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Electric resistance welding (ERW) tube mill machines are widely used for producing medium- to large-diameter tubes from carbon and alloy steels. Shijiazhuang Faith Machinery Co., Ltd. designs ERW lines that integrate pay-off stands, forming sections, induction welding units, sizing stands, and press-quench systems into a cohesive production train.
ERW welding relies on applying high-frequency current to strip edges, heating them to plastic deformation temperatures before pressing them together under controlled roll pressure. The induction coil’s design—in terms of turns, coil width, and cooling channels—determines heating uniformity and power efficiency.
The forming section comprises multiple stands of molding rolls that guide the strip into an open seam. Precise mandrel alignment is achieved through position-controlled roll stands, which adjust in response to feedback from laser micrometers measuring tube outer diameter. After welding, aging rolls maintain tube geometry while the weld bead remains malleable. Downstream sizing stands and stretch forming units refine roundness and eliminate minor ovality, ensuring tubes meet tight geometric tolerances.
A press-quench setup often follows: the tube passes through a cooling ring where water quenching improves mechanical properties by refining the weld microstructure.
Shijiazhuang Faith’s ERW machines incorporate automatic gauge control (AGC) systems that adjust roll gaps to maintain constant wall thickness despite minor strip variations. In addition, vision systems inspect the weld seam for surface defects such as laps or wrinkles. On-line ultrasonic testing (UT) units provide volumetric inspection, detecting internal voids or inconsistent fusion.
Data from UT and surface cameras feed into a rejection station, which automatically diverts defective sections to a scrap conveyor without interrupting the main production flow.
Core mechanical components—gearboxes, bearings, roll shafts, and mandrels—are selected based on fatigue life simulations to withstand continuous high-speed operation. Couplings include bellows or grid types to absorb misalignment and torsional vibrations. Motors driving the induction coil and pull-through units feature water-cooled housings and insulation monitoring to ensure reliable performance under high electrical stresses.
By combining advanced welding technology, precise forming, and comprehensive inspection systems, Shijiazhuang Faith’s ERW tube mill machines deliver consistent tube quality for structural, mechanical, and fluid-conveyance applications.
