DOM tubing is not technically a tube at all. Actually, it is the process from which the DOM tube is formed. Drawn Over Mandrel is a metal forming process. It starts with an electrically welded formed tube. The ERW is cold drawn through a die and over the sides of a mandrel.
Thus, the die size and angle determine the outside diameter and Mandrel determines the inside diameter. Afterward, multiple applications further form and refine the finish and mechanical properties necessary for its final application. You can contact us if you want to buy DOM tubes for industrial purposes.
Drawn Over Mandrel
Drawn Over Mandrel is one of many tube milling techniques. There are other similar Cold Tube Drawing methods to size and finish tube to desired dimensions. DOM Tubing starts out as a Hollow or CREW (Cold-Rolled ERW tube).
Firstly, the larger ERW tube is “pointed” in order to be grabbed by a trolley jaw. The trolley is a conveyor-like platform that pulls the tube through the die. After Pointing the raw tube, a carbide mandrel is inserted inside the tube’s bore. Then, the tube is set inside a carbide. After which, a solvent lubricates the tube’s surface. Then, the trolley jaws grip the tube at the pointing end pulling via the trolley hook drawing the pipe through the die.
As a newly resized DOM tube, ultimately the die and mandrel determine the OD (Outside Diameter) and ID (Inside Diameter) of the final tube. In other words, a high-angle die will thin a heavy-wall tube while a low-angle die will thicken a thin-wall tube. Optimum die positioning and its angle determine the correct diameter-to-thickness (D/t) ratio.