Lost foam casting method for heavy casting

Abstract

The invention discloses a lost foam casting method for a heavy casting. The method comprises the following steps of: a. manufacturing a foam model; b. mounting a counter-deformation bracket: manufacturing the steel-structured counter-deformation bracket according to the size and the length of a workpiece and placing the counter-deformation bracket on the bottom of the foam model; c. painting: the thickness of the paint is not less than 4mm; d. drying: placing the painted foam model in a drying room for drying at the constant temperature of 50 DEG C; e. fixing core: placing the steel-structured bracket in an inner cavity of the foam model so as to fix the model, and putting the whole foam model into a sandbox together; f. boxing: enabling the sandbox containing the foam model to drop sand evenly, vibrating the sandbox during sand dropping, gradually enhancing the vibration amplitude with the increasing of added sand quantity, mounting a main runner and a branch runner of a ceramic tube, and placing a pouring cup; g. pouring: opening a vacuum pump for vacuum pumping before pouring; h. releasing negative pressure: after pouring, keeping the negative pressure for 8 to 15 minutes until solidification of an iron liquid, and then releasing the negative pressure; and i. cleaning.

Description

technical field [0001] The invention relates to a casting method, in particular to a lost foam casting method for large castings. Background technique [0002] Casting large castings places high demands on the model. Using different models, casting methods are also different. The traditional method is to use ground mold sand casting, that is, to make the outer mold of the model first, then dry, place the sand core, close the box, pour, clean and polish. Using this traditional method, although large-scale castings can be cast, it is labor-intensive, time-consuming and labor-intensive, and the quality of the castings is unstable: the smoothness does not meet the requirements, the shape is easily deformed, and it is often overweight, which consumes a lot of energy and costs. high. Later, people tried to use the lost foam casting method. Lost foam casting is a relatively advanced casting method, which has the advantages of saving time and effort, smooth surface and stable ca...

AI Technical Summary

Problems solved by technology

However, there are still technical problems in the existing large-scale castings of more than 5 tons in lost foam casting: due to the large space and complex structure of large-scale castings, the casting speed and the solidification speed of molten iron often cannot keep up with the gasification speed of the foam model during casting, thus causing collapse , resulting in casting deformation or even complete scrapping