Avaliação do Desempenho de Lâminas para Corte de Vergalhões Revestidas por Soldagem FCAW Utilizando a liga de FeCrC

Abstract

This work is an applied or practical research of a real problem in the metallurgical industry segment that cuts rebar for use in metal structures for civil construction. This company uses knives or blades to cut rebar bars for the production of structures such as beams, trusses, columns, among others. These knives operate under dynamic loading when shearing the material, which leads to the deterioration of their surface over time. This deterioration may occur due to factors such as friction, abrasion, and fatigue. The recovery of rebar cutting knives is necessary because, with constant use, severe failures can occur during operation, leading to material loss that affects the quality of cuts, accident risks, and low productivity. To restore the knives due to wear, reduce process costs, and achieve longer durability in the work cycle, a coating was applied using the FCAW welding process with a consumable based on iron, chromium, and carbon. The consumable has good mechanical properties and features such as abrasive resistance and high hardness due to the formation of carbides in its microstructures. The methodology consisted of conducting tests on knives coated with one and two layers of coating on the material originally used by the company and on common carbon steel. Tests were also carried out on a new knife from the company. The parameters for the coating were chosen by analyzing the weld beads, considering their width and penetration, as well as dilution. The cutting tests were conducted using approximately 1,000 cuts or knife failure as the stopping criterion. The results showed that the new knife, without coating, performed better than the coated knives. Among the coated knives, the one that showed the best performance had a single layer on the VC-131 steel substrate. All coating samples presented primary carbides (Cr7C3) in their microstructures in rod and hexagonal shapes.