Special sand proportiom for casting

Abstract

The invention discloses a special sand proportion for casting, comprising the following substances by weight percent: 20-30% of graphite sand, 20-30% of chromite sand, 10-20% of iron pink, 1-3% of coke powder, 0.5-2% of furan resin and the balance of silica sand. The proportion disclosed by the invention is low in cost, and good in fire-resistant and chilling effects, and can be applied to facing sand or a hot spot of nodular iron casting and steel casting; the burnt-on sand on the surface of the casting is solved; the shrinkage cavity and shrinkage porosity can be over 90%; and the surface smoothness and the yield of the casting are improved.

Description

technical field [0001] The invention belongs to the field of casting raw and auxiliary materials, and in particular relates to a special molding sand ratio for casting. Background technique [0002] In the process of casting molding, traditional steel castings generally use water glass sand, resin sand, etc. as surface sand, and increase risers and cold irons at hot joints to reduce shrinkage and shrinkage defects; but in the casting process of hot oil pump parts Among them, due to its complex shape, large difference in thickness, good pressure bearing effect, anti-leakage and other characteristics, the traditional process can not achieve the ideal effect, and the scrap rate is often 40-50%, mainly because the surface of the casting is sticky sand, the casting Shrinkage and porosity at the hot joints are scrapped. Contents of the invention [0003] The purpose of the present invention is to provide a high-efficiency chilled molding sand ratio that can effectively solve th...

AI Technical Summary

Problems solved by technology

[0002] In the process of casting molding, traditional steel castings generally use water glass sand, resin sand, etc. as surface sand, and increase risers and cold irons at hot joints to reduce shrinkage and shrinkage defects; but in the casting process of hot oil pump parts Among them, due to its complex shape, large difference in thickness, good pressure bearing effect, anti-leakage and other characteristics, the traditional process can not achieve the ideal effect, and the scrap rate is often 40-50%, mainly because the surface of the casting is sticky sand, the casting Shrinkage cavity and porosity at hot joints and scrap