| 摘要 |
This steel material has a chemical composition containing, in terms of mass%, 0.050-0.40% C, 0.50-3.0% Si, 3.0-8.0% Mn, and 0.001-3.0% sol.Al and has a metallographic structure containing, in terms of vol%, 10-40% austenite, the austenite having an average C concentration of 0.30-0.60% in terms of mass% and the metallographic structure having a structure evenness, which is a value obtained by subtracting the minimum of measured Vickers hardness values from the maximum thereof, of 30 Hv or less. The steel material has a tensile strength of 900-1,800 MPa. |
