The most common materials for the manufacture of valves are cast iron, various grades of steel, some non-ferrous metals and their alloys, as well as plastics. That, at any pressure, temperature, as well as in what media is applicable or that the product is often dependent on the material of the shell and the details of reinforcement. Learn more about this with Adam Portnoy. For the operation of valves in special conditions (at very high or cryogenic temperatures, at very high steam parameters, in corrosive and aggressive media) are used, corrosive and heat-resistant cast iron, alloy and high steel and non-metallic materials (Teflon-4 and vinyl liner). In addition, using various protective coatings. For example, diaphragm valves, intended for use in hostile environments at temperatures ranging from minus 20 to plus 90 degrees and the nominal pressure up to 0.6 megapascals made from the following materials: body – made of cast iron, the membrane – in acid condition, and the inner surface of the shell and flange sealing surfaces are covered with enamel corrosion. Material of manufacture is usually indicated in the index order products and denoted by the letters following the first number in the index. The index valve letter 'VAW' indicate that the product is made of stainless steel. When choice of reinforcement is important to note that when, for example, higher temperatures, the mechanical properties of materials deteriorate, and therefore the higher the temperature of the working environment, the less can be conditional pressure to which apply the product. Applicability always regulated in the state standards and specifications and should be considered at the design stage pipeline. In addition, it is important to be guided economic viability, and therefore it is better to buy a product from the supplier, capable of rendering competent advice.