Process for improving surface quality of castings

Abstract

The invention provides a process for improving surface quality of castings. When the size of a sand box is less than 500mm and after sand injection, a distance from the outer side of a shell mold to the sand box is greater than or equal to 50mm, and a distance from the bottom of the shell mold to the bottom of the sand box is greater than or equal to 120mm; the shell mold is placed in the sand box prepared according to a forming process, a gate, used for pouring, of the shell mold and an insulation riser thereof are sealed with adhesive tapes, mixed sand prepared is put in the shell mold, after the shell mold is full, compacting is performed via a compactor, and a sand mold is formed; the mixed sand comprises sea sand, alkaline phenolic resin and curing agent, in a weight ratio of (99-104):(1.7-1.9):(0.35-0.37). The mixed sand added with the alkaline phenolic resin is injected into the sand box, the sand box is better in strength and stability, surface precision of castings is further improved, and quality of the castings is improved.

Description

technical field [0001] The invention relates to a process for improving the surface quality of castings, belonging to the technical field of machinery. Background technique [0002] The commonly used precision casting method is usually to obtain castings from mold making, wax mold making, shell mold making, roasting, and pouring metal. For some castings with complex structures, especially the shell molds with different thicknesses and sizes, the strength cannot be guaranteed, and the quality of the castings is also difficult to guarantee. Therefore, in the industry, this kind of castings are generally completed by sand casting, but Sand casting cannot achieve the dimensional accuracy of precision casting, and the surface quality and precision of castings are poor. Contents of the invention [0003] In order to overcome the defects of the prior art, the invention provides a process for improving the surface quality of castings. [0004] Technical scheme of the present inv...

AI Technical Summary

Problems solved by technology

For some castings with complex structures, especially the shell molds with different thicknesses and sizes, the strength cannot be guaranteed, and the quality of the castings is also difficult to guarantee. Therefore, in the industry, this kind of castings are generally completed by sand casting, but Sand casting cannot achieve the dimensional accuracy of precision casting, and the surface quality and precision of castings are poor