Sand core good in air permeability and preparation method thereof

Abstract

The invention discloses a sand core good in air permeability and a preparation method thereof. The sand core good in air permeability is prepared from 12-13.5% of pottery clay, 4.5-6.5% of activated carbon powder, 3.5-6% of dry sand, 4-6% of aerogel and the balance molding sand and inevitable impurity elements. The preparation method includes the following steps of dry sand filling, aerogel layer wrapping, sand core box coating, drying, shaping and material taking. The surface of a core bar is filled with dry sand through honeycomb holes, and the dry sand is used for adsorption for air. Because the surface of the core bar is further wrapped by an aerogel layer, the air permeability of the aerogel is especially good, good air permeability is achieved, the problems that because a sand core in the prior art is poor in air permeability once the core bar is adopted, and consequently a casting is prone to the cavity defect are solved, and therefore the air permeability of the sand core is improved, occurrence of the cavity defect of the casting is avoided, the aerogel layer further has high high-temperature resistance, damage to an air-permeable layer caused by high-temperature casting is avoided, and the requirement of casting work of various materials can be met.

Description

technical field [0001] The invention relates to the technical field of lost foam, in particular to a sand core with good air permeability and a preparation method thereof. Background technique [0002] Sand mold is an indispensable part for casting products in the foundry industry. As the name suggests, sand mold is a casting mold made of sand. Sand casting involves placing a model of the finished part or a wooden model in the sand, then filling the model with sand over the weekend, and after the model is taken out of the box, the sand forms the mold. According to the structural characteristics such as the shape of the product, sand cores are often fixed in the sand mold to form the cavity in the casting. In order to ensure that the sand core is not deformed, cracked or broken during the process of manufacturing, transportation, assembly and pouring, the sand core should have sufficient strength and rigidity. Therefore, core bone is usually embedded in the sand core to inc...

AI Technical Summary

Problems solved by technology

However, once the sand core produced in the prior art adopts the core bone, its air permeability will be poor. When the sand core has poor air permeability and poor exhaust, these gases will invade into the molten metal, making Castings are prone to porosity defects, which affect the quality of castings