Abstract
To improve friction and wear performance and service life of the disc-brake pair material of a drilling rig, a new type of asbestos-free frictional material with better performance for disc-brake blocks is developed, and its wear mechanism is investigated by friction and wear experiments. Topography and elementary components of the brake block’s wear surface are analyzed by employing SEM and EDAX patterns, revealing its tribological behaviour and wear mechanism. When the frictional temperature is lower, the surface film of the brake block is thinner, dense, smooth with plasticity, and divided into the mixture area, Feabundant area, carbon-abundant area and spalling area. The mixture area consists of various constituents of frictional pairs without ploughing and rolling trace. The Fe-abundant area mainly consists of iron and other constituents. The carbon-abundant area is the zone where graphite and organic fibre are comparatively gathered, while the spalling area is the zone where the surface film is spalled and its surface is rough and uneven, with a loose and denuded state. During the period of high frictional temperature, the frictional surface is also divided into the mixture area, Feabundant area and spalling area. In this case, the mixture area consists of abrasive dust from friction pairs, and the surface film is distributed with crumby hard granules, exiguous oxide, carbide granules and sheared slender fibre. The Fe-abundant area is mostly an oxide layer of iron with a flaky distribution. Fracture and spalling traces as well as an overlapping structure of multilayer surface films can be easily found on the surface film. The components of the spalling area are basically the same as that of the matrix. At the beginning of wear, the hard peaks from the friction surface of the disc-brake plough on the surface of the brake block. With increasing frictional temperature, the friction surface begins to soften and expand, and oxidized wear occurs at the same time. During the high-temperature wear period, severely influenced by friction heat, obvious softening and plastic flow can be found on the friction surface of the brake block, its anti-shearing ability is weakened, and adhesive wear is intensified. Thermal decomposition of cohesive material in the brake block is simultaneously strengthened, so that constituents shed due to loss of adhesion. Organic fibre is in a flowing state and obviously generates drawing, shearing, carbonization and oxidization. In addition, thermal cracking, thermal oxidization, carbonization and cyclization of organic substances on the surface of brake block can make the friction surface produce pores or cracks, thus fatigue wear occurs.
Similar content being viewed by others
References
Yi Maozhong, Han Zhihai, Chen Hua, et al. The study on the brake friction characteristic of plasma sprayed fe-ni-co-wc coating. Tribology, 1996, 16(2): 150–155
Wang Xinhua, Zhang Siwei, Fan Qiyun. Experimental study in screening and matching of disc brake pair materials of drilling rig. Tribology, 2002, 22(3): 197–201
Zhang Siwei, Wang Xinhua, Fan Qiyun, et al. Investigation of the tribological performance of friction pair for disc brake of drilling rig. Science in China (Series A), 2001, 44(Supplement): 253–258
Fan Qiyun, Zhang Siwei, Li Weiming. Thermal design, a new concept of the disc brake design. Oil Field Equipment, 1995, 24(3): 22–25
Jia Xian, Zhou Benlian, Chen Yongtan, et al. Study on worn surface layers of the friction pair vonsisting of semimetallic friction materials and grey cast iron. Tribology, 1995, 15(2): 171–176
Wang Bozhan, Yao Anyou. Research on meerschaum brakefriction material and analysis of its friction and wear mechanism. In: Proceedings of the 5th National Symposium on Tribology, Part I, 1992, 591–596
Zhang Mingzhe, Liu Yongbing, Yang Xiaohong. The progress in the tribological investigation of automotive friction materials. Tribology, 1999, 19(4): 379–384
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Wang, X., Wang, S., Zhang, S. et al. Wear mechanism of disc-brake block material for new type of drilling rig. Front. Mech. Eng. China 3, 10–16 (2008). https://doi.org/10.1007/s11465-008-0009-2
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s11465-008-0009-2