electrochemical pitting

Why Do Nylon Garage Door Rollers Squeal and Seize? Decoding Bearing Pitting and Hygroscopic Swelling Reference Standard: ASTM G85 (Standard Practice for Modified Salt Spray (Fog) Testing) and ASTM D570 (Standard Test Method for Water Absorption of Plastics). Short Answer Nylon garage door rollers fail primarily due to dew point condensation causing electrochemical pitting in unsealed bearing raceways, transforming smooth rolling into high-frequency metal shrieking. Additionally, hygroscopic swelling of the polyamide shell drastically alters its geometry, while fretting wear at the stem-hinge interface strips zinc plating, inducing severe galvanic locking. Dew Point Condensation and Electrochemical Pitting Kinetics in Micro-Bearing Raceways When standard 11-ball nylon garage door wheels begin to emit … 続きを読む