ISSN   1004-0595

CN  62-1095/O4

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陈金华, 李淑欣, 鲁思渊, 曹均, 金永生. 轴承钢滚动接触疲劳亚表面夹杂处损伤分析[J]. 摩擦学学报, 2024, 44(3): 1−13. doi: 10.16078/j.tribology.2023012
引用本文: 陈金华, 李淑欣, 鲁思渊, 曹均, 金永生. 轴承钢滚动接触疲劳亚表面夹杂处损伤分析[J]. 摩擦学学报, 2024, 44(3): 1−13. doi: 10.16078/j.tribology.2023012
CHEN Jinhua, LI Shuxin, LU Siyuan, CAO Jun, JIN Yongsheng. Damage Analysis at Surface Inclusion in Rolling Contact Fatigue of Bearing Steels[J]. Tribology, 2024, 44 (3): 1−13. doi: 10.16078/j.tribology.2023012
Citation: CHEN Jinhua, LI Shuxin, LU Siyuan, CAO Jun, JIN Yongsheng. Damage Analysis at Surface Inclusion in Rolling Contact Fatigue of Bearing Steels[J]. Tribology, 2024, 44 (3): 1−13. doi: 10.16078/j.tribology.2023012

轴承钢滚动接触疲劳亚表面夹杂处损伤分析

Damage Analysis at Surface Inclusion in Rolling Contact Fatigue of Bearing Steels

  • 摘要: 轴承钢在滚动接触疲劳(RCF)中失效的主要原因之一是亚表面白蚀区(WEA)的形成. 本文中从塑性应变累积引起剪切局域化新的角度对WEA进行了研究. 通过耦合晶体塑性和相场损伤理论建立了损伤演化本构模型,研究了非金属夹杂处塑性应变累积和损伤演化. 研究表明,接触疲劳载荷引起的塑性应变局域化导致了剪切带的形成. 剪切带的形貌、取向和应变与WEA的一致,表明WEA实际上是应变局域化的剪切带. 晶体取向对WEA损伤的形成和发展有很大的影响,WEA仅在择优的晶体取向下形成. 与软夹杂周围的剪切带和损伤演化不同,硬夹杂处的剪切带与夹杂相切,形成的4条剪切变形带将夹杂“包围”. 剪切带内部处于高应变和低应力的状态,带中心处应变达到最大,随带宽两侧急剧减小,而中心处应力却最小,几乎为零,沿带宽两侧增大,这说明裂纹在剪切带内萌生和扩展. 该结论阐明了裂纹和WEA形成的关系,即裂纹是在WEA形成过程中因应变不协调产生,而非裂纹先产生,裂纹上下表面相互摩擦导致WEA形成.

     

    Abstract: One of the dominant failure modes for bearing steels under rolling contact fatigue (RCF) loading is the formation of white etching area (WEA) in the subsurface. The presence of WEA has a great influence on the contact fatigue life. WEA leads to decrease in load carrying capacity of bearing materials due to microstructural degradation and accompanied cracks. As stress rises, the subsurface non-metallic inclusions are preferential places for WEA initiation, forming butterfly-shaped WEA. Extensive studies have been conducted regarding WEA’s microstructure, composition, influential factors and formation mechanism. However, there is a large discrepancy in the formation mechanism, and some are even contradictory. In order to reveal the essence of the WEA and the underlying mechanism, the WEA was investigated from a new perspective of shear localization due to plastic strain accumulation. Firstly, rolling contact fatigue tests were carried out to generate WEAs of various morphologies. Secondly, a damage evolution constitutive model was established through coupling the crystal plasticity and phase field damage theory to study plastic strain accumulation and damage evolution at a non-metallic inclusion. The equation was programmed and incorporated into the finite element software of ABAQUS. The constitutive relationship for crystal plasticity damage consists of user subroutines UMAT and HETVAL. Finally, various morphologies of WEAs were compared with the simulation results. The results showed that the localization of the plastic strain leaded to shear band formation. The morphology, orientation and strain of the shear band showed good consistency with those of the WEA, indicating that the WEA was actually the shear band as a result of strain localization. The crystal orientation had a great influence on the WEA damage development. The WEA formed only at preferential crystal orientations. This well explained why various morphologies of WEAs were present in the same section of the sample. The WEA was also influenced by the elastic modulus of the non-metallic inclusion. In contrast to the WEA at the soft inclusion (WEA was along 50°~60° ), the shear band and WEA developped tangent to the inclusion at the hard inclusion, forming four bands. Whatever at the soft or hard inclusion, the center of the band had the largest damage and plastic strain. Therefore, it was suggested that the effect of the elastic modulus of the inclusion was mainly on the WEA’s morphology and distribution. The interior of the shear band was in a state of high strain and low stress. The shear strain and damage reached the maximum in the center of the shear band, and decreased sharply along sides of the band. Whereas, the stress in the band center was the smallest, approaching to zero, and increased along the band width. The result indicated that crack initiated and propagated in the WEA. This clarified the relationship between the crack and the WEA formation. That was, cracks were generated due to inhomogeneous strain during the formation of WEA, rather than as reported that, the cracks were generated first, and then the friction between the upper and lower crack faces leaded to the formation of the WEA.

     

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