Papers by Keyword: Abrasion

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Authors: Ye Han, Shu Yu Yao, Wei Wei Zhang, Ming Gu, Yu Sui Yao
Abstract: A novel wear resistant glass-ceramic coating system (based on SiO2-B2O3-Al2O3 glass system) on iron based substrate was developed. Friction coefficient, wear rate and coefficient of thermal expansion of coating material were evaluated using suitable methods. The coating materials and the resultant coatings were characterized using differential thermal analysis (DTA), X-ray diffraction analysis (XRD) and Scanning Electron Microscope (SEM). XRD analysis of the coating materials showed presence of a number of microcrystal. SEM micrographs indicate strong chemical bonding at the iron-ceramic interface. The coating material showed perfect properties for protection the iron substrate from abrasion.
521
Authors: Zhao Zhong Zhou, Kai Ping Feng, Ju Long Yuan
Abstract: A new polishing method by using fixed soft abrasive film is proposed to polish the end-face of the optic fiber connector. In order to study the wear property of the fixed soft abrasive film, the Particle Flow Code program was employed to simulate the interaction of surface topography. The discrete element model of the optic fiber connector and the fixed soft abrasive film were established. Through the interaction of the surface of two models, the process of contact and friction between the fixed soft abrasive film and the end-face of the optic fiber connector could be simulated. Simulation results showed that the main factors affecting the wear of the fixed soft abrasive film were pressure and speed, which mainly affected the normal stress and the tangential stress respectively. And the wear of the surface was mainly related to pressure and speed. The greater the speed and pressure were, the more serious wear of the fixed soft abrasive film was.
452
Authors: Masanori Hirose, Kaoru Yamamoto, Hirofumi Miyahara, Kazunori Sakata, Keisaku Ogi
Abstract: A series of abrasion tests on high Cr-V-Nb cast irons revealed that the addition of MC type carbide formers, V and Nb, remarkably enhances the abrasion resistance of high Cr cast iron, and the abrasion resistance becomes higher with the increase in MC type carbides[1]. Therefore, hyper eutectic Fe-4.7%C-15%Cr-7%V-5%Nb-5%Mo alloy melt was poured into 30kg and 1kg sand mold castings to distribute different sizes of primary and eutectic carbides in hardenable matrix. The abrasion test specimens cut from each casting were austenitized at 1323K for 1h then cooled in air. These specimens were tempered at 773K for 1h followed by air cooling. The hardness of specimens was 1015-1018HV50. The rubber wheel abrasion test, a typical 3 body type one, was performed on these quenched and tempered specimens with 56-107, 107-150 and 297 μm dia. silica grit. The testing load was 86.3N and 172.5N, and the rubber wheel rotation speed was varied from 1s-1 to 4s-1. Though the higher testing load increases the wear loss, the wear rate expressed by the wear volume/( testing load × wear distance) changes depending on the wear condition and the microstructure. In case of 30kg cast specimen, the silica grit preferentially attack and scrape off the matrix, and the wear rate increases with the increase in the testing load. The fine carbides in 1kg cast specimens effectively protect the matrix from the attack of silica grit, and the wear rate decreases with increasing load which causes silica grit blunt and fracture. However, fine carbides tend to be fractured by silica grit and diminish the protective effect. Based on the worn surface structures, the abrasion mechanism is discussed comparing those of steel and eutectic 25%Cr cast iron.
243
Authors: Hui Bin Hu, Xin Wen Cao, Shu Xiao Chen, Ji Sheng Ma
Abstract: Breech mechanism is the key and important device to improve reliability and maintenance for large caliber guns. It’s major fault mode is grain abrasion caused by dry sliding friction. There is no feasible and practical technologies to simulate and predict the abrasion failure life of key parts for breech mechanism. A new simulation and prediction method is firstly put forward in this paper. Based on Pro/E and ADAMS, the virtual prototype of breech mechanism of semiautomatic vertical sliding-wedge type is established. To validate its precision and effectivity, qualitative and quantitative verification method are adopted to check the virtual prototype of breech mechanism. Virtual prototype produces key parts’ load spectrums and failure theresholds. Dry sliding friction and abrasion experiment provides abrasion rules of typical materials. Finial simulation and prediction results are given as abrasion thresholds and operating items, which provide sufficient references for breech mechanism’s maintenance and safeguard.
2233
Authors: Xin Jie Shao, Li Jun Cao, Guang Tian, Qiao Ma, Jin Hua Liu, Hui Bin Hu
Abstract: Breech mechanism serves to close the breech, fire the ammunition and extract the cartridge case in firing process. In firing process, breech mechanism completes complicated actions, bears tremendous impact forces and produces huge percussive forces between components. Its major fault mode is grain abrasion caused by dry sliding friction. There are no feasible and practical technologies to simulate and predict the abrasion failure life of key parts for breech mechanism. A new simulation and prediction method is firstly put forward in this paper. Based on Pro/E and ADAMS, the virtual prototype of breech mechanism of semiautomatic vertical sliding-wedge type is established. To validate its precision and affectivity, qualitative and quantitative verification methods are adopted to check the virtual prototype of breech mechanism. Virtual prototype produces key parts’ load spectrums and failure thresholds. Dry sliding friction and abrasion experiment provides abrasion rules of typical materials. Finial simulation and prediction results are given as abrasion thresholds and operating items, which provides sufficient references for breech mechanism’s maintenance and safeguard.
762
Authors: Xin Li, Gao Liang Peng, Wen Jian Liu
Abstract: Modeling for the abrasion behavior of the rubber-like material is needed in designing a sliding seal in a hydraulic system. The abrasion mechanism of elastomeric material differs from metals or other polymers. In this paper the abrasion behavior of the seal was studied through numerical simulation method. An FE contact model was built. Considering the actual manufacturing situation, a sinusoidal function was used to describe the surface roughness of the rod. An abrasion algorithm based on the linear abrasion theory was adopted. The nonlinear behavior of the seal material and extreme working conditions were also considered. The birth and death element technology was used in the simulation process to imitate the loss of the material. The results displayed the worn profile of the seal and the influences to the sealing pressure caused by the working conditions outside and the roughness of the rod.
253
Authors: Zhen Jun He, Peng Xu, Jian Rong Lu
Abstract: To demonstrate the importance of abrasion and clearance to machinery, this paper studied abrasion of Cam mechanism contact surface, illustrated how abrasion and clearance relate to each other and investigated how they influence kinematic accuracy of the mechanism. In the case of Cam mechanism with flat-bottomed translation follower, it elaborated abrasion styles and bad points and depicted heart-shaped abrasion rate curve. It proposed a mathematical model and optimized design for cam profile, taking abrasion design as an objective function. Aided by Matlab and its optimization toolbox, it also proposed a optimized solution to the objective function mathematical model. And powered by computing capabilities of Matlab, it determined the coefficients in a high-order five-term function and found the optimal value of the objective function quickly in need. By optimization, mechanism abrasion improves and its kinematic accuracy and reliability increase, prolong its life.
1120
Authors: Jenny Andersson, P. Hollman, S. Jacobson
141
Authors: X.L. Jin, Liang Chi Zhang
Abstract: This paper develops a statistical model to analyze the chemical effect on the material removal rate (MRR) in chemo-mechanical polishing of material surfaces (MS). It was considered that the chemical effect comes into play through a passivated layer on the MS. It was found that the effect of such layer on MRR depends on the mean particle radius, the elastic modulus of the pad, and the hardnesses of the passivated layer and the workpiece material.
451
Authors: Yong Yan Zhou, Yong Fu Zhao, Tian Sheng Chen, Guo Hua Lu
Abstract: Several different kinds of flue-gas side abrasions occurred in thermal power plant were discussed. And the occurring positions, characteristics, influence factors as well as identification and prevention methods were also introduced in detail. So some advice may serve a reference for efficiently identificating and preventing boiler failure caused by flue-gas side abrasion.
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