Nb微合金化U型肋桥梁钢Q420qD静态再结晶行为研究  

Research on static recrystallization behavior of Nb microalloyed U-ribbed bridge steel Q420qD

作　　者：吴一萌 赵宪明[1] 周晓光[1] 王厚昕 高宇 吴家君 WU Yimeng;ZHAO Xianming;ZHOU Xiaoguang;WANG Houxin;GAO Yu;WU Jiajun(State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China;CITIC-CBMM Microalloying Technology Center,Beijing 100004,China;Liaoning Zizhu High-tech Design and Development Co.,Ltd.,Anshan 114000,China)

机构地区：[1]东北大学轧制技术及连轧自动化国家重点实验室,辽宁沈阳110819 [2]中信微合金化技术中心,北京100004 [3]辽宁紫竹高新技术设计研发有限公司,辽宁鞍山114015

出　　处：《轧钢》2023年第4期52-57,共6页Steel Rolling

基　　金：CITIC-CBMM铌钢研究与开发基金项目(D155/2021-M1586)。

摘　　要：为研究Nb含量与工艺参数对U型肋桥梁钢Q420qD静态再结晶行为的影响,利用热膨胀相变仪与金相显微镜等手段对其进行了分析与讨论,并确定了实验钢的静态再结晶动力学模型和静态再结晶激活能。结果表明:Nb对实验钢的静态再结晶产生阻碍作用,阻碍作用随Nb含量增大而增强,应变诱导析出的“鼻尖”温度在950~1000℃;Nb质量分数为0、0.044%和0.062%的3种实验钢再结晶激活能分别为242.43、268.77、291.96 kJ·mol^(-1),静态再结晶动力学模型分别为X_(S)=1-exp[-0.693×(t/t_(0.5))^(0.2367)],X_(S)=1-exp[-0.693×(t/t_(0.5))^(0.4777)],X_(S)=1-exp[-0.693×(t/t_(0.5))^(0.3783)];实验钢再结晶率随变形温度升高不断增大,同样变形温度下其静态再结晶率随道次间隔时间延长而增大;在Nb的应变诱导析出阶段实验钢静态再结晶率变化不明显,“平台期”结束后晶粒细化、再结晶形核增多;U型肋生产的待温阶段应控制温度在950~1000℃,并将待温结束时间锁定在“平台期”结束之前,以确保Nb元素对实验钢再结晶晶粒长大的抑制效果,达到细化晶粒、提升强韧性的目的。To study the effect of Nb content and process parameters on the static recrystallization behavior of U-ribbed bridge steel Q420qD,it was analyzed and discussed by means of deformation thermal expansion phase transducer and metallographic microscope,and the static recrystallization kinetic model and static recrystallization activation energy of the experimental steels were determined.The results show that Nb has a hindering effect on the static recrystallization of the experimental steels,and the hindering effect increases with the increase of Nb content,and the strain-induced precipitation“tip”temperature is 950-1000℃.The recrystallization activation energy of the three experimental steels with 0,0.044%and 0.062%Nb mass fraction are 242.43,268.77,291.77 kJ·mol^(-1).Static recrystallization kinetic models of the three experimental steels are X_S=1-exp[-0.693×(t/t_(0.5))^(0.2367)],X_S=1-exp[-0.693×(t/t_(0.5))^(0.4777)],X_S=1-exp[-0.693×(t/t_(0.5))^(0.3783)].The recrystallization rate of experimental steels increases with the increase of deformation temperature,and the static recrystallization rate increases with the increase of interval time under the same deformation temperature.The change of static recrystallization rate of experimental steels is not obvious at the stage of strain-induced precipitation of Nb,and the grain refinement and recrystallization nucleation increase after the end of“plateau period”.The waiting temperature of U-rib production should be controlled at 950-1000℃,and the interval time between passes should be locked before the end of“plateau period”to ensure the inhibiting effect of Nb element on the recrystallization grain growth of the experimental steels,so as to achieve the purpose of refining the grain and improving the strength and toughness.

关 键 词：U型肋型钢 桥梁钢Q420qD NB微合金化 静态再结晶 变形温度 道次间隔时间 

分 类 号：TG142.1[一般工业技术—材料科学与工程]