To start the seamless tubemaking process, round billets from one of our rolling mills are reheated in a rotary furnace to the appropriate piercing temperature. The heated billets are transferred to the piercing mill, where they are drawn by two rotating drive rolls over a bullet-shaped piercing plug. As the hole in the tube is created, the tube grows to approximately twice as long as when it entered as a solid billet.

The rough tube shell coming from the piercing mill then enters a three-roll unit called the elongator. This device fine-tunes the wall dimensions of the tube by controlling the outside diameter size while a mandrel supports the tube along the entire ID surface.

Each tube completes its processing by passing through the reducing mill and rotary sizer. These devices make the last adjustments to the OD size by passing the hot tube through a series of rolls.

Along the entire piercing process, a variety of optical and laser gauging systems are used to ensure that the OD and wall dimensions of each tube meet customer requirements.