Nickel-based metallurgical coating architectures for superior wear resistance in high-temperature P91 steel applications

Abstract

This study delves into an improved hardfacing approach for addressing high-temperature wear issues in engineering valves used in power plants. The suggested approach uses plasma transfer arc welding (PTAW) of Colmonoy 6 with an SS-309L buffer layer on P91 steel (CoSP91). Comparative investigation shows that CoSP91 has a 67 % improvement in wear resistance at elevated temperatures (600°C), with a documented wear loss of 0.01239 g compared to present industry practices (StP91: 0.08593 g). This increase is due to the formation of Cr₇C₃, Cr₂B, and Cr₅B₃ hard phases, as well as a protective oxide layer, that functions together to improve wear resistance. The findings demonstrate CoSP91 as a technically viable and cost-effective hardfacing solution for high-temperature components, with improved wear resistance and low cracking susceptibility.