Buttweld pipe fittings, also known as welded pipe fittings, are a type of pipe fittings that are welded to the pipe rather than threaded. They are used to connect pipes of various sizes and shapes in a piping system, allowing for changes in direction, branch off, or connect different components of the system. Buttweld pipe fittings are commonly used in industries such as oil and gas, chemical, petrochemical, and power generation.