Molding sand for casting

Abstract

The invention discloses molding sand for casting. The molding sand for casting comprises the following raw materials in parts by weight: 35-40 parts of chromite sand, 40-45 parts of ceramsite, 0.2-1 part of adhesive, 20-30 parts of silica sand, 5-10 parts of white sand, 18-25 parts of magnesium sand, and 3-6 parts of olivine sand. The molding sand for casting uses the silica sand, the magnesium sand, the white sand and the olivine sand as main components of raw sand; the expansion coefficients of the white sand and the magnesium sand are lower during heating; the white sand, the magnesium sand and the silica sand are mixed as the the raw sand of the molding sand for casting; the expansion coefficient of the silica sand is reduced; the structure stability is improved; the casting condensation speed is uniform; condensed castings are not easy to generate cracks and shrinkage holes in surfaces; the ceramsite is added to improve the high-temperature resistance and the acid-alkali erosion resistance of the molding sand, and can be recycled; and a little adhesive is added to enhance the viscosity of the molding sand for casting.

Description

technical field [0001] The invention belongs to the technical field of casting, in particular to a casting sand. Background technique [0002] Foundry sand is a molding material used to prepare molding sand and core sand in foundry production. In the case of using clay as the sand binder, about 1 ton of new sand is needed to produce 1 ton of qualified castings, so the amount of foundry sand is the largest in sand casting production. [0003] China has used silica sand as a modeling material in the 17th century AD to make castings such as clocks, mirrors, pots and cannons. However, the natural silica sand containing clay, namely mountain sand and river sand, was mostly used in the early days. It has good plasticity and can be directly used to make molds and cores, which is suitable for the conditions of manual production at that time. After the castings enter the industrialized mass production, especially after the modeling is mechanized, the performance uniformity of this ...

AI Technical Summary

Problems solved by technology

[0004] Various casting defects often occur in the production process of castings, such as trachoma, cracks, pores, shrinkage cavities, etc., and the generation of cracks is related to the condensation speed of castings. In the prior art, quartz sand is used as casting sand to condense castings , but the condensation ability of quartz sand is weak, and the expansion coefficient is large. Simply using quartz sand and clay will cause local sudden expansion of the casting, resulting in local condensation of the casting, which makes the condensation speed of the casting uneven, resulting in stress, and prone to cracks and shrinkage. hole