Chemical Composition Characterization of Recycled Aluminum as a Basis for Evaluating Ship Propeller Materials

Abstract

Chemical composition provides essential information for evaluating recycled aluminum intended for cast components. This study identifies the elemental composition of a recycled aluminum sample associated with ship propeller research and examines the limitations of using these results for material evaluation. A descriptive analysis was conducted using a chemical composition certificate and its supporting measurement records issued by PT Guna Sukses Inti. The documentation contains one sample code and three readings obtained using a Hitachi FM Expert instrument. The analysis covered elemental composition, variation among readings, and interpretation supported by relevant literature. The certificate summary reports 84.90 wt.% Al, 11.00 wt.% Si, 2.12 wt.% Fe, 1,440 wt.% Zn, 0.184 wt.% Mn, and 0.076 wt.% Mg. These results indicate an aluminum–silicon-based composition containing iron and zinc that warrants further evaluation. The Mn-to-Fe mass ratio calculated from the certificate summary is approximately 0.087. Document examination also identified a copper result reported as >0.0010 wt.%, a difference between the stated aluminum average and the arithmetic mean of the displayed readings, and a testing standard whose applicability requires clarification. The composition data provides a preliminary basis for sample characterization but does not establish a specific alloy grade, mechanical properties, or operational suitability for ship propellers.