Tianjin Brisk Steel is one of the manufacturers of Cold Formed Round Pipe in China. Our products are mainly exported to the Middle East, Southeast Asia, Europe, New Zealand, and other regions.If you would like to learn more about our products, feel free to contact us and send your purchase list.
Manufacturing Process
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Uncoiling & Slitting: Flat-rolled steel coil (hot-rolled or cold-rolled) is uncoiled and slit to the exact width required for the pipe's circumference.
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Cold Roll Forming: The flat steel strip passes through a series of progressive rollers at room temperature, gradually bending it into a circular shape.
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Welding: The meeting edges are continuously joined using Electric Resistance Welding (ERW) or High-Frequency Induction (HFW) welding, requiring no filler metal.
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Sizing & Straightening: The welded tube passes through sizing rolls to achieve exact outer diameter (OD) and wall thickness dimensions.
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Cutting: Tubes are cut to standard or custom structural lengths.
ERW PROCESS
Cold Formed ERW VS Cold Drawn Seamless
Cold Formed ERW Round Pipe (Cold Roll Formed CHS)
Flat steel strip is continuously bent into a tubular shape at room temperature through multi-pass forming rolls. The longitudinal joint is sealed by high-frequency electric resistance welding (ERW). Only the welding seam gets instant local high heat while the base steel material remains in cold forming status. After weld bead trimming, sizing and straightening, finished structural hollow pipe is produced. It is a welded tubular product with an inevitable welding line.
Cold Drawn Seamless Tube (CDS Tube)
The raw material is hot-rolled seamless tube blank without any joint. Under normal temperature, the rough tube is forcibly pulled through precision dies with or without inner mandrels to realize diameter reduction and wall thickness calibration. The whole tube maintains integrated metallic structure with zero weld seam throughout processing. Cold drawing acts as a precision finishing procedure for seamless pipes instead of primary pipe forming.
Relevant International Standards
| Item | Cold Formed ERW Round Pipe | Cold Drawn Seamless Tube |
|---|---|---|
| American Standard | ASTM A500 Grade B / Grade C | ASTM A179, ASTM A214, ASTM A519 |
| European Standard | EN 10219 | EN 10305 |
Dimensional Accuracy & Surface Quality
- Tolerance: Cold formed ERW pipe owns moderate dimensional tolerance; wall thickness is basically uniform except slight thickening at the welding position. Cold drawn seamless tube achieves ultra-tight tolerance up to ±0.05 mm, with highly consistent outer diameter and wall thickness.
- Inner & Outer Surface: Cold formed CHS has plain black surface; minor welding marks exist on the inner wall which needs simple grinding treatment. Cold drawn tube features smooth inner and outer walls with low roughness, normally delivered in bright surface condition for direct precision machining.
- Common Specifications: Cold formed ERW pipe covers a full range from small to large diameters, focusing on thin-wall structural pipes. Cold drawn products are mainly concentrated in small & medium bore tubes, dominating the market of precise thick-wall tubular parts.
Mechanical Property & Working Pressure Performance
- Cold formed ERW pipe has stable mechanical performance for static structural loads. The welding zone becomes a natural weak point under high pressure, frequent vibration or fatigue load. It is only applicable for building bearing structures and low-pressure gas/water delivery.
- Cold drawn seamless tube has homogeneous metal microstructure without welding stress concentration. It performs well in pressure resistance, shock resistance and anti-fatigue capacity, matching medium & high-pressure hydraulic pipelines, pneumatic lines and precision fluid conveying systems.
Typical Application Scenarios
- Cold Formed ERW Round Pipe: Bus station frame, solar support bracket, highway guardrail, steel structure workshop column, advertising pole, scaffolding, building enclosure framework.
- Cold Drawn Seamless Tube: Hydraulic oil pipeline, mechanical shaft sleeves, instrument piping, heat exchanger tubes, air compressor pipelines, precision mechanical assembly components.
Frequently Asked Questions (FAQ)
Q: Can cold formed ERW pipe be used for high-pressure fluid transportation?
A: Not recommended. The welding area is a stress concentration point under high pressure or frequent vibration. Cold formed ERW pipe is only designed for static structural bearing and low-pressure water/gas delivery. Cold drawn seamless tube is the qualified option for medium and high-pressure hydraulic & fluid pipelines.
Q: In terms of price, MOQ and delivery time, which option is more cost-effective?
A: Cold formed ERW pipe costs 20%–40% less than cold drawn seamless tube. Brisk Steel's standard MOQ for cold formed CHS is 25 tons with sufficient stock and fast lead time. Cold drawn tubes require extra precision processing, resulting in higher costs, higher MOQ and longer production cycles.
Q: What surface treatments can Brisk Steel provide for these two pipes?
A: Both pipes support black paint, hot-dip galvanizing (85μm standard coating) and FBE coating. Cold drawn seamless tubes can additionally provide bright finished delivery for direct mechanical machining without secondary polishing.
Q: How should customers select the correct pipe type for their projects?
A: Pick cold formed ERW round pipe if you need structural supports to cut overall project expenditure. Choose cold drawn seamless tube when your project requires high precision size control, pressure resistance and long-term service stability.
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