High-permeability composite modified sodium silicate-bonded sand easy to strip for pump valve castings and preparation method of high-permeability composite modified sodium silicate-bonded sand

Abstract

The invention discloses high-permeability composite modified sodium silicate-bonded sand easy to strip for pump valve castings. Compared with a conventional modified sodium silicate adhesive, a modified sodium silicate adhesive in the sodium silicate-bonded sand is more excellent in normal-temperature wet strength, the thixotropy and rheological property are better, and the reaction binding activity is high; in addition, environmental friendliness is achieved, and the use amount of the sodium silicate is greatly reduced; through spherical sealed expanded perlite and negative ion rock flour added in raw materials, the plasticity and permeability of the molding sand can be improved; nano calcium fluoride carried by bentonite is dispersed in the sand, the lubricating effect and the reinforcing effect are achieved, and a non-stick impermeable layer can be formed, so that the sand is prevented from adhering to the castings. The composite modified sodium silicate-bonded sand is excellent in comprehensive performance, stable network structures are formed between sand materials, compact and permeable sintered layers can be formed on the surfaces of the castings, the sand is easy to strip and scatter, and accordingly the casting products with bright and clean surfaces are obtained.

Description

technical field [0001] The invention relates to the technical field of water glass sand, in particular to an easy-peeling high-permeability composite modified water glass sand for pump 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