| 摘要 |
PURPOSE:To provide the titled high Mn nonmagnetic steel having superior ductility and toughness over a wide temp. range and low thermal expansion by adding a predetermined percentage each of C, Si, Mn, Cr, N and Al and specifying the content of C+N. CONSTITUTION:This high Mn nonmagnetic steel consists of <=0.2% C, <=1.5% Si, 17-31% Mn, <=12% Cr, <=0.025% N, 0.2-2% Al and the balance essentially Fe, satisfies C+N<=0.2%, and has a (gamma+epsilon) two-phase structure contg. 1-45vol% epsilon-phase. By especially adding Al and controlling the ratio of gamma-phase to epsilon-phase to the above-mentioned value, the steel has a remarkably lowered thermal expansion coefft. as compared with a conventional gamma-phase single phase high Mn steel. The steel is applicable to various kinds of products and structure requiring ductility, toughness and especially low thermal expansion in a low temp. region of room temp. or below. |
