Baoding Ningxin Molten Metal Filters: Foam Ceramics and Glass Fibre Mesh

Selection and quotation of Baoding Ningxin molten metal filters: SiC foam ceramics for iron, zirconia for steel, alumina for aluminium, honeycomb filters and glass fibre mesh.

Silicon Carbide Foam Ceramic Filters for Iron

Silicon carbide (SiC) foam ceramic filters are used for pouring grey, ductile and malleable iron. The open three-dimensional structure traps non-metallic inclusions and calms the metal flow. Square and round shapes are made, with sizes and pore density to order.

Square sizes from 35x35 mm to 360x360 mm
Round sizes from 40 mm to 360 mm diameter
Thickness from 11 mm to 40 mm
20 ppi for grey iron, 10 ppi for ductile iron

Zirconia Foam Ceramic Filters for Steel

Zirconia (ZrO2) foam ceramic filters are designed for pouring steel: the maker states a tolerance temperature above 1700 °C. Their impact strength is higher than that of silicon carbide filters. They also serve aluminium, copper and iron alloys.

Tolerance temperature above 1700 °C
Steel, iron, copper and aluminium
Higher impact strength than silicon carbide
Edge seat of 15 mm per side in green sand

Alumina Foam Ceramic Filters for Aluminium

Alumina (Al2O3) foam ceramic filters purify the melt in aluminium and aluminium alloy production. They remove micron-level inclusions and turn the flow into a stable layer, which helps mould filling and reduces bubbles. Pore density ranges from 10 to 60 ppi.

Pore density 10–60 ppi
Aluminium foundry and melting
Low gas evolution during pouring
Shapes and sizes to order

Straight Hole Honeycomb Ceramic Filters

Straight hole honeycomb ceramic filters are made by precision die extrusion for consistent dimensions. Rated use temperature is up to 1500 °C. The filter stabilises metal flow, reduces vortex and gas porosity and improves the surface of the finished part.

Use temperature up to 1500 °C
Cell count 50, 100, 200 or 300
Porosity 38–60%
Compressive strength from 20 MPa

High Silica Glass Fibre Mesh for Steel and Iron

Filter meshes are woven from high silica glass fibre yarn and coated with a refractory coating. The thickened steel mesh is close to three times thicker than iron mesh and holds 1620 °C for several seconds. It suits steel, iron, copper and aluminium and can act as a runner break-off point.

Mesh openings 1.5x1.5 mm to 4.0x4.0 mm
Short exposure up to 1620 °C for steel
Flat sheets and cap shapes
Runner break-off at the mesh after solidification

Alkali-Free Glass Fibre Mesh for Aluminium

Aluminium filter meshes are woven from high-twist alkali-free glass fibre and coated with a heat-resistant coating. Working temperature is 700–800 °C, heat resistance up to 900 °C. Shapes include flat sheets, caps, cones and combined filters, including smokeless types for pistons.

Working temperature 700–800 °C
Heat resistance up to 900 °C
Weight 150–350 g/m²
Gates with mesh go back to the furnace

Choosing a Filter by Alloy and Pore Density

The filter material follows the alloy and the pouring temperature. Grey, ductile and malleable iron are filtered with silicon carbide foam ceramics; the maker gives a filtration capacity of 4.0 kg/cm² for grey iron, 2.0 kg/cm² for ductile iron and 1.0–2.0 kg/cm² for alloyed iron.

Grey iron usually takes 20 ppi and ductile iron 10 ppi, with 15 and 25 ppi as options. Steel needs zirconia (above 1700 °C), aluminium takes alumina with 10–60 ppi. The filter area is sized from the capacity and the required pouring time.

Filter Seat Design in the Mould

The filter sits in the pouring cup, at the sprue base or in the runner, horizontally or vertically; in a vertical runner the stream hits the filter face, so its impact strength matters.

Leave a support of at least 5 mm on the inflow side, a gap of 1–1.5 mm and a sand trap groove around the filter, and keep its top face 0.5–1 mm below the parting line. Round the edges of the seat to avoid sand wash. The size tolerance of ±2 mm is matched to the seat.

Placing Mesh in the Gating System

The mesh goes into the runner close to the mould cavity, ideally at the parting line. Where that is not possible it is placed on a horizontal section of the runner or ingate, with the runner in the cope, since inclusions float in the upper part of the stream.

The mould edge clamps the mesh by 15 mm per side in green sand and 20–30 mm per side in dry sand. An oversized runner lets the mesh sag at high temperature and slag passes under it.

Aluminium Mesh Types by Process

Roll mesh is fixed in launders for continuous production of ingots, rods and strip. Cut squares and discs with a resin coating go into the gating system of shaped parts. Caps and cylinders with resin coating or carbonized treatment serve low-pressure production of alloy wheels and cylinder heads.

Smokeless carbonized mesh does not burn during filtration and suits pistons. Gates with glass fibre mesh return to the furnace, unlike gates with iron wire mesh.

Baoding Ningxin and model names are trademarks of their respective owners and are used only to identify the equipment for which we source parts. SpareX is not an official dealer, distributor or representative of Baoding Ningxin and is not affiliated with the trademark owner. Origin, documents and warranty are stated for each item in the quotation.