What Is As-Welded Mechanical Tubing? The term “as-welded mechanical tubing” refers to tubing that has been produced by the electric resistance welding (ERW) process. It is provided in the state in which it leaves the welder, with only minimal downstream processing such as stress-relieving or annealing to meet particular customer specifications. The lack of additional processing such as cold drawing makes as-welded tubing a cost-effective product for many mechanical applications. It is produced in a wide variety of sizes with close tolerances that allow the tubing to be used in mechanical parts with little or no metal removal or machining. Contact one of the Steel Tube Institute’s as-welded member companies to inquire about particular product sizes, availability and delivery schedules.