Precision cold-drawn thick-wall steel tubing engineered for high-pressure hydraulic cylinders, heavy machinery chassis, and demanding structural applications. Manufactured to exact dimensional tolerances with superior mechanical strength, uniform wall thickness, and certified metallurgical consistency.
Process Type: Cold-drawn seamless / cold-drawn precision welded (stress-relieved / annealed).
Core Size Range: Outer Diameter (OD) 50 mm - 400 mm, Wall Thickness (WT) 5 mm - 50 mm.
Standard Length: 5,800 mm, 6,000 mm, or custom cut-to-length up to 12,000 mm.
Delivery Condition: BK, BKW, GBK, NBK (as-drawn, stress-relieved, normalized per EN 10305-1).
Specifications
|
Specification Item |
Industrial Standard Range / Value |
|
Applicable Standards |
EN 10305-1, EN 10305-2, ASTM A519, DIN 2391, ISO 2938 |
|
Common Steel Grades |
E355 (St 52), E235, 4140 (42CrMo4), CK45 (C45E), 1020, 1045 |
|
Dimensional Tolerance |
OD: ±0.08 mm to ±0.15 mm; WT: ±5% max (Strict concentricity control) |
|
Straightness |
≤ 1.0 mm / 1000 mm (Max total deviation ≤ 0.15% of length) |
|
Surface Finish |
Internal Ra ≤ 0.8 µm (honed or smooth cold-drawn finish available) |
|
Tube Ends |
Plain square cut, deburred, or bevelled per engineering drawing |
Material & Manufacturing
Raw Material Control: Sourced exclusively from primary steel mills with full ladle analysis, certified chemical composition, and Mill Test Reports (MTC 3.1 per EN 10204).
Cold Drawing Capabilities: Multi-pass cold drawing benches (100-ton to 400-ton capacity) ensuring uniform micro-structure grain refinement and enhanced tensile properties.
Thermal Treatment: Controlled-atmosphere roller hearth annealing furnaces for stress relief (600°C - 680°C) or normalization, preventing scale formation and eliminating residual internal stresses prior to deep-hole boring or CNC machining.
Quality Inspection
100% automated eddy current testing for longitudinal defects and surface micro-cracks per ASTM E309 / EN 10246-3.
Laser OD/ID micrometers and ultrasonic wall thickness gauges measuring at regular intervals along the entire tube length.
Tensile testing (yield strength, tensile strength, elongation), Brinell/Rockwell hardness testing, and grain size/inclusion rating performed on every production heat.
Applications
Hydraulic Cylinders: Precision inner-diameter performance for hydraulic piston barrels, steering rams, and heavy-duty fluid power actuators.
Heavy Machinery: Structural pivot points, boom arms, and high-load chassis components for construction and mining equipment.
Automotive Drivetrain: Drive shafts, axle housing tubes, transmission components, and high-strength suspension parts.
Energy & Drilling: Downhole drilling tools, mud pump components, and wind turbine structural mechanical elements.
Customization & Supply
Custom Geometries:
Non-standard OD, ID, and heavy wall combinations drawn precisely to customer blueprints.
Value-Added Machining:
Automated cold-saw cutting to tight length tolerances (±0.5 mm), external turning, boring, and roller burnishing/honing.
Packaging & Protection:
Anti-rust phosphated or oiled surfaces, plastic end caps, bundled with high-strength steel straps, and wrapped in moisture-resistant woven fabric. Wooden crating available for international container shipping.
MOQ & Lead Time:
Standard production sizes: 2 metric tons per item. Custom specifications: 5 metric tons. Standard lead time: 25-35 days depending on heat treatment and test requirements.
FAQ
Q: What is the maximum wall thickness-to-outer diameter ratio you can achieve?
A: We regularly produce heavy-wall tubes with wall thicknesses up to 25% of the outer diameter, maintaining strict concentricity to minimize eccentric drift during subsequent machining.
Q: Are your tubes supplied in normalized or stress-relieved condition?
A: Standard supply condition is NBK (normalized) or BK+S (stress-relieved). Specific thermal states can be tailored to your subsequent machining and welding requirements.
Q: Do you provide EN 10204 3.1 Mill Test Certificates?
A: Yes. Every shipment includes a fully traceable 3.1 test certificate detailing actual chemical analysis, mechanical test results, and NDT verification records.
Q: Can you supply tubes cut to exact fixed lengths?
A: Yes. We utilize automated high-speed cold saws to supply cut-to-length tubes with length tolerances within ±0.5 mm and clean, deburred ends.
Q: What corrosion protection is applied during ocean freight?
A: Tubes are coated with a neutral anti-rust oil, sealed with plastic caps at both ends, and packaged to withstand maritime transit without oxidation.
Q: What is your standard inspection protocol for dimensional tolerance?
A: We apply Statistical Process Control (SPC) across every batch, verifying OD, ID, and wall thickness at both ends and the midpoint of each tube before factory release.
Request a Quote
To receive a formal quotation from our engineering sales team, please include the following details in your inquiry:
1.Steel grade and execution standard (e.g., EN 10305-1 E355, ASTM A519 4140)
2.Outer Diameter (OD) and Wall Thickness (WT), or Inner Diameter (ID)
3.Length requirements (Random length or fixed cut-to-length)
4.Surface finish condition and required testing/inspection standards
5.Destination port and target delivery timeframe
[Submit RFQ / Contact Engineering Sales]
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