What is Foundry Coating?

When molten metal with high temperature is poured into sand molds, destructive reactions occur between the melt and the sand or adhesive, which create defects such as roughness and unevenness on the surface of the part, and in many cases make the part unusable. Defects such as sand burning, sand scuffing and chemical reactions between molten metal and sand are among these. Now, by using a suitable coating to cover the sand surface that is in contact with the molten metal in various compounds of cast iron, steel, copper, nickel, etc. in green sand, sodium silicate and molds with organic resin connections, and when casting alloys with high melting point such as steel, cast iron, etc., it is necessary to use a coating to prevent the penetration of melt into the sand and the reaction of melt and mold, so that we can eliminate such defects.

Foundry Coating

Refractory coating along with Exothermic Sleeve, Ferroalloys, Pure Metals and Graphite will result in high-quality parts with excellent efficiency.

Foundry Refractory Coating

Refractory coatings can be considered a type of formulated paint for use in the sand casting industry. Their difference from ordinary paints is that they are designed to resist the high temperature of molten metal and act as a barrier against molten metal and the surface of the core or sand mold. The advantages of using refractory foundry coating can be achieved when it is selected, prepared and applied to the mold correctly. Failure to observe any of these points can lead to an unsuitable part surface or the occurrence of various defects such as blistering, gas porosity, inclusion, etc.

The mold is coated by a slurry, which after drying, creates strong shells on the surface of the mold. Mold coating is usually done by dipping in a pool (immersion), spraying, brush, shower, etc. The chemical composition of the coating includes refractory powder, suspending agent, adhesive, thixotropic materials and carrier. Refractory powders are usually made of zircon, silica, alumina, chromite and aluminosilicates such as pyrophyllite and mullite. The coating is applied to the mold in one or more stages and the drying process is carried out by various methods, depending on the type of coating. The thickness of the coating is usually about 0.25 to 0.5 mm. The most important purpose of using coating is to hold the sand and prevent it from collapsing. Using refractory coatings in casting molds keeps the heat inside the melt and increases the fluidity of the melt.

Purchase of Foundry Refractory Coating (Foundry Mold Refractory Paint)

Avangard Company, with more than 20 years of experience in the field of supply and production of foundry raw materials, such as alcohol-based coatings for steel and cast iron casting and water-based coatings for cast iron casting and foundry coatings by lost foam method and complete mold with different refractories including graphite, zircon, alumina, magnesite, etc., is ready to offer sales services with competitive price and excellent quality to you dear customers. You can now purchase foundry refractory coating by contacting our sales experts.

Advantages of Using Foundry Coating or Refractory Paint:

• Reduction or elimination of melt penetration into the mold
• Reduction or elimination of sand burning in the cast part
• Prevention of sand washing by melt in the process
• Completely smooth part surface
• Increasing the quality of the cast part
• Reducing waste in the production of cast parts
• Reducing cleaning costs in the finishing process
• Helping to increase production
• By minimizing casting defects in the part, it helps the environment in the finishing process.
• Very excellent mixing and excellent immersion ability
• Causes the production of minimal gas defects, penetration and oxide defects.

Types of Foundry Refractory Coating:

1. Alcohol-based coatings for steel and cast iron casting
2. Water-based coatings for cast iron casting
3. Foundry coatings by lost foam method and complete mold

Alcohol-Based Coatings for Steel and Cast Iron Casting:

These refractory coatings with alumina or zircon or graphite refractories, etc., with excellent immersion and high coating properties, are suitable for use in green sand, Co2 method, core mold with resin connections and casting of all melts including sensitive and heavy parts in the casting of various types of steel and cast iron. You can contact Avangard sales experts to prepare foundry refractory coating and other foundry raw materials.

*Alcohol-Based Foundry Coating with Alumina Refractory:

Alcohol-based foundry coating with alumina refractory has high strength to the mold or core and creates a high surface quality in heavy sections for casting various types of refractory steels and prevents sand burning and the reaction between molten metal and mold.

* Alcohol-Based Foundry Coating with Zircon Refractory:

Alcohol-based foundry coating with zircon refractory is very suitable for molds and cores for steel parts and gray and ductile cast iron.

* Alcohol-Based Foundry Coating with Magnesite Refractory:

Alcohol-based foundry coating with magnesite refractory is in the form of paste which is ready to use, and this product is designed for use in casting manganese steel or Hadfield and has suitable coating capability and simple application for coating molds and cores connected with various resins, especially in the sodium silicate process.

*Alcohol-Based Foundry Coating with Graphite Refractory:

Alcohol-based foundry coating with graphite refractory creates a mold and core coating for casting cast iron and non-ferrous alloys and is suitable for casting various alloys of gray and ductile cast iron.

Water-Based Coating for Cast Iron Casting:

Various types of water-based coatings for cores, hot boxes and cold boxes in ocher, brown, black, milky, cream and gray colors, each with different refractories such as graphite, zircon, alumina, etc. with immersion, shower, spray and brush application methods for casting various cast iron and aluminum parts in the production and coating of hot rolling rolls of aluminum sheets, for the production of steel rolls by centrifugal method, die casting of cast iron connections and cast iron ingots are produced.

Foundry Coating by Lost Foam Method and Complete Mold:

For casting molds that are cast with single-use foam or polystyrene models, and the model is not removed from the mold, foam casting coating with a combination of various refractories such as zircon, etc., which are produced in milky, pink and ocher colors and can be sprayed by immersion, spray and brush is very suitable.

Application of Foundry Refractory Coating

A suitable coating for high-temperature castings to create a barrier between the melt and the mold and core surface prevents sand burning, melt penetration, abrasion and washing of sand, reaction between molten metal and mold, and other common defects during high-temperature casting in steel, cast iron and non-ferrous melts.
These types of coatings are designed based on high refractory, non-wetting, non-reacting with the melt, and having optimal properties to create an excellent surface.

How to Use Foundry Refractory Coating:

1- Before use, the coating should be completely mixed and homogenized.
2- The coating is applied by immersion in a pool (immersion), spraying, brush, or shower on the core and mold. If a second layer is needed, dry the first layer and allow the coating to completely burn and cool, then apply the second layer.
3- If the mold/core has a large surface area, the coating should be applied in smaller areas and dried quickly.
4- After coating, alcohol evaporation should be prevented and the paint should be dried immediately by burning it.
5- After coating the mold or core with casting paint, the coating should be allowed to completely burn and cool to ambient temperature and then the mold should be assembled, or the mold should be assembled while the coating is still warm and the casting should be done immediately, but assembling a dried mold that has not yet reached the ambient temperature should be avoided.

Consumption Rate of Alcohol-Based Foundry Coatings:

Mold painting method with brush: 3-5 weight parts of the product with 1 weight part of alcohol
Mold painting method with spray: 2 weight parts of the product with 1 weight part of alcohol
Mold painting method with immersion: 2 weight parts of the product with 1 weight part of alcohol
Packaging of foundry refractory coating:
35 kg cans

Storage of foundry refractory coating:
Approximately 3 to 6 months depending on the different refractory components and should be stored in a dry and cool place.

Sale of Foundry Refractory Coating

Sales experts of foundry refractory coating (foundry mold refractory paint) are ready to provide reliable services and technical and specialized advice to respected foundrymen.

Price of Foundry Refractory Coating

The price of coatings (foundry mold paints) is variable due to the fluctuations in the price of raw materials. Contact our experts at Avangard Company to order the desired coating. Avangard's technical team, relying on more than two decades of production experience, as well as the high scientific level of the chemical and metallurgical engineers graduated from the top universities inside and outside the country, assures the respected foundrymen and industrialists that the desired mold coating is produced with the best quality, excellent performance and high efficiency.