Wet-Process Phosphoric Acid Plants
Phosphoric acid plants built on the wet process use Alloy 31 for their acid transfer and recirculation piping, with each run specified by NPS and schedule to match the plant's piping class.
ASTM B622 / ASME SB-622 / UNS N08031 / W.Nr. 1.4562
Alloy 31 Seamless Pipes Manufacturer in Thailand
From its Ban Bueng, Chonburi plant and Bang Phli, Samut Prakan office, Thaida Stainless Steel Manufacturing (Thailand) Co., Ltd. manufactures Alloy 31 seamless pipes to ASTM B622 / ASME SB-622 in UNS N08031 (W.Nr. 1.4562). Built on an iron balance, this low-carbon nickel-iron-chromium-molybdenum-copper alloy with added nitrogen is one of the three iron-bearing nickel alloys in our nickel alloy seamless pipes range, made for sulfuric acid, wet-process phosphoric acid, flue gas desulfurization and brine lines.
Alloy 31 seamless pipeUNS N08031 / W.Nr. 1.4562
- 6 to 610 mmOutside diameter
- 0.5 to 40 mmWall thickness
- Up to 18 mLength
- EN 10204 3.1Test certificate
EN 10204 3.1 certificate / 3.2 on request
Specifications of ASTM B622 Alloy 31 Seamless Pipes
Each line is written as an NPS with its schedule, and the pipe leaves the mill solution annealed and descaled. The table sets out the size range we quote, the delivery condition and the tests applied before dispatch.
- Standard
- ASTM B622 / ASME SB-622
- Grade
- Alloy 31 (UNS N08031)
- Outside Diameter
- 6 to 610 mm
- Wall Thickness
- 0.5 to 40 mm
- Length
- Up to 18 m
- Ordering Basis
- Standard pipe size (NPS) and schedule
- Form
- Seamless
- Delivery Condition
- Solution annealed and descaled
- Ends
- Plain cut and deburred
- Testing
- Chemical analysis and tension test per lot
- Hydrostatic or nondestructive electric test on each pipe
- Test Certificate
- EN 10204 3.13.2 on request
ASTM B622, the Standard Specification for Seamless Nickel and Nickel-Cobalt Alloy Pipe and Tube, names UNS N08031 among the alloys that can be certified to it, and that UNS number is the designation marked on each UNS N08031 seamless pipe and printed on its certificate. ASME SB-622 is the related specification for Boiler and Pressure Vessel Code work, so an ASME SB-622 UNS N08031 seamless pipe is ordered and reported against the same UNS number. The inch-pound values in B622 are the requirement, and the SI figures beside them are conversions for information. Pipe is ordered by standard pipe size and schedule, while Alloy 31 seamless tubes are ordered under the same specification by outside diameter and minimum or average wall.
One chemical analysis covers each heat, and one tension test covers each lot of the same heat, nominal size and condition. Every length is then either hydrostatically tested or examined by a nondestructive electric test, eddy current or ultrasonic. The hydrostatic test applies 1000 psi (6.9 MPa) of internal pressure, held for at least 5 seconds, unless the allowable fiber stress for the wall and diameter sets a lower figure, and any pipe that leaks is rejected. ASTM B622 calls for a manufacturer's certification and a test report when the order specifies them; we issue both as an EN 10204 3.1 (3.2 on request) material test certificate. If you want to witness tests at the mill, the purchase order should say so, and third-party inspection is available on request.
UNS N08031 Seamless Pipe Chemical Composition
ASTM B622 places this alloy in its low-carbon Ni-Fe-Cr-Mo-Cu group, with iron as the balance and nitrogen specified as a range of its own. Values without a range are maximums.
- FeIron, Balance
- NiNickel, 30.0 to 32.0
- CrChromium, 26.0 to 28.0
- MoMolybdenum, 6.0 to 7.0
- MnManganese, 2.0 max
UNS N0803131
| Element | Limit per ASTM B622 / ASME SB-622 (%) |
|---|---|
| Ni (Nickel) | 30.0 to 32.0 |
| Cr (Chromium) | 26.0 to 28.0 |
| Mo (Molybdenum) | 6.0 to 7.0 |
| Fe (Iron) | Balance |
| Cu (Copper) | 1.0 to 1.4 |
| N (Nitrogen) | 0.15 to 0.25 |
| C (Carbon) | 0.015 max |
| Mn (Manganese) | 2.0 max |
| Si (Silicon) | 0.3 max |
| P (Phosphorus) | 0.020 max |
| S (Sulfur) | 0.010 max |
Tungsten, cobalt, titanium, niobium and the other elements in the B622 table carry no requirement for UNS N08031, so the heat analysis on the certificate is read against these eleven rows. A product check analysis on delivered pipe is the purchaser's responsibility; state on the order whether samples should be furnished.
Mechanical Properties and Condition of Seamless Nickel Alloy 31 Pipe
B622 gives UNS N08031 a single row of room-temperature minimums that applies to pipe and tube alike, with no split by size, wall or condition.
| Property | Value | Unit |
|---|---|---|
| Tensile Strength, min | 94 (650) | ksi (MPa) |
| Yield Strength (0.2% offset), min | 40 (276) | ksi (MPa) |
| Elongation in 2 in. (50.8 mm) or 4D, min | 40 | % |
These minimums apply to seamless nickel alloy 31 pipe in the solution annealed and descaled condition that B622 requires; when the anneal runs under a controlled atmosphere, descaling is not necessary. Tension specimens are cut after final heat treatment and tested in the direction of fabrication, in full tubular size whenever the pipe size allows, otherwise as longitudinal strips or the largest round specimen the wall permits.
Equivalent Designations of Alloy 31
Alloy 31 drawings from American and European projects use different designations. ASTM B622 identifies the alloy by its UNS number; the W.Nr. and EN material name below are cross-references for reading a European callout.
- Commercial nameAlloy 31
- ASTM B622 / ASME SB-622 (USA)UNS N08031
- Europe (W.Nr.)1.4562
- Europe (EN material name)X1NiCrMoCu32-28-7
A requisition written as 1.4562 or X1NiCrMoCu32-28-7 is entered against UNS N08031, the number our certificate reports.
Seamless WNR 1.4562 Pipe Sizes, Schedules and Tolerances
We quote seamless WNR 1.4562 pipe from 6 mm to 610 mm OD and 0.5 mm to 40 mm wall, in lengths up to 18 m. The pipe-schedule appendix of ASTM B622 lists Schedules 10, 40 and 80 for NPS 1/4 to NPS 3 as regularly available, for information only, with no Schedule 80 entry at NPS 1/4.
Diameter and wall are held to the cold-worked tolerances that apply to ASTM B622 pipe, shown below and read against nominal wall or, when the order states a minimum wall, against that minimum.
| OD (D) mm | OD Tolerance (mm) | Nominal Wall Tolerance | Minimum Wall Tolerance |
|---|---|---|---|
| D ≤ 10 | ±0.10 | ±15.0% | +30% / 0 |
| 10 < D < 16 | ±0.13 | ±15.0% | +30% / 0 |
| 16 ≤ D ≤ 38 | ±0.19 | ±10.0% | +22% / 0 |
| 38 < D ≤ 76 | ±0.25 | ±10.0% | +22% / 0 |
| 76 < D ≤ 114 | ±0.38 | ±10.0% | +22% / 0 |
| 114 < D ≤ 152 | ±0.51 | ±12.5% | +28% / 0 |
| 152 < D ≤ 168 | ±0.64 | ±12.5% | +28% / 0 |
| 168 < D ≤ 219 | ±0.79 | ±12.5% | +28% / 0 |
| 219 < D ≤ 356 | +1.57 / -0.79 | +15.0% / -12.5% | +30.0% / 0 |
| 356 < D ≤ 610 | +3.18 / -0.79 | +15.0% / -12.5% | +30.0% / 0 |
Swipe sideways to see the full table.
On pipe over 114 mm OD with a wall above 3% of the OD, the mean diameter must meet the table and single readings may reach twice the table value; where the wall is 3% of the OD or less, the mean diameter meets the table and single readings including ovality may exceed it by 0.5% of the nominal OD. Cut lengths up to 7.3 m carry plus-only length limits of 3.2 mm below 50.8 mm OD and 4.8 mm at 50.8 mm OD and over, and each further 3 m or part of it adds 3.2 mm, up to 12.7 mm extra.
How Alloy 31 Compares with Alloy 20 and 904L
Nickel Alloy 20 seamless pipes are made to ASTM B729 with a different balance: 3.00 to 4.00% copper, 2.00 to 3.00% molybdenum, 19.00 to 21.00% chromium and a niobium plus tantalum addition for stabilization, with carbon up to 0.07%. Alloy 31 shifts the weight toward 6.0 to 7.0% molybdenum and 26.0 to 28.0% chromium, holds copper lower at 1.0 to 1.4%, adds 0.15 to 0.25% nitrogen and caps carbon at 0.015%, with no niobium requirement. Where a line class allows an austenitic stainless steel, stainless steel 904L seamless pipes are made to a stainless steel pipe specification instead, so that choice also changes the standard written on the order.
Industrial Applications of Seamless 1.4562 Alloy Pipe
Seamless 1.4562 alloy pipe is selected for its pitting and crevice resistance in chloride media and for sulfuric and wet-process phosphoric acid service.
Sulfuric Acid Concentration and Handling
Concentration units and acid handling systems carry sulfuric acid through Alloy 31 circulation and transfer lines, welded into spools that are fabricated to the plant's line drawings.
Flue Gas Desulfurization Absorbers
Flue gas desulfurization systems route their absorber and duct piping in this alloy, including the acidic, chloride-bearing recirculation lines around the scrubber.
Pulp Bleaching Circuits
Pulp mills run the chlorine dioxide and hypochlorite circuits of their bleach plants in this alloy, from the chemical feed lines to the filtrate return piping between the washing stages.
Mixed-Acid Reactor Transfer Lines
Chemical plants connect reactors and heat exchangers that handle mixed acids and halides with Alloy 31 transfer lines, each ordered in the schedule its pressure rating calls for.
Seawater, Brine and Produced Water
Offshore processing facilities and coastal chemical plants pipe seawater and brine in this alloy, and offshore operators also use it for produced-water handling and injection piping.
Shipping and Packaging of Seamless N08031 Pipe
Packing
Full lengths bundled and strapped on timber skids, small-bore and cut pieces in wooden cases, with end protectors on every pipe.
Marking
Manufacturer name, UNS N08031, ASTM B622, heat number and nominal size on each pipe of 3/4 in. (19.0 mm) OD and larger and longer than 3 ft (914 mm); smaller or shorter pieces are marked individually or on a tag fixed to the bundle or case.
Package labels
UNS number, heat number, condition, ASTM B622, nominal pipe size, gross, tare and net weight, consignor and consignee addresses and the order number.
Documents
EN 10204 3.1 (3.2 on request) material test certificate with the ASTM B622 test report, plus a packing list for each bundle or case.
Terms
FOB, CIF or CFR, with the port of loading stated in the offer.
Timing
Production slot and dispatch date confirmed with the order acknowledgment.
Seamless Alloy 31 Pipe Price per kg
Seamless Alloy 31 pipe is indicatively priced at USD 22 to 50 per kg. The nickel market moves that figure first and molybdenum second. Within the range the NPS and schedule matter, since small bores and light walls need more cold-working and annealing passes for each kilogram, while order quantity, cut lengths and any extra inspection or witness testing decide how close a quotation sits to the upper end. Send the line list with quantities for a firm offer.
Indicative price, Alloy 31 Seamless Pipes
USD 22 to 50 per kg
Indicative only. Send your sizes and specification to Thaida for a firm quotation.
- Outside diameter
- Wall thickness
- Schedule
- Length
- Quantity
- Testing and certification
- Nickel price
- Molybdenum price
Production and Sales Offices
We manufacture Alloy 31 seamless pipes at 154 Moo.1 Map Phai, Ban Bueng, Chonburi 20170, Thailand. Quotations, certificates and export documents are prepared at our office, 89/18 Moo.15 Enterprize Park, Bangna-Trad Road, Bang Kaeo, Bang Phli, Samut Prakan 10540, Thailand. We supply projects across Thailand and export to Singapore, Malaysia, Vietnam, Indonesia, the Philippines and India.
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
Alloy 31 Seamless Pipe FAQ
What nitrogen and molybdenum ranges does ASTM B622 set for UNS N08031?
Nitrogen 0.15 to 0.25% and molybdenum 6.0 to 7.0%. Both are closed ranges with a lower as well as an upper limit, unlike the maximum-only elements such as carbon, so a heat analysis below either minimum fails the specification just as one above the maximum does. Check both ends on the certificate.
Can a size outside the B622 schedule appendix be ordered?
Yes. The appendix lists the schedules regularly available in the smaller sizes and is published for information only, so it does not cap the order. Larger NPS and other walls within our size range are quoted on request; give the NPS and the schedule or wall you need on each line.
How large can seamless N08031 pipe be ordered?
Up to 610 mm OD with walls to 40 mm, in lengths up to 18 m. In the top band, above 356 mm OD, the OD may run 3.18 mm over or 0.79 mm under and nominal wall +15.0% / -12.5%, while a minimum-wall order allows +30.0% / 0, so state which wall basis the design uses.
Does the pipe need heat treatment after bending or welding?
ASTM B622 notes that proper heat treatment during or after fabrication is necessary for optimum performance and that the manufacturer shall be consulted for details. Send the bending and welding plan for your spools with the inquiry, and we confirm the heat treatment to apply before the pipe goes into service.
What does the certificate for seamless N08031 pipe report?
The heat analysis against the B622 chemistry limits, the lot tension result against 94 ksi (650 MPa) tensile, 40 ksi (276 MPa) yield and 40% elongation, and confirmation of the hydrostatic or electric test on each pipe. It is issued as EN 10204 3.1 (3.2 on request) and carries the heat number marked on the pipe.
What happens if a lot fails its tension test?
Two more specimens are taken from different sample pieces of that lot, and both must meet the minimums for the lot to pass. A lot that still fails may be reheat treated and resubmitted, with no more than two reheat treatments permitted, so every pipe that ships is covered by a passing result.
Should a line be specified in Alloy 31 or Alloy 20?
Let the piping class and the documents decide. Alloy 31 is ordered to ASTM B622 / ASME SB-622, solution annealed and descaled, with certification when the order calls for it. Alloy 20 is ordered to ASTM B729 alone, stabilized-annealed, and that standard makes a manufacturer's certification mandatory. Send the media and the line class for a recommendation.
Request a Quote for Alloy 31 Seamless Pipes
or email sales@thaida.co.th