High-quality foam ceramic filter plates play a crucial role in improving casting quality by effectively removing primary and secondary liquid/solid non-metallic inclusions from molten metal. This reduces slag holes, enhances mechanical properties, decreases machining allowances, improves surface finish, and extends tool life. As complex castings like cylinder blocks and heads increasingly require these filters (annual usage reaching tens of millions), the market has seen numerous manufacturers with varying product quality. Current quality checks rely solely on practical production, lacking standards and methods to control fluctuations, leading to price competition and quality risks. This study aims to establish a complete quality control system, including technical standards, testing equipment, and methods.
Experimental Methods Foam Ceramic Filter Plates
Based on research and technical exchanges with domestic manufacturers, standard casting test blocks (300mm×200mm×70mm) were prepared. The gating system used two sprue channels to ensure equal capacity and pressure. Furan resin binder (≤1.5% addition) and AFS55 silica sand were used for molding. HT250 molten iron was poured at (1350±10)°C. Filter plates from Factories A, B, and C (100mm×50mm×10mm) were tested. After removing risers and gates, test blocks were machined (1mm surface removal, Ra1.6 roughness), degreased, sprayed with red penetrant (15-minute penetration), cleaned, sprayed with developer (3-minute development), and photographed.
Results and Analysis
Test block surfaces showed varying numbers of pinkish casting inclusions, indicating non-metallic inclusions.
Result Processing and Analysis
Filtration efficiency was evaluated by the ratio of defect area to total surface area after machining. Surface defects (pink under white background) were visualized via color penetrant testing. https://www.rtoceramic.com/products/
Conclusions
- An experimental and evaluation method for filter plate filtration effect was established, solving quality testing issues.
- MATLAB-based image analysis enables quantitative evaluation of filtration capacity.
- This simple method applies to quality control in cast iron (spheroidal, vermicular) and non-ferrous alloy casting, providing an effective tool for casting quality assurance.