| 摘要 |
PURPOSE:To advantageously obtain a titled steel which satisfies various requirements for a material for an outer rotor of a superconductive generator by specifying the range of C and V of a specifically composed high-Mn steel, the upper limit of N and O thereof and the range of precipitation heat treatment conditions for the V-C compd. thereof. CONSTITUTION:The steel contg., by weight, 0.2-0.6% C, 26-30% Mn, 6-8% Cr, 1.0-2.0% V, <0.02% N and <=0.005% O and consisting of the balance <=0.015% P, 0.010 S and other impurities to be unavoidably incorporated therein and Fe is prepd. Such steel is subjected a soln. heat treatment for 0.5-3hr at 1,050-1,100 deg.C then to a precipitation hardening treatment for 5-80hr at 625-675 deg.C. The high Mn-steel satisfying the performances required for the nonmagnetic material for which the extreme cold strength, good ductility as well as toughness, castability, machinability and weldability are required is thus obtd. at a low cost without using Al and REM, Ca, etc. |
