Reliability evaluation of hardness test methods of hardfacing coatings with hypoeutectic and hypereutectic microstructures

摘要

Hardfacing coatings involve hard carbide/boride phases dispersed in a relatively soft steel matrix. For the hardness measurements of hardfacing coatings, depending on the micro structure, both the hardness test method and the applied load affect the hardness results; therefore, they affect the wear performance predictions of the coating. For this reason, the proper hardness test method should be determined according to the microstructure of the coating, and the reliability of the obtained hardness data should be established. This study aimed to determine the most suitable hardness test method for hypoeutectic and hypereutectic microstructures of hardfacing coatings by analyzing the reliability of Rockwell-C and Vickers hardness test results. Reliability analyses showed that Rockwell-C is not a suitable hardness test method for hypereutectic hardfacing coatings. Based on the relationship between wear resistance and hardness, Vickers hardness method was found more suitable for the considered materials.