How to Select Foam Ceramic Filters Correctly?
To correctly select foam ceramic filters, several factors need to be considered. The key points are as follows:
- Selection Based on Material
- Silicon Carbide: Ideal for copper alloys such as copper, bronze, and brass due to its high strength, heat and corrosion resistance, and can withstand up to about 1560°C, reducing copper liquid turbulence and purifying it.
- Zirconia: Made of ZrO₂, with a heat resistance over about 1760°C, high strength, and excellent impact resistance. It’s suitable for all steel types, including carbon steel, stainless steel, and superalloys.
- Alumina: With an applicable temperature of 1250°C, it’s mainly used for filtering and purifying aluminum and its alloy solutions, widely applied in common sand casting and permanent mold casting for automotive aluminum parts.
- Selection According to Pore Size
- 10ppi: Commonly used for ductile iron castings, large gray iron castings, and steel castings.
- 20ppi: Suitable for small gray iron castings, malleable steel castings, and non-ferrous metal castings.
- Selection by Thickness
- Light Alloy Castings like Aluminum Alloys: Choose 12-15mm for small ones and 20-25mm for large non-ferrous alloy castings.
- Cast Iron Castings: Select a thickness of 10-22mm.
- Steel Castings: Select a thickness of ≥20mm to prevent the filter from burning through and avoid casting scrap caused by slag inclusion.
- Consideration of Placement Position
- In casting production, the foam ceramic filter can be placed horizontally at the bottom of the sprue, horizontally or vertically in the runner and ingate. When vertically parting, place it on one side of the sprue. Also, design the gating system as semi-closed or open to avoid metal liquid turbulence, and increase the size of relevant gating system units due to the filter’s flow resistance.