Modified alkaline phenolic resin self-hardening sand for high-precision pump valve castings and preparation method of self-hardening sand

Abstract

The invention discloses modified alkaline phenolic resin self-hardening sand for high-precision pump valve castings. A modified phenolic resin adhesive adopted by the resin self-hardening sand has the advantages of being low in viscosity, high in bonding strength, good in plasticity, low in brittleness, lower in content of free phenol and free formaldehyde, fewer in usage amount, low in hardening speed and the like, and therefore the using performance and the reusing performance of the casting sand can be effectively improved; sepiolite fabric porous polypropylene fibers mixed in the sand have high thermal stability and are obvious in toughening effect and reinforcing effect, a complex and uniform meshed structure is formed by the fibers in a sand mold, so that the plasticity of the casting sand is improved, and compactness and air permeability of the casting sand are improved; moreover, the sand can be scattered and stripped more easily in the casting demolding process, so that work efficiency is improved; the modified alkaline phenolic resin self-hardening sand is compact and air-permeable in molding, resistant to molten metal scouring and erosion and small in thermal expansion coefficient, and the sand mold is not prone to deformation or scattering in the pouring process and can be used for pouring of the high-precision pump valve castings.

Description

technical field [0001] The invention relates to the technical field of resin sand, in particular to a modified alkaline phenolic resin self-setting sand for high-precision pump valve castings and a preparation method thereof. Background technique [0002] Castings for 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, and the quality of molding sand is also an important factor related to the quality of castings. 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, phenolic resin sand is widely used in the domestic foundry industry, and no-bake phenolic resin sand is widely used in the industry because of its...

AI Technical Summary

Problems solved by technology

[0003] Although no-bake phenolic resin sand has its unique advantages, it also has some prominent shortcomings, mainly in high viscosity, high brittleness, high gas generation, easy pinholes in castings, high cost, and difficult recycling. etc., with the development of pump and valve castings in the direction of large-scale production and high precision, the development of high-efficiency, pollution-free, low-cost, and excellent comprehensive performance phenolic resin adhesives is an important prerequisite for casting high-quality castings