Study On Characteristics Of Fretting Wear Of Alloy 690 Tube With Plasma Spraying WC-12Co Coating

In the thermal conduction devices of the pressure reactor nuclear power plant, steam generator plays an important role. But flow induced vibration causes fretting wear between the heat transfer tubes and the support plates, which leads to the steam generator tube failure. By plasma spraying high-temperature and wear-resistant coatings-WC-12Co on the support plate material 1Cr13 stainless steel and simulating fretting behavior with the heat transfer tube 690 alloy material in different conditions, research the effect of the coating to reduce fretting wear between the heat transfer tube and support plate, provide some data to improve the service performance of the steam generator.This paper takes the fretting test by tube/contact manner in the PLINT fretting wear tester, at different temperatures (25 ℃,200 ℃,300 ℃), different loads (50N,80N,100N), and different displacements (80μm,150μm,200μm).By comparing to the friction coefficients,3D friction characteristic curves, the amounts of wear, microscopic morphology s of 690 alloy/1Cr13 stainless steel and 690 alloy/plasma sprayed WC-12Co, the conclusions come as follows:1. At room temperature, displacement amplitude has little effect on the friction coefficient of 690 alloy tube/plasma sprayed WC-12Co coating; the friction coefficient increases with the normal load increasing. At the high temperature of 300 ℃,the friction coefficient of 690 alloy tube/WC-12Co coating is increasing with displacement amplitude and normal load increasing. No matter at 25 ℃ or 300℃,690 alloy tube’s wear depth is deepen with normal load, displacement amplitude increasing.2. With the increase of temperature, the friction coefficient of alloy 690 tube/WC-12Co coating increases.690 alloy tube’s wear depth in this friction pair also increases with the increasing temperature. At 200 ℃and 300℃, the 690 alloy tube wear depth changes little.3. At room temperature 25 ℃, the wear mechanism of 690 alloys is mainly abrasive wear, delimitation and some adhesive wear, mechanism of plasma WC-12Co coating is mainly delamination wear. At 300 ℃, the wear mechanism of 690 alloy is abrasive wear and oxidation wear and some adhesive wear. Wear mechanism of plasma sprayed WC-12Co coating is mainly delamination wear, existing oxidation wear.4. In any condition, the wear depths of 690 alloy/plasma WC-12Co coating pair always are less than the wear depths of 690 alloy/1Cr13 stainless steel.Date shows the plasma spraying WC-12Co coating on the support material 1Cr13 stainless steel can significantly reduce the fretting wear of steam generator tube.