摘要: |
基于热模拟、中试试验、组织观察、拉伸试验、TEM以及热力学软件等技术手段,研究了Nb含量与轧制工艺对Nb,V微合金化600MPa级高强度钢筋(HRB600)组织、力学性能及析出行为的影响.结果表明:在连续冷却过程中,当冷却速率<3℃/s时,试验钢的组织为铁素体与珠光体;当冷却速率为5℃/s时,试验钢中开始出现贝氏体,且贝氏体量随Nb含量的增加而增加;终轧后空冷与弱水冷的钢组织为铁素体与珠光体,且珠光体含量(质量分数)为42%~47%;随Nb含量与冷却速率的增加及轧制温度的降低,铁素体晶粒与珠光体片层间距减小;Nb在钢中以方形、圆形与棒状析出,随着Nb含量的增加,其析出物尺寸增大,钢中Nb含量不宜超过0.04%(质量分数);终轧至800~1000℃时应快速冷却,以防止Nb析出物粗化,相变范围内冷却速率宜控制在1~3℃/s. |
关键词: 微合金化 高强度钢筋 组织转变 力学性能 析出物 热力学 |
DOI:10.3969/j.issn.1007 9629.2017.03.012 |
分类号: |
基金项目:安徽省教育厅自然科学重点项目(KJ2016A091);安徽省自然科学基金资助项目(1708085ME116) |
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Effect of Nb Content and Process on Microstructure and Mechanical Properties of HRB600 Steel Rebar |
PAN Hongbo1, WANG Yang2, YAN Jun1, XIE Changsheng2, ZHU Guohui2
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1.Key Laboratory of Metallurgical Emission Reduction & Resources Recycling of Ministry of Education, Anhui University of Technology, Maanshan 243002, China;2.School of Metallurgical Engineering, Anhui University of Technology, Ma anshan 243002, China
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Abstract: |
Based on thermal simulation, pilot test, metallographic observation, tensile test, TEM and thermodynamics software, effects of cooling rate and rolling process on microstructure, mechanical properties and precipitation of Nb, V microalloyed 600MPa grade high strength steel rebar HRB600 were studied. The results show that the microstructure of the tested steels are composed of ferrite and pearlite when cooling rate is lower than 3℃/s; bainite is grown when cooling rate is 5℃/s, and with the increase of Nb content, the bainite content increases. The air cooling and light water cooling after finishing rolling, the microstructures of the tested steels are ferrite and pearlite, and the pearlite content(by mass) is about 42%47%. With the increase of Nb content and cooling rate, as well as the decrease of rolling temperature, ferrite grains and pearlite lamellar spacing decrease. Nb is precipitated with square, circular and bar shape, and with the increase of Nb content, the size of the precipitates increases. The content of Nb should be controlled within 0.04%(by mass). And accelerated cooling after finishing rolling to 8001000℃ should be used to prevent the coarsening of Nb precipitates, and cooling rate should be controlled 13℃/s in the phase transition temperature range. |
Key words: microalloyed high strength steel rebar microstructure transformation mechanical property precipitate thermodynamics |