METHOD FOR COOLING STEEL SHEET, COOLING SYSTEM FOR STEEL SHEET, AND METHOD FOR MANUFACTURING STEEL SHEET

• Main Author: SUGIHARA HIROKAZU
• Format: Patent
• Language: English; Japanese
• Published: 12.12.2019
• Subjects: CHEMISTRY; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS

To provide a cooling device for a steel sheet, a method for cooling a steel sheet and a method for manufacturing a steel sheet, in which cooling of a steel sheet is performed while causing the steel sheet to pass through a cooling zone of a continuous annealing line.SOLUTION: In the method for cooling a steel sheet used in a cooling zone of a continuous annealing line, after gentle cooling of an annealed steel sheet is started, the gentle cooling is stopped at a temperature higher than the martensitic transformation start temperature of the steel sheet. Then rapid cooling is started at a temperature equal to or higher than the martensitic transformation start temperature of the steel sheet. The rapid cooling is stopped at a temperature equal to or lower than the martensitic transformation end temperature of the steel sheet.SELECTED DRAWING: Figure 1 【課題】連続焼鈍ラインの冷却帯を通板しながら鋼板の冷却を行う、鋼板の冷却装置、鋼板の冷却方法、および鋼板の製造方法を提供する。【解決手段】連続焼鈍ラインの冷却帯で用いられる鋼板の冷却方法であって、焼鈍後の鋼板の緩冷却を開始し、鋼板のマルテンサイト変態開始温度より高い温度で緩冷却を停止した後、マルテンサイト変態開始温度以上の温度から急冷却を開始し、鋼板のマルテンサイト変態終了温度以下の温度で冷却を停止する制御を行う。【選択図】図１