This process is manufacturing tubes up to approx. 230 mm outside diameter. The usual starting material takes the form of round steel billets/blooms, rolled, forged or continuously cast, with diameters up to 300 mm.

Following heating to forming temperature, the starting material is inserted in the cylindrical recipient of the extruder, which features a round-bored die in its bottom. The bloom is initially pierced through the centre by a mandrel driven by a hydraulic ram. As the piercing mandrel passes through the die, it forms an annular gap through which the material is extruded under the pressure exerted by the ram to form the tube .The material remaining in the extruder is subsequently cut from the tube as recyclable discard