金属热处理 ›› 2024, Vol. 49 ›› Issue (12): 46-51.DOI: 10.13251/j.issn.0254-6051.2024.12.007

• 工艺研究 • 上一篇    下一篇

回火冷却方式对80 mm厚高强韧Q690D钢组织性能的影响

杨维宇1, 刘颖2, 刘泽田2, 姜秉坤1   

  1. 1.内蒙古包钢钢联股份有限公司 技术中心, 内蒙古 包头 014010;
    2.内蒙古工业大学 材料科学与工程学院, 内蒙古 呼和浩特 010051
  • 收稿日期:2024-06-21 修回日期:2024-10-19 出版日期:2024-12-25 发布日期:2025-02-05
  • 通讯作者: 刘泽田,讲师,博士,E-mail:lzt_727@163.com
  • 作者简介:杨维宇(1982—),男,高级工程师,硕士,主要研究方向为板材新产品开发及金属材料失效分析,E-mail:153884843@qq.com。
  • 基金资助:
    中央引导地方科技发展资金项目(2024ZY0099);内蒙古自治区自然科学基金(2022QN05005);内蒙古自治区直属高校基本科研业务费项目(JY20220109);内蒙古工业大学科学研究项目(ZZ202104)

Effect of tempering cooling method on microstructure and properties of 80 mm thick high strength and toughness Q690D steel

Yang Weiyu1, Liu Ying2, Liu Zetian2, Jiang Bingkun1   

  1. 1. Technical Center, Inner Mongolia Baotou Steel Union Co., Ltd., Baotou Inner Mongolia 014010, China;
    2. School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot Inner Mongolia 010051, China
  • Received:2024-06-21 Revised:2024-10-19 Online:2024-12-25 Published:2025-02-05

摘要: 采用洛氏硬度计、光学显微镜、扫描电镜、透射电镜等研究了回火冷却方式对80 mm厚Q690D钢硬度、微观组织、-20 ℃低温冲击性能的影响。结果表明,回火冷却方式对试验钢调质态厚度方向上的硬度分布基本没有影响,和淬火态硬度相比,最大硬度差由13 HRC降低至6 HRC。620 ℃回火后空冷,碳化物沿奥氏体晶界、板条界析出,试验钢-20 ℃冲击吸收能量为65 J,冲击断口形貌为准解理特征。回火后采用5~8 ℃/s的水冷,碳化物在晶界、板条界的析出受到抑制,试验钢-20 ℃冲击吸收能量提高到210 J,断口形貌以韧窝为主。采用回火后水冷,工业化生产的试验钢-20 ℃低温冲击吸收能量为174~252 J,和空冷工艺相比,冲击性能提高了105%~397%。

关键词: Q690D钢, 厚规格, 回火冷却方式, 碳化物析出, 力学性能

Abstract: Rockwell hardness tester, optical microscope, scanning electron microscope and transmission electron microscope were used to study the effects of tempering cooling method on the hardness, microstructure and -20 ℃ low-temperature impact toughness of 80 mm thick Q690D steel. The results show that the tempering cooling method has little effect on the hardness distribution in the thickness direction of the quenched and tempered steel, compared with the quenched state hardness, the maximum hardness difference decreases from 13 HRC to 6 HRC. After tempering at 620 ℃ followed by air cooling, carbides precipitate along austenite grain boundary and lath boundary, the impact absorbed energy of the steel at -20 ℃ is 65 J, and the impact fracture morphology is quasi cleavage. After tempering followed by water cooling (5-8 ℃/s), the precipitation of carbide at grain boundary and strip boundary is restrained, the impact absorbed energy of the steel at -20 ℃ is increased to 210 J, and the fracture morphology is mainly dimples. After tempering followed by water cooling, the impact absorbed energy at -20 ℃ of industrial produced steel is 174-252 J, which is increased by 105% to 397% compared with air cooling.

Key words: Q690D, thickness specification, tempering cooling method, carbide precipitation, mechanical properties

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