Study of wear resistance of different piston ring materials

Piston rings are one of the most important sub-components of the IC engine. Cast Iron and Steels are among the materials used to manufacture Piston Rings. The common wear factors of a Piston Ring are friction, corrosion and thermal loads. Many researchers have come up with various effective methods such as improved Lubrication methods and Coatings to significantly reduce the wear factors improving the life and efficiency of the Piston rings. Existing coating technologies include plasma spraying, gas nitriding, chromium plating, physical vapor deposition which provide improved wear resistance. The sustained improvement of engine performance has compelled the engineers to develop piston rings of significantly greater efficiency. This induces various stresses in the moving assemblies such as adverse mechanical and thermal load specifically on the engine piston assembly. This research deals with study of different aspects of stress under the real conditions of loading such as mechanical stresses and wear, which will improve engine efficiency and effectively control oil lubrication. Chromium plating is one of the earliest coatings which is cost effective but requires improvements to cater to increasing demands. This paper deals with the testing of different chrome coatings on piston rings. The materials are Normal Chrome Coating, Moly Ceramic Chrome (MCC) and MC coated piston rings. The wear resistance tests conducted on Linear Reciprocating wear test tribometer produced valuable outputs. The tribometer works on the principle of pressing the test specimen on a cylinder liner in a reciprocating fashion simulating the action of an IC engine. The test was conducted in lubricated conditions with constant load of 50N and frequency 5Hz at 100°C for a time period of 60 minutes. The post wear tests including weight loss and contour analysis on worn out rings was performed.