金属热处理 ›› 2022, Vol. 47 ›› Issue (6): 33-38.DOI: 10.13251/j.issn.0254-6051.2022.06.006

• 工艺研究 • 上一篇    下一篇

保温时间对U75V重轨钢中夹杂物的影响

樊志明1, 杨吉春1, 张滢2, 李向川1, 朱君1   

  1. 1.内蒙古科技大学 材料与冶金学院, 内蒙古 包头 014000;
    2.包头天和磁材科技股份有限公司, 内蒙古 包头 014000
  • 收稿日期:2022-01-19 修回日期:2022-04-16 出版日期:2022-06-25 发布日期:2022-07-05
  • 通讯作者: 杨吉春,教授,博士,E-mail:yangjichun1963@163.com
  • 作者简介:樊志明(1996—),男,硕士研究生,主要研究方向为稀土钢,E-mail:153344735@qq.com。
  • 基金资助:
    国家自然科学基金(51774190)

Effect of holding time on inclusions in U75V heavy rail steel

Fan Zhiming1, Yang Jichun1, Zhang Ying2, Li Xiangchuan1, Zhu Jun1   

  1. 1. School of Materials and Metallurgy, Inner Mongolia University of Science and Technology, Baotou Inner Mongolia 014000, China;
    2. Baotou Tianhe Magnetic Materials Technology Co., Ltd., Baotou Inner Mongolia 014000, China
  • Received:2022-01-19 Revised:2022-04-16 Online:2022-06-25 Published:2022-07-05

摘要: 通过真空感应炉冶炼U75V重轨钢,在箱式电阻炉中将试样加热到1100 ℃,分别保温30、60、90 min,使用扫描电镜对夹杂物进行分析。结果表明,未经热处理的试验钢中,夹杂物类型主要有3种,分别为MnS、Al2O3及MnS-Al2O3夹杂物。长条状MnS夹杂物随保温时间的延长有分裂趋势,保温90 min时,MnS夹杂物平均圆形度为1.86,与未经热处理的试样相比,圆形度降低了1.52。Al2O3夹杂物在保温30、60 min时,形态、大小变化不大,但数量减少,保温90 min时,部分Al2O3夹杂物尖锐棱角发生钝化,圆形度略微减小。试样经1100 ℃均热处理后,复合夹杂物增多,随着保温时间的延长,MnS-Al2O3夹杂物中MnS和Al2O3成分分布发生变化,外层的Al2O3有向内部运动的趋势,保温90 min时,夹杂物内部Al2O3富集,外包裹层中Al2O3含量极低,MnS-Al2O3夹杂物逐渐形成以Al2O3为核心,MnS外层包裹的复合型夹杂物,从而减小了对钢基体的损伤。

关键词: U75V重轨钢, 保温时间, 夹杂物, MnS, Al2O3

Abstract: U75V heavy rail steel was smelted in a vacuum induction furnace, then the steel specimens were heated to 1100 ℃ in a box-type resistance furnace and held for 30, 60, and 90 min respectively, and the inclusions were analyzed by scanning electron microscope. The results show that in the steel without heat treatment there are three main types of inclusions MnS, Al2O3 and MnS-Al2O3. The elongated MnS inclusions tend to split with the prolongation of holding time. The average circularity of the MnS inclusions is 1.86 when the holding time is 90 min, and the circularity decreases by 1.52 compared with the specimen without heat treatment. When held for 30 and 60 min, the morphology and size of the Al2O3 inclusions change little, but the quantity decreases. When held for 90 min, the sharp edges and corners of some Al2O3 inclusions are obtused, and the circularity slightly decreases. After heated at 1100 ℃, the number of composite inclusions increases. With the extension of holding time, the distributions of MnS and Al2O3 in the MnS-Al2O3 inclusions change, and the Al2O3 in the outer layer tends to move inward. The Al2O3 is enriched inside the inclusions, and the content of Al2O3 in the outer coating is extremely low. The MnS-Al2O3 inclusions gradually form composite inclusions with Al2O3 as the core and MnS as outer coating, thereby reducing the damage to the steel matrix.

Key words: U75V heavy rail steel, holding time, inclusions, MnS, Al2O3

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