| 摘要 |
PURPOSE:To maintain excellent strength and toughness at an ultra-low temp. as well in producing a nonmagnetic steel plate of high Mn austenitic stainless steel by subjecting the steel to a heat treatment under specific conditions. CONSTITUTION:A nonmagnetic steel material of a high Mn austenitic stainless steel contg. 0.01-0.20% C, 0.01-2.0% Si, 10-30% Mn, 0.01-10.0% Ni, 12-20% Cr and 0.01-0.30% N, satisfying the formula 0.20%<=C+N<=0.40% or contg. further 1 or >=2 kinds among Cn, Mo, W, Nb, V, Ti, Al, Ca, Cl and Zr at 0.01- 3% in total in the case of Cu, Mo and W, 0.01-1.0% in total in the case of Nb, V, Ti and Al or 0.001-0.10 in total in the case of Ca, Cl and Zr as a structural material for supporting a superconductive magnet used in a cryogenic temp. such as liquid He or the like is held for 1-60min at 800 deg.C or is quickly cooled down to a temp. region of <=500 deg.C after air cooling upon ending of hot rolling at 950 deg.C. |
