Molding sand

Abstract

The invention relates to molding sand. The molding sand is characterized by comprising the following components in parts by weight: 15-25 parts of clay sand, 15-25 parts of quartz sand, 20-25 parts ofwhite sand, 20-25 parts of magnesia, 8-15 parts of bentonite, 5-8 parts of zeolite powder, 3-6 parts of rosin, 2-5 parts of gypsum powder, 5-10 parts of pulverized coals, 25-35 parts of binding agent, 10-15 parts of hardening agent, 5-10 parts of starch, and 10-13 parts of water. Compared with the prior art, the clay sand is adopted as the raw materials, so that the binding performance is prominent; and the molding sand is simple in manufacturing, low in cost and suitable for secondary utilization after recovery, and greatly reduces the use cost. When the white sand and the magnesia are heated, the expansion coefficient is lower; the white sand and the magnesia are mixed with the quartz sand as raw sand for casting the molding sand, so that the expansion coefficient of the quartz sand isreduced, the condensation speed of castings is uniform, and the surfaces of the condensed castings are not easy to generate cracks and shrunk holes; and the pulverized coals and the clay can be addedto improve viscosity of the cast molding sand.

Description

technical field [0001] The invention relates to the field of ore sand, in particular to a molding sand. Background technique [0002] Molding sand is a material used for molding in sand casting. Molding sand plays an extremely important role in casting production. The casting waste caused by poor quality of molding sand accounts for about 30-50% of the total casting waste. The bonding ability of molding sand is an important indicator to measure the quality of molding sand. The existing molding sand usually uses water glass as a binder to make water glass sand. Although the bonding effect is better, but because water glass is more expensive, so The manufacturing cost of molding sand is also relatively high, and in the actual use of water glass sand, there will be problems such as difficulty in falling sand and difficult regeneration of old sand. [0003] Various casting defects often occur in the production process of castings, such as trachoma, cracks, pores, shrinkage cavi...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a kind of molding sand, which can solve the problems of cracks and shrinkage holes caused by uneven condensation speed of general molding sand castings, and the problem of poor reuse effect