When selecting materials for the main parts of the valve, the physical properties (temperature, pressure) and chemical properties (corrosion) of the working medium must first be considered. Also know the cleanliness of the medium (with or without solid particles). In addition, the relevant regulations of the country and the user department should also be consulted.
A variety of materials can meet the use requirements of the valve under various conditions. However, correct and reasonable selection of valve materials can obtain the most economical service life and the best performance.
As far as the material of valve parts is concerned, the most commonly used classification method is to classify according to the materials used in the solenoid valve three-way housing: for example, cast iron valves, valves whose housing materials are made of gray cast iron, malleable cast iron or ductile iron; steel valves , The shell is made of carbon steel, alloy steel or stainless acid-resistant steel; titanium valve, the shell is made of titanium alloy; copper valve, the shell is made of copper alloy; aluminum Valves, valves whose shells are made of aluminum alloy; plastic valves, whose shells are made of plastic; ceramic valves, whose shells are lined with ceramic valves, and so on.
Cast iron valves.
Cast iron valves have the characteristics of low cost, simple manufacturing process, and good corrosion resistance. They are widely used in various sectors of the national economy, such as water pipelines, construction equipment, gas equipment, ships, fire fighting equipment, petrochemical equipment, ironmaking equipment, food Indispensable piping accessories such as processing equipment. The operating temperature range of the casting valve is generally below 225°C of the ambient (room temperature) temperature. However, gray cast iron is a brittle material, which limits the scope of use of solenoid valve type cast iron valves.
Due to the changes in the internal structure of malleable cast iron and ductile cast iron, the surface layer of the malleable cast iron valve is ferrite and the middle part is pearlite, which is basically the same as mild steel. Nodular cast iron is a spheroidal graphite obtained in the casting process through modification of added elements, so its mechanical properties are much better than general gray cast iron, and its working pressure can be slightly higher.