USA Piping Solution is a trusted manufacturer and supplier of Stainless Steel 431 Tubes to the USA and worldwide markets. A high-chromium, low-nickel martensitic stainless steel with a remarkable corrosion resistance, impact strength and high hardness. Grade 431 is the most corrosion resistant of the martensitic stainless grades, and is therefore used in types of applications where both mechanical toughness and chemical exposure are important. Stainless Steel 431 Tubes are usually delivered in the hardened and tempered condition with the Tensile Strength of 850MPa-1000MPa (Condition T) and Brinell Hardness of 248-302. USA Piping Solution offers these tubes in either round, square or rectangular shape and a wide range of dimensions, with full mill test certifications to EN 10204 3.1 or 3.2. They are used in valves, pumps, aircraft fasteners, high strength structural members, and marine pump shafts.
SS 431 Tube Specifications
Parameter | Details |
|---|---|
Grade | SS 431, UNS S43100, DIN 1.4057, W.Nr. 1.4057, AISI 431, EN X17CrNi16-2 |
Standards | ASTM A268 / ASME SA268 (Ferritic/Martensitic Tubing for General Service) |
Form | Round, Square, Rectangular, Hexagonal on request |
Outer Diameter | 10 mm to 350 mm; custom sizes available |
Wall Thickness | 0.5 mm to 100 mm |
Length | 2000 mm, 3000 mm, 6000 mm standard; custom cut lengths available |
Surface Finish | 2B, 2D, BA, No.1, No.4, No.8, 8K, Mirror, Hairline, Satin |
Finish Method | Hot Rolled (HR), Cold Rolled (CR), Bright Annealed (BA) |
Condition Supplied | Annealed; Hardened and Tempered (Condition T); as specified |
Certification | EN 10204 3.1 / 3.2; NABL Lab; SGS, TUV, DNV, LLOYDS, ABS |
SS 431 Chemical Composition
Grade | C (max) | Mn (max) | Si (max) | P (max) | S (max) | Cr | Ni |
|---|---|---|---|---|---|---|---|
431 | 0.20 | 1.00 | 1.00 | 0.04 | 0.03 | 15.0 to 17.0 | 1.25 to 2.50 |
SS 431 Mechanical Properties vs Tempering Temperature
Tempering Temp (C) | Tensile Str. (MPa) | Yield Str. 0.2% (MPa) | Elongation % (50 mm) | Brinell HB | Charpy V (J) |
|---|---|---|---|---|---|
Annealed | 862 | 655 | 20 | 285 max | N/A |
204 | 1345 | 1055 | 20 | 388 | 50 |
316 | 1295 | 1035 | 19 | 375 | 53 |
538 | 1140 | 965 | 19 | 321 | N/A |
593 | 1015 | 770 | 20 | 293 | 64 |
650 | 960 | 695 | 20 | 277 | 84 |
SS 431 Physical Properties
Property | Value |
|---|---|
Density | 7800 kg/m3 |
Electrical Resistivity | 720 nOhm.m |
Thermal Conductivity at 100 C | 20.2 W/m.K |
Specific Heat (0-100 C) | 460 J/kg.K |
Thermal Expansion (0-100 C) | 12.1 mm/m/C |
Working Temperature | Up to 500 C |
International Equivalent Grades for SS 431
Standard | Designation |
|---|---|
AISI / ASTM | 431 |
UNS | S43100 |
EN / DIN | X17CrNi16-2 / 1.4057 |
JIS | SUS 431 |
SS (Swedish) | SS 2321 |
Types of Stainless Steel 431 Tubes
- SS 431 Seamless Tubes
- SS 431 Welded Tubes (ERW)
- SS 431 Round Tubes
- SS 431 Square Tubes
- SS 431 Rectangular Tubes
- SS 431 Hollow Bars / Thick-wall Tubes
SS 431 Tube Weight Chart (Per Metre)
OD x Wall (mm) | Weight (kg/m) | OD x Wall (mm) | Weight (kg/m) |
|---|---|---|---|
6 x 1 | 0.125 | 12 x 2 | 0.498 |
6 x 1.5 | 0.168 | 14 x 2 | 0.598 |
8 x 1 | 0.174 | 16 x 2 | 0.697 |
8 x 1.5 | 0.243 | 16 x 3 | 0.971 |
10 x 1 | 0.224 | 18 x 2 | 0.797 |
10 x 1.5 | 0.318 | 20 x 2 | 0.897 |
12 x 1.5 | 0.392 | 22 x 2.5 | 1.214 |
Applications of Stainless Steel 431 Tubes
- Marine hardware and pump shaft tubing
- Valve bodies and seat components
- Bolt and fastener manufacture
- Aircraft and aerospace structural members
- Hydraulic system components
- Oil and gas equipment parts
- Mining and quarrying equipment
- Chemical plant fittings requiring corrosion and strength
Frequently Asked Questions (FAQs)
Q1: We need SS 431 tubes for marine pump shafts. What tempering temperature do you recommend to achieve a target tensile strength of 1000 MPa while retaining good impact toughness?
A: Tempering at 593 C gives SS 431 a tensile strength of around 1015 MPa with Charpy V impact of 64 J and good corrosion resistance. We can supply in this condition and provide heat treatment certificates. Please share your shaft diameter and length.
Q2: Can SS 431 tubes be through-hardened in large diameters above 75 mm OD? We are concerned about core hardness uniformity on a thick-walled shaft application.
A: SS 431 has good hardenability. In sections up to 75 mm, uniform through-hardening is achievable. Above this, core hardness may reduce slightly. We can arrange test hardening on sample pieces and report Jominy curves if required for your specification.
Q3: Our engineering team is comparing SS 431 tubes against SS 316L for a chemical pump shaft operating in
dilute nitric acid. Which offers better performance?
A: For dilute nitric acid service, SS 431 offers higher strength and comparable corrosion resistance to 316L, but 316L has better resistance to pitting. The right choice depends on concentration and temperature. Our technical team can review your exact media conditions.
Q4: Is SS 431 tube material non-magnetic? Our instrumentation design requires this for minimizing
electromagnetic interference near sensors.
A: No. SS 431 is martensitic and is magnetic in all conditions. It is not suitable for non-magnetic applications. For non-magnetic requirements in high-strength tubes, consider SS 316L or duplex grades. We supply both and can assist with grade selection.
Q5: Do you supply SS 431 tubes with Charpy impact test reports, and what is the minimum guaranteed
impact value at room temperature?
A: Yes. SS 431 tubes can be supplied with Charpy V-notch impact test certificates. Minimum impact at room temperature in the annealed condition is not specified by ASTM A268 but typical values are 50 J or above. Specific minimum requirements can be agreed at order placement.
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SS 431 Tubes in Stock | Hardened, Tempered, or Annealed Condition
Serving aerospace, marine, chemical, and oil and gas industries. Dimensional inspection, Charpy impact testing, and full EN 10204 3.1 MTRs available. Contact USA Piping Solution today.
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