Basic Studies on the Role of Softer Metallic Coatings in Ball Bearings
Suresha Gowda M. V1, Ranganatha S2, Vidyasagar H. N3
1Suresha Gowda M. V, Department of Mechanical Engineering, University Visweswaraya College of Engineering, Bangalore (Karnataka), India.
2Dr. Ranganatha S, Department of Mechanical Engineering, University Visweswaraya College of Engineering, Bangalore (Karnataka), India.
3Dr. Vidyasagar H. N, Department of Mechanical Engineering, University Visweswaraya College of Engineering, Bangalore (Karnataka), India.
Manuscript received on 15 February 2016 | Revised Manuscript received on 20 February 2016 | Manuscript Published on 28 February 2016 | PP: 24-31 | Volume-5 Issue-9, February 2016 | Retrieval Number: I2266025916/16©BEIESP
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC-BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Abstract: The performance, reliability and load transferring capabilities of bearing elements are very important in industrial applications. The newer design of high speed machines demands better bearing system. The reliability is of primary importance in case of bearing elements used in aerospace industries. Exhaustive studies have been carried out by different researchers under two extreme conditions. One is using a fluid as lubricants which do not bear shear loads. The other extreme were using hard coatings which bears enormous amount of shear loads. In the present investigation an attempt has been made to understand the kinematics of deformation of coatings which are not as hard as conventional coatings. Casehardened carbon steel balls were coated with tin, zinc and nickel by electroplating technique. The thickness of the coating was maintained at 25 µm. Four ball test rig was used to simulate the field conditions. The experiments were conducted without lubricants. The normal loads were 100N, 300N and 500N respectively and run for a period of 5 minutes. The frictional load and normal load were monitored and coefficient of friction was estimated. The wear scar was studied under scanning electron microscope. The co-efficient of friction was found to be dependent on normal load and type of coating material. The co-efficient of friction was found to be minimum of value 0.28 for a maximum normal load of 500N for tin coating. The morphology of wear scar studied in scanning electron microscope explains the dependency of co-efficient of friction on normal load and different coating materials
Keywords: Rolling Contact Fatigue, Four Ball Tester, Coatings.
Scope of the Article: Metallurgy