Pub Date : 2023-12-14DOI: 10.3390/lubricants11120532
Ming Ying, Xinghua Liu, Yue Zhang, Chongbing Zhang
The critical speed is a crucial factor that impacts the stability of high-speed compressors. However, limited research has simultaneously considered the influence of gas foil bearings (GFBs), labyrinth seals, and impellers on critical speed. In this study, we develop a rotordynamic model that incorporates the aerodynamic forces of GFBs, labyrinth seals, and impellers to explore the effects of each component on the critical speed. To validate the developed model, experimental tests are conducted on a centrifugal compressor test bed, and the results exhibit a high level of agreement with the model calculations. By comparing the model calculations that include different components, we comprehensively analyze the influence of each component on the critical speed. The findings reveal that, for centrifugal compressors used in fuel cell vehicles, the rotordynamic coefficients resulting from GFBs are significantly larger than those resulting from impellers and labyrinth seals. Thus, it is reasonable to disregard the aerodynamic forces caused by impellers and labyrinth seals when calculating the critical speed. Furthermore, substituting rigid gas bearings for GFBs as a means to simplify the calculations has only a very slight impact on the results. This study aims to optimize the design process of centrifugal compressors for fuel cell vehicles and offers valuable insights for designing compressors of similar sizes.
{"title":"Impact of Gas Foil Bearings, Labyrinth Seals, and Impellers on the Critical Speed of Centrifugal Compressors for Fuel Cell Vehicles: A Comprehensive Investigation","authors":"Ming Ying, Xinghua Liu, Yue Zhang, Chongbing Zhang","doi":"10.3390/lubricants11120532","DOIUrl":"https://doi.org/10.3390/lubricants11120532","url":null,"abstract":"The critical speed is a crucial factor that impacts the stability of high-speed compressors. However, limited research has simultaneously considered the influence of gas foil bearings (GFBs), labyrinth seals, and impellers on critical speed. In this study, we develop a rotordynamic model that incorporates the aerodynamic forces of GFBs, labyrinth seals, and impellers to explore the effects of each component on the critical speed. To validate the developed model, experimental tests are conducted on a centrifugal compressor test bed, and the results exhibit a high level of agreement with the model calculations. By comparing the model calculations that include different components, we comprehensively analyze the influence of each component on the critical speed. The findings reveal that, for centrifugal compressors used in fuel cell vehicles, the rotordynamic coefficients resulting from GFBs are significantly larger than those resulting from impellers and labyrinth seals. Thus, it is reasonable to disregard the aerodynamic forces caused by impellers and labyrinth seals when calculating the critical speed. Furthermore, substituting rigid gas bearings for GFBs as a means to simplify the calculations has only a very slight impact on the results. This study aims to optimize the design process of centrifugal compressors for fuel cell vehicles and offers valuable insights for designing compressors of similar sizes.","PeriodicalId":18135,"journal":{"name":"Lubricants","volume":"10 3","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138975434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-14DOI: 10.3390/lubricants11120531
Q. Liu, Yimin Mo, Juncheng Lv, Hong Zhang
To evaluate the impact of various proportions of erucamide and N-phenyl-α-naphthylamine on grease’s tribological performance for roller bearings, lithium complex grease (LCG) and polyurea grease (PG) were prepared with erucamide and N-phenyl-α-naphthylamine proportions of (0,0), (0,3), (1,2), (2,1), and (3,0). An investigation was conducted into the microscopic structures of the ten greases and their effects on the friction coefficients and wear scars of GCr15 steel. These findings were validated through bearing friction torque tests. The results indicate that the addition of 2 wt. % erucamide and 1 wt. % N-phenyl-α-naphthylamine to PG/LCG significantly enhances their tribological properties and reduces friction torque, with PG exhibiting superior performance. This enhancement was attributed to the synergistic interaction of erucamide and N-phenyl-α-naphthylamine with the lamellar thickener within PG. Erucamide contributed to friction reduction, while N acted as an antioxidant.
{"title":"Effects of Erucamide and N-phenyl-α-naphthylamine on the Friction and Torque Behaviors of Grease on Roller Bearings","authors":"Q. Liu, Yimin Mo, Juncheng Lv, Hong Zhang","doi":"10.3390/lubricants11120531","DOIUrl":"https://doi.org/10.3390/lubricants11120531","url":null,"abstract":"To evaluate the impact of various proportions of erucamide and N-phenyl-α-naphthylamine on grease’s tribological performance for roller bearings, lithium complex grease (LCG) and polyurea grease (PG) were prepared with erucamide and N-phenyl-α-naphthylamine proportions of (0,0), (0,3), (1,2), (2,1), and (3,0). An investigation was conducted into the microscopic structures of the ten greases and their effects on the friction coefficients and wear scars of GCr15 steel. These findings were validated through bearing friction torque tests. The results indicate that the addition of 2 wt. % erucamide and 1 wt. % N-phenyl-α-naphthylamine to PG/LCG significantly enhances their tribological properties and reduces friction torque, with PG exhibiting superior performance. This enhancement was attributed to the synergistic interaction of erucamide and N-phenyl-α-naphthylamine with the lamellar thickener within PG. Erucamide contributed to friction reduction, while N acted as an antioxidant.","PeriodicalId":18135,"journal":{"name":"Lubricants","volume":"22 21","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138972202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-13DOI: 10.3390/lubricants11120530
Lei He, Haijun Wei, Wenjie Gao
The wear particle classification algorithm proposed is based on an integrated ResNet50 and Vision Transformer, aiming to address the problems of a complex background, overlapping and similar characteristics of wear particles, low classification accuracy, and the difficult identification of small target wear particles in the region. Firstly, an ESRGAN algorithm is used to improve image resolution, and then the Separable Vision Transformer (SepViT) is introduced to replace ViT. The ResNet50-SepViT model (SV-ERnet) is integrated by combining the ResNet50 network with SepViT through weighted soft voting, enabling the intelligent identification of wear particles through transfer learning. Finally, in order to reveal the action mechanism of SepViT, the different abrasive characteristics extracted by the SepViT model are visually explained using the Grad-CAM visualization method. The experimental results show that the proposed integrated SV-ERnet has a high recognition rate and robustness, with an accuracy of 94.1% on the test set. This accuracy is 1.8%, 6.5%, 4.7%, 4.4%, and 6.8% higher than that of ResNet101, VGG16, MobileNetV2, AlexNet, and EfficientV1, respectively; furthermore, it was found that the optimal weighting factors are 0.5 and 0.5.
{"title":"Research on an Intelligent Classification Algorithm of Ferrography Wear Particles Based on Integrated ResNet50 and SepViT","authors":"Lei He, Haijun Wei, Wenjie Gao","doi":"10.3390/lubricants11120530","DOIUrl":"https://doi.org/10.3390/lubricants11120530","url":null,"abstract":"The wear particle classification algorithm proposed is based on an integrated ResNet50 and Vision Transformer, aiming to address the problems of a complex background, overlapping and similar characteristics of wear particles, low classification accuracy, and the difficult identification of small target wear particles in the region. Firstly, an ESRGAN algorithm is used to improve image resolution, and then the Separable Vision Transformer (SepViT) is introduced to replace ViT. The ResNet50-SepViT model (SV-ERnet) is integrated by combining the ResNet50 network with SepViT through weighted soft voting, enabling the intelligent identification of wear particles through transfer learning. Finally, in order to reveal the action mechanism of SepViT, the different abrasive characteristics extracted by the SepViT model are visually explained using the Grad-CAM visualization method. The experimental results show that the proposed integrated SV-ERnet has a high recognition rate and robustness, with an accuracy of 94.1% on the test set. This accuracy is 1.8%, 6.5%, 4.7%, 4.4%, and 6.8% higher than that of ResNet101, VGG16, MobileNetV2, AlexNet, and EfficientV1, respectively; furthermore, it was found that the optimal weighting factors are 0.5 and 0.5.","PeriodicalId":18135,"journal":{"name":"Lubricants","volume":"107 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139004146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-13DOI: 10.3390/lubricants11120529
Ouyang Wu, Ziyang Yan, Xincong Zhou, Bin Luo, Bin Wang, Jian Huang
On maritime vessels, external factors such as explosions, collisions, and grounding can cause the emulsification of lubricating oil by seawater pollution, which can affect the lubrication of a ship’s thrust bearing. To explore the influence of the mixed emulsification of lubricating oil and seawater on the lubrication performance of thrust bearings, this study conducted an emulsification experiment, from which the viscosity equation of the oil–water mixture was obtained. A thermal hydrodynamic model (THD) of bearings considering oil–water mixed emulsification was established, and the Finite Difference Method (FDM) was used for analysis. The results show that according to the characteristics of the manifold, the mixture is divided into water-in-oil (W/O) and oil-in-water (O/W). In the W/O flow with higher viscosity, the film thickness becomes higher, but the power loss increases. In the O/W manifold with low viscosity, the thin film easily causes mixed friction. In the demulsification stage of the mixed liquid, the thickness loss of the film is huge, and the collision between the thrust-bearing pad and the inference plate may cause the pad to be ablated. The influence of specific heat capacity on temperature is greater than the temperature rise caused by viscosity.
{"title":"A Thermal Hydrodynamic Model for Emulsified Oil-Lubricated Tilting-Pad Thrust Bearings","authors":"Ouyang Wu, Ziyang Yan, Xincong Zhou, Bin Luo, Bin Wang, Jian Huang","doi":"10.3390/lubricants11120529","DOIUrl":"https://doi.org/10.3390/lubricants11120529","url":null,"abstract":"On maritime vessels, external factors such as explosions, collisions, and grounding can cause the emulsification of lubricating oil by seawater pollution, which can affect the lubrication of a ship’s thrust bearing. To explore the influence of the mixed emulsification of lubricating oil and seawater on the lubrication performance of thrust bearings, this study conducted an emulsification experiment, from which the viscosity equation of the oil–water mixture was obtained. A thermal hydrodynamic model (THD) of bearings considering oil–water mixed emulsification was established, and the Finite Difference Method (FDM) was used for analysis. The results show that according to the characteristics of the manifold, the mixture is divided into water-in-oil (W/O) and oil-in-water (O/W). In the W/O flow with higher viscosity, the film thickness becomes higher, but the power loss increases. In the O/W manifold with low viscosity, the thin film easily causes mixed friction. In the demulsification stage of the mixed liquid, the thickness loss of the film is huge, and the collision between the thrust-bearing pad and the inference plate may cause the pad to be ablated. The influence of specific heat capacity on temperature is greater than the temperature rise caused by viscosity.","PeriodicalId":18135,"journal":{"name":"Lubricants","volume":"35 6","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139005616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-13DOI: 10.3390/lubricants11120528
Fei Gao, Ling Tian, Yongcun Cui, Yan Zhao, Bing Su, Liming Sun
Aerospace bearings need to withstand the low-temperature environment of space, which will cause changes in the internal lubrication state of the bearings. This article aims to assess the traction properties of aerospace lubricants under low-temperature micro-oil droplet (hereinafter referred to as ‘micro-oil’) supply conditions, and provide a lubrication theoretical basis for studying the motion characteristics of aerospace bearings in a low-temperature environment. An experimental study on the low-temperature micro-oil traction properties of high-speed bearing lubricants was conducted on a specially designed aerospace bearing lubricant traction characteristic tester. A modified Herschel–Bulkley model (modified H–B model) was presented based on test data analysis, and the fitting results were compared with the Tevaarwerk–Johnson model (T–J model). The findings demonstrated that the traction coefficient of this lubricant decreased at a higher load and entrainment velocity, and decreased with a decreasing inlet oil temperature from 0 °C to −50 °C. The modified H–B model accurately fitted the test data and was suitable for the engineering traction coefficient calculation of lubricants and high viscosities at low temperatures. This paper can provide fundamental information for analyzing aerospace bearing friction torque variation.
航天轴承需要承受太空低温环境，这将导致轴承内部润滑状态发生变化。本文旨在评估航天润滑剂在低温微油滴（以下简称 "微油"）供给条件下的牵引特性，为研究航天轴承在低温环境下的运动特性提供润滑理论依据。在专门设计的航空航天轴承润滑剂牵引特性测试仪上对高速轴承润滑剂的低温微油牵引特性进行了实验研究。根据测试数据分析，提出了改进的赫歇尔-布克雷模型（改进的 H-B 模型），并将拟合结果与特瓦韦克-约翰逊模型（T-J 模型）进行了比较。研究结果表明，该润滑油的牵引系数在较高载荷和夹带速度下降低，并随着入口油温从 0 °C 降至 -50 °C 而降低。改进后的 H-B 模型准确地拟合了测试数据，适用于低温下高粘度润滑油的工程牵引系数计算。本文可为分析航空航天轴承摩擦力矩变化提供基础信息。
{"title":"Traction Properties of Aerospace Lubricant under Low-Temperature Micro-Oil Droplet Supply Conditions","authors":"Fei Gao, Ling Tian, Yongcun Cui, Yan Zhao, Bing Su, Liming Sun","doi":"10.3390/lubricants11120528","DOIUrl":"https://doi.org/10.3390/lubricants11120528","url":null,"abstract":"Aerospace bearings need to withstand the low-temperature environment of space, which will cause changes in the internal lubrication state of the bearings. This article aims to assess the traction properties of aerospace lubricants under low-temperature micro-oil droplet (hereinafter referred to as ‘micro-oil’) supply conditions, and provide a lubrication theoretical basis for studying the motion characteristics of aerospace bearings in a low-temperature environment. An experimental study on the low-temperature micro-oil traction properties of high-speed bearing lubricants was conducted on a specially designed aerospace bearing lubricant traction characteristic tester. A modified Herschel–Bulkley model (modified H–B model) was presented based on test data analysis, and the fitting results were compared with the Tevaarwerk–Johnson model (T–J model). The findings demonstrated that the traction coefficient of this lubricant decreased at a higher load and entrainment velocity, and decreased with a decreasing inlet oil temperature from 0 °C to −50 °C. The modified H–B model accurately fitted the test data and was suitable for the engineering traction coefficient calculation of lubricants and high viscosities at low temperatures. This paper can provide fundamental information for analyzing aerospace bearing friction torque variation.","PeriodicalId":18135,"journal":{"name":"Lubricants","volume":"56 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138976494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-11DOI: 10.3390/lubricants11120525
Wenhu Zhang, Shili Li, Gang Zhou, Ningning Zhou, Yan Zhao, Wanjia Li
In this paper, a dynamic simulation analysis model was established for CMGB (control moment gyroscope bearing) under the conditions of time-varying moment. The influences of the moment’s response time, axial preload, and working temperature on the dynamic characteristics and friction torque of CMGB were analyzed, and the relevant verification tests were conducted. The results show that the friction torque fluctuation of CMGB directly corresponds to the dynamic characteristics. The faster the response time of the time-varying moment, the larger the friction torque fluctuation of CMGB. The larger preload minimizes the difference in the ball’s loading state, which is the actual reason for reducing the friction torque fluctuation. Moreover, as the working temperature increases, the friction torque fluctuation of CMGB decreases.
{"title":"Research on the Relationship between Dynamic Characteristics and Friction Torque Fluctuation of CMGB under the Condition of Time-Varying Moment","authors":"Wenhu Zhang, Shili Li, Gang Zhou, Ningning Zhou, Yan Zhao, Wanjia Li","doi":"10.3390/lubricants11120525","DOIUrl":"https://doi.org/10.3390/lubricants11120525","url":null,"abstract":"In this paper, a dynamic simulation analysis model was established for CMGB (control moment gyroscope bearing) under the conditions of time-varying moment. The influences of the moment’s response time, axial preload, and working temperature on the dynamic characteristics and friction torque of CMGB were analyzed, and the relevant verification tests were conducted. The results show that the friction torque fluctuation of CMGB directly corresponds to the dynamic characteristics. The faster the response time of the time-varying moment, the larger the friction torque fluctuation of CMGB. The larger preload minimizes the difference in the ball’s loading state, which is the actual reason for reducing the friction torque fluctuation. Moreover, as the working temperature increases, the friction torque fluctuation of CMGB decreases.","PeriodicalId":18135,"journal":{"name":"Lubricants","volume":"52 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138981465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-11DOI: 10.3390/lubricants11120527
Ziyan Lu, Qingqing Lin, Zhaotao Cao, Wanyuan Li, Junjie Gong, Yan Wang, Kunhong Hu, Xianguo Hu
Improving the lubricating properties of base oils through additives is a crucial objective of tribological research, as it helps to reduce friction and wear of materials. Molybdenum disulfide (MoS2) is a 2D nanomaterial with excellent tribological properties that is often used as a lubricant additive. Several studies have been conducted on the preparation and utilization of MoS2 and its nanocomposites as lubricant additives. This paper reviews the research progress on MoS2 nanomaterials as lubricant additives. It firstly introduces various synthesis methods of MoS2 nanomaterials while focusing on the preparation of nano-MoS2 as lubricant additives. It then summarizes the dispersion stability of nano-MoS2 in lubricating oils which has been paid extensive attention. Moreover, this paper reviews and discusses the tribological properties of nano-MoS2 and its various composites as lubricant additives. The possible anti-wear and friction reduction mechanisms of nano-MoS2 and its composites are also discussed. Finally, this paper presents the challenges faced by nano-MoS2 additives in the field of lubrication and the prospects for future research in view of previous studies.
{"title":"MoS2 Nanomaterials as Lubricant Additives: A Review","authors":"Ziyan Lu, Qingqing Lin, Zhaotao Cao, Wanyuan Li, Junjie Gong, Yan Wang, Kunhong Hu, Xianguo Hu","doi":"10.3390/lubricants11120527","DOIUrl":"https://doi.org/10.3390/lubricants11120527","url":null,"abstract":"Improving the lubricating properties of base oils through additives is a crucial objective of tribological research, as it helps to reduce friction and wear of materials. Molybdenum disulfide (MoS2) is a 2D nanomaterial with excellent tribological properties that is often used as a lubricant additive. Several studies have been conducted on the preparation and utilization of MoS2 and its nanocomposites as lubricant additives. This paper reviews the research progress on MoS2 nanomaterials as lubricant additives. It firstly introduces various synthesis methods of MoS2 nanomaterials while focusing on the preparation of nano-MoS2 as lubricant additives. It then summarizes the dispersion stability of nano-MoS2 in lubricating oils which has been paid extensive attention. Moreover, this paper reviews and discusses the tribological properties of nano-MoS2 and its various composites as lubricant additives. The possible anti-wear and friction reduction mechanisms of nano-MoS2 and its composites are also discussed. Finally, this paper presents the challenges faced by nano-MoS2 additives in the field of lubrication and the prospects for future research in view of previous studies.","PeriodicalId":18135,"journal":{"name":"Lubricants","volume":"242 3","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138981281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-11DOI: 10.3390/lubricants11120526
Museob Jeong, Won Cheol Shin, Yoonsuk Oh, Jungju Lee, Seung Hun Huh, J. Pee, Hyungjo Seo, Ho Jang, Jong-Young Kim
In this work, we evaluated the impact of disc rotors of gray cast iron (GCI), nitrocarburized (NC), and superhard ceramic-coated (SCC) GCI on the brake wear PM emissions of passenger vehicles using dynamometric measurements. The brake emission factor (BEF) of the SCC was greatly reduced by more than a factor of 1/5 compared with those for the GCI and NC for both low-steel and non-steel friction materials. Surface topological and microstructural analyses confirmed that more severe wear was pronounced for the NC rotor compared with the SCC, as evidenced by large concave pits in the wear tracks. Analysis of the size-classified airborne PM suggests that reduced micron-sized particles, which originated from the GCI disc, were responsible for the lower BEF due to the increased hardness of the SCC.
{"title":"Dynamometric Investigation on Airborne Particulate Matter from Automobile Brake: Impact of Disc Materials on Brake Emission Factor","authors":"Museob Jeong, Won Cheol Shin, Yoonsuk Oh, Jungju Lee, Seung Hun Huh, J. Pee, Hyungjo Seo, Ho Jang, Jong-Young Kim","doi":"10.3390/lubricants11120526","DOIUrl":"https://doi.org/10.3390/lubricants11120526","url":null,"abstract":"In this work, we evaluated the impact of disc rotors of gray cast iron (GCI), nitrocarburized (NC), and superhard ceramic-coated (SCC) GCI on the brake wear PM emissions of passenger vehicles using dynamometric measurements. The brake emission factor (BEF) of the SCC was greatly reduced by more than a factor of 1/5 compared with those for the GCI and NC for both low-steel and non-steel friction materials. Surface topological and microstructural analyses confirmed that more severe wear was pronounced for the NC rotor compared with the SCC, as evidenced by large concave pits in the wear tracks. Analysis of the size-classified airborne PM suggests that reduced micron-sized particles, which originated from the GCI disc, were responsible for the lower BEF due to the increased hardness of the SCC.","PeriodicalId":18135,"journal":{"name":"Lubricants","volume":"53 2","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138982080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-10DOI: 10.3390/lubricants11120523
Ozan Can Ozaner, A. Kapil, Yuji Sato, Yoshihiko Hayashi, Keiichiro Ikeda, Tetsuo Suga, Masahiro Tsukamoto, Ş. Karabulut, Musa Bilgin, Abhay Sharma
Inconel 718 (IN718), a Ni-based superalloy, is immensely popular in the aerospace, nuclear, and chemical industries. In these industrial fields, IN718 parts fabricated using conventional and additive manufacturing routes require subsequent machining to meet the dimensional accuracy and surface quality requirements of practical applications. The machining of IN718 has been a prominent research topic for conventionally cast, wrought, and forged parts. However, very little attention has been given to the machinability of IN718 additively manufactured using laser metal deposition (LMD). This lack of research can lead to numerous issues derived from the assumption that the machining behavior corresponds to conventionally fabricated parts. To address this, our study comprehensively assesses the machinability of LMDed IN718 in dry and minimum quantity lubrication (MQL) cutting environments. Our main goal is to understand how LMD process variables and the cutting environment affect cutting forces, tool wear, surface quality, and energy consumption when working with LMDed IN718 walls. To achieve this, we deposited IN718 on SS309L substrates while varying the following LMD process parameters: laser power, powder feed rate, and scanning speed. The results unveil that machining the deposited wall closer to the substrate is significantly more difficult than away from the substrate, owing to the variance in hardness along the build direction. MQL greatly improves machining across all processing parameters regardless of the machining location along the build direction. Laser power is identified as the most influential parameter, along with the recommendation for a specific combination of power feed rate and scanning speed, providing practical guidelines for optimizing the machining process. While MQL positively impacts machinability, hourly energy consumption remains comparable to dry cutting. This work offers practical guidance for improving the machinability of LMDed IN718 walls and the successful adoption of LMD and the additive–subtractive machining chain. The outcomes of this work provide a significant and critical understanding of location-dependent machinability that can help develop targeted approaches to overcome machining difficulties associated with specific areas of the LMDed structure. The finding that MQL significantly improves machining across all processing parameters, particularly in the challenging bottom region, offers practical guidance for selecting optimal cutting conditions. The potential economic benefits of MQL in terms of tool longevity without a substantial increase in energy costs is also highlighted, which has implications for incorporating MQL in several advanced manufacturing processes.
{"title":"Dry and Minimum Quantity Lubrication Machining of Additively Manufactured IN718 Produced via Laser Metal Deposition","authors":"Ozan Can Ozaner, A. Kapil, Yuji Sato, Yoshihiko Hayashi, Keiichiro Ikeda, Tetsuo Suga, Masahiro Tsukamoto, Ş. Karabulut, Musa Bilgin, Abhay Sharma","doi":"10.3390/lubricants11120523","DOIUrl":"https://doi.org/10.3390/lubricants11120523","url":null,"abstract":"Inconel 718 (IN718), a Ni-based superalloy, is immensely popular in the aerospace, nuclear, and chemical industries. In these industrial fields, IN718 parts fabricated using conventional and additive manufacturing routes require subsequent machining to meet the dimensional accuracy and surface quality requirements of practical applications. The machining of IN718 has been a prominent research topic for conventionally cast, wrought, and forged parts. However, very little attention has been given to the machinability of IN718 additively manufactured using laser metal deposition (LMD). This lack of research can lead to numerous issues derived from the assumption that the machining behavior corresponds to conventionally fabricated parts. To address this, our study comprehensively assesses the machinability of LMDed IN718 in dry and minimum quantity lubrication (MQL) cutting environments. Our main goal is to understand how LMD process variables and the cutting environment affect cutting forces, tool wear, surface quality, and energy consumption when working with LMDed IN718 walls. To achieve this, we deposited IN718 on SS309L substrates while varying the following LMD process parameters: laser power, powder feed rate, and scanning speed. The results unveil that machining the deposited wall closer to the substrate is significantly more difficult than away from the substrate, owing to the variance in hardness along the build direction. MQL greatly improves machining across all processing parameters regardless of the machining location along the build direction. Laser power is identified as the most influential parameter, along with the recommendation for a specific combination of power feed rate and scanning speed, providing practical guidelines for optimizing the machining process. While MQL positively impacts machinability, hourly energy consumption remains comparable to dry cutting. This work offers practical guidance for improving the machinability of LMDed IN718 walls and the successful adoption of LMD and the additive–subtractive machining chain. The outcomes of this work provide a significant and critical understanding of location-dependent machinability that can help develop targeted approaches to overcome machining difficulties associated with specific areas of the LMDed structure. The finding that MQL significantly improves machining across all processing parameters, particularly in the challenging bottom region, offers practical guidance for selecting optimal cutting conditions. The potential economic benefits of MQL in terms of tool longevity without a substantial increase in energy costs is also highlighted, which has implications for incorporating MQL in several advanced manufacturing processes.","PeriodicalId":18135,"journal":{"name":"Lubricants","volume":"803 ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138982645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, willow catkins/MoS2 nanoparticles (denoted as WCMSs) have been prepared using a hydrothermal method. The WCMSs were modified with oleic acid (OA) to improve dispersion in base oil. The friction and wear properties of WCMSs in liquid paraffin (LP) for steel balls were investigated using a four-ball wear tester. The results have shown that at a high reaction temperature, willow catkins (being used as a template) and urea (being used as a nitrogen resource) can effectively decrease the wear scar diameters (WSDs) and coefficients of friction (COFs). At a concentration of 0.5 wt.%, the WSD and COF of steel balls, when lubricated using LP containing modified WCMS with urea, decreased from 0.65 mm and 0.175 of pure LP to 0.46 mm and 0.09, respectively. The addition of urea and hydroxylated catkins can generate a significant number of loose nano-sheets and even graphene-like sheets. The weak van der Waals forces, decreasing the shear forces that the steel balls must overcome, provide effective lubrication during rotation. On the other hand, the tribo-films containing MoS2, FeS, azide, metal oxides and other compounds play important roles in reducing friction and facilitating anti-wear properties.
{"title":"Preparation and Tribological Behavior of Nitrogen-Doped Willow Catkins/MoS2 Nanocomposites as Lubricant Additives in Liquid Paraffin","authors":"Yaping Xing, Ebo Liu, Bailin Ren, Lisha Liu, Zhiguo Liu, Bocheng Zhu, Xiaotian Wang, Zhengfeng Jia, Weifang Han, Yungang Bai","doi":"10.3390/lubricants11120524","DOIUrl":"https://doi.org/10.3390/lubricants11120524","url":null,"abstract":"In this study, willow catkins/MoS2 nanoparticles (denoted as WCMSs) have been prepared using a hydrothermal method. The WCMSs were modified with oleic acid (OA) to improve dispersion in base oil. The friction and wear properties of WCMSs in liquid paraffin (LP) for steel balls were investigated using a four-ball wear tester. The results have shown that at a high reaction temperature, willow catkins (being used as a template) and urea (being used as a nitrogen resource) can effectively decrease the wear scar diameters (WSDs) and coefficients of friction (COFs). At a concentration of 0.5 wt.%, the WSD and COF of steel balls, when lubricated using LP containing modified WCMS with urea, decreased from 0.65 mm and 0.175 of pure LP to 0.46 mm and 0.09, respectively. The addition of urea and hydroxylated catkins can generate a significant number of loose nano-sheets and even graphene-like sheets. The weak van der Waals forces, decreasing the shear forces that the steel balls must overcome, provide effective lubrication during rotation. On the other hand, the tribo-films containing MoS2, FeS, azide, metal oxides and other compounds play important roles in reducing friction and facilitating anti-wear properties.","PeriodicalId":18135,"journal":{"name":"Lubricants","volume":"628 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138982860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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