Q500qENH桥梁耐候钢CCT曲线的测定及其组织、硬度  

Determination of CCT curve,microstructure and hardness of Q500qENH bridge weathering steel

作　　者：黄重[1] 张可 徐党委[1] 孟少博 王新志[1] 杜海明[1] 张熹 HUANG Zhong;ZHANG Ke;XU Dang-wei;MENG Shao-bo;WANG Xin-zhi;DU Hai-ming;ZHANG Xi(Anyang Iron&Steel Group Co Ltd,Anyang 455004,China;School of Metallurgical Engineering,Anhui University of Technology,Ma’anshan 243032,China;Tianjin Bridge Welding Materials Group Co Ltd,Tianjin 300385,China)

机构地区：[1]安阳钢铁集团有限责任公司,河南安阳455004 [2]安徽工业大学冶金工程学院,安徽马鞍山243032 [3]天津大桥焊材集团有限公司,天津300385

出　　处：《材料热处理学报》2022年第11期121-127,共7页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51704008);河南省博士后科研启动项目(202103098)。

摘　　要：为了深入了解Q500qENH钢在连续冷却相变过程中组织及硬度的变化及原因,通过热膨胀法和金相-硬度法绘制了Q500qENH钢的动态连续冷却转变曲线(CCT曲线),研究了冷却速度对其组织、硬度及相变行为的影响。结果表明:冷速在0.1~0.3℃/s时,试验钢的组织为多边形铁素体和少量珠光体与贝氏体;冷速在0.5~10℃/s时,组织主要为粒状贝氏体,冷速在15~30℃/s时,组织主要为板条贝氏体和粒状贝氏体,随着冷速的增大,粒状贝氏体的含量逐渐降低,板条贝氏体的含量不断增加,在25~30℃/s较大冷速时,有极少量的马氏体产生。随着冷速由0.1℃/s增加至30℃/s,试验钢的硬度基本呈线性增大,由154 HV0.2增加至352 HV0.2,基体组织的细化是硬度不断增大的主要因素。In order to understand the changes and causes of microstructure and hardness of Q500 qENH steel during continuous cooling transformation,the dynamic continuous cooling transformation curve(CCT curve)of the Q500 qENH steel was drawn by thermal expansion method and metallographic hardness method,and the influence of cooling rate on microstructure,hardness and transformation behavior of the Q500 qENH steel was studied.The results show that when the cooling rate is 0.1-0.3℃/s,the microstructure of the experimental steel is composed of polygonal ferrite and a small amount of pearlite and bainite.When the cooling rate is 0.5-10℃/s,the microstructure is mainly granular bainite.When the cooling rate is 15-30℃/s,the microstructure is mainly lath bainite and granular bainite.With the increase of the cooling rate,the content of granular bainite gradually decreases,and the content of lath bainite increases continuously.When the cooling rate is 25-30℃/s,a very small amount of martensite is obtained.As the cooling rate increases from 0.1℃/s to 30℃/s,the hardness of the experimental steel increases linearly,from 154 HV0.2 to 352 HV0.2.The refinement of the matrix microstructure is the main factor for the increasing hardness.

关 键 词：桥梁耐候钢 CCT曲线 贝氏体 冷却速度 硬度 

分 类 号：TG142.3[一般工业技术—材料科学与工程]