金属热处理 ›› 2023, Vol. 48 ›› Issue (11): 210-215.DOI: 10.13251/j.issn.0254-6051.2023.11.033

• 工艺研究 • 上一篇    下一篇

珠光体形态对SK85钢球化退火组织和硬度的影响

邓素怀1, 梁江涛1, 刘锟1, 李悦2, 徐海卫2   

  1. 1.首钢集团有限公司技术研究院, 北京 100043;
    2.首钢京唐钢铁联合有限责任公司 制造部, 河北 唐山 063210
  • 收稿日期:2023-06-05 修回日期:2023-09-28 出版日期:2023-11-25 发布日期:2023-12-27
  • 作者简介:邓素怀(1976—),女,高级工程师,硕士,主要研究方向为钢铁材料开发及热处理工艺,E-mail:tgsdeng@126.com

Effect of pearlite morphology on microstructure and hardness after spheroidizing annealing of SK85 steel

Deng Suhuai1, Liang Jiangtao1, Liu Kun1, Li Yue2, Xu Haiwei2   

  1. 1. Research Institute of Technology, Shougang Group Co., Ltd., Beijing 100043, China;
    2. Manufacturing Department, Shougang Jingtang United Iron & Steel Co., Ltd., Tangshan Hebei 063210, China
  • Received:2023-06-05 Revised:2023-09-28 Online:2023-11-25 Published:2023-12-27

摘要: 利用同步差热分析仪对SK85钢冷轧板进行球化退火工艺模拟。采用光学显微镜、扫描电镜、硬度计等研究变形珠光体和粒状珠光体形态对球化组织与性能的影响。结果表明,随着退火温度的升高,两种形态珠光体试样的球化硬度先降低后升高,在740~750 ℃时为最小值。当退火温度低于740 ℃时,球化组织为粒状珠光体,变形珠光体的球化速度大于粒状珠光体,退火硬度大于粒状珠光体试样。当退火温度高于750 ℃时,球化组织均为片层珠光体和粒状珠光体,两者硬度变化趋于一致。粒状珠光体球化后获得的碳化物颗粒尺寸大于变形珠光体,是粒状珠光体球化硬度小于变形珠光体的原因。通过软化退火工艺设计调节碳化物弥散度可以进一步降低SK85钢冷轧板的硬度,满足冷冲压行业要求。

关键词: 珠光体形态, SK85钢, 球化退火, 碳化物

Abstract: Simulation of spheroidizing annealing process of the SK85 steel cold rolled sheet was carried on by simultaneous thermal analyzer. The effect of morphology of deformed pearlite and granular pearlite on the spheroidized structure and properties was studied by means of optical microscope, scanning electron microscope and hardness tester. The results show that as the annealing temperature increases, the spheroidizing hardness of two morphic pearlites specimens first decreases and then increases, and reaches the minimum values when the annealing temperature is 740-750 ℃. When the annealing temperature is lower than 740 ℃, the spheroidized microstructure is granular pearlite, the spheroidizing speed of deformed pearlite is greater than that of granular pearlite, and the annealing hardness is greater than that of granular pearlite specimen. When the annealing temperature is higher than 750 ℃, the spheroidized microstructure is lamellar pearlite and granular pearlite, and both hardness changes tend to be consistent. The carbide particle size obtained after granular pearlite spheroidizing is larger than that of deformed pearlite, which is the reason why the spheroidization hardness of granular pearlite is lower than that of deformed pearlite. Adjusting the carbide dispersion through softening annealing process design can further reduce the hardness of SK85 steel cold rolled sheet and meet the industry requirements of cold stamping.

Key words: pearlite morphology, SK85 steel, spheroidizing annealing, carbide

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