ASTM A789 UNS S32205 Duplex Stainless Steel Tube

ASTM A789 / A789M is the product specification for seamless and welded ferritic/austenitic stainless steel tubing for general corrosion service, with particular emphasis on resistance to stress corrosion cracking. UNS S32205 is the modern 2205-class duplex with heat limits of carbon ≤0.030%, chromium 22.0–23.0%, nickel 4.5–6.5%, molybdenum 3.0–3.5%, and nitrogen 0.14–0.20% in A789/A789M-24 Table 1. Those tightened Cr and N floors were introduced so that heats sold as 2205 actually deliver the corrosion performance engineers expect — unlike the wider older A789 S31803 window that still shares the same marketplace nickname.

SHH STEEL can produce and supply ASTM A789 UNS S32205 duplex stainless steel tube as seamless and welded product (welded without filler metal) in the usual heat-exchanger and process OD × wall / BWG band, documented on EN 10204 3.1 mill test certificates that report ladle chemistry and the tensile plus hardness acceptance set. Dual A789 / SA789 marking is available only when the purchase order asks for both independent standards. Browse the grade family on the A789/A789M hub.

Commercially the same tube is called 2205, 1.4462, duplex 2205, or S32205 tube; none of those phrases replace the UNS grade on the stencil or MTC. When a datasheet says “2205” without a UNS, confirm whether S32205 or S31803 is intended before the heat is reserved. Sister lean options include A789 S32101; super duplex step-ups include A789 S32750 and A789 S32760. Plate: A240.

Heat analysis must meet A789/A789M-24 Table 1. Product analysis uses A480/A480M annex tolerances when ordered.

Mid-range PREN = Cr + 3.3Mo + 16N at Cr 22.5, Mo 3.25, N 0.17 is about PREN ≈ 36 — squarely in the standard duplex band Wikipedia cites (roughly 28–38). The Mo 3.0–3.5% working range is the crevice-performance heart of 2205; nitrogen ≥0.14% is what separates S32205 from a low-corner S31803 heat. Always verify the heat certificate against any project PREN floor.

Tensile and hardness floors are prescribed in A789’s tensile/hardness table (Table 4 in recent editions). The public -24 sample lacked that table; values below are from older Table 4 reprints and should be reconfirmed on the PO edition.

The 70 ksi yield floor is why designers often cut wall thickness versus 316L when switching to 2205 tube. Hardness stays capped at 290 HBW / 30 HRC, so cold work and quench practice must stay inside the mill procedure. Note older copies list S31803 lower at 90/65 ksi — another reason the two UNS numbers are not identical.

A789 Section 5 allows seamless or welded manufacture with no filler metal added. Seamless S32205 tube is typically hot-finished then cold-drawn to final OD and wall; welded tube is roll-formed from matching strip and autogenously welded, then usually cold-worked and re-annealed so the seam meets parent-metal heat treatment and mechanical floors.

Seamless lots take a flaring test (minimum 10% inside-diameter expansion); welded lots take a flange test plus a reverse flattening test on a specimen from each 1500 ft [450 m] of finished tubing. Tension and hardness sampling apply to both routes. SHH STEEL produces and supplies both seamless and welded A789 S32205 against the route named on the enquiry, with EN 10204 3.1 coverage of chemistry and mechanicals.

Average wall is the default under A789; specify minimum wall on the order when that is the design basis. Outside diameter and wall are ordered as tube sizes (metric or inch OD × wall / BWG). General dimensional requirements sit in Specification A1016/A1016M unless A789 states otherwise.

When converting a pipe schedule into tube wall, state clearly whether acceptance is average or minimum wall — the two are not interchangeable on the mill ticket. SHH STEEL confirms OD × wall, length, and finish before the heat is reserved.

UNS S32205 shares EN 1.4462 / 2205 commerce with S31803; specify the UNS you mean.

Dual A789/SA789 on request. Older wider-window sister: A789 S31803. Hub: A789/A789M.

A789/A789M-24 Table 2 lists UNS S32205 at 1870–2010 °F [1020–1100 °C] with rapid cooling in water or by other means. Seamless tube may be quenched directly after hot forming while at or above the minimum solution temperature.

That rapid quench is critical: Mo-bearing 2205 forms sigma and other intermetallics if it lingers in the roughly 700–1000 °C window, and all A789 duplex grades carry the scope warning about embrittlement after prolonged elevated-temperature use — including 475 °C (885 °F) ferrite embrittlement from spinodal decomposition between about 400 and 500 °C. S32205 is an aqueous corrosion-and-strength tube grade, not a continuous high-temperature alloy. SHH STEEL supplies it solution-annealed and quenched per Table 2.

S32205 is the default duplex choice when chloride SCC resistance and mid-range pitting/crevice performance are required without stepping to super duplex. Mid-range PREN ≈36 and Mo 3.0–3.5% underpin that reputation — provided the heat actually meets the S32205 window rather than a low-corner S31803 melt sold under a “2205” nickname.

Against lean grades such as A789 S32101 it offers clearly more Mo-driven crevice margin. Against super duplex A789 S32750 / A789 S32760 it is a step down for seawater crevice and PREN ≥40 duties. Screen with heat-certificate chemistry and project chloride/temperature limits.

Oil-and-gas process and utility tube, chemical-plant heat exchangers and coolers, desalination and brine-handling circuits, pulp-and-paper liquor lines, and general chloride-SCC-resistant service where 2205 / S32205 is frozen on the datasheet. Higher yield than 316L supports thinner walls and lower weight.

If untreated seawater crevice service or PREN ≥40 is mandatory, step to A789 S32750 or A789 S32760 rather than stretching S32205. SHH STEEL produces and supplies A789 S32205 for the enquiry sizes and test scope.

Autogenous A789 welded tube must meet parent anneal and mechanicals without filler. Fabrication welds typically use 2209-type duplex fillers with controlled heat input and interpass temperature so weld and HAZ ferrite–austenite balance stays qualified. Re-anneal and rapid quench after heavy hot work when the procedure requires it; keep stress-relief and coating-cure cycles out of the sigma nose and the 400–500 °C embrittlement band unless a qualified procedure says otherwise.

Standard delivery is solution-annealed and pickled (or otherwise descaled) so the passive film can form uniformly. Bright-annealed or lightly polished OD/ID finishes are available by agreement when the exchanger or hygienic duty needs a smoother bore. Passivation after pickling or after fabrication welding is good practice in chloride service; remove carbon-steel tooling contamination before commissioning. SHH STEEL states the finish route on the quotation and on the MTC.

Each A789 tube takes either a nondestructive electric test or a hydrostatic test. Mechanical sampling covers tension, hardness, and flaring for seamless or flange plus reverse flattening for welded, with full heat analysis on the mill test certificate. Product analysis and supplementary corrosion or ferrite tests are added when the purchase order asks for them. SHH STEEL issues EN 10204 3.1 as standard and arranges third-party inspection / 3.2 when the enquiry names an agency, with lot identity per A789 Notes 1 and 2.

Tube is typically packed in hexagonal bundles or plywood cases with end protectors and waterproof wrapping for ocean freight, with bundle tags repeating heat number, size, and standard. Cut-to-length exchanger tube may be boxed by length group; U-bends travel in purpose-built crates when ordered. SHH STEEL ships FOB, CFR, CIF, or EXW under the Incoterm on the order, with commercial invoice, packing list, and the EN 10204 3.1 or 3.2 certificate set.

SHH STEEL is a Shanghai stainless manufacturer and exporter that produces and supplies duplex tube — including the workhorse ASTM A789 UNS S32205. Melting to the tightened S32205 window, tube making, solution anneal, testing, and EN 10204 3.1 documentation are coordinated to the purchase order. That is production capability, not a trader-only offer of “2205” of uncertain UNS.

Buyers choose SHH STEEL when they need seamless or welded S32205 with clear traceability, honest S31803-versus-S32205 guidance, and a supplier who understands sigma and 475 °C risks in 2205 fabrication.

SHH STEEL can produce and supply ASTM A789 UNS S32205 against the edition, size, and finish route named on your enquiry. The capability table below summarizes what we regularly quote, followed by the Stock / Available sizes map.

Stock / Available sizes

SHH STEEL quotes S32205 tube against a practical production-and-stock enquiry range rather than a frozen warehouse SKU list with published tonnages. Availability of any single line on a given week depends on mill drawing and inbound schedule — treat the table as a supply map for enquiry.

When you send an enquiry, include the ASTM edition if known, seamless or welded, OD × wall (avg or min), length, finish, test extras, and destination port. Sister grades such as A789 S31803, A789 S32101, and A789 S32750 can be quoted on the same enquiry when the project mixes duplex classes.

ASTM A789 UNS S32205 is the reference modern 2205 duplex stainless steel tube grade for chloride SCC-resistant heat-exchanger and process service. SHH STEEL produces and supplies seamless and welded S32205 to the A789 anneal and test regime with EN 10204 3.1 documentation. For availability, dual marking, or a comparison with A789 S31803 or A789 S32750, contact admin@steelspecs.com.