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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。
The phase transition points Ac1, Accm and Ms of 80MnSiCrWAl steel were measured by differential scanning calorimetry and thermomechanical simulator. The steel sample heated to 1000 ℃ austenitizing 30 min after holding, in a slightly higher than Ms temperature salt bath isothermal quenching. The microstructure and phase composition of treated steel were studied by optical microscope, transmission electron microscope and X-ray diffraction. The hardness and impact energy were measured. The results show that the austempering of the steel obtained by the lath bainitic ferrite and film-like retained austenite carbide-free bainite. With the increase of isothermal quenching temperature, the thickness of bainitic ferrite lath increases, the volume fraction of retained austenite decreases, the hardness and strength decrease, and the impact energy decreases slightly.