Method of manufacturing non-magnetic Fe-Mn steels having low thermal expansion coefficients and high yield points

摘要

Low nonmagnetic steel having a thermal expansion coefficient of 1.0 DIFFERENCE 1.3x10-5/ DEG C. and a high yielding point of higher than 36 Kg/mm2 consists of less than 0.5% by weight of C, less than 2% by weight of Si, 20 DIFFERENCE 30% by weight of Mn, and 0.005 DIFFERENCE 0.04% by weight of N and the balance of iron and impurities, wherein the following relationships between the amounts of C and Mn are simultaneously satisfied. Mn(%)>16xC(%)+18 Mn(%)>-12xC(%)+21.5 The steel described above is heated to a temperature of less than 1220 DEG C., and then hot rolled. A finishing rolling temperature is maintained to be less than 800 DEG C.+400 DEG C.xC(%) depending upon the amount of carbon. After cold working the nonmagnetic steel has a permeability of less than 1.1.