Lost foam casting coating is a surface treatment material used for castings in lost foam casting. It is a special covering material that can melt and evaporate under high temperature conditions, forming a protective film to protect the surface of castings from the erosion of high-temperature molten metal. Meanwhile, the lost foam casting coating also has the effect of reducing infiltration and improving surface quality.

The impact of lost foam casting coatings on the surface quality of castings is manifested in the following aspects:

1. Improvement of surface quality: During the lost foam casting process, the coating melts and evaporates at high temperatures, forming a protective layer. This protective layer can isolate direct contact between the casting and high-temperature molten metal, ensuring that the surface of the casting is not corroded or contaminated by the metal. Therefore, under the protection of lost foam casting coatings, the surface quality of castings can be effectively protected and improved.

2. Improvement of wetting: A common casting defect is poor wetting, which means that the molten metal cannot well infiltrate the surface of the mold when filling it, resulting in defects on the surface of the casting. Lost foam casting coatings can play a role in controlling the infiltration of molten metal. They can absorb or change the wetting ability of the metal, adjust the interfacial tension between the metal and the mold, and thus improve the infiltration status of the metal in the mold.

3. Improvement of adhesion: The lost foam casting coating melts at high temperatures and is applied to the surface of the casting. It has a certain degree of adhesion and adhesion, which can bond the casting sand particles with the coating. This bonding effect can increase the strength and wear resistance of the casting surface, thereby reducing defects and damage on the casting surface.

4. Improvement of anti adhesion: After melting and volatilizing at high temperatures, the lost foam casting coating will form a thin protective film on the surface of the casting. This protective film can reduce the adhesion between the casting and the mold, making it easier for the casting to separate when removed from the mold, thereby reducing hot cracks and surface damage to the casting.

In summary, the coating of lost foam casting has a significant impact on the surface quality of castings. It can improve the surface smoothness, density, and damage resistance of castings, as well as improve the wetting and separation properties of castings. Therefore, selecting the appropriate coating in the lost foam casting process and correctly using and controlling the performance of the coating is of great significance for obtaining high-quality casting surfaces.