海洋平台用E550级钢板的试制开发

Development of Offshore Platform Steel Plate with Grade E550

通过分析钢的成分及性能要求,设计了低碳Nb、V、Ti微合金化成分,设计了两阶段轧制工艺,在高温区大压下量轧制,低温区大压缩比轧制,配合920℃淬火、630℃回火的调质处理工艺,开发了60 mm厚海洋平台用E550钢板。钢板厚度方向组织均匀,主要为板条状贝氏体,少量粒状贝氏体、铁素体及一定量的M/A;屈服强度>680 MPa,抗拉强度>740MP,-40℃低温冲击功在200 J以上,达到了船级社规范要求。

Chemical composition of E550 steel was designed with Nb、V、Ti micro alloying through theoretical analysis. Based on the E550’S thermodynamic properties, a two-stage rolling process was determined.In this process, high reduction rolling is used in high temperature and large compression ratio rolling is used in lower temperature. The quenching temperature was 920 ℃ and the tempering temperature was 630 ℃ . After tempering, the microstructure is lath Bainite and mixed with a small amount of grainy Bainite and Ferrite and M/A at 1/4 of the thickness. The structure of the plate was homogenized in the area from the place at 1/4 of the thickness to the center. The mechanical properties of the E550 steel plate （with 60 mm thickness） conform to the classification society standards and had a certain amount of surplus capacity.