Valve material (1) valves in the water supply network, the past valve body, valve cover, gearbox material is mostly gray cast iron, some ductile iron. In view of pipe, pipe fittings are promoting the use of ductile iron, the valve material should be so. To improve the quality of castings, and reduce the weight of the valve, especially the valve plate should first use ductile iron pieces (QT405-10). It should be noted that, due to the different parts of the body thickness, casting ball is more difficult, there should be appropriate measures to ensure the quality of castings. At present there are still some problems casting body, such as the physical and chemical indicators of ductile iron in addition to individual manufacturers, the majority of lax control, and the use of sand casting, a large number of mechanical processing molding. It is suggested that all manufacturers establish a strict quality control system. For the large number of small and medium caliber valves, the model of lost foam molding is adopted. The large-caliber valves are made of resin sand, and the castings should have effective measures to eliminate the internal stress so as to promote the shot blasting and sand removal measures . Casting defects, welding does not allow the way to eliminate, or should take measures to eliminate the internal stress caused by welding repair, a more rigorous test, and to explain to the user. In the inspection also learned that many valve manufacturers casting the use of outsourcing to solve the way to complement each other, the acquisition of outsourcing parts assembly is also a mode of operation, the key is to control the quality of the outer parts should be strict. Of course, the purchase of low-quality components, a little decoration, buckle their own labels, the sale of high prices should be stopped. (2) Stem recommended 2CR13 stainless steel. (3) stem nut recommended cast aluminum brass or cast aluminum bronze, and the nut hardness and strength greater than the stem. Opening and closing the valve opening and closing moment for manual or mechanical light, the valve opening and closing torque under the working pressure? 240N? M, that is, a person can operate. Hope that the valve manufacturer first optimize the valve structure design, improve the concentricity of the components, moving parts of the contact surface finish, reducing the opening and closing resistance. If only by variable speed gearbox ratio, increase the number of ways to reduce hoist torque is not ideal. To this end, the means of mechanical processing can not be updated, such as a valve factory in Tianjin in order to improve the quality of machining, a large number of computer-controlled machine tools and machining centers, is commendable. Search Keyword: More Valve Product Information
