390 MPa级大线能量焊接海洋平台用钢板研发

Research and Development of 390 MPa Grade Steel Plate for Offshore Platform with Large Heat Input Welding

采用低C、高Mn、Nb-Ti微合金化的成分体系,冶炼时采取合理的合金加入顺序,并采用控轧控冷工艺,获得了一种390 MPa级的海洋平台用试验钢。试验结果表明:试验钢的上屈服强度为488 MPa,抗拉强度为550 MPa,断后伸长率为30%,-20℃纵向冲击功为242 J,横向冲击功155 J;显微组织为细小的铁素体和珠光体,夹杂物细小,尺寸为2~3μm;试验钢进行焊接线能量为100 kJ/cm的焊接热模拟试验后,力学性能检测及金相组织具备了大线能量焊接用钢的基本特征,验证了产品具有良好的低温冲击韧性及焊接性能。

In this paper,the 390 MPa grade test steel for offshore platform is obtained with the component system of low C,high Mn and Nb-Ti microalloying and reasonable adding sequence of alloys during smelting as well as the controlled rolling and controlled cooling process.The test results showed that the upper yield strength was 488 MPa,tensile strength was 550 MPa,elongation after fracture was 30%,longitudinal and transverse impact energies at-20℃were 242 J and 155 J;the microstructure was fine ferrite and pearlite as well as the inclusions were fine and with the size of 2~3μm;after the welding thermal simulation test with welding heat input of 100 kJ/cm for test steel,the mechanical property test and metallographic structure were with the basic characteristics of steel with large heat input welding as well as the products are verified to be with good low-temperature impact toughness and welding performances.