Welded and floating plug drawn

After welding, the tube is drawn through a die with a floating plug in the bore to rework the weld seam. The plug is not attached to a rod or mandrel, but “floating” inside the tube surrounded by lubricant. The weld seam is
reworked internally and externally by the die. By drawing through a die, the tube has an improved sealing surface, and a truly round OD and a better internal and external surface finish. This tubing is referred to as “smooth”
bore.