CAJ | 학술논문

为了开发Q500GJE高性能超高层建筑用钢，利用Gleeble热/力学模拟、扫描电镜、透射电镜、背散射电子衍射、着色腐蚀金相等方法研究了轧后控冷冷速对TMCP交货低屈强比（≤0.80）Q500GJE钢组织和拉伸性能的影响。结果表明：试验钢在冷速5~25℃/s的范围内，形成由针状铁素体、粒状贝氏体以及M-A岛构成的混合组织。随着轧后冷速的提高，针状铁素体数量减少，粒状贝氏体数量增多，晶粒发生细化，位错密度升高，屈服强度和抗拉强度升高；随着轧后冷速的适当降低，硬相 M-A岛的含量增加，尺寸增大，屈强比下降，应变硬化量增加。拉伸性能满足低屈强比Q500GJE钢要求的轧后控冷冷速是15~20℃/s。
위료개발Q500GJE고성능초고층건축용강，이용Gleeble열/역학모의、소묘전경、투사전경、배산사전자연사、착색부식금상등방법연구료알후공랭랭속대TMCP교화저굴강비（≤0.80）Q500GJE강조직화랍신성능적영향。결과표명：시험강재랭속5~25℃/s적범위내，형성유침상철소체、립상패씨체이급M-A도구성적혼합조직。수착알후랭속적제고，침상철소체수량감소，립상패씨체수량증다，정립발생세화，위착밀도승고，굴복강도화항랍강도승고；수착알후랭속적괄당강저，경상 M-A도적함량증가，척촌증대，굴강비하강，응변경화량증가。랍신성능만족저굴강비Q500GJE강요구적알후공랭랭속시15~20℃/s。
The effect of the post-roll cooling rate on the microstructure and tensile properties of a Q500E-class building steel under TMCP delivery is investigated using the Gleeble thermo-mechanical simulator together with SEM, TEM, EBSD and coloring met-allography. The results indicate that as the cooling rate increases from 5℃/s to 25℃/s, the amount of granular bainite increases at the expense of acicular ferrite, along with the grain refinement and increase of dislocation density, leading to the enhancement of the yield strength and the tensile strength. When decreasing the cooling rate moderately, the M-A constituents become larger and increase significantly in the amount, resulting to the decreased yield ratio and the increased strain hardening capacity. The op-timum cooling rate required for the tensile properties of the low yield ratio Q500E-class building steel is determined ranging from 15℃/s to 20℃/s.