Static CCT curve measurement and microstructure analysis of HRB400E anti-seismic structural rebar

doi:10.13251/j.issn.0254-6051.2022.09.033

Abstract

Abstract: The static continuous cooling transformation (CCT)experiments for anti-seismic rebar steel HRB400E were conducted on Gleeble-3500 thermal simulation test machine by expansion method, The microstructure and hardness of the steel under different cooling rates were observed and measured by optical microscope (OM), scanning electron microscope (SEM) and micro-Vickers hardness tester, and the effect of cooling rate on the transformation structure and properties of the steel was analyzed. The results show that when the cooling rate is below 3 ℃/s, the microstructure of the tested steel is ferrite and pearlite. With the increase of cooling rate, the pearlite content in the tested steel increases gradually and the lamellar spacing decreases. Bainite appears in the tested steel when the cooling rate is 4-10 ℃/s. When the cooling rate is higher than 10 ℃/s, the tested steel begins to undergo martensitic transformation. With the increase of cooling rate, the hardness of the tested steel increases gradually. When the cooling rate is within the range of 2-3 ℃/s, the pearlite content, lamellar spacing and mechanical properties of the tested steel meet the technical requirements of the national standard GB/T 1499.2—2018. The experimental results are in good agreement with the mechanical properties of industrial products, in which, the pearlite content and lamellar spacing of the finished specimen of ϕ8 mm rebar at the cooling rate of 3 ℃/s are 47% and 0.184 μm respectively, and yield strength R_eL, tensile strength R_m, ratio of R_m/R_eL, ratio of R_eL/R^s_eL, fracture total elongation A and total elongation at maximum force A_gt are 440 MPa, 569 MPa, 1.29, 1.10, 27.2% and 17.8%, respectively.

Key words: anti-seismic structural rebar HRB400E, CCT curves, cooling rate, microstructure, properties

CLC Number:

TG151.3

Luo Yanping, Wang Jiahan, Li Muze, Zhang Yunxiang, Zhou Jianxun, Zhao Zhiheng. Static CCT curve measurement and microstructure analysis of HRB400E anti-seismic structural rebar[J]. Heat Treatment of Metals, 2022, 47(9): 188-193.

References

[1]王宁, 王雅姝. 高强钢筋在工程中应用的探讨[J]. 现代经济信息, 2018(5): 382-386.
Wang Ning, Wang Yashu. Discussion on the application of high strength reinforcement in engineering[J]. Modern Economic Information, 2018(5): 382-386.
[2]包卫平, 潘儒乾, 王瑞芳, 等. 20MnSi钢奥氏体连续冷却转变曲线[J]. 热加工工艺, 2009, 38(18): 34-36.
Bao Weiping, Pan Ruqian, Wang Ruifang, et al. Continuous cooling transformation curve of overcooling austenite for 20MnSi steel[J]. Hot Working Technology, 2009, 38(18): 34-36.
[3]陈其安, 陈颖, 黄原慧, 等. 生态钢筋对高级别热轧带肋钢筋研发的思考[C]//全国建筑钢筋生产, 设计与应用技术交流研讨会. 2009: 120-121.
Chen Qi'an, Chen Ying, Huang Yuanhui, et al. Eco Rebar-On the R＆D of hot rolled rebar with high strength grade[C]//National Symposium on the Production, Design and Application of Building Steel Bars. 2009: 120-121.
[4]马正洪, 张玺成, 钱萍, 等. 低锰HRB400E盘螺控冷机理分析[J]. 轧钢, 2015, 32(1): 79-81.
Ma Zhenghong, Zhang Xicheng, Qian Ping, et al. Mechanism analysis of controlled cooling for HRB400E rebar coil with lower Mn content[J]. Steel Rolling, 2015, 32(1): 79-81.
[5]曹建春, 叶亚平, 阴树标, 等. 铌微合金化抗震钢筋形变奥氏体连续冷却转变[J]. 钢铁, 2019, 54(12): 87-94.
Cao Jianchun, Ye Yaping, Yin Shubiao, et al. Deformed austenite continuous cooling transformation in Nb micro-alloyed anti-seismic rebar[J]. Iron and Steel, 2019, 54(12): 87-94.
[6]朱占涛, 张文俊. 盘螺生产中贝氏体组织产生的原因及预防措施[C]//2008, 214-215.
Zhu Zhantao, Zhang Wenjun. Causes and preventive measures of bainite formation in the production of rebar coil[C]//2008 National Small Section Steel Production Technology Exchange Meeting. 2008: 214-215.
[7]郭然, 王福明, 孙丽娟. HRB400热轧带肋钢筋冷弯断裂原因的分析[J]. 金属热处理, 2021, 46(10): 257-262.
Guo Ran, Wang Fuming, Sun Lijuan. Analysis on cause of cold bending fracture of HRB400 hot-rolled ribbed bar[J]. Heat Treatment of Metals, 2021, 46(10): 257-262.
[8]宋仲明, 焦辉, 朱正锋, 等. ZG25MnCrNi钢正火组织中贝氏体的形成原因及预防措施分析[J]. 铸造技术, 2015, 36(7): 1722-1724, 1730.
Song Zhongming, Jiao Hui, Zhu Zhengfeng, et al. Analysis of formation mechanisms and preventing methods of bainite in ZG25MnCrNi steel after normalizing treatment[J]. Foundry Technology, 2015, 36(7): 1722-1724, 1730.
[9]赵贤平, 邓深, 余轶峰, 等. 铌微合金化HRB400E高强钢筋CCT曲线测定及应用[J]. 中国冶金, 2019(8): 58-63.
Zhao Xianping, Deng Shen, Yu Yifeng, et al. Measurement and application of CCT curve of Nb microalloyed HRB400E high strength rebar[J]. China Metallurgy, 2019(8): 58-63.
[10]关大伟, 孙显东, 王彦武, 等. SG80链条用钢动态CCT曲线的研究[J]. 轧钢, 2014, 31(S1): 55-57.
Guan Dawei, Sun Xiandong, Wang Yanwu, et al. Research on SG80 steel CCT curve[J]. Steel Rolling, 2014, 31(S1): 55-57.
[11]崔忠圻, 刘北兴. 金属学与热处理原理[M]. 哈尔滨: 哈尔滨工业大学出版社, 2004.
[12]Gong W, Tomota Y, Adachi Y, et al. Effects of ausforming temperature on bainite transformation, microstructure and variant selection in nanobainite steel[J]. Acta Materialia, 2013, 61(11): 4142-4154.
[13]Morito S, Tanaka H, Konishi R, et al. The morphology and crystallography of lath martensite in Fe-C alloys[J]. Acta Materialia, 2003, 51(6): 1789-1799.

[1]	Wang Zhiwen, Yang Rongdong, Huang Yuanchun, Li Hui. Effect of aging treatment on microstructure and mechanical properties of extruded 2195 Al-Li alloy [J]. Heat Treatment of Metals, 2022, 47(9): 6-11.
[2]	Gao Xing, Zhang Ning, Ding Yan, Jiang Bo. Effect of heat treatment time on microstructure and mechanical properties of TC4 titanium alloy fabricated by selective laser melting [J]. Heat Treatment of Metals, 2022, 47(9): 12-17.
[3]	Xia Pengzhao, Xu Ying, Cai Yanqing, Zhao Sitan, Lou Bingjie. Effect of microwave sintering process on microstructure and properties of Ti-Mg composites [J]. Heat Treatment of Metals, 2022, 47(9): 18-26.
[4]	Lin Lingfeng, Yuan Gecheng, Yang Lian, Ding Canpei. Effect of average pass reduction on microstructure of asynchronous rolled-solution treated 6016 aluminum alloy sheet [J]. Heat Treatment of Metals, 2022, 47(9): 36-40.
[5]	Wang Lu, Wang Feng, Zhang Mingwei, Liu Rui, Fu Zhengyuan, Liu Jingshun. Effect of annealing process on microstructure and corrosion resistance of Ti-4Al-2V alloy [J]. Heat Treatment of Metals, 2022, 47(9): 41-46.
[6]	Li Lei, Zhu Xujun, Zhang Li, Tian Fuzheng. Effect of shot peening diameter on properties and damage evolution of GH4169 alloy [J]. Heat Treatment of Metals, 2022, 47(9): 47-53.
[7]	Pan Ran, Liu Baosheng, Zeng Yuansong, Qu Haitao, Wang Dong, Mu Yanhong. Effect of cryogenic treatment on microstructure and mechanical properties of 15%SiC_p/2009 aluminum matrix composite [J]. Heat Treatment of Metals, 2022, 47(9): 65-70.
[8]	Zhang Haoze, Wang Junsheng, Gong Penghui, Zhan Haiyi, Wang Kai. Effect of heat treatment on microstructure and mechanical properties of TC4 alloy plate directly rolled by EB ingot [J]. Heat Treatment of Metals, 2022, 47(9): 71-78.
[9]	Zhong Liwei, Feng Zhaohui, Gao Wenli, Chen Junzhou, Lu Zheng. Effects of multi-axial forging and T852 heat treatment on microstructure and mechanical properties of Al-Cu-Li alloy [J]. Heat Treatment of Metals, 2022, 47(9): 79-86.
[10]	Xiao Jieliang, Sun Hao, Li Fei, Hu Ping, Chen Jinggang, Jiang Zhaofeng. Low temperature normalizing process of nodular cast iron travel wheel [J]. Heat Treatment of Metals, 2022, 47(9): 98-102.
[11]	Ji Dejing, Yang Weiyu, Bai Yaqiong. Optimization of quenching process of high strength and toughness Q690D steel for construction machines [J]. Heat Treatment of Metals, 2022, 47(9): 108-112.
[12]	Wen Fangming, Hao Xiaobo, Cao Heng, Zhang Qiang, Li Bobo, Liu Yinqi. Effect of heat treatment process on microstructure and mechanical properties of N06600 alloy hot rolled plate [J]. Heat Treatment of Metals, 2022, 47(9): 113-118.
[13]	Ai Bingquan, Kuang Shuang, Tian Xiugang, Yang Feng, Wang Yuhui, Lu Zhiqiang, Wang Zhao, Hao Lei. Effect of soaking temperature on microstructure and properties of 980 MPa grade high strength steel with different chemical composition [J]. Heat Treatment of Metals, 2022, 47(9): 119-124.
[14]	Wang Shikai, Wang Rui, Kang Yan, Yu Zhiqiang, Yan Zhijie. Effect of quenching temperature on microstructure and properties of Cr5MoVNi steel [J]. Heat Treatment of Metals, 2022, 47(9): 125-129.
[15]	Xiong Weiliang, Liang Wen, Wu Teng, Liang Liang, Wu Haohong. Effect of controlled cooling process on microstructure and mechanical properties of hot-rolled dual phase steel [J]. Heat Treatment of Metals, 2022, 47(9): 130-133.