(1) Select low-density molding materials. When using EPS, the density of the pattern is controlled at 0.016-0.025 grams per cubic centimeter, and low-carbon mold material EPS (C8H8) is changed to EPMMA (C5H8) to reduce the carbon content of the pattern. Hollow structure patterns and hollow structure pouring systems can also be used.
(2) The appropriate pouring temperature and pouring speed, as well as the establishment of the pouring system, determine the flow direction and speed of the molten steel; As the pouring temperature increases, the pouring speed also increases, and the decomposition of the mold material accelerates, making it difficult to completely vaporize. The amount of liquid phase in the product also increases. At the same time, the gap between the molten steel and the mold decreases, and the liquid phase decomposition products are often squeezed out of the gap and squeezed between the coating and the metal industry, causing an increase in the contact surface and carbon concentration, resulting in an increase in the amount of carburizing in these areas.
(3) Choose a reasonable pouring process. The design of casting and pouring processes should be able to accelerate the gasification of mold materials, reduce and stagger the contact and reaction time between liquid and solid phases in their decomposition products, which can reduce or avoid carburizing of steel parts.
(4) Improving the breathability of coatings or dry sand molds, the better their breathability, the faster the decomposition products of the mold material escape, thereby reducing the concentration and contact time of decomposition products in the gap between the molten steel and the mold.
(5) Add additives (decarburization agents) to the mold to prevent carburizing of cast steel parts.
(6) Adopting precision molds that conform to the casting process.
(7) Use anti-seepage carbon coating.