(Reprinted from: Metal Gang)
Yulin Hongzetong Coal Transportation and Sales Co., Ltd. was established in March 2016. It is a medium-sized transportation and sales processing process for washing with coal business license approved by the Shaanxi Provincial People's Government.Coal selectiona large coal washing and sewing enterprise mainly consists of steel casting coal powder and coal storage, processing and transportation. It has a registered capital of 50 million yuan, an annual production volume of 1.2 million tons, and an annual sales capacity of 1 million tons. Our factory has a superior geographical location and has more than 10 weakly bonded coal mines of various types around it. Our factory has a privately owned modern CNC casting coal powder and coal washing enterprise, with a fully enclosed coal shed, with a raw coal storage capacity of 200,000 tons, a refined coal storage capacity of 100,000 tons, an annual design capacity of 5 million tons, an area of 100,000 square meters, and an annual output value of 3 billion.
Coal powder for wet sand casting
The role of coal powder in wet sand
After adding coal powder to wet sand for cast iron parts, due to the heat decomposition of metal liquid, the coal powder is heated and reductive gas is released in the mold cavity, which inhibits the formation of FeO. At the same time, the coal powder precipitated hydrocarbon gas forms a bright carbon film on the surface of the casting, preventing sand-adhesive defects on the surface of the casting, improving the smoothness of the casting surface, and reducing the tendency of sand-bearing defects in the casting. For casting ductile iron parts with wet sand, adding coal powder to the molding sand can also prevent subcutaneous pore defects.
Main indicators of casting molding powder (coal powder)
Note: If there are special requirements for technical indicators, both the supply and demand parties may negotiate and formulate them.
The basic principle of coal powder preventing castings from sticking to sand
The main function of coal powder is to prevent sand from being adhered to the surface of wet cast iron parts and improve the smoothness of the surface. In addition, it can also prevent the casting from producing subcutaneous pores to reduce theStained sandtend to improve casting dimensional stability.
There were multiple explanations before about the mechanism of coal powder preventing sand from cast iron parts, such as ① Air cushion theory: at the pouring temperature,sand moldA protective gas layer is formed between the molten iron to prevent the molten iron from drilling into the sand pores of the molded sand. ② Covering theory: The surface of the sand particles is covered with a protective layer generated by the softening of coal particles. ③Reduction theory coal powder is formed at high temperatureReducible atmosphereprevent the iron from oxidizing and prevent the chemical reaction between iron oxide and quartz sand particles. ④ Theory of precipitation of carbon: The volatile components precipitated by the heat of coal powder form carbon coated on the surface of the sand particles, isolating the contact between the molten iron and the sand particles.
Packaging, transportation and storage
Packaging: Woven bags with inner membrane, each bag has a net weight of 500kg/800kg/1000kg, and can also be customized according to customer requirements. Transportation: All kinds of vehicles can be transported to keep dry and equipped with rainproof and anti-airWater and moisture-proof facilities.
Storage: It should be stored in a dry, ventilated and cool place.
Shelf life: six months.
