USA Piping Solution is a committed supplier and stocking distributor of Stainless Steel 431 Seamless Tubes in the USA and overseas. Grade 4311 (UNS S43100/DIN 1.4057/AISI 431) is a martensitic stainless steel which contains nickel and is known as the most corrosion resistant of all the martensitic stainless grades. The seamless tube form provides a weld-seam-free structure with the best metallurgical properties, which have been obtained by a martensitic microstructure. The weld seam-free product provides a consistent corrosion resistance around the entire cross-section of the product, especially important for hydraulic, structural and shaft applications. USA Piping Solution offers AISI 431 Seamless Tubes in various diameters and wall thicknesses, in annealed, hardened and tempered, and other conditions, with complete documentation and mill test reports.
SS 431 Seamless Tube Technical Specifications
Parameter | Details |
|---|---|
Grade | AISI 431 Seamless Tube, UNS S43100, DIN 1.4057, W.Nr. 1.4057, EN X17CrNi16-2 |
Standard | ASTM A268 / ASME SA268 (Seamless and Welded Ferritic / Martensitic Tubing) |
OD Range | 10 mm to 350 mm |
Wall Thickness | 0.5 mm to 100 mm |
Length | Standard: 2000 mm to 6000 mm; Cut to length on request |
Condition Supplied | Annealed; Hardened and Tempered (Condition T); as specified |
Surface Finish | Bright Annealed (BA), 2B, Polished (No.4 / No.8), Pickled |
End Type | Plain End (PE) or Beveled End (BE) |
Certification | EN 10204 3.1; EN 10204 3.2 on request; Third-party: SGS, TUV, DNV |
Chemical Composition
Element | Min % | Max % |
|---|---|---|
Carbon (C) | N/A | 0.20 |
Manganese (Mn) | N/A | 1.00 |
Silicon (Si) | N/A | 1.00 |
Phosphorus (P) | N/A | 0.04 |
Sulfur (S) | N/A | 0.03 |
Chromium (Cr) | 15.0 | 17.0 |
Nickel (Ni) | 1.25 | 2.50 |
Iron (Fe) | Balance | Balance |
Mechanical Properties (Annealed Condition)
Property | Value |
|---|---|
Tensile Strength (UTS) | 862 MPa |
Yield Strength (0.2% offset) | 655 MPa |
Elongation (% in 50 mm) | 20% |
Hardness (max Brinell) | 285 HB |
Through-hardenability | Up to Rc 44 depending on section size |
SS 431 vs SS 410 Seamless Tubes Comparison
Property | SS 431 Seamless | SS 410 Seamless |
|---|---|---|
Nickel Content | 1.25 to 2.50% | None (straight Cr) |
Corrosion Resistance | Best among martensitics | Moderate |
Max Tensile Strength | Approx. 1345 MPa | Approx. 760 MPa |
Hardness (max) | Rc 44 | Rc 40 |
Impact Toughness | High (Charpy V up to 84 J) | Moderate |
Polishability | Excellent | Good |
Typical Use | Marine, aerospace, chemical | Cutlery, fasteners, general use |
Types of SS 431 Seamless Tubes
- ASTM A268 SS 431 Seamless Tubes (General Service)
- SS 431 Hydraulic Seamless Tubes (High Pressure)
- SS 431 Round Seamless Tubes
- SS 431 Seamless Mechanical Tubes (Thick-wall / Structural)
Applications of SS 431 Seamless Tubes
- Marine pump shafts and propeller shafts
- High-pressure hydraulic cylinders and actuators
- Precision valve and fluid control components
- Aerospace structural tubing and landing gear assemblies
- Offshore oil and gas equipment housings
- Chemical processing: nitric acid and organic acid service lines
- High-strength fastener and bolt manufacture
Frequently Asked Questions (FAQs)
Q1: We are designing hydraulic cylinder liners using SS 431 seamless tubes. Can you supply with a honed bore to H7 tolerance and Ra less than 0.4 micrometres finish?
A: Yes. We supply SS 431 seamless tubes as finished honed tube blanks with bore tolerance to H7 and Ra below 0.4 micrometres. Hardened-and-tempered condition is standard for cylinder liner applications. Please provide your bore diameter and required length.
Q2: For a propeller shaft application in a saltwater dredger, should we specify SS 431 seamless tubes in annealed or hardened-and-tempered condition?
A: Hardened and tempered at 593 to 650 C is recommended for propeller shafts, giving 960 to 1015 MPa UTS and Charpy values above 64 J. This condition also offers the best combination of marine corrosion resistance and fatigue strength for rotating shafts.
Q3: Can you supply SS 431 seamless tubes with EN 10204 3.2 inspection certification signed off by a third-party witness for our offshore project quality plan?
A: Yes. EN 10204 3.2 certification with third-party witness inspection is available through our partner agencies (Bureau Veritas, DNV GL, SGS, TUV). Please specify at the time of order so we can coordinate the inspection schedule with your quality plan.
Q4: What is the longest single seamless tube length available in SS 431 for a deep-sea survey instrument housing application requiring 5-metre tube blanks?
A: We can supply SS 431 seamless tubes in single piece lengths up to 6 metres. For custom lengths or special dimensional requirements for instrument housings, please share your OD, bore diameter, and surface finish requirements for a tailored quotation.
Q5: Our aerospace procurement team requires DFARS-compliant SS 431 seamless tubes sourced from domestic
US mills. Can you confirm domestic origin and traceability?
A: We maintain traceability records for all materials. DFARS-compliant domestic US mill sourcing for SS 431 seamless tubes can be arranged for qualifying orders. We provide full heat, lot, and country-of-origin certification at the time of shipment.
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SS 431 Seamless Tubes Ready for Aerospace, Marine & Hydraulic Use
Available in annealed or hardened-and-tempered condition. DFARS compliance, ASTM A268, EN 10204 3.2 third-party inspection. Get a quote from USA Piping Solution now.
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