Chrome-moly alloy steel tubes combine chromium and molybdenum for high tensile strength, creep resistance, and elevated-temperature stability. Engineered for high-stress, high-pressure, and high-temperature environments, these tubes maintain structural integrity where standard carbon steel fails. Available in seamless and welded configurations, cold-drawn or hot-rolled to meet precise industrial standards.
Specifications
|
Parameter |
Specification Range |
|
Standard Grades |
AISI / SAE 4130, 4140, 4150, 8620; ASTM A213 (T11, T22), ASTM A335 (P11, P22, P91) |
|
Outer Diameter (OD) |
6 mm – 610 mm (1/4 inch – 24 inch) |
|
Wall Thickness (WT) |
1 mm – 60 mm (Schedule 10 to XXS) |
|
Length |
5.8m, 6m, 11.8m, 12m, or custom cut lengths |
|
Delivery Condition |
Cold Drawn (BK), Annealed (GBK), Normalized (NBK), Quenched & Tempered (QT) |
|
Manufacturing Standards |
ASTM, ASME, DIN, EN, JIS |
Material & Manufacturing
Material Chemistry & Behavior
• Chromium (Cr): Increases hardenability, oxidation resistance, and high-temperature strength.
• Molybdenum (Mo): Enhances toughness, wear resistance, and creep rupture strength under thermal stress.
Mill Processing Workflow
• Rotary Piercing & Hot Rolling: Billets are heated in controlled rotary hearth furnaces, then pierced on mandrel mills to form uniform hollow shells.
• Cold Drawing / Cold Rolling: Reduces outer diameter and wall thickness to achieve tight dimensional tolerances (±0.05 mm) and clean interior/exterior surface finishes.
• Controlled Heat Treatment: Fully automated roller-hearth furnaces execute precise annealing, normalizing, or quenching and tempering cycles to align microstructure with mechanical property requirements.
Quality Inspection
Every production lot undergoes strict destructive and non-destructive verification before dispatch:
Non-Destructive Testing (NDT): 100% Eddy Current testing and Ultrasonic testing (UT) to detect internal inclusions and surface flaws.
Mechanical Testing: Tensile strength, yield strength, elongation measurement, and Rockwell/Brinell hardness testing per lot.
Chemical Composition: Direct-reading spectrometer analysis on raw material heats.
Dimensional Accuracy: Laser-verified OD, WT, and straightness control.
Traceability & Compliance: Mill Test Certificates (MTC) supplied per EN 10204 3.1 / 3.2. Third-party inspection (SGS, BV, TUV, Lloyd's Register) fully accommodated.
Applications
Oil & Gas: Downhole drilling tools, drill collars, high-pressure line pipes, and hydraulic fracturing equipment.
Power Generation: Boiler tubing, superheater headers, and high-temperature steam piping.
Automotive & Motorsport: Roll cages, chassis components, drive shafts, and precision suspension links.
Heavy Machinery: Hydraulic cylinders, crane booms, and high-load structural shafts.
Customization & Supply
Custom Dimensions:
Non-standard outer diameters, specific wall thicknesses, and strict tolerance machining available upon request.
Surface Protection:
Anti-rust oil coating, black painting, phosphating, or varnishing. Special end preparations (beveled, square-cut, or threaded).
Packaging:
Securely bundled with steel strips, wrapped in woven plastic, or packed in seaworthy wooden crates for international export.
Lead Time:
Stock sizes available for immediate dispatch; custom production runs delivered within 30 to 45 days.
FAQ
Q: What is the difference between AISI 4130 and AISI 4140 chrome-moly tubes?
A: AISI 4130 features lower carbon content (0.28–0.33%), offering superior weldability and formability for structural frames and roll cages. AISI 4140 features higher carbon (0.38–0.43%), delivering greater hardenability and wear resistance for heavy-duty mechanical shafts.
Q: Are these tubes delivered in a heat-treated condition?
A: Yes. Tubes are supplied in annealed, normalized, or quenched and tempered (QT) conditions based on client specifications, ready for immediate machining or fabrication.
Q: Can you accommodate third-party inspection (TPI)?
A: Yes. We routinely coordinate with independent agencies such as SGS, BV, TUV, and LRQA for pre-shipment inspection and verification.
Q: What is the standard length tolerance for cut-to-length tubes?
A: Standard length tolerance is ± 5 mm, with precision cutting tolerances down to ± 1 mm available upon request for automated machining lines.
Q: Do you supply Mill Test Certificates with each shipment?
A: Every order includes an MTC compliant with EN 10204 3.1, detailing chemical analysis, mechanical test results, heat numbers, and NDT compliance.
Q: What is the Minimum Order Quantity (MOQ) for custom sizes?
A: MOQ depends on steel grade and dimensions, typically starting at 2 metric tons per size for standard mill production runs. Trial orders can be evaluated based on current production schedules.
Request a Quote
Ready to source high-performance chrome-moly alloy steel tubes? Submit your project requirements to our engineering and sales team for a prompt, detailed quotation.
Please include the following in your RFQ:
• Steel Grade (e.g., AISI 4130, ASTM A335 P22)
• Outer Diameter (OD) & Wall Thickness (WT)
• Length and Total Quantity (Tons or Pieces)
• Delivery Condition (e.g., Normalized, QT)
• Target Port of Destination / Incoterms (FOB / CIF)
[Get a Fast Quote / Contact Engineering Team] (Button link to RFQ form)
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