Introduction

Fiberglass hat type filter (also known as fiberglass filter cap) is a disposable deep filtration product specially developed for molten aluminum purification in aluminum casting industry.

It is fabricated from high-purity E-fiberglass / high silica fiberglass, bonded with high-temperature resistant inorganic binder, formed into a hat-shaped three-dimensional structure.

Mainly used for filtering molten aluminum and aluminum alloy before pouring, removing solid impurities such as oxide inclusions, slag, refractory particles, and trapped gas bubbles in molten aluminum, improving the internal quality and surface finish of aluminum castings.

Key Features

1. Excellent high-temperature resistance

Stable working performance under 700~800°C molten aluminum environment; no softening, decomposition or fiber shedding. It will not contaminate the molten aluminum, and is compatible with all common aluminum alloys including A356, A380, 6061, 7075 etc.

2. 3D hat-shaped structural advantage

The hat design increases effective filtration area compared with flat filter screens. Molten aluminum flows steadily from inside to outside, reduces flow velocity, avoids turbulence and secondary oxidation of aluminum liquid. It can hold more slag and inclusions, extending filtration service life. Easy installation inside sprue cup / pouring basin.

3. Deep depth filtration & high inclusion capture rate

Multi-layer interlaced fiberglass forms micron-scale tortuous channels. It can trap both large slag blocks and tiny oxide film inclusions, effectively reduce casting defects like porosity, slag inclusion, shrinkage and pinholes. Greatly improve mechanical properties and surface quality of aluminum castings.

4. Good wettability with molten aluminum & low flow resistance

Specially treated fiber surface, moderate permeability. Balanced filtration efficiency and molten aluminum passing speed; no blocking easily under normal pouring flow. Smooth filling of mold cavity.

5. Low gas evolution & stable chemical inertness

Adopts inorganic high-temperature binder, extremely low gas release when contacting hot aluminum liquid. No smoke or volatile matter. Chemically inert to molten aluminum, no reaction, no introduction of foreign impurities.

6. Lightweight, easy operation & one-time use

Light weight, flexible cutting on site if needed. Simple placement in gating system. Single-use design avoids re-contamination caused by repeated filter cleaning. Suitable for manual pouring and automatic casting lines.

7. Customizable specifications

Multiple sizes, thickness and mesh grades available to match different sprue cup diameters and casting throughput. Optional non-asbestos edge wrapping for enhanced structural strength and anti-fraying.

Application Scenarios

Widely applied in aluminum alloy gravity casting, low-pressure casting, sand casting, investment casting and die casting pre-filtration.

Typical products: automotive aluminum wheel hubs, engine cylinder heads, aluminum chassis parts, aluminum pump bodies, aluminum pipe fittings, hardware aluminum castings.