Large Cast Iron Concentric Butterfly Valve

Butterfly valve. Valves and are generally made of plastic or steel, the latter being the most widely used in chemical and petrochemical applications. Steel grades range from the most common type, namely carbon steel, with standard stainless steel being the second most common. Stainless steel alloys, which include nickel or copper are used in applications that require higher corrosion or heat resistance. In such cases, the most commonly used valve configurations -- ball valves