Per: PIETRO PERUSSATTO (Universidade de Passo Fundo), gABRIEL FABIAN DOS SANTOS (Universidade de Passo Fundo), William Haupt (Universidade de Passo Fundo), MARIA LUIZA DOS SANTOS (Universidade de Passo Fundo), CHARLES LEONARDO ISRAEL (Universidade de Passo Fundo), deividi nardi (dstrac performance 4x4)
Abstract:
In the present work, a microstructural analysis was carried out on electric vehicle differential gears manufactured from microcast SAE 4320 and machined SAE 8620 steels, both subjected to carburizing, quenching and tempering processes. The objective of the analysis is to evaluate the thickness and uniformity of the cemented layer, using Vickers microhardness, macrography and micrography to identify microconstituents and micro defects. This analysis becomes relevant due to the fact that the components analyzed suffer wear and rolling contact with large loads. From the macrographic analysis, it can be concluded that the micro-cast gear in SAE 4320 steel presented a more uniform case-hardened layer compared to those machined in SAE 8620 steel, however, the microhardness test revealed that the former presented greater variability, in addition to the presence of austenite retained in the microstructure. Both cases exhibited martensite as the main microconstituent, in addition to the presence of micro defects, which had a larger area occupied in the machined SAE 8620 steel sample. In short, the microcast gears showed advantages in terms of uniformity with higher microhardness values in the case-hardened layer and the formation of micro defects, however, the machined samples exhibited less variability and did not show the formation of retained austenite.