The structure of silicon brass four-way elbow sand casting valve box is complex, and the wall thickness of general valve box is relatively thin. There are four flanges on one side of the valve box body; The other side of the main body of the valve box is equipped with a corresponding elbow, and the lower part of each elbow is also equipped with a circular flange; There is also a round flange on the top of the main body of the sand casting valve box. Obviously, this structure is prone to the following problems: first, it is difficult to demould; Second, it is more difficult to supplement; Third, oxidation inclusions are difficult to surface; Fourth, it is difficult to locate and support the sand core; Fifthly, it is difficult to discharge the gas in the sand core. As the oxidation tendency of silicon brass is smaller than that of aluminum bronze, it is not necessary to adopt the bottom pouring system like aluminum bronze, so as to facilitate the smooth floating of oxide inclusions. For the ZCuZn16Si4 four-way elbow sand casting valve box, the medium-injection pouring system is generally adopted, that is, pouring from the horizontal parting surface, which can shorten the flow of the alloy liquid, not only avoid the insufficient pouring of the sand casting, but also conducive to feeding, and the oxide inclusions are easy to emerge.
Use cold iron with riser. A side blind riser is set on one side of the flange of the four-way elbow sand casting valve box for feeding, and a graphite chill is set on the other side for quenching; A waist round riser is provided to supplement the round flange on the top of the sand casting valve box; Graphite chill iron is set to quench the round flange under the valve box elbow; Graphite chill is set to quench the round hole in the inner cavity of sand casting valve box. The gating system is closed before opening, and the filter screen is set behind the sprue. The ratio of each section of the gating system is: F straight: F filter: F horizontal: F inner=(1.5~2) ∶ 1 ∶ (2~3) ∶>5.