Analysis of changes in the microstructure of compression rings of an auxiliary marine engine
Authors:   Admiral Ushakov Maritime State University, Novorossiysk, Russian Federation, Syusyuka Elena , Amineva Elena ,   Admiral Ushakov Maritime State University, Novorossiysk, Russian Federation, Kabirov Yuri ,   South Federal University, Rostov-on-Don, Russian Federation, Prutsakova Natalia ,   Don State Technical University, Rostov-on-Don, Russian Federation
Published: December 2024

Introduction. The cylinder-piston group (CPG) of a marine-type internal combustion engine is subjected to high operational loads. The reliability, durability and efficiency of the engine depend on the proper operation of the CPG. The change in the direction of piston movement and the lack of lubrication caused by the spraying of lubricant during operation, lead to increased wear of the moving package of piston rings. Having determined the factors influencing the changes in the structure of the metal during operation, it can be taken into account in the manufacturing technology and hardening of these parts. The subject of the study: the object of research is the used-out upper and lower compression rings of the cylinder-piston group of the HIMSEN 4H21/32 auxiliary marine engine. Purpose of the work is to consider the change in the structure and microstructure of the material of the compression piston rings of the HIMSEN 4H21/32 auxiliary marine engine arising as a result of operation; to compare the results of evaluating microstresses and deformations of the surface layer of parts by metallographic methods and X-ray diffraction analysis for various operating conditions of the upper and lower compression rings. Methods. Metallographic and X-ray methods were used in the study. The conditions of X-ray photography are described; X-ray diffraction analysis was carried out on a Dron-3M diffractometer. Residual microdeformations were determined, as well as the sizes of coherent scattering regions (D) and the density of dislocations on the surfaces of the samples. Results of the work. The results of metallographic and X-ray diffraction analysis (XRD) are presented. The residual macro- and microstresses and the sizes of the coherent scattering regions (D) of the surface layer of compression rings are determined. The results of X-ray diffraction analysis are comparable with the results of metallographic studies, and the convergence of the results is observed. Scope of the results application: the results of the study can be used in the selection of manufacturing technology for compression rings of marine internal combustion engines (MICE). Conclusions. It is advisable to evaluate changes in the manifestations of the stress state of cast iron under the influence of various factors. This will allow selecting the optimal technology for manufacturing compression rings to ensure the reliability of its operation. Ring quality control by various methods of structure assessment also makes it possible to predict the conditions of destruction of compression rings during operation. An increase in the degree of defectiveness of the upper ring occurs due to various kinds of deformations of the crystallites. As a result of inelastic deformations during ring operation, the resulting dislocations cause strong mechanical stresses.