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Luoyang, China

Wang H.,Nanjing University of Technology | Wang H.,Luoyang LYC Bearing Co. | Hong R.,Nanjing University of Technology | Chen J.,Nanjing University of Technology | Tang M.,Nanjing University of Technology
International Journal of Engineering, Transactions A: Basics

Slewing bearing, which is widely applied in tank, excavator and wind turbine, is a critical component of rotational machines. Standard procedure for bearing life calculation and condition assessment has been established for general rolling bearings. Nevertheless, relatively less literatures in regard to the health condition assessment of slewing bearing has been published in past. Real time health condition assessment for slewing bearing is used for avoiding catastrophic failures by detectable and preventative measurement. In this paper, a new strategy is presented for health evaluation of slewing bearing based on multiple characteristic parameters, and ANN (Artificial Neural Network ) and ANFIS(Adaptive Neuro-Fuzzy Inference System ) models are demonstrated to predict the health condition of slewing bearings. The prediction capabilities offered by ANN and ANFIS are shown by data obtained from full life test of slewing bearings in NJUT test System. Various statistical performance indexes have been utilized to compare the performance of two predicted models. The results suggest that ANFIS-based prediction model outperforms ANN models. Source

Li Y.,Taiyuan University of Science and Technology | Qi H.,Taiyuan University of Science and Technology | Li Q.,Taiyuan University of Science and Technology | Chen G.,Luoyang LYC Bearing Co. | And 2 more authors.
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering

Aiming at many disadvantages such as long process, more heating times and wasting materials and energy in technology of manufacturing ring parts currently in use, a new cast-rolling forming technology of ring parts is put forward and researched. A cast ring blank is directly rolled into ring part in this new technology, so it possess many advantages such as saving energy, saving materials and shorten the process. In this new technology, the cast quality, organization and performance of cast blank has important influence to rolling process and the quality of ring part. Take 42CrMo commonly used in bearing ring for example, the smelt and casting process for producing high-quality ring casts is researched by means of theoretical analysis and simulation. The industrial test on blank cast of bearing rings is completed in Luoyang LYC Co. ltd. It is shown from the results of experiments and tests that the ring blank produced by this cast process possess favorable quality, microstructure and mechanical character and can provide high quality cast blanks for new cast-rolling forming technology. © 2013 Journal of Mechanical Engineering. Source

Effect of subzero treatment and cryogenic treatment on carbide morphology, Rockwell hardness, hardness gradient and the depth of the G20Cr2Ni4A steel carburized layer was investigated by means of SEM, hardness tester and micro-hardness tester. The results indicate that subzero treatment and cryogenic treatment can increase dispersed precipitation of the carbides, reduce retained austenite, thus the hardness of the carburized layer increases, while the effect of subzero treatment on depth may be very small. © 2016, Editorial Office of "Jinshu Rechuli". All right reserved. Source

Wu Y.Z.,University of Sichuan | Wang Q.Y.,University of Sichuan | Ouyang Q.L.,Luoyang LYC Bearing Co.
Applied Mechanics and Materials

Using the ultrasonic fatigue test method, the influence of subjection to plasma nitriding surface modifications on the ultra-high cycle fatigue behavior of Ti-6Al-4V was investigated, then a comparison with corresponding behaviors of the normal Ti-6Al-4V was made. The results show the S-N curve of Ti-6Al-4V with plasma nitriding surface modifications still continuously declines, no conventional fatigue limit exists for Ti-6Al-4V. Plasma nitriding surface modifications enhance surface hardness, but they make the material fatigue strength decrease by about 17 %. The fractography of fatigue failure has been observed by scanning electron microscopy. The observation shows that fatigue failure initiates from internal of specimen after the fatigue life of 10 8 cycles and fatigue cracks mainly initiate from the surface of specimen before the fatigue life of 10 8 cycles. © (2012) Trans Tech Publications. Source

Liu Y.-J.,Sichuan University | Ouyang Q.-L.,Luoyang LYC Bearing Co. | Tian R.-H.,Sichuan University | Wang Q.-Y.,Sichuan University
Yiyong Shengwu Lixue/Journal of Medical Biomechanics

Objective: To study the ultra-high cycle fatigue behaviors of the Ti-6Al-4V alloy implant after subjection to simulated body fluid (SBF) environment exceeding 107 cycles, and to predict its service life. Method: The Ti-6Al-4V alloy specimens were subjected to SBF in two groups for two days and six days respectively; using the ultrasonic fatigue testing technique, the ultra-high cycle fatigue properties of Ti-6Al-4V alloy after subjection to SBF in body temperature were studied and the initiation mechanisms of fatigue cracks were investigated and analyzed with scanning electron microscopy (SEM) and energy dispersive atomic X-ray (EDA X-ray). Then, a comparison with corresponding behaviors of the normal Ti-6Al-4V alloy was made. Results: The S-N curve of the Ti-6Al-4V alloy after subjection had the similar tendency as that of the normal one, showing that they descended continuously during 104 and 108 cycles and the descending tendency was lower in the region of 107~108 cycles; the life of the specimens after subjection dropped before the fatigue life of 107 cycles and was smaller after the fatigue life of 107 cycles than that of the normal ones; the life of the specimens subjected for six days had little difference with that subjected for two days; fracture could still occur beyond 107 cycles, showing that there was no fatigue limit as the traditional fatigue conception described. Fatigue cracks mainly initiated from the surface of specimen before the fatigue life of 107 cycles and some specimens had multiple crack initiation sites; fatigue failure initiated from internal inclusion where mostly the element Al aggregated after the fatigue life of 108 cycles. Conclusions: The ultra-high cycle fatigue properties of the Ti-6Al-4V alloy decreas a little with SBF subjection; the initiation site of the fatigue crack changes from the surface to the internal defect with the increase of the number of cycle. Source

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