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利用光学电镜、SEM和Formaster-FⅡ相变仪,研究800 MPa高强钢在连续冷却过程中的组织和性能变化。结果表明,由于钢中含有较高的Mn和Cr,因此能够在较低的冷却速度下发生马氏体转变,当冷却速度超过80.0℃/s时,钢中主要组织为马氏体;经过退火处理后,试验钢的抗拉强度达到800 MPa以上,且随退火温度的升高试验钢抗拉强度增大,伸长率先增大后减小;当退火温度为780℃时,试验钢伸长率、屈服强度、抗拉强度均达到最好。
The microstructures and properties of 800 MPa high strength steel during continuous cooling were studied by means of optical microscope, SEM and Formaster-FⅡ phase-change instrument. The results show that martensitic transformation can occur at a lower cooling rate due to the higher Mn and Cr content in the steel. When the cooling rate exceeds 80.0 ° C / s, the main structure in the steel is martensite. After annealing After treatment, the tensile strength of the test steel reaches more than 800 MPa. With the increase of annealing temperature, the tensile strength of the test steel increases and the elongation increases first and then decreases. When the annealing temperature is 780 ° C, the elongation of the test steel increases Rate, yield strength, tensile strength have reached the best.