Core making method for diphasic sand mould core hardened by CO2 gas

Abstract

The invention relates to a core making method for a diphasic sand mould core hardened by CO2 gas, which is characterized in that a CO2 gas hardening water glass sand phase as a body in the core, and a CO2 gas hardening water soluble resin sand phase as the surface of the core are filled in a core box, wherein the thickness of the the CO2 resin sand phase on the surface of the sand mould core is 15-25mm; after the sand is filled completely, the CO2 gas is introduced into the core box, wherein the pressure of the CO2 gas is controlled to be 0.3-0.5MPa; and the water glass sand phase is completely hardened so as to integrally mould the core sand. The method in the invention has the advantages of not generating harmful gas in the process of core making and pouring and being convenient to use; and the fettling efficiency is high, the production cost is low, the labor intensity is lowered, and the production efficiency is improved.

Description

technical field [0001] The present invention relates to a CO 2 The invention relates to a "two-phase" sand core making method of gas hardening, which belongs to the field of sand core making in the foundry industry. Background technique [0002] Currently domestic and foreign CO 2 The types of gas-hardened sand mainly include sodium silicate sand, alkaline phenolic resin sand and water-soluble resin sand. The basic process is to fill the core box with the mixed core sand, and then blow CO 2 The gas makes it harden and form, and because it is hardened first and then demolded, the dimensional accuracy of the core is accurate. CO 2 The production cost of air-hardened water glass sand is low, but there are problems such as poor collapsibility, difficult cleaning of core sand, sand sticking on the surface of castings after pouring, etc., which seriously restrict its application; while CO 2 Air-hard alkaline phenolic resin sand has poor control of gas blowing, and the CO 2 Th...

AI Technical Summary

Problems solved by technology

CO 2 The production cost of air-hardened water glass sand is low, but there are problems such as poor collapsibility, difficult cleaning of core sand, sand sticking on the surface of castings after pouring, etc., which seriously restrict its application; while CO 2 Air-hard alkaline phenolic resin sand has poor control of gas blowing, and the CO 2 The pressure and flow requirements of the gas are harsh, and the strength is low, the cost is high, and the smell is strong. After the casting is poured, phenol and formaldehyde diffuse, causing environmental pollution, which also greatly limits the promotion of this process.

The lack of economy of other core (core-making) processes and the constraints of technical complexity also hinder its engineering