摘要
为实现对HRB500E抗震钢筋生产工艺的精确控制,采用Gleeble 3500热模拟实验机测定了HRB500E抗震钢筋在不同变形温度和冷却速率条件下的膨胀曲线,同时结合金相法绘制了其过冷奥氏体动态连续冷却转变曲线(动态CCT曲线),研究了变形温度和冷却速率对HRB500E抗震钢筋相变规律、显微组织和硬度的影响。结果表明:HRB500E抗震钢筋的Ac1为768℃、Ac3为930℃,在不同变形温度下的相变规律一致;当冷却速率不大于1℃/s时,组织为铁素体+珠光体;当冷却速率为3℃/s时,组织中出现少量贝氏体;当冷却速率提高至5℃/s,铁素体和珠光体组织含量减少,贝氏体组织含量增加;当冷却速率进一步增加,过冷奥氏体大量转变为贝氏体和少量的马氏体,且随着冷却速率的增加,贝氏体逐渐减少,马氏体逐渐增多;当冷却速率达到30℃/s以上,组织基本由马氏体组成,同时存在少量贝氏体及少量晶界铁素体组织;此外,高温变形会扩大铁素体和珠光体的相变区,促进了铁素体和珠光体相变。以此为基础优化了现场生产工艺,成功试制出符合国家标准的抗震钢筋,其平均屈服强度为553 MPa,抗拉强度为706 MPa,伸长率为16.8%,ReL/Rm约为0.782 5。
In order to accurately control the production process of HRB500E anti-seismic reinforcement bar,the expansion curves of HRB500E anti-seismic reinforcement bar under different deformation temperatures and cooling rates were measured by Gleeble 3500 thermal simulation tester.The dynamic continuous cooling transformation curve of supercooled austenite(Dynamic CCT curve)was obtained by metallographic method.And the effects of deformation temperature and cooling rate on phase transformation,microstructure and hardness of HRB500E anti-seismic reinforcement bar were studied.The results show that the Ac1 and Ac3 of HRB500E anti-seismic reinforcement bar were 768℃and 930℃,respectively.And the phase transformation were consistent under different deformation temperatures.When the cooling rate was less than 1℃/s,the microstructure was ferrite+pearlite.A small amount of bainite appeared when the cooling rate was 3℃/s.When the cooling rate increased to 5℃/s,the amount of ferrite and pearlite decreased,while the bainite amount increased.With the further increase of cooling rate,a large amount of supercooled austenite transformed to bainite accompanied with a small amount of martensite.Besides,with the increase of cooling rate,bainite gradually decreased and martensite gradually increased.When the cooling rate was above 30℃/s,the microstructure was basically martensite,with a small amount of bainite and grain boundary ferrite.In addition,high temperature deformation enlarged the phase transformation zone of ferrite and pearlite,and promoted the phase transformation of ferrite and pearlite.The on-site production process was optimized based on dynamic CCT results,and the anti-seismic reinforcement bar conforming to the national standard was successfully produced.Its average yield strength is 553 MPa,tensile strength is 706 MPa,elongation is 16.8%,and ReL/Rm is about 0.7825.
作者
谭成楠
周民
白亚斌
袁清
徐光
TAN Chengnan;ZHOU Min;BAI Yabin;YUAN Qing;XU Guang(CISDI Shanghai Engineering Co.,Ltd.,Shanghai 200940,China;CISDI R&D Co.,Ltd.,Chongqing 401122,China;CISDI Engineering Co.,Ltd.,Chongqing 401122,China;Wuhan University of Science and Technology,Wuhan 430081,China)
出处
《轧钢》
2023年第3期65-71,共7页
Steel Rolling
基金
中冶赛迪技术研究中心有限公司产学研合作项目(90270614-KJ-012-0)。
关键词
HRB500E抗震钢筋
动态CCT曲线
变形温度
冷却速率
膨胀量
相变
HRB500E anti-seismic reinforcement bar
dynamic CCT curve
deformation temperature
cooling rate
expansion
phase transformation
