金属热处理 ›› 2022, Vol. 47 ›› Issue (1): 156-162.DOI: 10.13251/j.issn.0254-6051.2022.01.026

• 组织与性能 • 上一篇    下一篇

回火时间对高强抗震耐火钢板组织与力学性能的影响

陆春祥1,2, 林田子3, 曹建春1, 高鹏1, 詹放4, 刘星1   

  1. 1.昆明理工大学 材料科学与工程学院, 云南 昆明 650093;
    2.攀钢集团研究院有限公司 钒钛资源综合利用国家重点实验室, 四川 攀枝花 617000;
    3.鞍钢集团钢铁研究院, 辽宁 鞍山 114009;
    4.南京钢铁有限公司, 江苏 南京 210035
  • 收稿日期:2021-08-22 修回日期:2021-10-13 出版日期:2022-01-25 发布日期:2022-02-18
  • 通讯作者: 曹建春,教授,博士,E-mail:nmcjc@163.com
  • 作者简介:陆春祥(1994—),男,硕士研究生,主要研究方向为先进钢铁材料,E-mail:Luchunxiang1027@163.com。
  • 基金资助:
    国家重点研发计划(2017YFB0304701)

Effect of tempering time on mechanical properties and microstructure of high strength anti-seismic fire-resistant steel plate

Lu Chunxiang1,2, Lin Tianzi3, Cao Jianchun1, Gao Peng1, Zhan Fang4, Liu Xing1   

  1. 1. Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming Yunnan 650093, China;
    2. State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization, Pangang Croup Research Institute Co., Ltd., Panzhihua Sichuan 617000, China;
    3. Iron and Steel Research Institute, Anshan Iron and Steel Group, Anshan Liaoning 114009, China;
    4. Nanjing Iron and Steel Co., Ltd., Nanjing Jiangsu 210035, China
  • Received:2021-08-22 Revised:2021-10-13 Online:2022-01-25 Published:2022-02-18

摘要: 采用OM、SEM、TEM、拉伸试验和冲击试验等,研究了600 ℃回火不同时间对690 MPa级高强抗震耐火钢板的力学性能、微观组织及析出行为的影响。结果表明,不同回火时间对耐火钢板的力学性能和微观组织有重要影响。耐火钢板经过600 ℃回火后强度稍有降低,但伸长率增大,屈强比降低,综合力学性能提高,低温冲击吸收能量随回火时间的延长而降低。最优回火保温时间为15 min,此时试验钢板的屈服强度为976 MPa、硬度为396 HV,-40 ℃冲击吸收能量为164 J,其组织由贝氏体+铁素体+少量马氏体构成,在马氏体和铁素体中均存在位错和细小析出相,析出相为富Nb的Nb、Ti复合碳化物,发挥沉淀强化作用;当保温时间延长至60 min后,析出大量细小Nb、Ti和Mo复合碳化物,但此时的沉淀强化作用不能弥补铁素体造成的强度损失,所以在相同温度回火过程中,随着回火时间的延长,抗拉强度和硬度下降。

关键词: 690 MPa耐火钢板, 回火时间, 力学性能, 显微组织

Abstract: Effect of tempering at 600 ℃ for different time on mechanical properties, microstructure and precipitation behavior of a 690 MPa grade high strength anti-seismic fire-resistant steel sheet was studied by means of OM, SEM, TEM, tensile test and impact test. The results show that different tempering time has an important influence on mechanical properties and microstructure of the fire-resistant steel plates. When tempered at 600 ℃, the strength of the fire-resistant steel plate decreases slightly, but the elongation increases and the yield ratio decreases, which improves its comprehensive mechanical properties, meanwhile, the low temperature impact absorbed energy decreases with the extension of tempering time. The optimum tempering time is 15 min, by which the yield strength, the hardness and the impact absorbed energy at -40 ℃ of the tested steel plate are 976 MPa, 396 HV and 164 J, respectively, and the microstructure is composed of bainite, ferrite and a small amount of martensite. There are dislocations and fine precipitates in both martensite and ferrite, the precipitated phase is Nb-rich Nb and Ti composite carbides, which plays a role of precipitation strengthening. When the tempering time extends to 60 min, a large number of fine composite carbides containing Nb, Ti and Mo are precipitated, but the precipitation strengthening is not capable of making up for the strength loss caused by ferrite. Therefore, in the process of tempering at the same temperature, the tensile strength and hardness decrease with the extension of tempering time.

Key words: 690 MPa fire-resistant steel plate, tempering time, mechanical properties, microstructure

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