Investigation on the Failure of Gear Pump

Abstract

Failure investigation was carried out on an eroded gear pump used for dispensing hot melt adhesive. A comparative study was also done with respect to another pump which provided satisfactory service life earlier. From the investigation, it has been concluded that Pump1 and Pump2 are different in designs as well as in material specifications. Pump1 is made of AISI D2 grade tool steel and Pump2 is made of gray cast iron. The damage in Pump1 is mainly due to localized pitting corrosion arising due to galvanic reaction within the microstructure between the matrix and the carbide particles where as in Pump2 is mainly due to abrasion wear. Presence of chlorine, sulfur and oxygen has been detected in both the pump’s worn surfaces. These elements sourced from adhesive medium might have acted as corrosive medium. Hence, in order to properly select a material for a specific application, a thorough requirement for that application may be reviewed.