TJ957 : An experimental investigation on galling wear resistance of mextallic sheets fabricated by accumulative roll bonding
Thesis > Central Library of Shahrood University > Mechanical Engineering > MSc > 2024
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The phenomenon of galling is one of the most important factors in the degradation of industrial components. Galling, in technical terms, is a type of wear caused by adhesion between sliding surfaces, which leads to scratches and damage to the crystalline structure of the underlying surface. The creation of scratches on the surface of a component due to contact with the die surface during forming results in galling defects in the product. In this thesis, the Accumulative Roll Bonding (ARB), which is a method of severe plastic deformation of mextal sheets, is used to increase the strength of the sheet. Subsequently, galling wear tests were conducted on the surfaces of the accumulatively rolled sheets, and the effect of the rolling process on wear resistance was evaluated. The ARB process was executed for up to six passes on AA1050 aluminum sheets, and a wear testing tool was designed and fabricated. This tool is suitable for conducting sliding wear tests on the sheet surface. It is used to determine the width of galling wear in mextal sheets. Wear tests were conducted on the mextal sheets under dry conditions and with lubrication, using two types of sliders: flat and spherical, with variable forces of 20N, 250N, and 500N. With the increase in the number of passes, after six passes of the ARB process, the width of galling wear decreased by 19% compared to the initial sample. The results showed that at higher forces, galling tendency increased by 16% compared to lower forces. When comparing the use of flat and spherical sliders in the wear testing tool, the amount of wear generated on the sheet surface by the two sliders was not equal. While at 500N, the width of galling wear created by the spherical slider was reduced by 2% compared to the flat slider, at 250N, the reduction was 8%. The presence of drawing oil lubricant, due to its low viscosity, does not have a significant effect on controlling the galling phenomenon.
Keywords:
#NWear #Galling #Accumulative Roll Bonding #Sliding on the surface of the sheet #lubricatio Keeping place: Central Library of Shahrood University
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