Development and Validation of Accelerated Fretting Wear Test for Inconel 718 Against 304 Stainless Steel

Fretting wear significantly limits the service life of metal O-rings operating under harsh conditions. To address this limitation, this study investigates the wear behavior of metal O-rings under equivalent accelerated reciprocating motion and establishes an accelerated life prediction model based on similarity theory. Fretting wear experiments were conducted using Inconel 718 alloy and 304 stainless steel to replicate service conditions in a controlled laboratory environment. Wear morphology was characterized using laser scanning confocal microscopy, revealing a progressive transition from mild abrasive and adhesive wear to severe abrasive wear accompanied by material spalling. Based on the experimental results, regression analysis was performed to estimate the acceleration model coefficients, leading to the formulation of an equivalent acceleration equation capable of predicting seal wear life under practical service conditions. The resulting equivalent acceleration model can establish a quantitative connection between the acceleration test and the operating conditions. This model can shorten the testing time and can be used to predict parameters related to the surface morphology of static seals, providing a theoretical and experimental basis for reliable life assessment. This provides a practical basis for improving the reliability and safe operation of metal O-ring seals in critical applications, including nuclear energy and chemical processing systems.