Precision alloy steel tubes are engineered for demanding mechanical and hydraulic applications requiring strict dimensional accuracy, high tensile strength, and reliable fatigue resistance. Produced via precision cold drawing or cold rolling, these tubes deliver tight outer/inner diameter tolerances and optimized mechanical properties through controlled heat treatment.
Specifications
|
Parameter |
Specification Range |
|
Size Range |
Outer Diameter (OD): 10 mm - 219 mm |
|
Common Steel Grades |
AISI/SAE: 4140, 4340, 8620, 52100 |
|
Delivery Conditions (Heat Treatment) |
+C (BK) - Cold finished / hard |
|
Standard Lengths |
5 m - 12 m random or cut-to-length |
|
Applicable Standards |
ASTM A519, EN 10305-1, DIN 2391, GB/T 8162 |
Material & Manufacturing
Manufactured in-house using selected alloy billet inputs to ensure strict chemical composition control.
Cold Drawing & Pilgering: Multi-pass cold drawing benches achieve tight dimensional tolerances down to +/- 0.05 mm and smooth surface finishes (Ra <= 0.8 um).
Controlled Atmosphere Annealing: Continuous roller hearth furnaces with protective nitrogen-hydrogen atmospheres prevent surface oxidation and decarburization during heat treatment, ensuring uniform microstructure (tempered martensite or fine pearlite/ferrite depending on grade).
Straightening & Cutting: Precision multi-roll straightening machines control straightness within 1.0 mm / 1000 mm, followed by deburred rotary cutting.
Quality Inspection
Every production lot undergoes rigorous metallurgical and dimensional verification before dispatch.
Non-Destructive Testing (NDT): 100% Eddy Current testing for longitudinal defects and ultrasonic testing for internal wall integrity.
Dimensional Verification: Laser OD/WT micrometers paired with air-gauge internal diameter measurement.
Mechanical Testing: Tensile testing, yield strength testing, elongation measurement, and Rockwell/Brinell hardness testing per lot.
Metallographic Analysis: Grain size determination, inclusion rating, and decarburization depth checks performed in-house.
Mill Test Certificates: Full EN 10204 3.1 certification provided with every shipment, ensuring complete material traceability.
Applications
Hydraulic Systems: Seamless cylinders, piston rods, and high-pressure fluid transfer lines.
Automotive Powertrain: Drives shafts, axle tubes, gear blanks, and steering columns.
Industrial Machinery: Roller bearings, textile machinery spindles, and heavy-duty structural components.
Energy Sector: Downhole tool bodies and specialized drilling equipment parts.
Customization & Supply
Custom Tolerances:
Tailored ID/OD tolerance classes (e.g., H8/H9 for honed or roller-burnished tubes).
Surface Protection:
Anti-rust oil coating, phosphating, or external polyethylene/anti-corrosion coatings upon request.
Packaging:
Bundled with steel strapping, wrapped in waterproof woven plastic, or packed in sturdy wooden crates for export transit.
Lead Time:
3 to 5 weeks for standard production runs; expedited schedules available for recurring blanket orders.
FAQ
Q: What is the typical surface roughness (Ra) of the inner surface?
A: For cold-drawn execution, standard Ra is below 1.6 um. For applications requiring honing or roller burnishing, the internal surface can be finished down to Ra <= 0.4 um.
Q: Can you supply tubes cut to exact fixed lengths?
A: Yes. We offer precision cutting with length tolerances within +/- 0.5 mm, including chamfered or deburred ends per drawing requirements.
Q: What documentation is included with delivery?
A: Every order includes a complete EN 10204 3.1 Mill Test Certificate detailing chemical composition, mechanical test results, heat treatment logs, and NDT verification records.
Q: Do you accept orders for non-standard alloy steel grades?
A: Yes, provided minimum order quantities (MOQ) are met. We regularly process custom alloy variations according to specific client engineering specifications.
Q: How do you prevent corrosion during ocean freight?
A: Tubes are coated with a heavy-duty film of rust-preventive oil, bundled securely, and wrapped with moisture-resistant woven fabric to withstand long maritime transit.
Q: What is the standard Minimum Order Quantity (MOQ)?
A: MOQ varies by size and steel grade, typically starting at 2 metric tons per size to align with efficient mill rolling and heat treatment batch setups.
Request a Quote
To receive a formal quotation, please provide the following technical parameters:
• Steel Grade (e.g., AISI 4140, 34CrMo4)
• Dimensions (Outer Diameter x Wall Thickness x Required Length)
• Delivery Condition / Heat Treatment (e.g., +N, +SR)
• Quantity (Metric tons or total meters)
• Target Delivery Port / Destination
[Submit RFQ / Contact Engineering Team]
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