Composite Casting Process to Prevent Deformation of Bonnet Neck of Cryogenic Gate Valve

Abstract

The invention discloses a composite casting technology capable of preventing the neck part of a valve cap of a low-temperature brake valve from being deformed. The composite casting technology comprises the following steps: A, manufacturing a wax mold; B, manufacturing a mold shell; C, roasting the mold shell; D, smelting and pouring; and E, carrying out aftertreatment, namely, cutting, polishing, carrying out thermal treatment, acid pickling and shot blasting working procedures. The deformation probability and times of the type of products can be reduced by adopting the composite casting technology capable of preventing the neck part of the valve cap of the low-temperature brake valve from being deformed, and the product yield is improved.

Description

technical field [0001] The invention relates to a composite casting process for preventing deformation of the valve cover of a low-temperature gate valve, in particular to a composite manufacturing process for a valve cover of a low-temperature gate valve with a caliber of less than 400. Background technique [0002] Since the bonnet of the cryogenic gate valve needs to be used in a low temperature environment (generally, the detection temperature to be met is -240°C), for this reason, the upper end bracket of the bonnet adopts an integral casting structure, and the bracket is generally not less than 50 cm. Therefore, no matter in the steps of silica sol precision casting or water glass composite casting, slight carelessness in the steps of wax modeling, shell manufacturing, shell burning and pouring will cause the inner cavity of the bonnet and the connection end of the bonnet and the bracket to be damaged. (That is, the neck of the bonnet) is deformed. Due to the particula...

AI Technical Summary

Problems solved by technology

Therefore, no matter in the steps of silica sol precision casting or water glass composite casting, slight carelessness in the steps of wax molding, shell manufacturing, shell burning and pouring will cause the inner cavity of the bonnet and the connection end of the bonnet and the bracket to be damaged. (that is, the neck of the bonnet) is deformed. Due to the particularity of its structure after deformation, subsequent shaping is basically ineffective, resulting in that the failure rate of products cannot be effectively controlled when using conventional precision casting processes.