Fretting wear damage mechanism of Inconel 690 alloy tube in nuclear power plant

Abstract

The steam generator is subjected to the action of high temperature and high-pressure steam， and the flow induced vibration phenomenon of its heat transfer tube is caused by the secondary lateral flow. At the same time， the periodic loads cause fretting wear and fretting fatigue in the Inconel 690 alloy tube heat transfer tube and 403SS anti-vibration bar， which makes the heat transfer tube crack or even rupture and fail， and affects the safe operation of the nuclear power system. The friction and wear test of Inconel 690 alloy heat transfer tube and 403SS anti-vibration bar under different normal loads and displacement amplitudes was carried out by using fretting wear testing machine under normal temperature air and high-temperature air. The surface wear morphology and oxidation components of Inconel 690 alloy heat transfer tube were analyzed to reveal the wear failure mechanism of the heat transfer tube of the steam generator. The results show that with the increase of normal load at room temperature， debris accumulation and delamination appear on the surface of worn scars， and the degree of oxidation gradually intensifies. The fretting wear mechanism is mainly friction oxidation， abrasive wear， and delamination. Under the condition of high-temperature air， the peak friction force and the depth of worn scars increase， and the width of worn scars decrease. The plastic flow on the surface of the material is obvious， and the degree of oxidation and delamination deepens under the condition of high-temperature air. The fretting wear mechanism is mainly friction oxidation and delamination.

Keywords

• nuclear power steam generator
• inconel 690 alloy tube
• fretting wear
• damage mechanism