Understanding the Welded Tube Mill Manufacturing Process

A welded tube mill is an integrated production line designed to transform flat metal strips, or skelp, into continuously welded tubular products . This machinery is central to producing longitudinally welded pipes and tubes used in gas and water supply systems, structural scaffolding, and various industrial applications . Shijiazhuang Faith Machinery Co., Ltd. manufactures robust welded tube mills that employ established welding technologies like Electric Resistance Welding (ERW) and High-Frequency Welding (HFW) .

The formation of the weld seam is the defining operation of this equipment. In the welding station, the precisely aligned edges of the formed strip are heated to a forging temperature. In HFW mills, this is achieved using a high-frequency electrical current, delivered via an induction coil or contact shoes, which heats the strip edges through electrical resistance. The heated edges are then pressed together by squeeze rolls to form a solid-state weld without filler metal. Some mills may include a post-weld heat treatment or normalization process to refine the microstructure of the weld zone, enhancing its mechanical properties .

Key components that support this process include the uncoiler and feeding system, the forming section with its cascading roll stands, and the sizing unit that calibrates the welded tube's final dimensions . Modern mills from Shijiazhuang Faith Machinery Co., Ltd. often incorporate non-destructive testing (NDT) methods, such as ultrasonic or eddy current testing, integrated directly into the line to perform real-time inspection of the weld seam integrity .

The versatility of welded tube mills allows for the production of not only round tubes but also square, rectangular, and other custom profiles by adjusting the roll tooling in the forming and sizing sections. This flexibility, combined with the efficiency of a continuous production process, makes the welded tube mill a vital asset for manufacturers requiring high volumes of consistent and reliable tubular products.