The connection between casting and valve is after the 20th century. The rapid development of casting has created ductile iron, malleable iron, ultra-low carbon stainless steel and aluminum-copper, aluminum-silicon, aluminum-magnesium alloy, titanium, which are still often used in valve products. Cast metal materials such as base and nickel base alloys.
The main advantage of casting is that the cost of the blank produced by casting is low, and it is more economical for parts with complex shapes, especially with complex inner cavities. At the same time, it has wide adaptability and good comprehensive mechanical properties. However, there are many materials and equipment required for casting production, and dust, harmful gas and noise will be generated to pollute the environment.
Forging valve is a processing method that uses forging machinery to apply pressure to metal valve blanks to produce plastic deformation to obtain forgings with certain mechanical properties, certain shape and size. Forging can be divided into open forging (free forging) and closed mode forging according to the forming method. Forging can be divided into hot forging, warm forging and cold forging according to the deformation temperature.
Forging materials are mainly carbon steel and alloy steel of various compositions, followed by aluminum, magnesium, titanium, copper, etc. and their alloys. The original state of the material is bar, ingot, metal powder and liquid metal. The ratio of the cross-sectional area of the metal before deformation to the die cross-sectional area after deformation is called the forging ratio.
Through forging, the as-cast porosity and welding holes of the metal can be eliminated, and the mechanical properties of forgings are generally better than those of castings of the same material. For important parts in machinery with high load and severe working conditions, forgings are mostly used in addition to rolling plates, profiles or welded parts with simple shapes. Correct selection of forging ratio has a lot to do with improving product quality and reducing costs.
Casting valve is a valve made by casting. Generally, the pressure level of casting valves is relatively low (such as PN16, PN25, PN40, but there are also high-pressure ones, which can reach 1500Lb, 2500Lb, and most of the calibers are above DN50. Forged valves are forged valves. They are generally used in pipelines with high pressure levels. Forged valves are mainly small-diameter, generally below DN50.