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May 12, 2022
Abstract
The reactor pressure vessel was contact sealed with a double-channel O-ring made of Inconel 718 alloy and nuclear power material SA508. The fretting wear characteristics of Inconel 718 O-tube and SA508 plate friction pair were tested by fretting wear testing machine to explore the failure mechanism of reactor pressure vessel seal system. The test conditions are as follows: normal temperature, normal loads of 10, 20, and 40 N, displacement amplitude of 600 μm, the number of cycles of 10,000, and frequency of 4 Hz. Results show that the coefficient of friction (COF) increased with increasing normal force. Significant material losses were detected during the relative sliding of the contact surface of SA508. A large number of abrasive dust accumulated at the edge of the contact zone, forming a large number of oxides. During the friction of Inconel 718 O-ring, plastic deformation occurred, and a plastic flow layer was formed. The plastic deformation flow at the contact point formed an adhesive connection point, producing adhesive wear and oxidative wear. The wear mechanism was characterized by the combination of oxidative wear and abrasive wear.