控冷返红温度对Q460GJE高建钢组织和力学性能的影响

利用Gleeble热力学模拟机、扫描电镜、透射电镜、着色腐蚀金相等方法研究了控冷返红温度对TMCP交货态低屈强比(不大于0.80)Q460GJE高建钢组织和力学性能的影响。结果表明:随着返红温度的升高,一方面,粒状贝氏体数量减少,针状铁素体数量增加,晶粒显著粗化,屈服强度降低;另一方面,硬相M-A岛的数量增多、尺寸增大,抗拉强度略有上升,屈强比和冲击功(-40℃)降低。拉伸和冲击性能均满足低屈强比Q460GJE钢要求的返红温度范围是590~620℃。

Effect of Self-Tempering Temperature on Microstructure and Mechanical Properties of a Q460E-Class Steel for High-Rise Building

The effect of self-tempering temperature on microstructure and mechanical properties of Q460E-class building steel under TMCP delivery was investigated using Gleeble thermo-mechanical simulator, SEM, TEM and coloring metallography. The results indicate that with the self-tempering temperature increasing from 530 to 650??, the amount of acicular ferrite increases??the amount of granular bainite decreases and grain coarsens, leading to the reduction of the yield strength. On the other hand, the M-A constituents become larger and their amount increases significantly, resulting in the increase of tensile strength and the decrease of both yield ratio and impact toughness (-40??). The optimum self-tempering temperature satisfying the mechanical property requirements for low yield ratio Q460E-class building steel is 590-620??.