控轧控冷工艺对X80级抗大变形管线钢组织与性能的影响

Effects of thermo-mechanical control process on microstructure and mechanical properties of X80 grade high-strain line pipe steel

对试制的X80级抗大变形管线钢不同开始冷却温度下的力学性能进行了测试,并通过扫描电镜分析了不同开始冷却温度下钢板最终组织及形态,研究了控轧控冷工艺对X80级抗大变形管线钢组织与性能的影响。结果表明,随着钢板开始冷却温度的降低,X80级管线钢中的先共析铁素体量逐渐增加,贝氏体含量逐渐降低,钢板抗大变形性能参数提高。当开始冷却温度在740℃时,钢板具有最佳的综合力学性能,其屈服强度Rt0.5为565MPa,抗拉强度Rm为730MPa,伸长率A为42.7%,屈强比Rt0.5/Rm为0.75,Rt1.5/Rt0.5为1.181,Rt2.0/Rt1.0为1.116,均匀变形伸长率达到12.33%,具有较强的抗变形能力。

Mechanical properties of X80 grade high-strain pipeline steels at different initial cooling temperatures were tested,the final microstructure and morphology of the steel plates at different initial cooling temperatures were analyzed by SEM,and effects of the controlled rolling and cooling process on microstructure and mechanical properties of X80 steel were studied.The results show that with the decrease of initial cooling temperatures,the proeutectic ferrite in X80 grade pipe line steel gradually increases,the bainite gradually decrease and parameters of strain improved.At the initial cooling temperature of 740 ℃,the plate has the best mechanical properties,the yield strength Rt0.5 is 565 MPa,tensile strength Rm is 730 MPa,elongation rate of A is 42.7%,and the yield ratio Rt0.5/Rm is 0.75,Rt1.5/Rt0.5 is 1.181,Rt2.0/Rt1.0 is 1.116,uniform deformation elongation rate is 12.33%,the resistance to deformation is improved.