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研究了轧后中温缓慢冷却与中温等温两种不同的热机械控制工艺(thermomechanical control process,TMCP)对硅锰系贝氏体钢的组织与性能的影响.通过拉伸试验机测试试验钢的力学性能,利用扫描电子显微镜、电子背散射衍射等分析手段对试验钢进行显微组织结构分析,并利用X射线衍射测定残余奥氏体含量.结果表明:随着轧后连续缓慢冷却开始温度的升高,贝氏体钢的抗拉强度、硬度及拉伸应变硬化指数n值有所提高,伸长率和冲击韧性降低,屈强比先降低后升高.随着轧后等温时间的延长,贝氏体钢的抗拉强度与屈强比先降低后升高,伸长率及冲击韧性先升高后降低.相对于等温制度,连续缓慢冷却可得到更好的综合力学性能,强塑积明显高于前者,伸长率比前者高20%以上.
The effects of two different thermo-mechanical control processes (TMCP), ie slow cooling at medium temperature and intermediate temperature on the microstructure and properties of Si-Mn bainitic steels, were studied.Tensile testing machine was used to test the mechanical properties of test steel The microstructure and structure of the test steel were analyzed by scanning electron microscopy (SEM) and electron backscatter diffraction (XRD), and the residual austenite content was determined by X-ray diffraction.The results show that with the continuous slow cooling High, bainitic steel tensile strength, hardness and tensile strain hardening index n value increased, elongation and impact toughness decreased, yield ratio first decreased and then increased with the extension of the isothermal rolling time, The tensile strength and yield ratio of bainitic steels decrease first and then increase, while the elongation and impact toughness increase firstly and then decrease.Compared with isothermal system, continuous slow cooling can obtain better comprehensive mechanical properties, Obviously higher than the former, elongation more than 20% higher than the former.