Effect of the brass waste recycling process on mechanical properties with investment casting for gear materials

This study is an experimental research to analyze the characteristics and mechanical properties of the casting process of recycled brass alloy, which will be used as a material for gears. Currently, the remaining production and waste from brass alloys continue to increase. Another thing is the increase in the need for brass gears, so environmentally friendly material engineering is needed to provide good quality and efficient energy use, especially during the casting process. The casting process uses an electric furnace that melts brass alloys at 526 up to 900 °C within 1 hour and molds to make test specimens. The results of microstructural testing for grain size in recycled brass alloys range from 74.63 μm to 84.57 μm. The maximum tensile strength produced is up to 225.2 MPa, the maximum yield strength is up to 179.8 MPa, and the maximum elongation is up to 7.3 %. The roughness of recycled brass alloys has a maximum Ra value (average roughness) of up to 0.836 μm. Validation was carried out by comparing the mechanical properties of CAC 302 brass products and the study results. The data shows that recycled brass's maximum yield strength value is 179.8 MPa and CAC 302 brass material is 175 MPa, but for the ultimate tensile strength value, the value of recycled brass is far below CAC 302 products. These results can be a consideration for the industry to be able to use recycled brass alloys for gear products because the yield strength value is not far from CAC 302 brass products. The impact result of this study produces recycled brass alloys that are environmentally friendly, efficient in smelting energy consumption, and have good yield strength. The results of this research can benefit the manufacture of gear components made of brass alloys.