Abstract In order to develop 960MPa grade high strength steel, the effects of cooling rate and austenite deformation on the hardness and the microstructure of high strength steel has been studied by Scanning Electron microscope (SEM), Transmission Electron Microscope (TEM), Gleeble-3500 thermal simulation testing machine and T2500 Vickers hardness tester. The results show that only when the cooling rate was higher than 10∘C/s and the final cooling temperature was lower than 250∘C, the microstructure mainly consists of martensite, and the strength of high strength steel could be above 960MPa; and austenite deformation could effectively refine the width of martensite lath, thus improving the strength and toughness.

中文翻译：

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冷却速度和奥氏体变形对960MPa高强钢硬度和组织的影响

摘要 为开发 960MPa 级高强度钢，利用扫描电子显微镜 (SEM)、透射电子显微镜 (TEM)、Gleeble-3500 研究了冷却速度和奥氏体变形对高强度钢硬度和显微组织的影响。热模拟试验机和T2500维氏硬度计。结果表明，只有当冷却速度高于10∘C/s且终冷温度低于250∘C时，组织主要由马氏体组成，高强钢的强度才能达到960MPa以上；奥氏体变形能有效细化马氏体板条宽度，从而提高强度和韧性。