Wear resistance of a Metco 1030A hard coating deposited on Hadfield steel by laser cladding for ore comminution application

Abstract

The premature wear and/or failure of components and equipment used for ore comminution can result in unscheduled downtime and, therefore, significant losses for the mining industry, in which it is estimated that about half of the total maintenance cost in mining is due to the manufacture of damaged parts and the other half due to downtime and labor. In this sense, approaches to improve the wear resistance of this kind of equipment are of great interest. Therefore, the present work aims to evaluate the potential of coating a high manganese Hadfield steel used to manufacture grinding hammers with Metco 1030A alloy (Fe–C–Mo–V–B) via laser cladding (DED-L). The coatings were deposited on Hadfield steel substrates (cast) using different levels of laser power and scanning speed. The coatings were characterized in relation to the presence of surface and internal defects, morphology, microstructure, chemical composition, and microhardness. The wear resistance of the coatings was evaluated by pin-on-drum tests. For all deposition conditions, continuous tracks were formed. Despite the superficial cracks, the layers did not detach, confirming the metallurgical bond with the substrate. The microstructure of the coatings is typically composed of vanadium carbides (VCs) and molybdenum borides (Mo2B) in a martensitic matrix. For the same scanning speed, carbides and borides tend to become larger and more widely spaced with increasing laser power. Compared with the Hadfield steel substrate, the coatings have significantly higher hardness and wear resistance. Despite the cracks, normally acceptable in the intended application, it can be said that the application of the Metco 1030 alloy via laser cladding has the potential to increase the service life of Hadfield grinding hammers.