ISSN:1003-8620

CN:42-1243/TF

Governed by: CITIC Pacific Special Steel Group Co., LTD

Sponsored by: Daye Special Steel Co., LTD.

Special Steel ›› 2024, Vol. 45 ›› Issue (6): 73-82.DOI: 10.20057/j.1003-8620.2024-00119

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Influence of Quenching Process on the Microstructure Evolution and Hardness of A514CrQ Rack Steel

Zhao Guangdi1, Zang Ximin1,2, Liu Zhichao1, Jing Yu'an1   

  1. (1 School of Materials and Metallurgy, University of Science and Technology Liaoning, Anshan 114051,China;2 School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China)
  • Received:2024-04-30 Online:2024-11-30 Published:2024-12-01

淬火工艺对A514CrQ齿条钢显微组织演变及硬度的影响

赵广迪1, 臧喜民1,2, 刘志超1, 井玉安1   

  1. (1 辽宁科技大学材料与冶金学院,鞍山114051;2 沈阳工业大学材料科学与工程学院,沈阳110870)
  • 作者简介:赵广迪(1989—),男,博士,副教授,硕士生导师
  • 基金资助:
     国家自然科学基金项目(No. 52174317),辽宁省教育厅面上项目(JYTMS20230943)

Abstract: The influence of quenching process on the microstructure evolution and hardness of A514CrQ rack steel has been investigated in this paper. The results showed that granular bainite + a small amount of lath martensite can be obtained after water quenching at 790 ℃/30 min. After 820 ℃-950 ℃/30 min water quenching, full lath martensite was obtained, and with the increase of quenching temperature, the width of martensite block increased, and hence the hardness gradually decreased. The 820 ℃ was identified as the optimal quenching temperature. When the holding time was 1 min-5 min, granular bainite +lath martensite was obtained by water quenching at 820 ℃, and the hardness of the specimen was much lower. When the holding time was 10 min-70 min, full lath martensite was obtained after water quenching at 820 ℃, the martensite block width increased with the increasing holding time, and hence the hardness gradually decreased and tended to be flat. Then the optimal holding time was identified as 10 min. After 820 ℃/10 min air quenching or oil quenching, granular bainite + lath martensite/bainite was obtained, and the content of martensite/bainite after oil quenching was higher. This leads to the lowest hardness of air quenching, the center of oil quenching, and the largest hardness of water quenching. In the process of double cycle quenching process, the final microstructure was determined by the secondary quenching medium, and the martensite/bainite lath can be refined more effectively by using water as the primary quenching medium. After 820 ℃/10 min water quenching + 820 ℃/10 min water quenching, the martensitic block width was the smallest and the hardness was the highest. Thus, this double water quenching process can serve as the preferred quenching process for rack steels.

Key words: A514CrQ Rack Steel, Quenching Process, Microstructure Evolution, Hardness

摘要: 研究了淬火工艺对A514CrQ齿条钢组织演变及硬度的影响及机理。结果表明,经790 ℃/30 min水淬后得到粒状贝氏体+少量板条马氏体。经820~950 ℃/30 min水淬后得到全板条马氏体,且随淬火温度升高马氏体板条块宽度增大,硬度逐渐下降,得到820 ℃为最优淬火温度。在820 ℃保温1~5 min后水淬获得粒状贝氏体+板条马氏体组织,硬度较低;保温10~70 min后水淬获得全板条马氏体组织,且随保温时间延长马氏体板条块宽度增加,硬度逐渐下降并趋于持平,得到10 min为最优保温时间。经820 ℃/10 min空淬、油淬后均获得粒状贝氏体+板条马氏体/贝氏体组织,且油淬的马氏体/贝氏体含量更高。这导致空淬的硬度最低,油淬的居中,水淬的硬度最大。在双次循环淬火过程中,二次淬火介质决定了最终组织,且以水为一次淬火介质可更有效细化马氏体/贝氏体板条块。820 ℃/10 min水淬+820 ℃/10 min水淬的马氏体板条块最细小,硬度最高,可作为该齿条钢的优选淬火工艺。

关键词: A514CrQ齿条钢, 淬火工艺, 组织演变, 硬度

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