大规格V-N微合金化球扁钢连续冷却过程中的组织性能分析  

Analysis of microstructure and properties of large size V-N microalloying bulb flat steel during continuous cooling process

作　　者：陈密达 梁丰瑞[2] 沈俊杰 周乃鹏 张云祥[1] CHEN Mida;LIANG Fengrui;SHEN Junjie;ZHOU Naipeng;ZHANG Yunxiang(Key Laboratory of Iron and Steel Metallurgy and Resource Utilization,Ministry of Education,Wuhan University of Science and Technology,Wuhan 430081,China;Department of Structural Steels,Central Iron and Steel Research Institute Co.,Ltd.,Beijing 100081,China;Wuchuan Heavy Engineering Co.,Ltd.,Wuhan 430415,China)

机构地区：[1]武汉科技大学钢铁冶金及资源利用省部共建教育部重点实验室,湖北武汉430081 [2]钢铁研究总院有限公司工程用钢研究院,北京100081 [3]武船重型工程股份有限公司,湖北武汉430415

出　　处：《冶金分析》2023年第4期48-57,共10页Metallurgical Analysis

摘　　要：针对规格尺寸扩大带来的球扁钢截面性能不均匀问题,利用静态过冷奥氏体连续冷却转变曲线(CCT曲线)和ANSYS有限元多场耦合模拟相结合方法对V-N微合金化设计大规格球扁钢进行了性能预测。同时利用透射电镜、相分析等试验技术对球头和腹板的强化机理进行研究。结果表明:采用V-N微合金化设计18#不对称球扁钢全截面组织为铁素体+珠光体+贝氏体,冷却过程中球头的冷速比腹板冷速慢2℃/s左右,170 s达到最大温差104.6℃,球头和腹板晶粒尺寸差异2.7μm,硬度差异20 HV5。球头较长的高温停留时间使得V(C,N)析出量比腹板更多,析出尺寸更细小。同对比球扁钢相比,采用V-N微合金化设计的试验球扁钢屈服强度提高55~78 MPa,球头与腹板差异从22 MPa减少至1 MPa,显著改善了球扁钢截面均匀性。In view of the uneven cross-sectional properties of bulb flat steel caused by the expansion of size,the properties of V-N microalloying large size bulb flat steel were predicted by the combination of static undercooled austenite continuous cooling transformation curve(CCT)and ANSYS finite element multi field coupling simulation.At the same time,the strengthening mechanism of bulb and flat was studied by means of transmission electron microscope and phase analysis.The results show that the full section structure of 18#asymmetric bulb flat steel designed by V-N microalloying was ferrite+pearlite+bainite.The cooling speed of the ball was about 2℃/s slower than that of the flat during the cooling process,and the maximum temperature difference reached 104.6℃in 170 s.The grain size and hardness difference between the ball and the flat was 2.7μm and 20 HV5,respectively.The longer high temperature residence time of the bulb made the precipitation amount of V(C,N)more than that of the flat,and the precipitation size was smaller.Compared with the comparative bulb flat steel,the yield strength of the test bulb flat steel designed by V-N microalloying increased by 55-78 MPa,and the difference between the bulb and the flat was reduced from 22 MPa to 1 MPa,which significantly improved the section uniformity of the bulb flat steel.

关 键 词：球扁钢 温度场 过冷奥氏体连续冷却转变曲线(CCT曲线) ANSYS V-N微合金化 

分 类 号：TG142.33[一般工业技术—材料科学与工程] TF76[金属学及工艺—金属材料]