800MPa级水电用钢的微观组织和力学性能研究

INVESTIGATION OF MICROSTRUCTURES AND MECHANICAL PROPERTIES OF800 MPa GRADE HYDROELECTRIC STEEL

采用控轧控冷与调质工艺相结合的方法,开发了一种力学性能满足要求的800 MPa级高强度水电用钢,并利用组织观察和性能测试手段研究了该水电用钢的显微组织和力学性能。结果表明:经调质处理后,该水电用钢的显微组织为回火索氏体+回火马氏体,抗拉强度达880 MPa,断后延伸率为18.5%,40℃的冲击功为126 J。微观组织观察表明,该实验钢中碳化物在回火索氏体中分布均匀,在回火马氏体中主要分布在马氏体板条界处。

An 800 MPa grade hydroelectric steel has been developed which can meet the requirement for mechanical properties through controlled rolling and controlled cooling in combination with subsequent quenching and tempering. The microstructures and mechanical properties of this as- developed 800 MPa grade hydroelectric steel were investigated by means of microstructural observation and mechanical property measurement. The results show that the microstructure of this hydroelectric steel consists of tempered sorbite and tempered martensite after appropriate quenching and tempering treatment. The tensile strength of this steel reaches 880 MPa and the elongation is 18. 5%,while the impact energy at 40 ℃ is126 J. Microstructural observation indicates that the carbides are homogeneously distributed in tempered sorbite and located at the boundaries of lath martensite in tempered martensite.