Improvement of tribological properties of bearings by laser processing of cast-iron shafts of heavy-duty diesel engines

The article discusses the tribological properties of plain bearing materials in heavy-duty diesel engines with a cast-iron crankshaft. The effectiveness of the influence of laser hardening of shaft necks on the tribological properties of main and connecting rod bearings in comparison with nitriding is substantiated. Simulation comparative tribological tests have been carried out on a laboratory friction machine on samples of materials of an insert made of bronze Br-30 and a shaft made of high-strength cast iron with nodular graphite under conditions of sliding friction with lubrication after laser treatment hardening and nitriding. The influence of hardening treatments of the shaft necks on the antifriction properties and wear resistance of friction couples materials is investigated. Particular attention is paid to the scuff resistance of friction couples. The assumption of a higher efficiency of laser hardening in comparison with nitriding based on the tribological properties of friction surfaces is substantiated. Based on the study, it is recommended to use laser hardening of the crankshaft necks to increase the service life of heavy-duty low-speed diesel engines