Raw material composition for graphite-silicon carbide riser tube and manufacturing process thereof

Abstract

The invention discloses a raw material composition for a graphite-silicon carbide riser tube. The raw material composition comprises the following raw materials in percentage by weight: 30% to 50% of flake graphite, 20% to 50% of silicon carbide, 4% to 10% of elemental silicon powder, 1% to 5% of boron carbide powder, and 10% to 14% of a bonding agent. The manufacturing process of the graphite-silicon carbide riser tube comprises the following steps: mixing raw materials evenly, and manufacturing qualified mud materials; loading the qualified mud materials into mould cavities, putting the mould cavities into an isostatic press cylinder, and pressing and shaping; demoulding, and processing blanks into desired sizes; preheating the blanks, and coating anti-oxidation glaze when the blanks are hot; burning the blanks in a naked mode so that the glaze is melted into glass glaze; detecting an air hole rate, and obtaining finished products if burned blanks are qualified. The process disclosed by the invention is simple, the prepared riser tube has high heat stability, the riser tube is ensured not to be burst, in addition, the riser tube has strong resistance to the erosiveness of molten aluminum, the corrosion problem of an iron riser tube is overcome, and the situation that iron is increased in molten aluminum is prevented; compared with the common riser tube which is combined with silicon nitride and silicon carbide, the production cost is low, and the raw material composition is suitable for large-scale industrial promotion.

Description

technical field [0001] The invention relates to a riser tube for low-pressure aluminum casting, in particular to a raw material composition of a graphite-silicon carbide riser tube and a manufacturing process thereof. Background technique [0002] The riser pipe is one of the key components on the low-pressure casting machine, which directly affects the quality and production efficiency of cast aluminum products. When performing low-pressure casting on a low-pressure casting machine, the aluminum liquid is raised into the mold through the riser tube by pressure, and the lower end of the riser tube is immersed in the aluminum liquid in the crucible, and the temperature of the aluminum liquid is as high as 740 degrees. At present, there are two commonly used riser pipes, one is all made of iron or stainless steel, long-term immersion in molten aluminum will cause iron corrosion, resulting in the increase of iron in the aluminum liquid, which seriously affects the quality of ...

AI Technical Summary

Problems solved by technology

At present, there are two commonly used riser pipes, one is all made of iron or stainless steel, long-term immersion in molten aluminum will cause iron corrosion, resulting in the increase of iron in the aluminum liquid, which seriously affects the quality of castings, while the iron Corrosion will also cause damage to the riser pipe; the other is silicon nitride combined with silicon carbide, which has the advantages of high thermal stability, good corrosion resistance to molten aluminum, and no increase in iron, but the production process of this type of riser pipe is complicated , high production cost, expensive, unacceptable for general aluminum processing enterprises