Molding sand for gravity casting and preparation process thereof

Abstract

The invention discloses molding sand for gravity casting and a preparation process thereof. The molding sand comprises 100 parts of mixed sand, 0.8-1.2 parts of bentonite, coal dust accounting for 30-50% of the bentonite by mass, and 3-5 parts of water; and the 100 parts of mixed sand is prepared by mixing 93-96 parts of old sand with 4-7 parts of new sand, and the above-mentioned parts are by mass. Homogeneous and qualified clay green sand with stable performance can be obtained through the molding sand for gravity casting and the preparation process thereof.

Description

technical field [0001] The invention relates to the field of glass moulds, in particular to a molding sand for gravity casting and a preparation process thereof. Background technique [0002] In view of the production process and environment of glass bottles and jars, the surface of the blank inner cavity required for important glass mold parts must be cast with a dense chilled layer, instead of continuous casting bars or other molding materials. Based on the current experience and production practice in the industry, it is generally accepted that the casting process of gravity clay sand wet casting has significant advantages over resin sand casting or other casting methods. First, the production process is mature and the casting blanks are of good quality. The second is that the production cost is low, the pollution produced is less, and no irritating odor will be produced, which will affect the health of workers. The working environment of workers is relatively good. [...

AI Technical Summary

Problems solved by technology

In summary, the main defect of the existing technology is that the water content of the molding sand is not strictly controlled, resulting in the appearance of castings, subcutaneous pores, or sand washing, forming sand holes and fleshy

The compaction rate of the molding sand is difficult to control, resulting in difficulty in mold removal during molding, or poor fluidity of the molding sand, uneven compaction of the molding sand in the entire sandbox after molding, and local sand swelling and other defects.

The mixing time process of mixed molding sand is not strictly controlled, which leads to the inability to mix the components of the prepared molding sand or the mixing rhythm cannot keep up with the molding production rhythm

The distribution ratio of each component of the molding sand is not strictly regulated, which makes it difficult to control the overall quality of the molding sand

[0004] The above-mentioned deficiencies in the existing clay green sand preparation process have resulted in a low yield of glass mold casting blanks