Welded pipe is a type of pipe made by welding a steel plate or strip that has been welded together after it has been rolled and shaped by a welding process.
Product Overview
Our Alloy Cold Rolled Carbon Steel Welded Pipe is produced by precision cold rolling of hot-rolled coil strip followed by high-frequency electric resistance welding (ERW) or longitudinal submerged arc welding (LSAW). The addition of micro-alloying elements—such as manganese, silicon, and trace chromium—elevates the mechanical properties of standard carbon steel while maintaining excellent weldability and formability.
Unlike standard hot-rolled welded pipe, the cold rolling process delivers tighter wall thickness tolerances, smoother surface finish, and more consistent mechanical properties throughout the length of the tube. This makes it the preferred choice for applications requiring reliable dimensional accuracy, clean internal surfaces, and uniform load-bearing performance, including precision machinery, automotive fluid lines, structural supports, and hydraulic systems.
Features:
Cost advantage: the welding process is relatively simple, high production efficiency and lower cost.
High product precision: especially high wall thickness precision.
Wide range of application: can be used in a variety of application scenarios.
4m – 12m (fixed or random); cut-to-length available
Surface Finish
Black / Oiled / Pickled / Phosphated / Powder Coated
Tensile Strength
490 – 630 MPa (depending on alloy grade)
Yield Strength
≥355 MPa
Welded Pipes are Widely Used in Many Fields:
Construction field: used for steel structure frames, supports, protective railings, etc.
Pipeline transport: used for transporting water, gas, oil, natural gas and other fluids.
Mechanical manufacturing: used for manufacturing mechanical structure parts, auto parts, etc.
Electrical engineering: used for wire casing, etc.
Cold Rolled Welded Pipe Advantages
Feature
Benefit
Tight Dimensional Control
OD tolerance ±0.05mm to ±0.20mm; wall thickness variation ≤±8%—ideal for press-fit and bearing applications
Smooth Internal Surface
Cold rolling produces a uniform ID finish (Ra ≤3.2 μm), reducing fluid friction and pressure drop in conveying systems
Enhanced Mechanical Properties
Cold work strain-hardening increases yield strength by 10–20% over hot-rolled equivalents in the same grade
Consistent Weld Integrity
Automated ERW or LSAW processes with inline ultrasonic inspection ensure uniform penetration and absence of defects
Cost Efficiency
Significantly lower cost than seamless alloy pipe for diameters under 200mm, with comparable performance in non-critical pressure applications
Excellent Straightness
Cold rolling and tension leveling achieve straightness ≤1 mm/m, minimizing alignment issues during installation
Manufacturing Process
Slitting: Hot-rolled alloy steel coil is slit to precise strip width matching the target pipe circumference.
Forming: The flat strip is progressively cold-formed through a series of rollers into a cylindrical shape with precise edge alignment.
Welding: High-frequency induction heating (ERW) or submerged arc welding (LSAW) fuses the longitudinal seam under controlled pressure.
Sizing & Cold Rolling: The welded tube passes through sizing mills and cold reduction stands to achieve final OD, wall thickness, and mechanical properties.
Heat Treatment (Optional): Stress-relief annealing or normalizing is applied to specific grades to restore ductility after cold working.
Testing & Inspection: Hydrostatic testing, ultrasonic weld inspection, and dimensional verification ensure compliance before surface finishing.
Finishing: Cutting to length, end facing, surface oiling, or protective coating per customer specification.
Typical Applications
Automotive Systems: Drive shaft housings, steering column tubes, exhaust system supports, and chassis structural members
Hydraulic & Pneumatic: Cylinder barrels, jack tubes, and pressure line conduit where ID smoothness reduces seal wear
Mechanical Engineering: Precision roller tubes, conveyor idler shells, and linear guide housings
Construction & Infrastructure: Scaffolding poles, temporary structural columns, and handrail posts requiring uniform section properties
