the essential elements of the present invention i e fe cr and ni form an austenitic matrix and further the impurities are present in the form of minority phases such as carbides and sulfides the minority phases should be present in such a trace amount that the presence exerts an influence upon the measured valued of the strain induced martensite only within a range of measurement error the amount of strain induced martensite is obtained by applying external density with an intensity of 199000 a m i e 2 5 koe to an fe cr ni alloy measuring the magnetic flux density b t multiplying the magnetic flux density with 100 i e the result and dividing 100b by 1 6 t.