金属热处理 ›› 2023, Vol. 48 ›› Issue (1): 133-138.DOI: 10.13251/j.issn.0254-6051.2023.01.023

• 工艺研究 • 上一篇    下一篇

回火温度对55NiCrMoV7热作模具钢组织和性能的影响

元亚莎1,2, 汪雨昌2, 王文焱1, 石如星2, 元莎3, 张玉栋2   

  1. 1.河南科技大学 材料科学与工程学院, 河南 洛阳 471023;
    2.洛阳中重铸锻有限责任公司, 河南 洛阳 471039;
    3.中国机械总院集团北京机电研究所有限公司, 北京 100083
  • 收稿日期:2022-08-15 修回日期:2022-11-09 出版日期:2023-01-25 发布日期:2023-02-03
  • 通讯作者: 王文焱,教授,博士,E-mail:wangwy1963@163.com
  • 作者简介:元亚莎(1991—),女,工程师,博士研究生,主要研究方向为金属材料热处理工艺及新型模具钢的开发,E-mail:15138753540@163.com。
  • 基金资助:
    国家重点研发计划(2020YFB2008400)

Effect of tempering temperature on microstructure and mechanical properties of 55NiCrMoV7 hot working die steel

Yuan Yasha1,2, Wang Yuchang2, Wang Wenyan1, Shi Ruxing2, Yuan Sha3, Zhang Yudong2   

  1. 1. School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang Henan 471023, China;
    2. Luoyang CITIC HIC Casting and Forging Co., Ltd., Luoyang Henan 471039, China;
    3. Beijing Research Institute of Mechanical and Electrical Technology Co., Ltd., CAM, Beijing 100083, China
  • Received:2022-08-15 Revised:2022-11-09 Online:2023-01-25 Published:2023-02-03

摘要: 采用Formastor-FⅡ型膨胀仪测量55NiCrMoV7钢不同速度连续冷却时的膨胀曲线,利用膨胀法与金相—硬度法,确定相变温度点,并绘制出钢的CCT曲线,采用扫描电镜(SEM)、光学显微镜(OM)、洛氏硬度计、拉伸试验机和冲击试验机研究回火温度对55NiCrMoV7钢显微组织和力学性能的影响。结果表明,在520~600 ℃回火时,随着回火温度的升高,强硬度逐渐降低,塑韧性逐渐提高,回火温度在560~580 ℃时,由淬火产生的应力基本消除,马氏体分解、残留奥氏体转变基本完成。此时抗拉强度达到1300 MPa 左右,断后伸长率达到14.5%,冲击吸收能量达到30 J以上,综合力学性能最佳。

关键词: 55NiCrMoV7热作模具钢, 回火温度, 显微组织, 力学性能, 断口形貌

Abstract: The expansion curves of 55NiCrMoV7 steel during continuous coolingwith different speeds were measured by using Formastor-FII dilatometer, and the phase transformation temperature points were determined by expansion method and metallographic-hardness method, and then the CCT curves of the steel were drawn. Effect of tempering temperature on microstructure and mechanical properties of the 55NiCrMoV7 steel were studied by means of scanning electron microscope (SEM), optical microscope (OM), Rockwell hardness tester, tensile tester and impact tester. The results show that when the tempering temperature is in the range of 520-600 ℃, as tempering temperature increases, both the hardness and tensile strength of the 55NiCrMoV7 steel decrease, while the plasticity and toughness gradually increase. When the tempering temperature is 560-580 ℃, the hardening stress of the material is basically eliminated, martensite decomposing and retained austenite transformation is basically complete. The preferable mechanical properties of the 55NiCrMoV7 steel are obtained, with tensile strength, elongation and impact absorbed energy of 1300 MPa, 14.5% and more than 30 J, respectively.

Key words: 55NiCrMoV7 hot working die steel, tempering temperature, microstructure, mechanical properties, fracture morphology

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