退火工艺对780 MPa级复相钢组织与性能的影响

Effect of annealing process on microstructure and properties of 780 MPa complex phase steel

采用退火模拟器、拉伸试验机、光学显微镜和透射电镜等设备研究了连续退火工艺对780 MPa级复相钢组织性能的影响。结果表明,780 MPa级复相钢经连续退火后组织结构为铁素体、贝氏体加马氏体复相组织,同时在基体中含有大量Nb Ti碳氮化物析出相。随着退火温度升高,组织中的马氏体贝氏体含量逐渐增加,同时Nb Ti碳氮化物析出相数量逐渐降低;同时随着退火温度的升高,规定塑性延伸强度和抗拉强度逐渐增加,在810℃退火时达到最佳性能。

Effect of annealing process on microstructure and mechanical properties of 780 MPa complex phase（ CP780） steel was studied by means of annealing simulator,tensile tester,optical microscope and TEM. The results show that the microstructure of CP780 consists of ferrite,bainite and martensite after annealing progress,and a lot of Nb Ti precipitates homogeneously distributed in the ferrite base. The martensite and bainite increase with annealing temperature rises,while the number of precipitates gradually decreases,and at the same time,the proof strength,plastic extension and tensile strength increase,and the best properties can be obtained when annealed at 810 ℃.