Wear Properties and Scuffing Resistance of the Cr–Al2O3 Coated Piston Rings: The Effect of Convexity Position on Barrel Surface

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Siqi Ma ◽  
Wenbin Chen ◽  
Chengdi Li ◽  
Mei Jin ◽  
Ruoxuan Huang ◽  
...  

This work investigates the effect of convexity position of ring barrel surface on the wear properties and scuffing resistance of the Cr–Al2O3 coated piston rings against with the CuNiCr cast iron cylinder liner. The scuffed surface morphology and elements distribution as well as the oil film edge were analyzed to explore the influencing mechanism of the convexity position on the scuffing resistance. The results show that the convexity offset rate on the barrel surface of the ring has no noticeable influence on both friction coefficient and wear loss near the dead points, but a suitable convexity position will result in the improved scuffing resistance. The shape of the barrel face not only affects the worn area on the ring, but also determines the oil film wedge and pressure distribution, consequently influences the scuffing resistance.

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 139 ◽  
Author(s):  
Wenhua Li ◽  
Baihong Yu ◽  
Yutao Lv ◽  
Yan Shen ◽  
Ruoxuan Huang ◽  
...  

In order to investigate the friction and wear behavior between the nodular cast iron cylinder liner (Fe) and CuSn coated piston ring under heavy-duty conditions, piston rings with chromium(Cr) coating and CuSn-Cr coating were tested using the piston ring reciprocating liner test rig at the simulated working conditions of 56 MPa, 200 r/min, 190 °C. Compared with the Cr/Fe pair, the CuSn coating consumption of the CuSn-Cr/Fe pair made friction coefficient and cylinder wear loss decrease by 2.8% and 51.5%, respectively. Different size Sn patches worn from the CuSn coated piston ring were embedded into the cylinder liner surface based on the surface topography. This process was shown to reduce the surface roughness of a cylinder liner and form flatter plateau structures. Chemical elements analysis indicated that plateau structures on the cylinder liner surface matched with CuSn-Cr coated ring are helpful to promote the tribo-chemical reaction and generate the reactive products to protect the mutually contacted asperities.


2011 ◽  
Vol 175 ◽  
pp. 136-139 ◽  
Author(s):  
Bing Suo Pan ◽  
Xiao Hong Fang ◽  
Ming Yuan Niu

To reduce the friction coefficient between impregnated diamond bit and rock, experiments on addition of graphite to the matrix material of bit cutters were conducted. The cutters were made up of diamond contained working layers and binding layers. The friction and wear properties of cutters and binding layers were investigated using a pin-on-disc friction & wear tester with granite as tribopair. The results showed that with addition of graphite, the hardness and friction coefficient of binding layer decreased, but its wear resistance increased; compared to cutters without graphite, those cutters containing graphite had lower wear loss and friction coefficient and their sliding wear process was much steadier, but diamond protrusion was still normal.


2011 ◽  
Vol 314-316 ◽  
pp. 58-61 ◽  
Author(s):  
Wan Li Song ◽  
Chul Hee Lee ◽  
Seung Bok Choi ◽  
Myeong Woo Cho

In this paper, the effect of particle concentration and magnetic field on the tribological behavior of magneto-rheological (MR) fluid is investigated using a pin-on-disc tribometer. The wear loss and friction coefficient are measured to study the friction and wear properties of MR fluid. The morphology of the worn pin is also observed by scanning electron microscope (SEM) in order to analyze the wear mechanism. The results obtained in this work show that the wear loss and friction coefficient decrease with increasing particle concentration under the magnetic field. Furthermore, it is demonstrated that the magnetic field has a significant effect on improving tribological properties of MR fluid, especially the one with high particle concentration. The predominant wear mechanism of the MR fluid has been identified as abrasive wear.


2013 ◽  
Vol 470 ◽  
pp. 7-10
Author(s):  
Ki Woo Nam ◽  
Soo Chul Lee

Compacted vermicular (CV) graphitization cast iron is the name given to graphitization cast iron where the shape of the graphite looks like a vermicular. Castability and the thermal conductivity of CV graphitization cast iron is similar to those of Grey iron, while the strength of CV graphitization cast iron is similar to that of ductile iron. The thin film of diamond-like carbon (DLC) is one of the amorphous carbon thin films. It has various characteristics which are similar to those of diamond, such as high hardness, lubricity, abrasion resistance, chemical stability, electrical insulating properties and optical transparency. In this study, wear characteristics of Graphite Compacted Vermicular (GCV) material were investigated in accordance with changes in DLC coating time. The obtained results are as follows: the microstructure of GCV340 showed complex tissue with eccentric graphite and spherical graphite. The friction coefficient shows under 0.2 in all specimens. After enduring the wear test until 2000 m, the coating layer of the DLC coating specimen of 90 minute hardly showed any damage. It had only partial damage after taking the wear test until 2000 m. The friction coefficient was also the lowest.


SPE Journal ◽  
2021 ◽  
pp. 1-16
Author(s):  
Y. Zhou ◽  
J. H. Hu ◽  
B. Tan ◽  
Y. Jiang ◽  
Y. F. Tang

Summary Sealing is a technical bottleneck that affects drilling efficiency and cost in deep, difficult-to-drill formations. The spiral combination seal with active sand removal performance is a new type of seal, and the wear mechanism is not clear, resulting in no effective design. In this study, the wear properties of materials were measured by a friction-and-wear testing machine, and the measurement methods and criteria of wear loss and friction coefficient were established. The fitting function of working condition and friction coefficient was studied by fitting regression method. The law of influence of working conditions on friction coefficient and wear amount was determined. The actual wear model and evaluation criteria of wear condition were established by using wear test data and geometric relationship. The relationship among working conditions, contact stress, and wear depth is determined by numerical simulation method, and the wear mechanism of the new seal is revealed, which provides a theoretical basis for its application.


2011 ◽  
Vol 328-330 ◽  
pp. 1228-1231
Author(s):  
Ke Ping Zhang ◽  
Jian Long Huang ◽  
Jing Feng Wu

In this study, the abrasive testing machine which was similar to the roller mills was used. It used orthogonal test design and cast iron as the wear material. The main factor effected wear results such as abrasive particle size, rotation speed and rolling gap between the metal materials surface of two rollers were considered in order to find out the best value of each factor and optimize the condition of wheat grinding. Furthermore the wear properties of grain powder on cast iron and wear mechanisms were discussed. The results showed that powder size is the most important factor of the wear properties, the gap is the secondary factor and rotation speed is third. The wear loss is minimal while size is 0.2mm, gap is 0.5mm and rotation speed is 181± 2r/min.


1974 ◽  
Vol 188 (1) ◽  
pp. 253-261 ◽  
Author(s):  
G. M. Hamilton ◽  
S. L. Moore

A capacity gauge has been designed for operating in the conditions of a working engine. The method of using it for determining the oil-film thickness and piston-ring profile is described. Oil-film thicknesses in the range 0·4-2·5 μm between the piston rings and the cylinder liner have been observed. Their variation with speed, load and temperature has been measured and it is concluded that their behaviour is essentially hydrodynamic.


2015 ◽  
Vol 809-810 ◽  
pp. 572-577
Author(s):  
Costel Florea ◽  
Costică Bejinariu ◽  
Viorel Paleu ◽  
Daniela Chicet ◽  
Ioan Carcea ◽  
...  

A new cast iron material with a higher Cr content than usual is analyzed by chemical, micro-structural and friction coefficient point of view. The material was obtained by classical melting and the results compared with the experimental results obtained from a standard cast-iron used for applicative disk brake. Four different mechanical solicitation rates were used on the same material surface and the same load. The solicitation regime can be considered as semi-liquid and similar to a raining day experimental conditions. In this paper no thermal considerations were present or discussed. The results present a bigger friction coefficient of the new material and further considerations are necessary for example in a different friction regime.


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