Increasing the wear resistance of the ICE’s valves with the laser cladding method

Abstract

BACKGROUND: There is plenty of factors leading to failure and expensive repair of piston engines at their operation. One of the widespread factors capable of affecting the engine operation is combustion chamber sealing failure. During the engine operation, gases combusting in a chamber bring pressure on working surfaces of a valve and a valve seat. If these surfaces do not ensure sealing, exhaust gases begin to leak in the exhaust manifold untimely, in some cases in the intake manifold as well. In addition, filling of cylinders with inlet charge worsens. In majority of cases, combustion chamber sealing failure caused by defect formation at working surfaces of the valve — valve seat coupling. In order to avoid combustion chamber sealing failures and other issues of operation of piston engines, it is necessary to minimize working surfaces wearing by means of wear-resistant coating. AIMS: Wear- and corrosion-resistant coating of valve’s working surface to increase service life. METHODS: The factors affecting the reliability of the valve — valve seat coupling were defined by means of literary sources analysis. Laser cladding at the valve’s chamfer was conducted with the laser robotized facility based on ytterbium fiber laser. Quality of the coated surface at the valve’s working chamfer was defined by means of metallographic study and liquid penetrant test. RESULTS: After laser cladding of the PR-08Kh17N8S6G powder material at the valve’s working chamfer, the uniform coated surface with microhardness of 435–485 HV (44–48 HRC) was obtained. CONCLUSIONS: The study results may be used for development and implementation of new kinds of wear-resistant surfaces that make it possible to increase the service life and to repair worn-down surfaces of components.