Enhancement of wear and erosion-corrosion resistance of Inconel 718 alloy by liquid nitriding

Abstract

Inconel 718 alloy is often used for the oil and gas industry, which usually failed due to the erosion-corrosion of multi-phase flow. In this study, we expect to enhance the wear and erosion-corrosion resistance of Inconel 718 alloy by liquid nitriding and a high-hardness nitrided layer with the thickness of about 9.5 μ m on the surface of Inconel 718 alloy was formed by liquid nitriding. Wear and erosion-corrosion tests were performed on untreated and nitrided Inconel 718 alloys. Results show that abrasive wear and adhesive wear occurred in both nitrided and untreated samples at different temperatures (25 °C, 100 °C and 200 °C). The width and depth of the wear track and the wear rate of the nitrided samples are all smaller than that of the untreated samples. Liquid nitriding significantly improves the wear resistance of Inconel 718 alloy because of the high-hardness nitrided layer. The nitrided Inconel 718 alloy exhibited an improvement of almost 80.3% in the erosion-corrosion resistance compared to their untreated counterparts. The weight loss rate of the erosion-only shows an obvious reduction after liquid nitriding. The surface nitrided layer with high hardness effectively protects the substrate, and prevents the material from the erosion-corrosion of multi-phase flow consisting of the SiO _2 particles and the acidic solution, so that the total weight loss of nitrided Inconel 718 alloy decreased evidently.

Keywords

• Inconel 718 alloy
• liquid nitriding
• nitrided layer
• wear resistance
• erosion-corrosion resistance