High-pouring-precision composite modified sodium silicate-bonded sand for pump valve casting and preparation method thereof

Abstract

The invention discloses high-pouring-precision composite modified sodium silicate-bonded sand for a pump valve casting. Compared with conventional modified sodium silicate binding agents, modified sodium silicate binding agents in the sodium silicate-bonded sand have more excellent normal-temperature wet strength, better thixotropy and rheological property and higher binding speed, and are environmentally friendly, and the use amount of sodium silicate is small. In addition, aluminum titanate added into the sand is low in coefficient of thermal expansion, so that the thermal stability and air permeability of the sand form are improved, and the melt pouring precision is improved; bentonite-loaded nano calcium fluoride is dispersed into the sand to achieve the lubricating and reinforcing effects, a non-stick impermeable layer is formed, and the casting is prevented from carrying and adhering to the sand. The composite modified sodium silicate-bonded sand is excellent in comprehensive performance, compact in structure, rapid in scatter cleaning and high in casting precision and can meet the pouring requirements of the high-precision pump valve casting.

Description

technical field [0001] The invention relates to the technical field of water glass sand, in particular to a composite modified water glass sand with high pouring precision for pump and valve castings and a preparation method thereof. Background technique [0002] Molding sand is mainly a kind of material used for molding in casting, which is made by mixing sand materials, adhesives and auxiliary substances according to different proportions. According to the different adhesives used, it can be divided into clay sand and water glass sand. , resin sand, etc. Among them, water glass sand has the advantages of high strength, low cost, simple process, and low pollution, and is widely used. [0003] Castings of pumps and valves have the characteristics of thin walls and complex shapes. In the casting process, the quality requirements for molding sand are particularly strict. The quality of molding sand is also an important factor related to the quality of castings. Although water ...

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Problems solved by technology

[0003] Castings of pumps and valves have the characteristics of thin walls and complex shapes. In the casting process, the quality requirements for molding sand are particularly strict. The quality of molding sand is also an important factor related to the quality of castings. Although water glass molding sand has significant advantages, there are also many Disadvantages, obvious defects are mainly manifested in low strength at room temperature, poor collapsibility, and difficulty in regenerating old sand. If it is not modified, it is difficult to improve the quality of pump valve castings