王礼超, 田家龙, 任吉, 蒋成钢, 游志敏, 姜周华. Ce/Mg处理对M50轴承钢洁净度的影响[J]. 工程科学学报, 2022, 44(9): 1507-1515. DOI: 10.13374/j.issn2095-9389.2022.01.15.001
引用本文: 王礼超, 田家龙, 任吉, 蒋成钢, 游志敏, 姜周华. Ce/Mg处理对M50轴承钢洁净度的影响[J]. 工程科学学报, 2022, 44(9): 1507-1515. DOI: 10.13374/j.issn2095-9389.2022.01.15.001
WANG Li-chao, TIAN Jia-long, REN Ji, JIANG Cheng-gang, YOU Zhi-min, JIANG Zhou-hua. Effect of Ce/Mg addition on the cleanliness of M50-bearing steel[J]. Chinese Journal of Engineering, 2022, 44(9): 1507-1515. DOI: 10.13374/j.issn2095-9389.2022.01.15.001
Citation: WANG Li-chao, TIAN Jia-long, REN Ji, JIANG Cheng-gang, YOU Zhi-min, JIANG Zhou-hua. Effect of Ce/Mg addition on the cleanliness of M50-bearing steel[J]. Chinese Journal of Engineering, 2022, 44(9): 1507-1515. DOI: 10.13374/j.issn2095-9389.2022.01.15.001

Ce/Mg处理对M50轴承钢洁净度的影响

Effect of Ce/Mg addition on the cleanliness of M50-bearing steel

  • 摘要: 采用真空感应熔炼工艺冶炼航空轴承钢M50,对比分析了Ce处理、Mg处理和Ce–Mg复合处理对氧、硫含量和夹杂物分布特征的影响,结合热力学计算,阐明了加入Ce、Mg元素对钢液洁净度的影响机理。研究发现,Ce具有很强的脱氧、脱硫能力,加入Ce会优先生成Ce2O2S夹杂物,随着钢液中氧含量的降低,Ce还会与As等有害杂质元素结合,起到净化钢液的效果。过量的Ce会加剧其与镁铝尖晶石材质耐火材料的反应,导致钢中夹杂物数量的增加,Ce的质量分数为0.018%时,钢中夹杂物的尺寸和数量最小;添加Mg不仅可以脱氧、脱硫,还可以抑制Ce与镁铝尖晶石耐材的反应,Ce–Mg复合处理可以显著降低钢中的夹杂物的尺寸和数量,将钢中的氧的质量分数降低至0.00075%。

     

    Abstract: The cleanliness level and nonmetallic inclusion distribution characteristics of M50 aerospace-bearing steel are key factors affecting its quality and service life. The simultaneous addition of Ce–Mg has been proposed in this paper as an innovation to improve cleanliness dramatically. Based on the thermodynamic calculation, the underlying functional mechanism has been revealed. Additionally, the effects of Ce, Mg, and Ce–Mg simultaneous additions on oxygen content, sulfur content, and inclusion distribution characteristics have been analyzed comparatively. The vacuum induction melting process was used to prepare the M50 aerospace-bearing steel ingots. The chemical compositions of experimental steels were acquired using inductively coupled plasma-atomic spectroscopy, Leco TC500 N2/O2 analyzer, CS-3000 carbon/sulfur analyzer, and SPECTROLAB M11 stationary metal analyzer. The statistical distribution characteristics of inclusions were obtained using the image processing software based on optical microscopy images. The composition and morphology of inclusions have been characterized using scanning electron microscopy equipped with energy dispersive spectroscopy. The results indicated that Ce could significantly enhance the efficiency of deoxidation and desulfurization. Preferentially, Ce addition would lead to the formation of Ce2O2S inclusions in the steel. As the oxygen content in liquid steel decreases, Ce could also react with As to form a compound, and this could further purify the molten steel since As has generally been recognized as a harmful element. Meanwhile, Ce would also react with the magnesia–aluminum spinel refractory and cause an increase in the number density of inclusions in the steel. Thus, in comparison to the Ce-treated steel with higher Ce content, the smallest size and number of inclusions have been obtained in the steel with a total Ce mass fraction of 0.018%. In addition to deoxidation and desulfurization, Mg addition could also inhibit the reaction between Ce and magnesia–aluminum spinel refractories. The thermodynamic calculation results demonstrated that the dissolved Ce in the molten steel could react with the magnesia–aluminum spinel refractory material, resulting in an increase in the concentration of O and Al in the molten steel, while this reaction could significantly be inhibited by the dissolved Mg in the molten steel. In summary, Ce–Mg synergistic treatment could significantly decrease the number and size of inclusions in the steel. Based on this novel technology, the ultraclean M50 aerospace-bearing steel with an oxygen mass fraction of 0.00075% has successfully been obtained. This work has opened a new insight into the deoxidation mechanism of Ce–Mg synergistic treatment and provided a novel method to further improve the cleanliness of molten steel during the vacuum induction melting process.

     

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