Analisis Pengaruh Variasi Media Pendinginan terhadap Karakteristik Mikrostruktur dan Sifat Mekanis Hasil Pengecoran Gravity Die Casting Paduan Daur Ulang Aluminium 6061

Abstract

This study aims to investigate the effect of cooling media variations on the mechanical properties and microstructural characteristics of recycled Aluminum 6061 produced with gravity die casting. The mechanical tests conducted included Vickers hardness testing, tensile testing, 3-point bending testing, wear resistance testing, and microstructural analysis. The results indicate that variations in cooling media significantly affect the mechanical properties of the material. The use of cooling media increased the hardness value from 53 VHN with air cooling to 61.1 VHN under water cooling and improved the ultimate tensile strength from 111.14 MPa under air cooling to 148.43 MPa under candlenut oil cooling. Wear resistance also showed an improvement, as indicated by a change in the wear rate from 3.13×10⁻⁷ mm³/Nmm with air cooling to 1.12×10⁻⁶ mm³/Nmm under water cooling. However, the maximum flexural strength was achieved with air cooling at 642.28 MPa and decreased under candlenut oil cooling to 467.26 MPa. Microstructural analysis confirms that higher cooling rates tend to produce smaller and finer grain structures, contributing to the strengthening of the material. Overall, candlenut oil cooling provides a balanced combination of mechanical properties and shows potential as an alternative quenching medium to conventional automotive lubricating oil due to its economic and environmentally friendly characteristics.