Division 01 — Metallurgical / Ferrous / Feeding & Surface Treatment
Feeding & Surface Treatment
Feeding compounds, exothermic and insulating sleeves, and melt surface treatments that control the solidification sequence of iron and steel castings — keeping risers liquid longer than the casting body to compensate for volumetric shrinkage and eliminate internal voids and surface depressions.
Every ferrous casting shrinks as it solidifies. Grey iron shrinks by approximately 3%, ductile iron by 3–4%, and steel by 5–7% by volume. Without sufficient liquid metal fed into the last-to-solidify regions during this contraction, the result is shrinkage porosity — internal voids that weaken the casting — or visible surface sinks at heavy sections. CFC Egypt's EGYFEED exothermic feeding compound and EGYCOVER insulating covering compound are the primary tools for controlling this solidification-shrinkage problem. Applied to the top of the riser, EGYFEED generates heat that keeps the riser metal liquid longer than the casting below; EGYCOVER insulates the riser surface to slow heat loss to the atmosphere. EGYSLAG is used for ladle and furnace surface treatment, coagulating slag for clean removal before pouring and reducing the risk of slag inclusions in the casting. Together, these products give foundries control over the full solidification sequence from furnace to finished casting.
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Ce qu'il couvre
Feeding and surface treatment products address the solidification phase of the casting process — controlling how and when each region of the casting solidifies to prevent shrinkage defects and protect the melt surface from oxidation and slag.
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Exothermic Feeding — EGYFEED
EGYFEED is an exothermic feeding compound applied to the riser top after the pour. The compound ignites on contact with the hot metal surface and generates heat, raising the temperature of the riser metal and extending the period during which it remains liquid. By keeping the riser metal molten longer than the casting body beneath it, EGYFEED maximises the volume of liquid metal available to feed the casting as it contracts during solidification, eliminating internal shrinkage voids in critical sections.
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Insulating Cover — EGYCOVER
EGYCOVER is an insulating covering compound used on ladle surfaces and riser tops to reduce heat loss to the atmosphere and protect the metal surface from oxidation. Applied to the ladle, it maintains metal temperature during transport from furnace to mould, reducing temperature drop and improving pour consistency. Applied to the riser, it slows the solidification rate of the riser metal to extend feeding capacity. EGYCOVER may be used alone or in combination with EGYFEED for combined insulating and exothermic feeding.
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Slag Treatment — EGYSLAG
EGYSLAG is used for surface treatment of metal in ladles and furnaces to coagulate slag and facilitate its clean removal before pouring. Slag inclusions in castings — caused by slag drawn from the ladle surface into the mould with the metal stream — are a primary cause of casting rejection. EGYSLAG causes dispersed slag particles to coalesce into a coherent layer that can be cleanly skimmed from the metal surface, reducing slag inclusion risk in the poured casting.
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Riser Design & Feeding Efficiency
The effectiveness of feeding compounds depends on correct riser sizing and placement. Exothermic and insulating feeding compounds extend the feeding capacity of a given riser volume but cannot compensate for a riser that is fundamentally too small or incorrectly positioned relative to the casting's thickest sections. CFC Egypt's technical team can support riser calculation, feeding compound selection, and application rate optimisation for casting geometries in grey iron, ductile iron, and steel.
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Domaines d'utilisation
Feeding and surface treatment is required wherever the casting geometry, section weight, or metal type creates a risk of shrinkage porosity. These are the most common application areas.
Steel Castings
Steel has the highest volumetric shrinkage of all common casting alloys and therefore requires the most careful feeding. All sections of a steel casting above a critical modulus require a riser, and all risers require feeding compounds to extend their thermal life. Pump casings, valve bodies, and structural steel castings are subject to radiographic inspection to class standards — internal shrinkage porosity is a direct rejection cause. Exothermic EGYFEED applied correctly to the riser top eliminates shrinkage porosity in steel sections that would otherwise require oversized risers and heavy metal yield losses.
Heavy Ductile Iron Castings
Heavy section ductile iron castings — counterweights, gearbox housings, and hydraulic components — exhibit graphite expansion during solidification that partially offsets shrinkage, but the balance must be managed precisely through mould rigidity and feeding system design. In rigid no-bake moulds, feeding compounds maintain riser temperature to ensure the liquid metal reservoir remains available throughout the solidification window.
Pressure-Rated Castings
Castings subject to pressure testing — pump casings, valve bodies, pressure vessel flanges — require internal soundness across all sections. A single interconnected shrinkage void will cause leakage under hydrostatic test, resulting in rejection and costly repair or scrap. Feeding compound application is a key process control step in pressure casting production, ensuring that risers remain effective throughout the full solidification cycle.
Automotive & Engineering Castings
Thick-to-thin section transitions in complex automotive and engineering castings — where a boss or flange meets a thinner wall — are classic sites for shrinkage porosity. Directed solidification, achieved through a combination of chill placement and feeding compound application, ensures that these junctions solidify progressively towards the riser rather than forming isolated liquid pools that cannot be fed.