A promising martensitic steel with good hardenability is studied. In the cooling rate range 0.1–30°C/sec and the only transformation recorded by a dilatometer starts at an Ms temperature of 355 ± 10°C. Microstructure and mechanical properties of the steel studied are analyzed after various heat treatment regimes: cooling from the austenitizing temperature at various rates (from 0.02 to 20°C/sec), austempering at 280–380°C, and oil quenching and tempering at 200–600°C. It is shown that a 1000-fold change in the cooling rate has a weak effect on steel strength. Bainitic transformation in the steel in question occurs in the martensitic transformation temperature range, which leads to a reduction in impact strength compared with a martensitic microstructure both after slow cooling and isothermal hardening.

中文翻译：

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马氏体高强工程钢的显微组织和力学性能

研究了一种具有良好淬透性的有前途的马氏体钢。在 0.1–30°C/sec 的冷却速率范围内，膨胀计记录的唯一转变始于 355 ± 10°C 的 Ms 温度。在各种热处理制度后分析所研究钢的显微组织和机械性能：以各种速率（从 0.02 到 20°C/秒）从奥氏体化温度冷却，在 280-380°C 的奥氏体回火，以及在 200 度的油淬和回火–600°C。结果表明，冷却速度的 1000 倍变化对钢强度的影响很小。所讨论的钢中的贝氏体转变发生在马氏体转变温度范围内，与马氏体微观结构相比，在缓慢冷却和等温硬化后，这导致冲击强度降低。