A plug valve is a type of quarter-turn valve that uses a cylindrical or conical plug to regulate the flow of fluid or gas. The plug has a hollow passage that can be aligned with the flow path to allow flow or turned to block it. Plug valves are widely used in applications requiring quick and reliable shutoff, as well as flow control in pipelines.

Based on its intended use, plug valves can be made of a number of materials. Low-pressure, general-purpose systems frequently employ cast iron. High-pressure, corrosive, or sanitary settings are more suited for stainless steel. Alloys like Inconel and Monel are used for severe chemical handling and high temperatures, whereas brass is utilized in low-pressure systems with non-corrosive fluids. Compatibility with the operational circumstances is ensured by choosing the appropriate material.