【摘要】 以NM400级别贝氏体/马氏体双相耐磨钢为研究对象,利用热模拟实验、金相组织及硬度检测等方法,研究了实验钢种在变形后不同冷却速度下显微组织及硬度的演变规律,并绘制了动态连续冷却转变(CCT)曲线。结果表明,设计的贝氏体/马氏体双相耐磨钢具有良好的淬透性。连续冷却过程中,冷却速度介于0.1～1℃/s时,显微组织中出现了先共析铁素体相;随着冷却速度的增加,先共析铁素体逐渐减少;当冷却速度为1～10℃/s时,显微组织以贝氏体为主;冷却速度> 20℃/s后,显微组织基本为马氏体。随着冷却速度的增加,试样硬度值呈升高趋势,但后期硬度值变化不大。综合考虑,生产中为了得到以贝氏体组织为主的双相耐磨钢,轧制后冷却速度应控制在2～10℃/s。本研究结果可以为贝氏体/马氏体双相耐磨钢轧后冷却工艺的制定提供参考。更多还原

【Abstract】 Taking NM400 bainite/martensite dual phase w ear-resistant steel as the research object,the evolution law of microstructure and hardness of the experimental steel under different cooling rates after deformation is studied by means of thermal simulation experiment,metallographic structure and hardness detection,and the dynamic continuous cooling transformation( CCT) curve is draw n. The results show that the designed bainite/martensite dual phase w ear resistant steel has good hardenability. In the continuous cooling process,w hen the cooling rate is betw een 0. 1 ～ 1 ℃/s,the proeutectoid ferrite phase appears in the microstructure; w ith the increasing of cooling rate,the proeutectoid ferrite decreases gradually; w hen the cooling rate is 1 ～ 10 ℃/s,the microstructure is mainly bainite; w hen the cooling rate is more than 20 ℃/s,the microstructure is basically martensite. With the increasing of cooling rate,the hardness value of the sample increases w hile the hardness value changes little in the later stage. In order to obtain dual phase w ear-resistant steel dominated by bainite structure in production,the cooling rate after rolling should be controlled at 2 ～10 ℃/s. The results of this study can provide a reference for the formulation of post rolling cooling process of bainite/martensite dual phase w ear-resistant steel.更多还原