{"id":3359,"date":"2026-05-18T14:05:34","date_gmt":"2026-05-18T06:05:34","guid":{"rendered":"https:\/\/www.c-adtech.com\/?p=3359"},"modified":"2026-05-18T14:10:47","modified_gmt":"2026-05-18T06:10:47","slug":"how-to-reduce-porosity-in-aluminium-casting","status":"publish","type":"post","link":"https:\/\/www.c-adtech.com\/fr\/how-to-reduce-porosity-in-aluminium-casting\/","title":{"rendered":"Comment r\u00e9duire la porosit\u00e9 dans la coul\u00e9e de l'aluminium ?"},"content":{"rendered":"

Porosity in aluminium casting can be effectively reduced by combining four proven process controls: rotary degassing<\/a> to remove dissolved hydrogen, ceramic foam filtration<\/a> to eliminate non-metallic inclusions, flux treatment with refining agents and slag removers to clean the melt, and optimized solidification conditions including controlled cooling rates and gating system design. In our experience working with aluminium foundries across multiple casting processes, facilities that implement all four controls simultaneously achieve hydrogen levels below 0.10 cc\/100g and density index values under 1.5% \u2014 thresholds that essentially eliminate porosity as a rejection cause in structural castings. Treating only one or two of these variables while ignoring the others produces marginal improvement at best.<\/p>\n

If your project requires the use of degassing unit and aluminum flux, you can contact us<\/a>\u00a0for a free quote.<\/span><\/p>\n

What Is Porosity in Aluminium Casting and Why Does It Cause Casting Rejection?<\/h2>\n

Porosity refers to the presence of voids, holes, or discontinuities within a solidified aluminium casting. These internal defects reduce the effective load-bearing cross-section of the part, act as stress concentration points under mechanical loading, and create leak paths in pressure-tight applications. A casting that passes visual inspection can contain sufficient internal porosity to fail destructive mechanical testing or pressure testing \u2014 making porosity one of the most economically damaging and difficult-to-detect defect categories in aluminium casting production.<\/p>\n

\"Infographic
Infographic showing how to reduce porosity in aluminium casting through melt degassing, mold optimization, controlled pouring, solidification control, and post-casting treatment methods.<\/figcaption><\/figure>\n

The financial consequences of porosity-related rejection are substantial. Scrap rates of 5% to 15% attributable to porosity are common in foundries without systematic melt treatment programs. In high-value aluminium components for aerospace, automotive safety systems, and hydraulic equipment, even a single rejected casting can represent significant material and processing cost losses.<\/p>\n

Two Distinct Types of Porosity in Aluminium<\/h3>\n

Understanding the difference between gas porosity and shrinkage porosity is essential because each type has different root causes and requires different corrective actions.<\/p>\n

Gas Porosity (Hydrogen Porosity)<\/strong><\/p>\n

Gas porosity forms when dissolved hydrogen in the liquid aluminium precipitates as bubbles during solidification. The solubility of hydrogen in aluminium drops sharply at the liquidus temperature \u2014 from approximately 0.65 cc\/100g in liquid aluminium at 660\u00b0C to less than 0.034 cc\/100g in solid aluminium. Any hydrogen above this solubility limit must either escape to the surface before solidification completes or remains trapped as spherical or near-spherical pores within the casting.<\/p>\n

Gas pores are characteristically:<\/p>\n