Avaliação do processo de usinagem de revestimentos aspergidos por chama de alta velocidade

Abstract

The main objective of this work is to analyze the morphology and microhardness of the highspeed flame sprayed (HVOF) coating of Cr3C225NiCr after machining the coating. To analyze this process, different machining processes were performed on a coated sample, and microhardness, SEM and profilometry tests were performed before and after machining for comparison. In machining in which the tool has a nose radius smaller than 1 mm, there was a detachment of the coating, in one of the samples it is verified that the detachment happens from a depth of cut, occurring due to the increase of the interaction of the tool with the coating, recommending that the cutting depth be as small as possible when machining. In the other samples, it was analyzed that the lamellae ripped off in the machining process generate large valleys (Rv) compared to the peaks (Rp), happening that the largest peaks are caused due to the adhesion of the lamellae ripped off in the machining process, due to this there is a large difference in surface roughness, and the average roughness (Ra) does not follow a pattern, varying according to each machining process. In addition, the machining results of the coated tool were the best. In the microhardness results, lower values were obtained after machining, which may have occurred due to microcracks caused during the process.