Case Study on Surface Porosities in Green Sand Casting

This case study presents an investigation into surface porosities in cast aluminum products produced through the green sand-casting process. The study outlines the challenges faced by BQC Foundry as they adopted high-speed green sand molding processes, which revealed defects related to surface porosity. Traditional mitigation methods were deemed insufficient, prompting BQC to collaborate with a casting simulation software partner to explore the root causes of porosity formation at the mold/metal interface. The study details the methodology used, including adjustments to metal chemistry, specifically Strontium levels, and the implementation of iron mold chillers to optimize solidification rates. Experimental results indicate a significant correlation between solidification time and hydrogen diffusion, with findings showing that reducing Strontium levels and employing mold chillers effectively minimized surface porosity. The report concludes with a summary of the findings and their implications for improving product quality in automated green sand molding processes.