Casting method for valve body of expansion valve

Abstract

The invention provides a casting method for a valve body of an expansion valve. An insulating riser is installed at the part of a central flange of a sand core, blind risers are installed at the tail of the valve body of the sand core and the part of a drain hole of the valve body, the insulating riser is used for feeding on the central flange, the insulating riser of the central flange is used for feeding at the part of a valve belly by adopting the form of a feeding rib, and the blind risers are used for feeding at the tail of the valve body and the part of the drain hole of the valve body; the lower parts of a lower molding pit external mold real sample and an inner cavity sand core assembly are scraped to be planes by using a shaft rod scraper, and an upper molding cover core and a riser are calculated based on rod-shaped parts and divided into an upper layer and a lower layer. The casting technology for the main valve body of the expansion valve, provided by the invention, adopts a combination of the inner layer and the outer layer of open and blind risers with an external chill quenching process, so that the problems of shrinkage cavity and shrinkage porosity of a thin-walled steel casting in a production process are effectively eliminated, namely a complete set of inner quality control system is formed by the process.

Description

technical field [0001] The invention relates to a method for casting a valve body of an expansion valve, which belongs to the technical field of machinery. Background technique [0002] Due to the critical and special needs of the ZG20Mn carbon steel expansion valve for key control in the operating environment in hydropower equipment, the requirements for the internal quality of the main valve body are relatively high. However, limited by the existing casting technology At present, there is no unified casting process in the field of casting in our country, that is, the main valve body of the expansion valve produced by the current casting process cannot effectively guarantee that its internal quality can meet the requirements of stability and reliability, which invisibly gives the installation The safe and stable operation of related hydroelectric equipment using the expansion valve has brought hidden dangers. Contents of the invention [0003] The invention provides a va...

AI Technical Summary

Problems solved by technology

[0005] The valve body casting method of the expansion valve involved in the present invention, the main valve body casting process of the expansion valve adopts the combination of the inner and outer layers of open and dark risers and the chilling process of the outer cooling iron, which effectively eliminates the need for thin-walled steel castings in the production process. The problem of shrinkage cavity and shrinkage porosity, that is, the described process has formed a complete set of internal quality control system, thus effectively solving the problem of unsmooth casting feeding channel and upper and lower flange parts caused by the structural problems of the main valve body of the expansion valve. The difficulty of casting feeding can not be taken into account, which not only guarantees the stability and reliability of the internal quality of the main valve body of the expansion valve, but also greatly reduces the cost burden caused by repeated repairs when castings are repaired and cleaned for heat treatment, and then provides a basis for the application of this process. of enterprises have brought good economic benefits