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过程工程学报 ›› 2019, Vol. 19 ›› Issue (2): 362-369.DOI: 10.12034/j.issn.1009-606X.218227

• 过程与工艺 • 上一篇    下一篇

镁对GCr15轴承钢中液析碳化物的影响

常立忠1, 高 岗1,2, 施晓芳1*, 郑福舟1, 陈佳顺1   

  1. 1. 安徽工业大学冶金工程学院,安徽 马鞍山 243002 2. 中钢集团马鞍山矿山研究院有限公司,安徽 马鞍山 243000
  • 收稿日期:2018-06-21 修回日期:2018-07-10 出版日期:2019-04-22 发布日期:2019-04-18
  • 通讯作者: 施晓芳 shixiaofang602@163.com
  • 基金资助:
    工模具钢中镁细化碳化物机理及电渣重熔过程控镁机制研究;“氧化物&氮化钛”复合核心细化铁素体不锈钢凝固组织的基础研究

Effect of magnesium on eutectic carbides in GCr15 bearing steel

Lizhong CHANG1, Gang GAO1,2, Xiaofang SHI1*, Fuzhou ZHENG1, Jiashun CHEN1   

  1. 1. School of Metallurgy Engineering, Anhui University of Technology, Ma?anshan, Anhui 243002, China 2. SINO STEEL Ma?anshan Institute of Mining Research Co., Ltd., Ma?anshan, Anhui 243000, China
  • Received:2018-06-21 Revised:2018-07-10 Online:2019-04-22 Published:2019-04-18

摘要: 在实验室条件下向GCr15轴承钢中添加Ni?Mg合金进行镁合金化,研究了镁对液析碳化物的影响规律,用电感耦合等离子体原子发射光谱仪分析了钢中的镁含量,用光学显微镜统计了随机选取的100个视场中的液析碳化物出现的数量、最大尺寸及其平均值。结果表明,通过NiMg合金化,Mg能较顺利加入钢液中,在钢中的平均收率为9.20%。液析碳化物数量、最大尺寸、平均最大尺寸均随镁含量提高先减少后增加,镁含量为16?10?6(wt)时效果最佳。未添加镁时,液析碳化物呈大块状析出,加镁后仍以块状为主,但尺寸更细小。微量镁细化液析碳化物的主要原因在于,镁原子向晶界或相界偏聚,阻碍C和Cr等元素扩散,抑制液析碳化物长大;同时添加镁形成的大量细小MgS?MnS可诱导碳化物析出,使碳化物弥散化,也起到细化液析碳化物的效果。

关键词: 轴承钢, 镁, 液析碳化物, 凝固, 偏聚

Abstract: Eutectic carbides are very harmful to bearing steel, which is easy to cause stress concentration and lead to premature failure of bearing. Reducing the number of eutectic carbides and refining the size of carbide is one of the key factors to improve the fatigue life of bearing steel. Therefore, the effect of magnesium on the carbide was studied systematically by adding Ni?Mg alloy to GCr15 bearing steel. The magnesium content in steel was analyzed by ICP-OES method. The number, maximum size and average maximum size of the eutectic carbide in the 100 randomly selected field of view were counted by the optical microscope. The eutectic carbide was observed by SEM. The results showed that magnesium could be added to molten steel and the average yield of magnesium in steel was 9.20%. The number, maximum size and average maximum size of the eutectic carbide decreased first and then increased with the increase of magnesium content in the GCr15 steel. The refinement effect of magnesium on the eutectic carbide was best when the magnesium content in GCr15 bearing steel was 16?10?6(wt). The eutectic carbide precipitated in the large and lump shape in the steel without magnesium. When magnesium was added to the steel, carbides were still lumpy, but smaller in size. The main reason for the refinement of the eutectic carbide by trace magnesium was that the diffusion of magnesium atoms to the grain boundary or the phase boundary hindered the diffusion of C and Cr elements, so that the formation and growth of eutectic carbide was inhibited. At the same time, a large number of fine MgS?MnS could induce the precipitation of eutectic carbides, which led to the dispersion of carbides and make the carbide finer.

Key words: bearing steel, magnesium, eutectic carbide, solidification, segregation