Tribology in Industry

13-19

Authors: S. Milojević, R. Pešić, D. Taranović

Reducing vehicle weight contributes to reducing fuel consumption and exhaust emissions. In practice, this is achieved by application of lightweight materials and through optimization of tribo-systems on the vehicle. The benefit of using aluminium is evident due to the reduced mass of the parts, but in parallel there is a problem due to the low strength of this metal. This is especially evident during overheating when can form cracks. The wear resistance and tribo-properties of aluminium are the problem, too. To achieve the strength and tribo-properties of aluminium alloys similar to grey cast iron, we applied eco-tribological knowledge during construction of reciprocating machines. The result of researches is patented prototype of aluminium piston and cylinder whose contact surfaces are coated or modified with inserts based on the tribo-materials.

29-33

Authors: I. Popa, L.S. Stanciu

Portable masts are parts of mobile servicing rigs designed to work at drilling or extraction wells and are made of three sections: fixed section, lower section and upper section. During transportation, the mast is placed in a horizontal position on a truck chassis, with the upper section nested inside the lower section. Before putting into service the mobile servicing rig, the lower and upper sections are erected as a unit, in a slightly inclined position. In this paper, the authors present the results of a research regarding the safety in functioning for such a mast which is under the action of the wind with high velocities. The wind’s action direction with respect to the mast is analyzed in two cases: front-back and lateral, with stress and strain values that occur.

42-54

Authors: P.C. Mishra, S. Bhattacharya, P. Pandey

Piston Compression ring is the constituent part of ring-liner sliding pair that is subjected to high load and speed condition. Due to lubrication regime transition, there is the greater chance of wear and tear in the ring as well as in the liner. In order to reduce the wear and to enhance the ring and liner life, ceramic coatings are provided on the surface of such contact pairs. Current paper uses a finite element method to analyze the coating strength of a compression ring at compression and power stroke transition, where peak combustion pressure is higher than other crank positions. The deformation, von Misses stress and strain in the core and coating interface are discussed elaborately.

60-65

Authors: K. Bouzid, N.E. Beliardouh, C. Nouveau

A comparative study was conducted to evaluate the performances against wear and corrosion of CrN, CrMoN, CrZrN, CrVN single layer thin films. The latest are synthesized onto steel substrates (DIN 90CrMoV8), using R.F reactive magnetron co-sputtering. The experimental work was achieved using ball-on-disc configuration in dry conditions against WC balls. The main conclusions are: (i) electrochemical tests in 0.3 wt.% NaCl solution indicated that CrZrN are improved anticorrosion performance when compared to CrN, while CrMoN demonstrated a poor corrosion resistance;(ii) the CrN coating presents the better tribological properties when compared to the ternary nitride coatings.

72-80

Authors: G. Pantazopoulos, A. Tsolakis, P. Psyllaki, A. Vazdirvanidis

The wear and degradation mechanisms of two principle vehicle tribosystems are presented to elucidate the main causes of their premature failure. The first case study concerns the malfunction of an automotive cast iron pressure plate operated in an automobile clutch system. The second is related to the unexpected failure of a stainless steel brake disk of a high performance motorcycle. Both components are designed to function under sliding friction conditions that lead to the severe wear of consumable non-metallic parts of the tribosystems: the clutch disk and the brake pad, respectively. However, in both cases it was the unexpected failure of the conjugate metallic parts that resulted in terminal system damage. The experimental approach to identify the root cause of failure involved both microstructure characterization, as well as observations of the metallic contact surfaces by means of optical and scanning electron microscopy, in conjunction with microhardness and surface topography measurements. For the case of the stainless steel brake disk in particular, Finite Element Analysis was employed to simulate the operating tribosystem, identify the site(s) prone for crack initiation and validate the failure mechanisms hypotheses.

88-96

Authors: M.A.C. Besnea, D.C. Trufasu, G. Andrei, M. Bastiurea, M.S. Rodeanu

Wear behavior of polyphenylene sulphide composites was investigated according to load and test speed. Two types of materials were studied: first, with 40 wt% glass fiber, and second, with 10 wt% carbon fiber, 10 wt% graphite and 10 wt%. Tribological tests were performed on the universal tribometer UMT-2, using a pin-on-disc device. The friction coefficient and wear rate for the composites were analyzed. As a result of experimental tests, it was established that polymer composite with polyphenylene sulphide matrix, carbon fibers, graphite and polytetrafluorethylene exhibit good wear behavior under operating conditions.

107-116

Authors: J.O. Agunsoye, S.A. Bello, I.S. Talabi, A.A. Yekinni, I.A. Raheem, A.D. Oderinde, T.E. Idegbekwu

Aluminium based metal matrix composites have been produced from recycled aluminium cans and 150µm sized eggshell particles using a stir cast process. The mechanical properties of the control and aluminium can/eggshell composites produced have been investigated. The microstructures of the aluminium can/eggshell composites were examined with the aids of Scanning Electron Microscope (SEM) after the sample surfaces have been carefully prepared and etched with aqueous solution of 0.5 cm3 nitric acid. Micrographs revealed that there was a homogenous distribution of eggshell particles within the aluminium can matrix. An indication of effective stirring action during the melting process. The wear resistance was also investigated under different applied loads (6 to 14 N) on an abrasive surface emery paper of grade 220. The results revealed an increase in Young’s modulus of elasticity and yield stress from 1,206.45 and 50.23 Mpa respectively of the cast aluminium can with 0 % eggshell particle to the maximum of 3,258.87and 73.2 MPa of aluminium can/12 % eggshell composites. The hardness values increased from 66.23 to 75.13 VN. There was a gradual increase in wear rate of the tested samples as the applied load increased. However, the wear resistance of the aluminium can/6 % eggshell and aluminium can/12 % eggshell composites increased significantly. Hence, recycling of aluminium cans and eggshells can be harnessed into development of useful engineering metal matrix composite materials.