80MnSiCrWAl钢的低温等温淬火组织及力学性能
Microstructure and Mechanical Properties of 80MnSiCrWAl Steel Austempered at Low-temperature
董汉雄1, 王天生2, 王青峰2, 董中波1
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作者单位：1. 武汉钢铁(集团)公司研究院, 湖北 武汉 430080; 2. 燕山大学 亚稳材料制备技术与科学国家重点实验室, 河北 秦皇岛 066004)
中文关键字：高碳钢； 等温淬火； 组织； 力学性能
英文关键字：high-carbon steel; austempering; microstructure; mechanical properties
中文摘要：用差示扫描量热法和热机械模拟试验机分别测定了80MnSiCrWAl钢的相变点Ac1、Accm和Ms。该钢试样加热到1000 ℃保温30 min奥氏体化后，在稍高于Ms温度的盐浴中进行等温淬火处理。采用光学显微镜、透射电镜和X射线衍射仪对处理后钢的组织和相组成进行研究，并测定硬度和冲击功。结果表明，该钢等温淬火后得到由板条状贝氏体铁素体和薄膜状残余奥氏体组成的无碳化物贝氏体组织。随等温淬火温度的升高，贝氏体铁素体板条厚度增大，残余奥氏体的体积分数减少，硬度和强度降低，冲击功略微减小。
英文摘要：Phase transformation points Ac1, Accm and Ms, of 80MnSiCrWAl steel were measured by differential scanning calorimeter and thermomechanical simulator. Samples of the steel were austempered at temperature slightly over Ms in salt bath after austenization at 1000 ℃ for 30 min. The microstructure and phase composition was investigated by optical microscopy, transmission electron microscopy and X-ray diffractometry. The hardness and impact energy was measured. The results show that the carbide-free bainite microstructure is composed of lath-like bainite ferrite and film-like retained austenite is obtained. As the austempering temperature increasing, the lath thickness of bainite ferrite increases; the retained austenite fraction and hardness decreases; the impact energy slightly decreases.