Matters needing attention in the process of Dongguan precision castings
- 2020-05-30-

Cheng Mao Dongguan precision castings use the world's advanced silica sol precision casting technology. Cheng Mao has a complete set of advanced equipment and material composition testing instruments. The whole process of processed products from melting wax, injection, dewaxing, roasting and casting is automatically controlled. For each furnace of molten steel with different materials, use a spectrometer to follow the on-site material composition measurement and analysis. If the material composition is short or too high, precision casting is definitely not allowed, which fundamentally ensures the quality and reliability of the product.

1. Due to the poor fluidity of molten steel, in order to avoid cold barriers and short pouring of steel castings, the wall thickness of steel castings should not be less than 8mm; the structure of the casting system should be simple and the section specification should be larger than that of cast iron; dry casting is used Or hot mold; appropriately increase the pouring temperature, generally 1520°~1600°C. Due to the high pouring temperature, the molten steel has a high degree of overheating, and the liquid stays for a long time, the fluidity can be improved. However, if the pouring temperature is too high, it will cause defects such as coarse grains, thermal cracks, pores and sand sticking. Therefore, the casting temperature of small, thin-walled and disorderly shaped castings is generally about the melting point temperature of steel +150°C; the casting temperature of large, thick-walled castings is about 100°C higher than its melting point.

2. Since the shortening of cast steel greatly exceeds that of cast iron, in order to avoid shrinkage and porosity defects in castings, risers, chilled iron, and subsidies are mostly used in the casting process to complete the second condensation. In addition, in order to avoid shrinkage cavities, shrinkage porosity, pores and cracks in steel castings, the wall thickness should be uniform, sharp corners and right-angle structures should be avoided, sawdust is added to the casting sand, coke is added to the core, and Use hollow cores and oil sand cores to improve the concession and air permeability of sand molds or cores.

The melting point of precision cast steel is high, correspondingly its pouring temperature is also high. The interaction between molten steel and mold material at high temperature can easily produce sticky sand defects. Therefore, artificial quartz sand with high refractoriness should be used as the mold, and the surface of the mold should be brushed with a coating made of quartz powder or zirconium sand powder.

Dongguan Chengmao Dewaxing Casting is an excellent domestic supplier of investment casting and fine machining. In the more than ten years since its establishment, we have been focusing on developing and improving the investment casting process. The factory has established a superior production management system in accordance with ISO9000 standards. Now it has more than 150 employees and an annual output of more than 600 tons. The products are supplied to domestic, European and American customers. Over the years, Cheng Mao has gathered a group of outstanding production and research talents. We have accumulated a wealth of experience in the production of various stainless steel, carbon steel, alloy steel and other fine casting blank parts and machined parts. The products of Dongguan Chengmao Hardware Products Co., Ltd. are widely used in the production of construction hardware, construction machinery, boats, automobiles and motorcycles, pipe valves, electrical and pneumatic tools, medical care, food, and aerospace.