It discusses in detail the main tooling patterns, iron molds, pouring system, sand shooting board, template, template base design points in the iron sand coating production, as well as the common layout forms of iron sand coating molding lines and the characteristics of the equipment structure. The characteristics of the semi-automatic iron sand-coated molding line developed and the melting of molten iron are introduced.
With the development of casting technology and the continuous improvement of the requirements of the equipment manufacturing industry for castings, the iron mold sand-coated casting process has been more and more widely used in casting production, especially in the production of ductile iron. The iron mold sand coating process is to cover about 5-8 mm in the iron mold cavity conforming to the casting.
Thermosetting phenolic resin coated sand, due to the fine particle size of the coated sand used, the strength after solidification is very high, and after the molten iron is poured, an effective gas barrier film is formed between the sand layer and the molten iron, which can effectively prevent the casting Sand sticking defects, so castings with good surface quality can be obtained; the iron type is generally gray cast iron material with sufficient rigidity; the sand coating layer is thin and high in strength, which can be used in the production of ductile iron.
In order to resist the expansion caused by graphite precipitation, the castings are denser, and the riser-free casting can be realized; the iron mold has a rapid cooling effect on the castings, so that the graphite balls in the castings are more round and smaller, and the distribution is more uniform. thinner. Under the same conditions, compared with the green sand process, the surface quality and the internal quality of the castings are one level higher than that of the green sand process.
Due to the thinner sand layer and less sand consumption, there are now professional coated sand manufacturers. Therefore, in small and medium-sized foundry manufacturers, the application of coated sand is mostly one-off. In this way, the sand processing system of the green sand process is omitted, the production environment is improved, and the casting production is more
Simple and orderly. Compared with the green sand process, the iron type sand coating process has the advantages of good iron type rigidity, high sand coating strength and no moisture, which greatly reduces the generation of waste products such as pores, shrinkage porosity, and sand inclusions, and avoids the weather such as the rainy season. Influence, greatly reduce the casting rejection rate. Since our company began to use this process to produce crankshaft blanks in 2003, the scrap rate has been controlled at about 2.5%. With the increasing maturity of the iron sand coating process technology, our company has successfully applied the process to the production of fan rotors, pressure plates and rocker arms in recent years, and has achieved good results.