| 引用本文: | 徐笑笑,梁斐,张亚平,林研,陈翔,赵永好.梯度纳米结构轴承钢的高温摩擦磨损行为[J].中国表面工程,2024,37(5):77~87 |
| XU Xiaoxiao,LIANG Fei,ZHANG Yaping,LIN Yan,CHEN Xiang,ZHAO Yonghao.Tribological Behavior of Gradient Nanostructured Bearing Steel at Elevated Temperatures[J].China Surface Engineering,2024,37(5):77~87 |
|
| 摘要: |
| 高温轴承作为航空发动机和高铁转向架等重大机械装备的核心支承构件，其表面高温磨损失效成为制约高温轴承可靠性和耐久性的关键瓶颈问题。因此，实现高温轴承表面减摩耐磨对于国民经济和国防安全具有重要的战略意义。采用表面机械滚压技术在 CSS-42L 轴承钢表面构筑梯度纳米结构（GNG），通过结构表征、高温摩擦磨损测试、磨痕形貌和亚表层结构演化分析研究 GNG CSS-42L 轴承钢的高温摩擦磨损行为。研究发现，轴承钢最表层的平均晶粒尺寸约为 25 nm，并随深度增加而逐渐增大。对 GNG CSS-42L 轴承钢进行室温（25 ℃）至 500 ℃范围内的高温摩擦试验，并与粗晶（CG）CSS-42L 轴承钢的摩擦磨损性能相比较。结果表明，在室温 25 ℃至 350 ℃范围内，相比于 CG CSS-42L 轴承钢，GNG CSS-42L 轴承钢的摩擦因数和磨损率同时降低，而 500 ℃下两种材料的摩擦磨损性能几乎一致。通过对两种材料磨痕表面形貌和亚表层结构分析发现，GNG CSS-42L 轴承钢的高耐磨性归功于梯度纳米层的高硬度和良好的应变协调能力可以有效抑制应变局域化。 500 ℃时，GNG CSS-42L 轴承钢磨痕表面发生明显氧化，氧化层的剥落导致材料磨损加剧。研究结果可以为高温轴承表面延寿提供新的研究思路和试验依据。 |
| 关键词: 梯度纳米结构 CSS-42L 轴承钢 高温摩擦 氧化层 微观结构演化 |
| DOI：10.11933/j.issn.1007-9289.20240311002 |
| 分类号:TG156 |
| 基金项目:国家自然科学基金重大研究计划重点项目（92366201）；国家自然科学基金面上项目（52371068） |
|
| Tribological Behavior of Gradient Nanostructured Bearing Steel at Elevated Temperatures |
|
XU Xiaoxiao1，LIANG Fei1，ZHANG Yaping1，LIN Yan1，CHEN Xiang1，ZHAO Yonghao1，2
|
|
1.School of Materials Science and Engineering, Nanjing University of Science and Technology,Nanjing 210094 , China ；2.College of Materials Science and Engineering, Hohai University, Changzhou 213200 , China
|
| Abstract: |
| Bearings, as the core components of mechanical equipment, reduce friction and ensure rotational accuracy. Bearing steels, which are critical materials for the realization of advanced bearings, must have a long service life and high reliability. With the rapid development of the aerospace and military fields, the local temperature of bearings in aircraft engines, high-speed-train bogies, and rapid-fire weapon systems can reach 350 ℃ or higher. This exceeds the upper temperature limit of conventional bearing steels such as GCr15 and M50NiL. Thus, third-generation bearing steel, exemplified by CSS-42L high-alloy steel, which exhibits excellent corrosion resistance and fracture toughness, has been developed in recent years. It is known that friction and wear damage on the surface of bearing steel under rolling contact are the main factors causing failure of bearing components at elevated temperatures.Researchers found that gradient nanograined (GNG) materials can effectively reduce friction and wear damage by preventing surface roughening and the formation of brittle tribo-layers. However, there is limited research on the tribological behavior of GNG CSS-42L bearing steel at elevated temperatures. In this study, GNG CSS-42L bearing steel was fabricated using surface mechanical rolling treatment. The effect of the gradient nanostructure on the tribological properties of CSS-42L bearing steel was investigated. By also analyzing wear morphology and subsurface microstructure evolution, the corresponding friction and wear mechanisms were clarified. The average grain size of the topmost layer of the GNG CSS-42L bearing steel was 25 nm, which gradually increased with the depth from the surface. The grain size at a depth of 100 μm reached 500 nm or more. Notably, the entire GNG layer exhibited a martensitic structure. High-temperature friction tests within the temperature range of 25-500 ℃ were conducted on the coarse-grained (CG) and GNG CSS-42L bearing steels. The factor of friction of CG CSS-42L decreased from 0.64 to 0.43 as the temperature increased to 500 ℃, and the wear rate initially increased to 3.5×10?5 mm3 / (N·m) at 350 ℃ and then decreased to 6×10?6 mm3 / (N·m) at 500 ℃. Compared to CG bearing steel, the factor of friction of GNG CSS-42L bearing steel was lower than 0.2 at 25 and 200 ℃, then increased to 0.45 at 500 ℃. The wear rates of GNG CSS-42L at 25 and 200 ℃ were 3.8×10?6 and 3.66×10?5 mm3 / (N·m), respectively, much lower than those of CG CSS-42L bearing steel. As the temperature increased to 500 ℃, the wear rates of both CG CSS-42L and GNG CSS-42L bearing steels tended to be comparable. The surface morphology of wear scars showed that the proportion of the oxidation layer in the wear scars increased with the wear temperature. This indicates a transition in the wear mechanism of the GNG CSS-42L bearing steel from abrasive wear to oxidation wear as the temperature increased from 25 to 500 ℃. Subsurface microstructure evolution results demonstrated that the original surface gradient structure remained stable within the range of 25-350 ℃. It is believed that the excellent synergy of strength and ductility, along with the strain accommodation in the GNG layer, suppresses surface roughening and the formation of wear debris, leading to enhanced wear resistance. At 500 ℃, the original gradient structure was fully replaced by a nanograined oxidation layer with a thickness of 3 μm during the wear process. Under friction pair contact, microcracks nucleated and propagated in the oxidation layer, causing the spalling of oxidation debris and increased surface roughness. Thus, the factor of friction and wear rate sharply increased at 500 ℃. These results provide an experimental basis and theoretical foundation for prolonging the service life of bearing components at elevated temperatures. |
| Key words: gradient nanostructure CSS-42L bearing steel high temperature friction oxidation layer microstructure evolution |
