| 摘要 |
PURPOSE:To enable production of a high-Mn nonmagnetic cold-rolled steel sheet under a stable condition, by properly controlling the chemical components, cold- rolling condition and annealing condition of a high-Mn nonmagnetic steel to properly control precipitation of carbides at grain boundaries. CONSTITUTION:When a hot-rolled steel sheet containing 0.80-1.10% C, 13.00- 17.00% Mn and 0.20-0.60% Si is cold-rolled, the steel sheet is formed into a state having a desired thickness by one or more repetition of cold-rolling with a reduction of 60% or less by one stage and annealing under a cooling speed condition represented by the formula. In this case, the steel sheet shall be annealed under the heating condition of (900-1,050 deg.C)X(0.5-2.0min) to obtain a sufficient softening effect. According to this method, the cold-rolled sheet of a high-Mn nonmagnetic steel, which has been considered as a difficult one, can be produced with excellent productivity. Moreover, the cold-rolled steel sheet is excellent in workability and work-hardenability. |
