ASTM A789 UNS S32707 Super Duplex Stainless Steel Tube

ASTM A789 / A789M covers seamless and welded ferritic/austenitic stainless steel tubing for general corrosion service with particular emphasis on stress corrosion cracking resistance. UNS S32707 is listed with heat limits of carbon ≤0.030%, chromium 26.0–29.0%, nickel 5.5–9.5%, molybdenum 4.0–5.0%, nitrogen 0.30–0.50%, copper 1.0% max, and cobalt 0.5–2.0% in A789/A789M-24 Table 1. The QUEUE titles this page Super Duplex, but in industry practice S32707 is widely marketed as a hyper duplex grade — PREN typically above the conventional super duplex band (public overviews often cite hyper duplex above about PREN 45) — developed for the most aggressive chloride and deepwater duties where 2507-class alloys are not enough.

SHH STEEL can produce and supply ASTM A789 UNS S32707 super duplex (hyper duplex class) stainless steel tube as seamless and welded product (welded without filler metal) in typical heat-exchanger and process OD × wall / BWG sizes, with EN 10204 3.1 mill test certificates. Dual A789/SA789 marking only when both standards are on the order. Hub: A789/A789M.

EN 1.4658 appears with S32707 in public duplex tables. Compare with sister hyper duplex A789 S33207 and with conventional super duplex A789 S32750 / A789 S32760. Plate: A240.

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

Mid-range PREN = Cr + 3.3Mo + 16N at Cr 27.5, Mo 4.5, N 0.40 is about PREN ≈ 49 — hyper duplex territory. Cobalt 0.5–2.0% is a required range unique among many A789 grades. High Mo+N sharply increases sigma sensitivity; quench discipline is non-negotiable.

Tensile and hardness floors come from older A789 Table 4 reprints; the public A789/A789M-24 sample did not include that table. Reconfirm on the PO edition.

Older Table 4 copies list 133/101 ksi — among the highest strength floors in A789 — with hardness max 318 HBW / 34 HRC.

A789 Section 5 allows seamless or welded manufacture with no filler metal added. Seamless S32707 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 S32707 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.

Often marketed as hyper duplex / SAF 2707-type; certify to UNS S32707 on A789 orders. Title on this site remains Super Duplex per QUEUE.

Dual A789/SA789 on request. Hub: A789/A789M.

A789/A789M-24 Table 2 lists UNS S32707 at 1975–2050 °F [1080–1120 °C] with rapid cooling in water or by other means unless Table 2 states otherwise. Seamless tube may be quenched directly after hot forming while at or above the minimum solution temperature where that alternate is allowed.

Rapid cooling limits time in the sigma-forming window (roughly 700–1000 °C), which is especially important for highly alloyed duplex and super duplex. A789’s scope warns that these steels are susceptible to embrittlement if used for prolonged periods at elevated temperatures, including 475 °C (885 °F) ferrite embrittlement. SHH STEEL supplies S32707 solution-annealed and quenched per Table 2.

S32707 is specified when conventional super duplex PREN is insufficient — deepwater, hot chlorides, and the most aggressive process waters. Mid-range PREN ≈49 and Co-bearing chemistry support that hyper duplex positioning, but fabrication defects (sigma, poor quench) will erase the corrosion advantage quickly.

Do not substitute A789 S32750 into an S32707 line without engineering approval. Sister hyper duplex A789 S33207 is the other PREN≥48-class option on this site.

Deepwater oil-and-gas tubing, severe chloride heat exchangers, and process circuits that freeze hyper duplex / S32707 by name. Strength floors above 2507-class support thinner walls where code design allows.

SHH STEEL produces and supplies A789 S32707 and will discuss whether A789 S32750 or A789 S33207 better matches the project PREN floor.

Autogenous A789 welded tube must meet parent anneal and mechanicals without filler. Fabrication welds that use filler typically take matching or overalloyed duplex/super duplex consumables with controlled heat input and interpass temperature so ferrite–austenite balance stays qualified. Re-anneal after heavy hot work when required; keep bake and stress-relief 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 produces and supplies ASTM A789 UNS S32707 — explaining the hyper duplex marketing label while keeping the Super Duplex page title Jack set — with coordinated melting, tube making, high-temperature anneal, testing, and EN 10204 3.1 documents. Production capability, not trader-only.

We treat sigma and 475 °C risks as first-order fabrication controls on this alloyed grade.

SHH STEEL can produce and supply ASTM A789 UNS S32707 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 S32707 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 S33207, A789 S32750, and A789 S32760 can be quoted on the same enquiry when the project mixes duplex classes.

ASTM A789 UNS S32707 is covered on this page as super duplex stainless steel tube under the A789 seamless-and-welded duplex tubing specification. SHH STEEL produces and supplies seamless and welded S32707 to the A789 anneal and test regime with EN 10204 3.1 documentation. For sizes, dual marking, or grade comparisons, contact admin@steelspecs.com.