Sand core coating for foundry

Abstract

The invention discloses sand core paint for casting. The sand core paint for casting comprises the following components in parts by weight: 100 parts of silica sand, 20-40 parts of glimmerite-shaped aluminosilicate, 10-15 parts of bentonite, 8-12 parts of flaky graphite powder, 10-16 parts of talcum powder, 0.1-0.5 part of defoaming agent, 1-3 parts of aluminum polychlorid, 1-2 parts of polyvinyl alcohol, 2-4 parts of sodium alga acid, and 5-8 parts of polyacetic acid emulsion. The sand core paint is added with bentonite and flaky graphite powder for improving the absorption performance and the plasticity, can realize synchronous collapse with a sand core, is easy to strip a sintering layer from the surface of a casting, effectively prevents chemical sand bonding, uses silica sand and glimmerite-shaped aluminosilicate as refractory materials without generating chemical reaction with other substances, is excellent in high-temperature resistance and covering performance, is excellent in leveling property and shrinkage resistance, is better in stability and cohesiveness, and is not easy to deteriorate after long-time placement.

Description

technical field [0001] The invention belongs to the field of coatings, in particular to a sand core coating for casting. Background technique [0002] The main casting cylinder block and cylinder head on the engine generally use cold box cores in the casting process. The core making process is complicated and the precision requirements are high; The performance of the main coating is directly related to the quality of the casting. At present, the water-based dipping coatings used in domestic engine block and cylinder head production are all imported or produced by joint venture manufacturers. The key auxiliary materials used in the coating are of good quality, and the various performance indicators of the coating are high. After the coating is applied, the surface Bright and smooth, no holes, cracks, flow marks and other defects. The quality of foreign coatings is good, but the price is expensive. Domestic coatings are also relatively good, but the quality of coatings is n...

AI Technical Summary

Problems solved by technology

(1) The defoaming effect of the coating is poor: there will be more or less bubbles during use, some are large and some are small, and it is not easy to completely eliminate the foam; (2) The leveling of the coating is not good: After the sand core is dip-coated, the thickness of the coating is uneven, and there are obvious flow marks and accumulations on the surface; (3) The wettability of the coating and the sand core is poor: After the sand core is dip-coated, the wettability of the coating and the sand core is poor, and the coating cannot be quickly Effective penetration into the surface of the sand core, on the vertical plane, the continuity of the coating is destroyed, resulting in water-breaking defects of the coating