As we all know, the material of the valve is related to the safety of the valve in the future life and production and the service life of the valve.
1. The valve stem is recommended to be made of 2CR13 stainless steel.
2. The valve stem nut is recommended to be cast aluminum brass or cast aluminum bronze, and the hardness and strength of the nut are greater than that of the valve stem.
3. Valves in the water supply network, in the past, the valve body, valve cover, and variable speed transmission box were mostly made of gray cast iron, and some were made of ductile iron.In view of the promotion of the use of ductile iron for pipes and fittings, the material of the valve should also be the same.Thereby improving the quality of the casting and reducing the valveThe weight, especially the valve plate, should first use ductile iron (QT405-10).It should be pointed out that due to the different thickness of each part of the valve body, the difficulty of casting spheroidization is relatively large, and corresponding measures should be taken to ensure that the castingPiece quality.At present, there are still some problems in the casting of the valve body.Strict, and cast with sand, a large number of machining molding.It is recommended that manufacturers establish a strict quality control system.Large, medium and small diameter valves are modeled by the lost foam method, and large diameter valves are modeled by resin sand, and the castings are required to be effectively eliminated.Measures of internal stress, promotion of shot blasting and sand cleaning measures.Defects of castings are not allowed to be eliminated by welding repair, otherwise measures should be taken to eliminate themThe internal stress formed by welding repair, carry out more stringent inspection, and explain the situation to the user.
In order to further improve the quality of the valve, the design of the valve structure should be optimized to improve the concentricity of the component combination and the lightness of the contact surface of the moving parts.Cleanliness, reduce opening and closing resistance.If only relying on the gear ratio of the variable speed gearbox, the method of increasing the opening and closing revolutions to reduce the opening and closing torque isNot ideal.