Análise da influência dos parâmetros de pulso na microestrutura de revestimento duro pelo processo STAG-Pó(GTAW) utilizando a liga Stellite 6

Abstract

The hard facing process have a high importance for the manufacturing sector and with a new releases of how to make it there is lot of questions about how the hard facing will be if we change the pulse parameters. This work search to make a microstructural analysis aiming to identify the influence of the pulse parameters in microstructure using the new method GTAW-P (Gas Tungsten Arc Welding Powder). A cobalt base alloy was used for make the hard facing, and this alloy is a powder Stellite 6 WM manufacturer by Deloro Stellite with a grain size between a 45 and 180 microns and hardness 41.3 HRC, the substrate used was SAE 1020 steel. The hardfacing was done with pulse current and the pulse parameters variations were found in peak and base times, which resulted in the three samples with different parameters. Qualitative and quantitative metallographic analyzes were performed microanalysis, HRC hardness testing and analysis of the dilution of the material were also performed. The results show that the sample with the longer base obtained the best result set, namely the average grain size of approximately 100 microns, an average hardness of 65 HRC and dilution of 4.18%. Besides the spectrum of regions A and B suggests the formation of carbonates in the region B, this region contains the highest percentage of chromium, cobalt, iron and carbon. In addition, the spectrum of the test SEM suggests the formation of carbides in the interdendritic region of the microstructure.