Wear resistance and hardness of nanostructured hardfacing coatings

Abstract

Abrasive wear is an important problema in industrial applications. The wear of tools in the mining industry is a costly issue, and it reduces equipment uptime. This study examined welded coatings obtained using a manual metal arc process with improved wear resistance. Their microstructure was studied by optical and electron microscopy. ASTM G99 (pin-on-disc) and ASTM G65 (dry sand/rubber wheel) wear tests were performed, and the worn surfaces were inspected to understand the wear mechanisms. The results show that the coating has a hypereutectic microstructure composed of austenite, NbC, and M7C3 carbides. The size of the nanocarbides was 91 nm; and the volume content, 5.3%. Hardness values were found around 1029 HV200 g, 15 seg. Low values of mass losses were attributed to the hypereutectic nanostructured hardfacing coating with extremely high hardness. The main wear mechanisms were microfracture and detachment of carbides and microcutting on the matrix.

Keywords

• Nanostructured
• hardfacing
• Abrasion
• hypereutectic