High-compactness modified alkaline phenolic resin self-hardening sand for pump valve castings and preparation method of high-compactness modified alkaline phenolic resin self-hardening sand

Abstract

The invention discloses high-compactness modified alkaline phenolic resin self-hardening sand for pump valve castings. An adopted modified phenolic resin adhesive in the resin sand has the advantages that the viscosity is low, the bonding strength is high, the plasticity is good, the brittleness is low, the contents of free phenol and free formaldehyde are lower, the use amount is lower, the hardening speed is decreased, and the like, so that the use and reuse performance of the molding sand can be effectively improved; through the addition of polylactic acid fiber and porous polypropylene fiber added in the sand, the thermoplasticity time during the casting pouring process is longer, the stress generated after sand heating is relieved, the retention time of a sand mold is prolonged, the castings are prevented from cracking, the air permeability is improved, the rearrangement and densification of the sand are facilitated in the fiber low-temperature fusion introduction instant liquid state, and the precision of pump valve castings is improved.

Description

technical field [0001] The invention relates to the technical field of resin sand, in particular to a high-density modified alkaline phenolic resin self-setting sand for pump and 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 i...

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