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为发展热轧棒材双相钢,本文就化学成份、终轧温度及轧后冷却工艺与铁素体——马氏体双相钢的组织形成和机械性能之间的关系进行探索。结果表明:对一般低合金和含碳量在0.15～0.35％的碳钢,终轧温度控制在Ar_3±30℃,轧后立即水冷或空冷几秒再水冷至Ms以下;若终轧温度控制在1000℃左右,轧后应立即水冷至Ar_3,并缓慢冷却数秒后再水冷至Ms以下均可获得双相组织和良好的综合机械性能。在Ar_3附近缓慢冷却,可迅速形成铁素体,使奥氏体、铁素体两相分离。钢中含碳量增加,强度上升塑性下降;而锰和硅在一定含量范围内,可增加强度而对塑性影响较小,最后对冷却装置进行讨论,并设计出适合实际生产使用的喷水冷却装置。
In order to develop dual-phase hot-rolled bar dual-phase steel, this paper explores the relationship between chemical composition, finishing temperature and post-rolling cooling process and microstructure and mechanical properties of ferritic-martensitic dual phase steel. The results show that for the low alloy and carbon steel containing 0.15-0.35% carbon, the finish rolling temperature is controlled at Ar 3 ± 30 ℃, water cooling or air cooling is performed immediately after the rolling, and then water cooled to below Ms. If the finishing temperature is controlled at 1000 ℃ or so, immediately after rolling water cooled to Ar_3, and slowly cooled a few seconds and then cooled to below Ms can get dual-phase organization and good overall mechanical properties. Slow cooling in the Ar_3 near, rapid formation of ferrite, austenite, ferrite two phase separation. The content of carbon in steel increases and the plasticity of plasticity decreases; while the content of manganese and silicon in a certain content can increase the strength and have little effect on plasticity. Finally, the cooling device is discussed and the water jet cooling suitable for practical production is designed Device.