40th International Conference on Production Engineering of Serbia
ICPES 2025
Nis, Serbia, 18-19th september 2025
IMPACT OF GATING SYSTEM DESIGNA ON MECHANICAL PROPERTIES OF ALUMINIUM SAND CASTINGS
Marko Zagoricnik, Lazar Kovacevic, Vladimir Terek, Zoran Bobic, Pal Terek
DOI: 10.46793/ICPES25.151Z
Aluminium alloys are extensively employed across modern industries, appreciated for their advantageous combination of low weight, corrosion resistance, strength, and ductility. Nonetheless, casting defects—including inclusions, porosity, hydrogen absorption, and particularly bifilms—can significantly compromise the mechanical properties of cast components. The present investigation centres on bifilm-related defects, which originate from the oxidation behaviour of aluminium alloys. Upon exposure to air, a thin oxide layer instantly forms on the molten metal surface. When disrupted, this film is immediately replaced by a new one, and such layers can become entrained within the melt during various stages of processing. Once inside the liquid metal, these oxide films retain their structural integrity due to their inert nature, remaining as compacted and folded entities that do not dissolve or disperse. Their presence has a pronounced negative impact on mechanical properties and can result in internal discontinuities that reduce mechanical properties and manifest as leak paths after machining. While bifilms can be introduced during melting, charging, or refining, the pouring phase presents a critical opportunity for their entrapment. Thus, the design of the gating system becomes essential. In this preliminary study, the role of flow dynamics during mould filling was examined by comparing two distinctly configured gating systems in sand casting of aluminium alloy: a top-gated setup promoting turbulent flow, and a bottom-gated arrangement intended to minimize flow disturbance. Advanced simulation using Magmasoft software confirmed the expected flow behaviours, illustrating greater splashing and air entrapment in the top-gated configuration. Following casting, samples were machined and subjected to tensile testing. Results demonstrated a statistically significant increase in ultimate tensile strength for specimens produced via the bottom-gated system. This exploratory experiment lays the groundwork for continued investigations into bifilm mitigation through optimized gating design
Bifilms, casting, entrainment, aluminium alloy, gating systems
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