What is a covering agent used for in metal casting?

A covering agent is used to form a protective refractory layer on molten metal surfaces to prevent oxidation, reduce heat loss, and improve casting quality in foundry and metallurgy operations.

Which metals can be protected with a covering agent?

Covering agents are suitable for molten steel, cast iron, aluminum, copper, and other non-ferrous alloys to enhance surface quality and reduce oxidation during pouring.

How does a covering agent improve casting yield?

By providing thermal insulation and oxidation prevention, covering agents reduce metal burn-off, lower scrap rates, and ensure a more uniform solidification, thereby increasing overall casting yield.

What is the difference between insulation and exothermic covering agents?

Insulating covering agents focus on minimizing heat loss, while exothermic covering agents release controlled heat to maintain molten metal temperature, especially in long pours and riser applications.

How should a covering agent be applied?

A covering agent should be evenly applied to the molten metal surface before pouring or at the ladle stage. The specific application and dosage depend on metal type, furnace conditions, and foundry process requirements.

Covering Agent for Steel & Foundry

Name: Covering Agent for Steel Foundry
Brand: Highland Refractory
Rating: 4.7 (28 reviews)

A covering agent is a specialized powder or granular material that covers molten metal surfaces. Its main functions include:

Forming a protective thermal layer
Reducing oxidation and dross formation
Improving metal cleanliness and quality
Providing energy-efficient insulation

Exothermic and insulating covering agents differ in their heat release properties and application methods, allowing users to select the right type for ladles, risers, and furnaces.

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Product Usage Method

When the molten steel (iron) level rises to more than half the height of the sprue, a sufficient amount should be added in time, and for castings with multiple sprues, they should be added in order from far to near. After covering, no point pouring should be done to prevent damage to the covering surface and loss of function. The dosage is 1%-3% of the sprue weight. The product must be stored in a fireproof and moisture-proof environment.

Product Feature

1. This product has high calorific value and outstanding insulation performance. After use, it can keep the steel in the sprue in a liquid state for a longer period, so as to continuously replenish the volume shrinkage of the casting during the solidification process, making the final shrinkage hole located above the sprue, ensuring that the casting has a dense structure without shrinkage holes and looseness, significantly improving the yield rate of castings.

2. After using this product, the sprue shrinks and forms a shell with a "U" or "dish" shape at the upper end. Its excellent feeding performance can save 30%-50% of molten steel (iron) in the sprue weight during pouring, maximizing the process output rate.

Product Property

Main Chemical Composition
SiO₂	AI₂O₃	Fe₂O₃	CaO	C	AI
≥10	≥12	≥10	≥11	≥15	≥5

Physical Properties
Melting Point℃	Expansion Multiplier	Particle Size mm	Moisture%
≥1000	≥3.5	<1.5	≤0.02

Covering Agent for Steel & Foundry – TZ-M1 Riser Exothermic & Insulation Solutions

Covering agents are essential metallurgical additives designed to protect molten metal during ladle handling, riser applications, and furnace operations. Our TZ-M1 Riser Exothermic Covering Agent provides superior thermal insulation, prevents oxidation, and ensures high-quality steel and alloy production in foundries and metallurgical plants.

By forming a stable protective layer on molten metal surfaces, our covering agent reduces metal loss, maintains temperature, and improves casting consistency. It is suitable for steel, aluminum, copper, and other non-ferrous metals across various furnace types.

What Is a Covering Agent?

A covering agent is a specialized powder or granular material that covers molten metal surfaces. Its main functions include:

Forming a protective thermal layer
Reducing oxidation and dross formation
Improving metal cleanliness and quality
Providing energy-efficient insulation

Exothermic and insulating covering agents differ in their heat release properties and application methods, allowing users to select the right type for ladles, risers, and furnaces.

Key Features of TZ-M1 Covering Agent

Superior Thermal Insulation – Maintains molten metal temperature for longer periods.
Oxidation Protection – Reduces metal loss and prevents inclusion formation.
Exothermic Reaction (Riser Type) – Releases heat to support solidification in risers.
Durable & Stable – High structural integrity even under high-temperature conditions.
Versatile Application – Suitable for steel, aluminum, copper, and alloy processing.

Applications of Covering Agent

Steel Industry

Ladle covering during steel transfer
Riser protection in continuous casting
Secondary metallurgy and holding furnaces

Foundry Applications

Molten aluminum or copper protection
Low-pressure and gravity casting operations
Dross and inclusion reduction during pouring

Metallurgical Furnaces

Electric arc furnace (EAF) covering
Induction furnace insulation
Ladle and tundish protective cover

Covering agents are effective in improving metal quality, reducing oxidation losses, and enhancing production efficiency across all metal types.

How to Use a Covering Agent

Preheat the molten metal to the target temperature.
Sprinkle the covering agent evenly over the molten surface.
Allow the protective layer to form and, if using a riser type, let the exothermic reaction assist solidification.
Monitor temperature and add additional covering agent if necessary.

Dosage depends on metal type, furnace capacity, and operational requirements. Always follow technical guidance or trial runs for best results.

Benefits of Using TZ-M1 Covering Agent

Improved Metal Quality – Reduces inclusions and defects.
Energy Efficiency – Maintains temperature, lowering energy consumption.
Reduced Metal Loss – Prevents metal entrapment in slag or dross.
Customizable for Application – Different grades for ladles, risers, and insulation.
Safe and Non-Toxic – Does not react with molten metal or contaminate alloys.

Frequently Asked Questions (FAQ)

Q: What is a covering agent used for?
A: It protects molten metal from oxidation, dross, and temperature loss during ladle, riser, or furnace operations.

Q: What types of covering agent are available?
A: Exothermic riser types and insulating types, depending on whether heat support or pure insulation is required.

Q: Can it be used for aluminum or copper?
A: Yes, TZ-M1 is suitable for steel, aluminum, copper, and other alloy molten metals.

Q: How much should be applied?
A: Dosage depends on metal type, furnace size, and temperature. Technical guidance or trial usage is recommended.

Q: Does it affect molten metal chemistry?
A: No, our covering agent is chemically stable and non-toxic, ensuring no contamination.

Why Choose Highland Refractory’s Covering Agent

Highland Refractory has over 30 years of experience producing high-quality foundry and metallurgical additives. Our TZ-M1 Riser Exothermic Covering Agent is:

ISO 9001:2015 certified
Tested for superior heat retention and insulation
Customizable for diverse industrial furnace types
Proven to improve casting quality and reduce operational costs

Request a Quote or Technical Support

For technical advice, product selection guidance, or to request a sample, contact our sales and technical team. We provide personalized solutions for your foundry and metallurgical processes, ensuring optimal performance and cost efficiency.