ASME SA789 UNS S32202 Lean Duplex Stainless Steel Tube

ASME SA-789 / SA-789M adopts seamless and welded duplex stainless tubing for general service into Section II Part A of the Boiler and Pressure Vessel Code. UNS S32202 is a lean duplex with chromium 21.5–24.0%, nickel only 1.00–2.80%, molybdenum 0.45% maximum, and nitrogen 0.18–0.26% at carbon ≤0.030%. Low nickel with elevated nitrogen is the cost-and-strength idea; molybdenum stays intentionally lean.

SHH STEEL can produce and supply ASME SA789 UNS S32202 lean duplex stainless steel tube in seamless and welded (no filler metal) forms, in typical heat-exchanger OD × wall sizes, with EN 10204 3.1 certificates reporting ladle chemistry, the 94/65 ksi tensile pair, and Table 2 heat treatment. We manufacture to the SA-789 tables for this UNS rather than offering an unnamed lean-duplex substitute. Dual SA-789/A789 marking is available when the PO requests both names.

Compare SA789 S32101 when manganese enrichment and wall-dependent tensile matter; compare SA789 S32304 for 2304-type lean chemistry; step to SA789 S32205 for ~3% Mo standard duplex; use SA789 S32750 for PREN ≥40. Plate under A240 / SA240. Hub: SA789/SA789M.

Table 1 fixes heat analysis for S32202. Sulfur is held to a tight 0.010% max. Product analysis, when invoked, follows Section 8 via A1016/A1016M and A480/A480M tolerances. Copper is not required (ellipsis in Table 1).

Mid-range PREN with Cr ≈22.75, Mo ≈0.22, N ≈0.22 gives PREN ≈ 27.0 using %Cr + 3.3×%Mo + 16×%N. Nitrogen again carries much of the pitting resistance on this lean row. SA-789 does not publish a PREN minimum for S32202.

Table 4 gives a single tensile row for S32202 — unlike the wall-split used on S32101 or S32003. Lot sampling follows Section 9; properties do not apply below 1/8 in. OD or 0.015 in. wall.

Tensile 94 ksi [650 MPa] min, yield 65 ksi [450 MPa] min, elongation 30% min, hardness max 290 HBW / 30 HRC / 290 HV. Source: ASME BPVC.II.A-2023 SA-789 Table 4. Design allowables remain in Section II Part D.

Both manufacture routes are allowed for S32202. Welded tube under Section 5 uses no filler metal; the finished length is heat-treated as a whole. The stencil must state seamless or welded and average or minimum wall.

Seamless lots take flaring (10% min ID expansion). Welded lots take flange testing plus reverse flattening every 1500 ft [450 m]. SHH STEEL produces both SA789 S32202 routes and records them on stencil and MTC.

Order OD × wall (average unless minimum is specified) and length in tube language. Table 5 tolerances apply by OD group; thin-wall ovality follows 12.2. Write average or minimum wall on every line item so Table 5 percentages are unambiguous.

Source: ASME BPVC.II.A-2023 SA-789 Table 5. SHH STEEL quotes average-versus-minimum wall explicitly on every S32202 enquiry. Write average or minimum wall on every line item so Table 5 percentages are unambiguous.

ASME SA-789 UNS S32202 is the governing designation. Similar lean-duplex trade names are chemistry-family hints, not automatic Code substitutes. Confirm the product standard before accepting a lean-duplex nickname on the certificate.

Spell the UNS on the purchase order so low-Mo lean grades are not mixed with 2205-class tube. Confirm the product standard before accepting a lean-duplex nickname on the certificate.

Table 2 requires S32202 at 1870–1975 °F [1020–1080 °C] with rapid cooling in air or water — a closed band slightly cooler at the top end than the 2010 °F maximum used for S32205.

Direct quench after hot forming is allowed for seamless tubes when temperature stays at or above the minimum. SHH STEEL ships only Table 2 heat-treated SA789 S32202 with the treatment on the MTC. Keep furnace records with the heat number so the MTC can cite the actual soak and quench route.

Estimated PREN near 27.0 places S32202 in the lean duplex band: better chloride SCC resistance than 304 in many waters, but not a mid-30s 2205 substitute and not a PREN ≥40 seawater grade. Step to SA789 S32205 or SA789 S32750 when those envelopes are written into the datasheet.

Observe SA-789’s elevated-temperature embrittlement warning and the 475 °C ferrite-embrittlement mechanism known in duplex practice. Keep continuous-service temperature inside engineering limits. Materials review should precede any attempt to stretch lean duplex into mid-alloy service.

S32202 suits lean-duplex heat-exchanger and general-service tube when the datasheet wants low nickel, elevated nitrogen, and only residual molybdenum. Select it by UNS, not as a silent stand-in for 2205. Match fluid chemistry and temperature to the lean-duplex PREN estimate before freezing the BOM.

For 2304-type lean chemistry see SA789 S32304; for standard duplex see SA789 S32205. Match fluid chemistry and temperature to the lean-duplex PREN estimate before freezing the BOM.

Fabrication welds usually use lean-duplex filler under a qualified WPS; the SA-789 welded tube seam stays autogenous. Low molybdenum and elevated nitrogen require ferrite-balance control different from 2209-on-2205 practice — qualify on S32202 heats. Procedure qualification on the actual UNS avoids ferrite surprises in the HAZ.

Limit heat input and interpass temperature, cool promptly, and clean after welding. SHH STEEL can discuss filler families; the fabricator owns WPS/PQR. Procedure qualification on the actual UNS avoids ferrite surprises in the HAZ.

Standard delivery is heat-treated and descaled/pickled per Section 13, suitable for inspection. Bright anneal or specified Ra finishes are agreement items that must appear on the order for SA789 S32202. Call out any Ra or bright requirement early so mill routing can include it.

SHH STEEL quotes special finishes against the written enquiry rather than assuming them with the grade stamp. Call out any Ra or bright requirement early so mill routing can include it.

Base testing covers Table 1 chemistry, Table 4 tension and hardness, flare or flange tests by route, reverse flattening for welded tube, and hydro or NDE on each length using the duplex hydrostatic factor 64000 (441.2). Manufacturer chooses hydro versus NDE unless the PO specifies.

Marking shows seamless or welded and wall basis. SHH STEEL 3.1 MTCs tie heat, chemistry, mechanicals, heat treatment, and test method together for receiving. Receiving teams should verify hydro-versus-NDE against the purchase order before releasing tube to fabrication.

Tagged bundles leave SHH STEEL with ASME SA789, UNS S32202, route, OD × wall, heat, and PO on the labels, plus end protection suited to the length mix for export or domestic delivery. Bundle tags should remain legible after ocean transit so port inspection can proceed without remarking.

Wrapped bundles or wooden cases are available for bright or small-bore material. Incoterms follow the order acknowledgment. Bundle tags should remain legible after ocean transit so port inspection can proceed without remarking.

SHH STEEL produces and supplies ASME SA789 UNS S32202 as manufactured lean-duplex Code Book tube — seamless and welded — with the low-Mo, high-N chemistry reported honestly on the EN 10204 3.1 MTC. We do not relabel it as 2205.

If the service needs ~3% molybdenum, we quote SA789 S32205. If 2304-type chemistry is written, we quote SA789 S32304. Dual marking is available on request. Honest grade selection protects Code stamp integrity when sister duplex grades would serve better.

SHH STEEL can produce and supply ASME SA789 UNS S32202 stainless steel tube against the edition, manufacture route, and finish named on your enquiry. Capability details and Stock / Available sizes follow for heat-exchanger and general-service planning.

Stock / Available sizes — SHH STEEL regularly enquires and produces SA789 S32202 in OD bands about 12.7–50.8 mm with common BWG / metric walls, and can extend into larger Table 5 OD groups on agreement. Cut lengths and end prep are quoted against the PO. Send OD × wall, length, route, and quantity for a production and near-stock reply without invented tonnage claims.

List ASME SA789 UNS S32202, seamless or welded, OD × wall, wall basis, length, quantity, and test preferences on the enquiry so the quotation matches the datasheet. Clear enquiry data shortens quotation turnaround for export and domestic Code jobs alike.

ASME SA789 UNS S32202 is the low-molybdenum, nitrogen-strengthened lean duplex tubing grade for Code and general service when nickel cost must stay low and full 2205 chemistry is not required. SHH STEEL produces and supplies seamless and welded (no filler metal) SA789 S32202, heat-treated per Table 2, tested per Section 9, and certified on EN 10204 3.1 MTCs. Confirm OD × wall, wall basis, route, and dual-marking needs on the purchase order. For technical follow-up, contact admin@steelspecs.com.