Failure Case Study Series Part Three: Investigation of Wear and Failure Mechanisms in Heavy-Duty Gear Coupling

Abstract

This paper investigates the failure mechanisms of the gear teeth in a heavyduty coupling, emphasizing the combined effects of mechanical loading, metallurgical microstructure, and tribological wear mechanisms.
Detailed characterization using optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and both chemical and mechanical testing identified pronounced wear and progressive degradation of the coupling sleeve, largely driven by operational misalignments and external contamination, such as mill cobbles. The analysis underscores the critical importance of precise material compatibility, a controlled hardness differential, and manufacturing accuracy in mitigating localized stress concentrations and wear. The findings highlight that abnormal wear progression results from a complex interaction among load redistribution owing to misalignment, tribological deterioration, manufacturing tolerances, and dynamic rotor–coupling interactions. Recommendations focus on optimizing design parameters, manufacturing processes, and operational routines to enhance the reliability, durability, and safety of high-torque coupling systems in harsh industrial environments.