Metal casting method

Abstract

The invention relates to a metal casting method which comprises the following steps: firstly, spraying sizing agent and investment precoat are prepared, an air inlet of a spraying gun is connected with a high-temperature wind pipe, and a sizing agent inlet of the spraying gun is inserted into the prepared spraying sizing agent; a casting mould is prewetted according to a conventional process; the high-pressure wind pipe is opened, a spout of the spraying gun is aligned with the surface of the casting mould to spray a layer of sizing agent, and a sizing agent layer is formed on the surface of the casting mould; the casting mould with the surface sprayed with the sizing agent is put into the prepared investment precoat and is then sprayed, rotatably coated and sand-filled according to the conventional process. The metal casting method has simple process, greatly improves the coating property of the investment precoat of the casting mould, better improves the phenomenon that bubbles appear on the surface of the casting mould, increases the size precision, the contour sharpness and the surface finish quality of the casting, solves the common casting defects of iron blains, iron pricks, bumps, and the like, lowers the production cost, and shortens the production period.

Description

technical field [0001] The present invention relates to a metal casting method. Background technique [0002] At present, when metal casting is carried out at home and abroad, the surface coating of the mold is generally made of silica sol surface coating. The coating preparation usually includes zircon powder, silica sol for the surface layer, defoaming agent, and wetting agent; The coating and hanging operation steps of the first layer of paint are: mold pre-wetting, surface layer brushing, rotary coating and hanging, and sand hanging. Casting various gear castings with small modulus tooth shapes generally require the tooth shape to be cast out, and the requirements for the integrity of the tooth shape, dimensional accuracy and surface roughness are relatively high, and the production of such castings will be in the gear Casting defects such as iron pox, iron thorns, and defects occur on the meshing surface of the tooth, and castings with blind holes, grooves, and dead co...

AI Technical Summary

Problems solved by technology

Casting various gear castings with small modulus tooth shapes generally require the tooth shape to be cast out, and the requirements for the integrity of the tooth shape, dimensional accuracy and surface roughness are relatively high, and the production of such castings will be in the gear Casting defects such as iron pox, iron thorns, and defects occur on the meshing surface of the tooth, and castings with blind holes, grooves, and dead corners are also prone to the above defects.

Due to the small modulus of the gear, the distance from the pitch circle to the dedendum circle and the addendum circle is short, and the involute extends to the addendum circle, so that the teeth become tapered. In addition, the tooth width is narrow and the coated area is small; in addition The viscosity of the silica sol surface coating is relatively large, the surface tension of the coating is large, and the poor fluidity is also a reason. Even if a wetting agent is added to the surface coating, the coating performance of the surface coating is still poor. The cleaning agent has been cleaned, but there will inevitably be dead corners that cannot be cleaned, so it is easy to generate air bubbles or not stick to the slurry at the gears, blind holes, grooves, and dead corners of the casting mold, resulting in iron pox, iron thorns, and fleshy castings. Casting defects such as casting defects, poor surface finish of castings, resulting in low product qualification rate, long production cycle, unable to meet production requirements