Effect of refining time on porosity and mechanical preperties of low-ressure casting made of ALSI7MG alloy
The study determines the effect of gas-bubbling refining time on porosity and mechanical properties of low-pressure AlSi7Mg alloy castings under industrial conditions. Refining was performed with an NH2 mixture (90% N + 10% H2) for 5.0–9.0 min. Porosity, density index, HB hardness, tensile strength Rm, 0.2% proof stress Rp0.2 and elongation A were evaluated. The optimum refining time was 7 min, giving minimum porosity and mechanical properties meeting customer requirements. Longer refining increased porosity and reduced selected mechanical properties.