热轧组织对高强度冷轧TRIP钢力学性能的影响

采用扫描电镜、X射线衍射、拉伸试验等方法研究了热轧组织对含Al冷轧TRIP钢热处理后组织与力学性能的影响.通过不同轧后冷却方式得到三种不同的热轧组织:组织细小的F+P+B试样;F+B试样;F+P试样.热轧组织细小的试样热处理后含有较多的粒状贝氏体和较少的残余奥氏体组织,强度最高达到996MPa,延伸率为20.8%.另两种试样组织为多边形铁素体、粒状贝氏体以及较多的残余奥氏体组织.F+B试样延伸率可达29.4%,强塑积为26 812.8 MPa·%.F+P试样热处理后带状组织的危害不易消除.

Effect of Hot Rolled Microstructure on Mechanical Properties of High Strength Cold Rolled TRIP Steel

The effect of hot rolled microstructure on the final microstructure and mechanical properties of the cold rolled TRIP steel containing Al was investigated by means of scanning electron microscope (SEM)， X-ray-diffraction (XRD) and tensile test. Three different kinds of microstructure， fine grains F+B+P， F+P and F+B， were obtained under different cooling processes. After heat treatment， the fine grains sample contained granular bainite and a few retained austenite. The tensile strength of the sample was 996 MPa and the elongation was 20.8%. The microstructure of other two samples was polygonal ferrite， granular bainite and some retained austenite. The elongation reached up to 29.4% and the strength-ductility balance of 26812.8MPa·% were obtained for F+B sample. The band structure of F+P sample was hard to eliminate after heat treating， which was harmful to final mechanical properties.