Sulfuric and Phosphoric Acid Process Lines
Transfer lines, reactor manifolds and process piping for sulfuric, phosphoric and nitric acids are made from seamless S32550 super duplex steel pipe.
ASTM A790 / ASME SA-790 / UNS S32550 / W.Nr. 1.4507
Super Duplex Steel UNS S32550 Seamless Pipes Manufacturer in Thailand
Thaida Stainless Steel Manufacturing (Thailand) Co., Ltd. manufactures ASTM A790 UNS S32550 super duplex steel seamless pipes in Ban Bueng, Chonburi, Thailand, for acid process lines, seawater handling and desalination piping. Cross-referenced to EN 1.4507, the grade is the high-copper member of our super duplex steel seamless pipes range, with 1.50 to 2.50% copper set by the standard alongside 24.0 to 27.0% chromium. Quotation, drawing review and certificate issue are managed from our sales office at Bang Phli, Samut Prakan.
Super Duplex Steel UNS S32550 seamless pipeUNS S32550 / W.Nr. 1.4507
- 6 to 720 mmOutside diameter
- 1 to 65 mmWall thickness
- Up to 18 mLength
- EN 10204 3.1Test certificate
EN 10204 3.1 certificate / 3.2 on request
ASTM A790 UNS S32550 Seamless Pipe Specifications
The values below apply to UNS S32550 seamless pipe made to ASTM A790 / ASME SA-790. Small-bore lines are usually ordered by NPS and schedule, while headers and special sizes can be ordered by outside diameter and wall within the same production envelope.
- Standard
- ASTM A790 / ASME SA-790
- Grade
- UNS S32550
- Outside Diameter
- 6 to 720 mm
- Wall Thickness
- 1 to 65 mmor Schedule 5S, 10S, 40S or 80S
- Length
- Up to 18 mcut to specified length
- End Type
- Plain endbeveled end; threaded on Schedule 40S and 80S
- Form
- Seamless
- Manufacturing Route
- Heated billet formed by hot extrusion or cold drawing
- Heat Treatment
- 1040 °C minimumrapid cooling in water or by other means
- Surface
- Pickled free of scaleor bright annealed
- Testing
- Hydrostatic or ultrasonic / eddy current test on every pipe
- Tension, flattening and hardness tests per lot
- Test Certificate
- EN 10204 3.13.2 on request
A790 is the standard for ferritic/austenitic pipe in corrosive duty, written with stress corrosion cracking in mind. For each ASTM A790 UNS S32550 seamless pipe that means a heat analysis within the limits tabulated below, solution treatment, pickling or bright annealing, and release only after the tensile, flattening, hardness and pressure or electric tests are passed. Acid coolers and exchangers that need tubing held to OD tolerances rather than pipe schedules are supplied in the same grade to ASTM A789 as our UNS S32550 seamless tubes.
Lot Tests and Pressure Proof for ASME SA-790 S32550 Seamless Pipe
The hydrostatic test, or in its place an ultrasonic or eddy current scan made once heat treatment and straightening are finished, is applied to each length separately. Sampling is then counted per heat-treated lot: a single tension specimen covers up to 100 pipes and a second is added above that, one pipe in twenty is flattened, and two pipes receive a Brinell or Rockwell hardness check. Results for each ASME SA-790 S32550 seamless pipe are reported with the heat analysis and PMI records on an EN 10204 3.1 (3.2 on request) material test certificate, and witnessing by an inspection agency you appoint can be arranged on request.
Chemical Composition of S32550 Super Duplex Stainless Steel Seamless Pipe
Heat analysis limits set by ASTM A790 for UNS S32550, in percent, maximum unless a range is given:
- CrChromium, 24.0 to 27.0
- NiNickel, 4.5 to 6.5
- MoMolybdenum, 2.9 to 3.9
- CuCopper, 1.50 to 2.50
- MnManganese, 1.50
UNS S32550S32550
| Element | UNS S32550 (%) |
|---|---|
| C (Carbon) | 0.04 |
| Mn (Manganese) | 1.50 |
| P (Phosphorus) | 0.040 |
| S (Sulfur) | 0.030 |
| Si (Silicon) | 1.00 |
| Ni (Nickel) | 4.5 to 6.5 |
| Cr (Chromium) | 24.0 to 27.0 |
| Mo (Molybdenum) | 2.9 to 3.9 |
| N (Nitrogen) | 0.10 to 0.25 |
| Cu (Copper) | 1.50 to 2.50 |
Copper is what sets this grade apart, because the addition improves its resistance to sulfuric acid. S32550 super duplex stainless steel seamless pipe therefore goes into process lines carrying sulfuric or phosphoric acid. Among the other super duplex grades we make, only UNS S32760 seamless pipes carry a copper range, at 0.50 to 1.00% alongside tungsten. Carbon is capped at 0.04%, and A790 sets no pitting-index requirement for S32550.
Super Duplex Steel S32550 Seamless Pipe Mechanical Properties
| Property | Requirement per ASTM A790 |
|---|---|
| Tensile Strength, min | 760 MPa (110 ksi) |
| Yield Strength, min | 550 MPa (80 ksi) |
| Elongation in 2 in. or 50 mm, min | 15% |
| Hardness, max | 297 HBW or 31 HRC |
Your design code converts the 760 MPa tensile and 550 MPa yield minimums into the allowable stress used to size each super duplex steel S32550 seamless pipe. For comparison, UNS S32750 seamless pipes share the 550 MPa yield and 15% elongation but carry an 800 MPa tensile minimum and a 300 HBW hardness ceiling. Each lot's Brinell or Rockwell reading is recorded on the certificate next to the 297 HBW or 31 HRC ceiling.
Equivalent Designations of UNS S32550
Other standard systems list UNS S32550 under the names below. They serve as cross-references only; the pipe itself is ordered and certified to UNS S32550 under ASTM A790.
- UNSS32550
- ASTM / ASME pipe specificationASTM A790 / ASME SA-790
- ASTM common name255
- EN steel number1.4507
- EN steel nameX2CrNiMoCuN25-6-3
- EN seamless product standardEN 10216-5
- GB03Cr25Ni6Mo3Cu2N; S25554 (ISC)
Small-Bore Schedules for Seamless 1.4507 Super Duplex Pipe
For manifolds and branch connections around acid reactors, the table gives ASTM A790 Appendix X1 wall thicknesses in mm for NPS 1/4 to 1:
| NPS | OD (mm) | Sch 10S | Sch 40S | Sch 80S |
|---|---|---|---|---|
| 1/4 | 13.72 | 1.65 | 2.24 | 3.02 |
| 3/8 | 17.15 | 1.65 | 2.31 | 3.20 |
| 1/2 | 21.34 | 2.11 | 2.77 | 3.73 |
| 3/4 | 26.67 | 2.11 | 2.87 | 3.91 |
| 1 | 33.40 | 2.77 | 3.38 | 4.55 |
Swipe sideways to see the full table.
In this size band the permitted variations that apply to A790 pipe are +0.4 / -0.8 mm on OD and +20.0 / -12.5% on nominal wall, and a cut length may run up to 6 mm long but never short. Our Super Duplex Steel UNS S32550 Seamless Pipes also cover 6 to 720 mm OD, 1 to 65 mm wall and lengths up to 18 m, so a project can source its small-bore seamless WNR 1.4507 pipe and its larger headers from one mill.
Process Duties for Seamless S32550 Super Duplex Steel Pipe
S32550 lines serve chemical, seawater, oil and gas and pulp mill duties, from reactor manifolds to bleach plant piping.
Flue Gas Desulfurization Spray Headers
Spray headers and absorber piping in flue gas desulfurization units circulate acidic scrubbing liquor, and S32550 lets these headers be built from seamless lengths with welded branch connections.
Seawater Reverse Osmosis Units
High-pressure feed and pump piping in seawater reverse osmosis units, along with brine heater connections, carries chloride-rich water under pressure, where super duplex strength keeps wall thickness moderate.
Subsea and Seawater Handling Piping
Marine engineering projects run seawater handling lines and subsea piping in S32550, with lengths cut and beveled for the butt-welded spools from which these systems are assembled.
Oil and Gas Flowlines
Production flowlines, including sour gas lines where the project specification accepts the grade, are run in S32550 for its stress corrosion cracking resistance and 550 MPa minimum yield.
Pulp Bleaching Stages
Pulp mills pipe chlorine dioxide bleaching stages, bleach washers and liquor lines in S32550, replacing worn sections in the same grade during shutdowns so that each line class stays unchanged.
Packing and Dispatch of Seamless S32550 Pipe Lengths
Each seamless WNR 1.4507 pipe consignment is packed to suit its bore and shipping route:
Bundling
Small-bore lengths strapped together by schedule and heat, while headers and bright annealed lengths ship in timber boxes.
Traceability
The stenciled heat number on each length matches the certificate and sits beside UNS S32550, ASTM A790, NPS and schedule.
Ends
Plastic closures fitted on every end once final inspection is complete, threaded ends included.
Documents
Material test certificates for every heat, packing list and invoice sent with the shipping set.
Sale terms
FOB at the Thai loading port, or CFR and CIF to your destination port.
Reach
Acid and chemical plants anywhere in Thailand, and container shipments to Singapore, Malaysia, Vietnam, Indonesia, the Philippines and India.
UNS S32550 Seamless Pipe Price
Indicative pricing for UNS S32550 seamless pipe to ASTM A790 runs at roughly USD 8 to 14 per kg according to current market quotations, a planning figure and not an offer. Each item moves within that band with its bore, wall and quantity and with any testing you add, the smallest bores costing the most per kg. Firm prices are issued item by item against your size list.
Indicative price, Super Duplex Steel UNS S32550 Seamless Pipes
USD 8 to 14 per kg
Indicative only. Send your sizes and specification to Thaida for a firm quotation.
- Outside diameter
- Wall thickness
- Quantity
- Testing and certification
Order Super Duplex Steel UNS S32550 Seamless Pipes from Ban Bueng
Billets for our Super Duplex Steel UNS S32550 Seamless Pipes are hot extruded or cold drawn, heat treated and inspected at our mill at 154 Moo.1 Map Phai, Ban Bueng, Chonburi 20170, Thailand. Enquiries, drawings and certificate questions go to our office at 89/18 Moo.15 Enterprize Park, Bangna-Trad Road, Bang Kaeo, Bang Phli, Samut Prakan 10540, Thailand, where stock, production slots and delivery are confirmed for each order.
Factory154 Moo.1 Map Phai, Ban Bueng,
Chonburi 20170, Thailand
Chonburi 20170, Thailand
Office89/18 Moo.15 Enterprize Park, Bangna-Trad Road,
Bang Kaeo, Bang Phli, Samut Prakan 10540, Thailand
Bang Kaeo, Bang Phli, Samut Prakan 10540, Thailand
Exporting to
- Singapore
- Malaysia
- Vietnam
- Indonesia
- Philippines
- India
Super Duplex S32550 Seamless Pipe FAQ
When is S32550 seamless pipe preferred over the S32750 grade?
When copper is the deciding factor. S32550 carries 1.50 to 2.50% copper, credited with its resistance to sulfuric acid, while S32750 is limited to 0.50%. S32750 instead offers up to 5.0% molybdenum and an ASTM pitting-index requirement (Cr + 3.3Mo + 16N) of at least 41, so a line specification that calls for that index points to S32750.
Is Schedule 10S S32550 seamless pipe thick enough to thread?
No. ASTM A790 Appendix X1 flags Schedule 5S and 10S walls as unsuitable for threading to ANSI B1.20.1, so 10S lengths go out with plain or weld-bevel ends and threads are cut only on 40S and 80S. At NPS 1/4 and 3/8 no 5S wall is tabulated, which leaves 10S as the lightest wall there.
Can my order require a hydrostatic test rather than an electric test on S32550 seamless pipe?
Yes. Unless the purchase order names a method, A790 lets the mill choose between hydrostatic and electric testing. For hydro, P = 2St/D uses S = 275 MPa (50% of the specified 550 MPa yield); the required pressure tops out at 17.0 MPa on pipe of 88.9 mm OD or less and 19.0 MPa above, held 5 seconds or more.
What heat treatment does S32550 seamless pipe receive before dispatch?
Solution treatment at 1040 °C minimum, followed by rapid cooling, either in water or by another method. For seamless pipe, A790 also allows each length to be quenched directly from hot forming, as long as its temperature has not dropped below 1040 °C. Scale is then removed by pickling, a step that bright annealed lengths skip.
Does a seamless WNR 1.4507 pipe call-out always mean UNS S32550?
Not on its own. 1.4507 is cross-referenced to UNS S32520 as well as S32550, and the two grades carry different copper limits, so an enquiry for seamless 1.4507 super duplex pipe leaves the chemistry open. Quote UNS S32550 together with ASTM A790 when ordering, and the material test certificate reports against the S32550 limits.
How is the copper content of S32550 seamless pipe confirmed?
Through the heat analysis on the EN 10204 3.1 (3.2 on request) certificate, which reports copper against the A790 range. Your inspector can also request a product analysis on two pipes from each lot, where a lot below NPS 2 is up to 400 lengths and a lot from NPS 2 to 5 up to 200.
How far up the NPS range do 40S and 80S walls go for S32550 seamless pipe?
Schedules 40S and 80S are tabulated up to NPS 12; above that, Appendix X1 lists only 5S and 10S, and NPS 24 (609.60 mm OD) is the largest of those within our 720 mm OD limit. Pipe with other dimensions, such as heavier walls up to 65 mm, can be supplied when it meets every other A790 requirement.
Request a Quote for Super Duplex Steel UNS S32550 Seamless Pipes
or email sales@thaida.co.th