Metallurgical Examination of Scored and Ridged Hypoid Gears

A metallurgical study has been made of the failure mechanisms of scored and ridged hypoid gears using light and electron microscopes. The existence of two scoring mechanisms, the adhesion theory and a delamination theory are firmly elucidated. An interesting phenomenon often termed “White Etching Zones,” concomitant with scoring, has been investigated. This white layer may be postulated to be evidenced of catastrophic thermoplastic shear.