Q355NH钢的CCT曲线及早期耐蚀性能  

CCT curves and initial corrosion properties of Q355NH steel

作　　者：王凌旭 何锦航 孙博 白洁 王勇 邓凤淋 曹长胜 梁宇[3] Wang Linxu;He Jinhang;Sun Bo;Bai Jie;Wang Yong;Deng Fenglin;Cao Changsheng;Liang Yu(Electric Power Research Institute of Guizhou Power Grid Co.,Ltd.,Guiyang Guizhou 550002,China;Powerchina Guizhou Electric Power Engineering Co.,Ltd.,Guiyang Guizhou 550002,China;College of Materials and Metallurgy,Guizhou University,Guiyang Guizhou 550025,China)

机构地区：[1]贵州电网有限责任公司电力科学研究院,贵州贵阳550002 [2]中国电建集团贵州电力设计研究院有限公司,贵州贵阳550002 [3]贵州大学材料与冶金学院,贵州贵阳550025

出　　处：《金属热处理》2021年第7期84-89,共6页Heat Treatment of Metals

基　　金：贵州省电力试验研究院项目(066600KK52180066)。

摘　　要：通过膨胀曲线并结合金相硬度法,测量了Q355NH低碳耐候钢840℃奥氏体化后在不同冷速下的相变点,并绘制其CCT曲线,对试验钢不同冷却方式下的显微组织、力学性能和耐腐蚀性能进行研究。结果表明,Q355NH钢在0.1~10℃/s冷速范围内均可获得铁素体+珠光体组织。随着冷速的增大,屈服强度从炉冷的360 MPa提高到风冷的420 MPa。炉冷时组织中存在沿晶界析出的碳化物,风冷时珠光体数量和密度最高。炉冷和风冷条件下试样具有较低的腐蚀电位,盐雾腐蚀试验早期的质量损失较大。Through dilation curves and metallographic-hardness method,the transformation point of Q355NH low-carbon weathering steel austenitized at 840℃and cooled with different cooling rates was measured,and the CCT curves were obtained.Based on this,the microstructure,mechanical properties and corrosion resistance of the steel under different cooling methods were studied.The results show that the microstructure of the Q355NH steel is composed of ferrite and pearlite when the cooling rate is in range of 0.1-10℃/s.As the cooling rate increases,the yield strength increases from 360 MPa(furnace cooling)to 420 MPa(wind cooling).Carbides precipitate along the grain boundary under furnace cooling methods,and the number and density of pearlite are highest under wind cooling method.Under these two cooling method,the steel has a lower corrosion potential,but the mass loss in the initial stage of the salt spray corrosion test is comparatively greater.

关 键 词：Q355NH钢 耐候钢 CCT曲线 早期腐蚀 

分 类 号：TG172[金属学及工艺—金属表面处理]