CDW Pipe (Small Diameter) — Cold Drawn Welded Precision Steel Tube for Automotive Parts
Material
This product is a Cold Drawn Welded (CDW) precision steel tube: steel strip is formed and welded into a tube, then cold drawn to achieve high dimensional accuracy, better concentricity, and a smoother surface—ideal for automotive components that require stable fit-up, repeatable forming, and consistent mechanical performance.
Specifications
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Type: Welded cold drawn precision tube (CDW)
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Size focus: Small diameter (typical automotive ranges; custom available)
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Order dimensions: OD/ID, OD/WT, or ID/WT (as required)
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Delivery conditions (select per application): +C, +LC, +SR, +A, +N
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Surface finish: Smooth inner/outer surfaces; standard maximum surface roughness requirement can be specified
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Inspection: Dimensional checks, tensile testing, visual inspection; optional roughness reporting and NDT can be specified
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Corrosion protection & packaging: Temporary corrosion protection is typically supplied unless otherwise agreed
Key Features
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Precision OD/ID & wall control for automated assembly and tight-fit parts
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Improved surface quality after cold drawing, supporting low-friction motion parts and clean forming
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Stable mechanical properties selectable by delivery condition (+SR / +N commonly chosen for balanced strength and formability)
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Good weldability and formability for bending, expanding, flaring, and subsequent fabrication
Our Advantages
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“Can you hold tight tolerances and surface requirements for robotic/automated assembly?”
Yes. Precision applications are supported by defined tolerance systems and a specified maximum surface roughness requirement; additional roughness measurement/reporting can also be agreed. -
“How do you ensure weld seam integrity and prevent hidden defects?”
We can supply tubes with non-destructive testing (NDT) as specified (e.g., eddy current testing for longitudinal imperfections and leak-tightness verification). Eddy current principles and acceptance-based inspection are widely used for welded tube quality control. -
“Do you provide full traceability and inspection certificates for audits?”
Yes. We support EN 10204 inspection documents (e.g., 3.1/3.2 as required) and can maintain heat/lot traceability through marking options (including cast/heat identification when specified).
Chemical Composition
| Grade | Steel No. | C max | Si max | Mn max | P max | S max | Al (total) min |
|---|---|---|---|---|---|---|---|
| E155 | 1.0033 | 0.11 | 0.35 | 0.70 | 0.025 | 0.025 | 0.015 |
| E195 | 1.0034 | 0.15 | 0.35 | 0.70 | 0.025 | 0.025 | 0.015 |
| E235 | 1.0308 | 0.17 | 0.35 | 1.20 | 0.025 | 0.025 | 0.015 |
| E275 | 1.0225 | 0.21 | 0.35 | 1.40 | 0.025 | 0.025 | 0.015 |
| E355 | 1.0580 | 0.22 | 0.55 | 1.60 | 0.025 | 0.025 | 0.020 |
Mechanical Properties
| Grade | Steel No. | +SR: Rm min (MPa) | +SR: ReH min (MPa) | +SR: A min (%) | +N: Rm (MPa) | +N: ReH min (MPa) | +N: A min (%) |
|---|---|---|---|---|---|---|---|
| E155 | 1.0033 | 350 | 245 | 18 | 270–410 | 155 | 28 |
| E195 | 1.0034 | 370 | 260 | 18 | 300–440 | 195 | 28 |
| E235 | 1.0308 | 440 | 325 | 14 | 340–480 | 235 | 25 |
| E275 | 1.0225 | 510 | 375 | 12 | 410–550 | 275 | 22 |
| E355 | 1.0580 | 590 | 435 | 10 | 490–630 | 355 | 22 |
Standards
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ASTM: ASTM A513 (ERW mechanical tubing; CDW/DOM-type finishing specified by type/requirement)
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EN: EN 10305-2 (welded cold drawn precision tubes; delivery conditions +C/+LC/+SR/+A/+N)
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GOST: GOST 10704 (electric-welded steel tubes; commonly referenced for welded tube supply chains)
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JIS: JIS G3445 (carbon steel tubes for machine structural purposes)
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GB: GB/T 24187 (cold-drawn precision single welded steel tubes)
Application Areas
Primary industries: Automotive, general engineering, machinery manufacturing, hydraulic/pneumatic-related assemblies, and precision structures.
Where it’s used in automotive (examples):
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Shock absorber / damper components (inner tubes, sleeves)
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Steering & chassis parts (spacers, sleeves, support tubes)
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Seat structures & safety sub-assemblies (precision structural tubes)
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Machined tubular parts requiring consistent ID/OD for press-fit, bushings, and bearing seats
