Browsing by Author "Yao, Ying"

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    Effect of re-melted textured patterns on the mechanical and tribological behavior of 70Mn steel
    (Springer Science and Business Media Deutschland GmbH, 2025) Chen, Yazhe; Shang, Qingyu; Zhang, Youwei; Yao, Ying; Tomar, Adesh Kumar; Long, Risheng; Marian, Max
    © 2025, Emerald Publishing Limited.Purpose: This study aims to investigate the mechanical and tribological behavior of 70Mn steel with different laser re-melted textured patterns. Design/methodology/approach: Laser surface re-melting (LSR) was used to manufacture various textured patterns (i.e. line, grid and mixed) on both the original and heat-treated 70Mn steel plates. The micro-hardness, microstructure, tensile strength, yield strength, elongation, coefficients of friction (COF) and worn morphologies were characterized to evaluate the impact of different textured patterns on the overall performance. Findings: The results show that re-melted unit exhibited the highest surface hardness on the subsurface. The increase in surface hardness of the re-melted unit for the heat-treated 70Mn steel samples was much lower than that of the original ones. The re-melted textured patterns did not improve the tensile strength, yield strength and elongation of either original or heat-treated 70Mn steel samples. The re-melted textured patterns effectively reduced the average COFs of heat-treated 70Mn steel samples, but increased friction of the non-heat-treated samples. Originality/value: This study provides valuable insights into enhancing the mechanical properties and tribological characteristics of 70Mn steel, particularly in the automotive, heavy machinery and high-load application sectors. These industries have stringent requirements for durability and friction control, and the findings of this research are expected to effectively extend the lifespan of mechanical components. Peer review: The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-11-2024-0443/
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    Synergistic Effects of Graphene-added Lubricants and Surface Micro-texturing on the Tribological Behavior of Thrust Roller Bearings
    (2024) Long, Risheng; Yao, Ying; Zhang, Longen; Shang, Qingyu; Sun, Shaoni; Hu, Jiashuai; Pape, Florian; Marian, Max
    The synergistic effects of graphene additive and surface micro-texturing on the friction and wear properties of rolling bearings are still a research gap. To this end, the tribological behavior of dimples textured thrust roller bearings (81107TN) are investigated under starved lubrication. The lubricants contained different mass fractions (0.06 %, 0.10 % and 0.14 %) of graphene. The evenly distributed dimples (diameter: 60 mu m or 250 mu m; depth: 1 mu m or 8 mu m) were manufactured only on the raceways of the shaft washers. By comparing the coefficients of friction (COF), wear losses and worn surfaces, the influence of various dimples dimensions and mass fractions of graphene on the tribological behavior of rolling bearings is discussed. The results show that appropriate dimple parameters and a suitable mass fraction of graphene can synergistically have a positive effect on the tribological properties of bearings. In this work, the textured group, with a dimple-diameter of 60 mu m and a dimple-depth of 1 mu m, can provide the best comprehensive friction-reducing and wear-reducing performance for the mass fraction of graphene with 0.10 wt%. Compared to the smooth bearings lubricated with base oil, its mean COF is reduced by 31 % and its wear loss by 35 %. This work can be a valuable reference for the improvement of rolling bearings and lubricants.