金属热处理 ›› 2020, Vol. 45 ›› Issue (4): 161-165.DOI: 10.13251/j.issn.0254-6051.2020.04.034

• 工艺研究 • 上一篇    下一篇

42CrMoVNb高强度螺栓钢的球化退火

杨周1,2, 赵秀明1,2, 孙建宇1,2, 刘凯旋1,2, 冯宇阳1,2, 汪杨鑫1,2, 王磊3   

  1. 1. 南京工程学院 材料工程学院, 江苏 南京 211167;
    2. 江苏省先进结构材料与应用技术重点实验室, 江苏 南京 211167;
    3. 南京钢铁股份有限公司, 江苏 南京 210035
  • 收稿日期:2019-10-20 出版日期:2020-04-25 发布日期:2020-05-08
  • 通讯作者: 赵秀明,教授,E-mail:13952096708@163.com
  • 作者简介:杨 周(1993—),男,硕士研究生,主要从事高性能金属材料的研究,E-mail:18351961803@163.com
  • 基金资助:
    2019年江苏省研究生实践创新计划(SJCX19-0600,SJCX19-0581,SJCX19-0583)

Spheroidizing annealing of 42CrMoVNb high strength bolt steel

Yang Zhou1,2, Zhao Xiuming1,2, Sun Jianyu1,2, Liu Kaixuan1,2, Feng Yuyang1,2, Wang Yangxin1,2, Wang Lei3   

  1. 1. School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing Jiangsu 211167, China;
    2. Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology, Nanjing Jiangsu 211167, China;
    3. Nanjing Iron & Steel Co., Ltd., Nanjing Jiangsu 210035, China
  • Received:2019-10-20 Online:2020-04-25 Published:2020-05-08

摘要: 根据热模拟试验测得42CrMoVNb高强度螺栓钢的Ac1、Ac3分别为773 ℃、811 ℃,并由此设计试验钢的球化退火工艺,通过改变保温温度、保温时间对其球化退火工艺进行了研究。通过光学显微镜、扫描电镜、显微维氏硬度以及冷镦试验,对不同球化退火工艺过程中碳化物的球化演变和硬度变化进行了分析。结果表明:试验钢经Ac1以上780 ℃短暂保温0.5 h,缓冷至710 ℃保温6 h球化退火及Ac1以下750 ℃保温3 h,缓冷至710 ℃保温6 h球化退火后,均能得到良好的球化组织与较低的硬度,碳化物形态均趋于球状且分布均匀,具有良好的塑性和冷镦性能。Ac1以下750 ℃球化时,保温时间越长碳化物球化越明显。

关键词: 42CrMoVNb高强度螺栓钢, 碳化物, 球化退火

Abstract: Based on Ac1 and Ac3, i.e. 773 ℃ and 811 ℃ respectively, evaluated by the thermal simulation experiment, the spheroidizing annealing treatment with different heating temperatures and holding time was carried out on 42CrMoVNb high strength bolt steel. The spheroidizing evolution and hardness of the steel were analyzed by means of optical microscope, scanning electron microscope, Vickers hardness and cold heading tests. The results show that after spheroidizing annealing at 780 ℃(above Ac1) for 0.5 h followed by low cooling to 710 ℃ for 6 h or at 750 ℃ (below Ac1) for 3 h followed by slow cooling to 710 ℃ for 6 h, the steel has good spheroidized structure with low hardness, meanwhile, the morphology of carbides tends to be spherical and uniformly distributed, and the steel has good plasticity and cold heading properties. When spheroidized annealing at 750 ℃, the longer the holding time, the more obvious of carbide spheroidization.

Key words: 42CrMoVNb high strength bolt steel, carbide, spheroidizing annealing

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