Failure analysis of ring die of a feed pellet machine

摘要

The severely worn position and failure mechanisms of the ring die of a feedpellet machine were investigated. The macroscopic and microscopic morphologiesof the failed surface, the chemical composition and mechanical properties of thecollected samples were analyzed using scanning electron microscopy, energy dispersespectroscopy, optical emission spectrometry, and a universal testing machine. Resultsshow that the dip angle at the entrance of the ring die hole between the roller andring die was severely worn. The feed powder could not be fully extruded through thedip angle at the entrance of the ring die holes, thus the density of the feed particlesproduced could not meet the requirements. Therefore, abrasive wear under high stressis the main reason of failure at the entrance of the ring die holes under the action offeeding powder; and cutting and fatigue spalling lead to substantial material loss. Inaddition, a high damp-heat environment aggravates abrasive wear on the die holeinternal surface.