1000 MPa级低碳高强钢的组织转变与性能研究

Study on Microstructure Transformation and Properties of 1 000 MPa Grade Low Carbon High Strength Steel

利用膨胀仪测定1000MPa级低碳高强钢临界点及CCT曲线,研究不同冷速对试验钢显微组织的影响。结果表明:在0.5~1℃/s冷速范围内,试验钢得到单一粒状贝氏体组织;在2~15℃/s冷速范围内,得到粒状贝氏体、板条贝氏体和马氏体的混合组织;在20~80℃/s的冷却速度范围内,得到板条贝氏体和马氏体的混合组织。以测定CCT曲线为参考依据制定调质工艺,试验钢经过调质后获得优异的综合力学性能。

By determining the critical point and CCT curve of 1 000 MPa grade low carbon high strength steel with dilatometer,the effect of different cooling rates on microstructure is studied.The results show that single granular bainite of the test steel is obtained at a cooling rate range between 0.5 and 1 C/s,mixed structure of granular bainite,lath bainite and martensite is obtained at a cooling rate range between 2 and 15 C/s,mixed structure of lath bainite and martensite is obtained at a cooling rate range between 20 and 80 C/s.Quenching process is established in accordance with the determined CCT curve,Excellent comprehensive mechanical properties of the test steel is attained after quenching and tempering.