TMCP工艺对Si—Mn系贝氏体钢组织与性能的影响  

Effect of TMCP on the microstructure and mechanical properties of Si-Mn series bainitic steel

作　　者：李明保[1] 胡水平[1] 

机构地区：[1]北京科技大学冶金工程研究院,北京100083

出　　处：《工程科学学报》2016年第8期1115-1122,共8页Chinese Journal of Engineering

基　　金：国家自然科学基金资助项目(51274036)

摘　　要：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 thermomechanical control processes （TMCP） including medium temperature slow cooling and medium temperature isothermal treatment after roiling on the microstructure and mechanical properties of Si-Mn series bainitic steel were investigated in this paper. The mechanical properties of the steel were studied by a tensile testing machine, the microstruc- ture was characterized by means of scanning electron microscopy and electron backscatter diffraction, and the amount of retained austenite in the steel was determined by X-ray diffraction analysis. The results show that, as the starting slow cooling temperature after rolling rises, the tensile strength, hardness and tensile strain hardening exponent n increase, the elongation rate and the impact tough- ness decrease, and the yield-strength ratio decreases first and then increases. When the isothermal time after rolling extends, the tensile strength and the yield- strength ratio of the steel first decrease and then increase, but the elongation and the impact toughness have a reverse trend. Compared with the isothermal regime, the continuous slow cooling can get better comprehensive mechanical prop- erties, the product of tensile strength and elongation is higher, and the elongation is 20% higher than that of the former.

关 键 词：贝氏体钢 热机械处理 显微组织 力学性能 

分 类 号：TG142.1[一般工业技术—材料科学与工程]