Study On High Temperature Fretting Wear Of Inconel690/1CR13SS And Inconel690/WC-25Co Coatings

Fretting is defined as the small displacement movement between two contact surface. Since fretting damage is mainly caused by the micro accidental vibration, it may result in catastrophic failure in the machinery parts when this no obvious symptom fretting damage accumulated. Steam generator tubes may sometimes emerge fretting wear damage at the tube-to-support locations because of the flow-caused vibration. Until now, no perfect solution of fretting damage is found in spite of a lot of effort had made.The fretting wear behaviors of Inconel690/1Cr13SS and Inconel690/WC-25Co Coating were studied experimentally on a high precision fretting test machine PLINT using tube to plate contact. This paper was designed to analysis the the friction characteristic curve, the fretting coefficients and the morphology of the worn surface, and the the mechanism of fretting wear was discussed. It came to the conclusions as follows:1There is a slight incidence of the displacement amplitude on the friction coefficient of Inconel690/1Cr13SS and Inconel690/WC-25Co Coating, while the friction coefficient of the two are directly correlated with the normal load, which rises with the increasing of the normal load.2The variation of normal load and amplitude have a significant influence on the fretting wear damage of Inconel690/1Cr13SS and Inconel690/WC-25Co Coating, and the wear volume of the two increase with the rise of normal load and amplitude respectively.3The total wear volume of Inconel690and WC-25Co Coating decreases with the rise of the temperature, while the max wear volume of Inconle690and1Cr13SS occurred at200℃, and the wear volume at300℃is larger than that at25℃.4The wear mechanism of the Inconel690Alloy and1Cr13SS at25℃were mainly a combination of abrasive wear and delamination while WC-25Co Coating was abrasive. At elavated temperature the wear mechanism of the Inconel690Alloy and1Cr13SS were a combination of abrasive wear, oxidization wear, and delamination, yet WC-25Co Coating was abrasive still at300℃.5Under any circumstances, the total wear volume of Inconel690and WC-25Co Coating was smaller than that of Inconel690and1Cr13SS. It can come to a conclusion that the WC-25Co Coating on the1Cr13SS substrate using Detonation Gun Spraying method could greatly reduce the fretting wear damge on the SG tube and its support board.