01
Seamless Tube
Cold drawn and annealed to ASTM B729, from 6 to 219 mm outside diameter.
Request Availability →Alloy 20 Pipe and Tube
Niobium-stabilised nickel-iron-chromium tube with copper, for acid coolers, exchanger bundles, and transfer lines.
Three Tube Documents Named
Seamless, welded pipe, and welded tube each carry their own ASTM number on the offer.
Anneal Chart on File
Therefore, the certificate for every bundle points back to the furnace record and the quench log.
Welded Bundles Without a Furnace Cycle
Consequently, niobium stabilisation lets a fabricated exchanger go to service as welded.
PRODUCT OVERVIEW
About Alloy 20 Pipe and Tube
Alloy 20 tube handles the acid that moves between vessels rather than the metal that sits in it. Seamless product covers the pressure duty, and welded product covers the larger diameters. Copper at 3 to 4% keeps dilute sulphuric and phosphoric acid in range.
Tubular product sits beside the bar and the flat product in one family, and each route names its own document. Meanwhile, seamless tube follows the tube document, and welded pipe and welded tube follow their own. As a result, a heat can supply exchanger tubes and the shell pipe around them.
However, the trade also markets the grade as 20Cb-3, and Carpenter Technology owns that name.
PRODUCT FEATURES
Key Features of Alloy 20 Pipe and Tube
Alloy 20 pipe and tube carries the UNS N08020 grade, an austenitic nickel-iron-chromium alloy stabilised with niobium and alloyed with copper. Copper at 3 to 4% keeps dilute sulphuric and phosphoric acid inside the working envelope, and nickel at 32 to 38% removes chloride stress-corrosion cracking from the failure list. Niobium at eight times the carbon content means welded bundles need no post-weld anneal. Southerly Alloy supplies and exports UNS N08020 seamless tube to ASTM B729, welded pipe to B464, and welded tube to B468.
Alloy 20
Copper Against Dilute Acid
Copper at 3 to 4% keeps sulphuric and phosphoric acid inside the working envelope.
01
Seamless and Welded Together
In fact, one heat supplies seamless tube, welded pipe, and welded tube.
02
Chloride Cracking Immunity
Nickel at 32 to 38% removes chloride stress-corrosion cracking from the failure list.
03
Welded Bundles as Welded
Moreover, niobium stabilisation means a fabricated bundle needs no post-weld anneal.
04
Through-Wall Consistency
Cold drawing and anneal give a wall that holds its thickness around the circumference.
05
Pressure Code Coverage
Therefore, the ASME editions take over once a pressure vessel or piping code applies.
06
Sour Service Listed
Specifically, the grade appears in NACE MR0175 and ISO 15156-3 for oilfield duty.
07
Repair Welding Supported
Low-residual filler metals match the base metal without a mismatch in the weld zone.
08
WHY CHOOSE US
Why Choose Alloy 20
Start with the duty and the diameter together. Where dilute acid runs at moderate temperature, seamless Alloy 20 tube outlasts 316L and costs far less than a nickel-molybdenum grade. Where the chloride level climbs, a higher-molybdenum alloy takes over.
01
Copper for the Acid Side
Indeed, copper at 3 to 4% carries dilute sulphuric and phosphoric duty that defeats 316L.
02
No Post-Weld Furnace Cycle
Consequently, a welded exchanger bundle goes to service without a second anneal.
03
Chloride Resistance Built In
Nickel at 32 to 38% keeps stress-corrosion cracking out of the design review.
04
Bundle Fabrication Support
In addition, we supply U-bend and coiled tube cut to the bundle drawing.
MANUFACTURING PROCESS
Reliable Production For Critical Applications
Tubular product runs through the same mill as the bar, on its own line. The anneal and the quench decide the corrosion result here too, so both steps stay under chart control.
01
Billet Preparation
A weighed billet from an approved heat becomes the starting stock for every seamless tube.
02
Piercing and Rolling
The mill pierces the billet, then rolls it to the ordered outside diameter and wall.
03
Cold Drawing
Drawing passes bring the tube to final size and tighten the wall tolerance.
04
Degreasing and Cleaning
We clean each length before the furnace so no residue carries into the anneal.
05
Stabilise Anneal
The charge holds at 982 to 1010 °C until the whole load reaches temperature.
06
Rapid Cooling
Consequently, the tube enters the quench straight from the furnace to hold the carbon in solution.
07
Straightening and Cutting
The line straightens, squares, and cuts each length to the ordered figure.
08
Hydrostatic and Flattening Test
Finally, the pressure test, the flattening test, and the dimensional check release the lot.
Manufacturing Facility
MANUFACTURING CAPABILITY
Advanced Production For Nickel Alloy Products
Our manufacturing facility provides reliable production capacity for seamless pipes, tubes, fittings, plates and bars with strict quality management systems.
20,000+ m²
Production Area
Piercing, drawing, annealing, and testing share one site.
50+
Tube Line Machines
Draw benches, pilger mills, and straighteners cover the seamless range.
600 Tons
Monthly Tonnage
Seamless and welded product run on one campaign calendar.
30+
Technical Staff
A metallurgist reviews every acid and sour duty enquiry before the offer.
QUALITY ASSURANCE
Strict Quality Control From Production To Delivery
Every tube leaves with a document set that matches the standard behind it. Therefore, the heat number ties the certificate back to the melt, the anneal chart, and the test results.
01
Chemistry Against the ASTM Window
The laboratory reads copper, niobium, and carbon, then checks each result against the limits.
02
Mechanics on the Finished Tube
Tensile and yield values come from the delivered product, not from a surrogate sample.
03
Pressure and Flattening Tests
Hydrostatic proof and flattening checks release each lot for the welded routes.
04
Eddy Current and Dimensional Check
Where the order calls for it, eddy current testing runs alongside the gauge check.
PRODUCT FORMS
Available Product Forms
Five supply routes cover the tubular shapes a project asks for. In addition, every route carries its own acceptance document.
02
Seamless Pipe
Heavier wall stock for pressure lines under code jurisdiction.
Request Availability →
03
Welded Pipe
Automatic welding without filler to ASTM B464, NPS 1/8 to 6 in Schedule 5S, 10S, and 40S.
Request Availability →
04
Welded Tube
Longitudinal weld to ASTM B468, from 3.2 to 88.9 mm outside diameter.
Request Availability →
05
U-Bend and Coiled Tube
Bent lengths and coils cut to the bundle or coil drawing.
Request Availability →
APPLICATIONS
Engineered For Demanding Industries
Acid plant and heat transfer are where this grade has served longest. Meanwhile, the high nickel content makes chlorinated cooling water a second home.
Discuss Your Application →
01
Exchanger Tube Bundles
Tubes that carry acid on one side and cooling water on the other.
02
Sulphuric Acid Coolers
Tube-side and shell-side parts in dilute acid service.
03
Phosphoric Acid Evaporators
Heating tubes in wet-process evaporator circuits.
04
Pickling Line Coils
Heating and cooling coils submerged in pickling baths.
05
Condenser Bundles
Tubes that see chlorinated water with a low acid load.
06
Sour Gas Line Pipe
Pipe specified under NACE MR0175 and ISO 15156-3.
07
Pharmaceutical Transfer Lines
Lines that carry acid and caustic during cleaning cycles.
08
Flue Gas Scrubber Piping
Finally, ducting and spray headers exposed to acid condensate.
TECHNICAL INFORMATION
Technical Specifications
Detailed technical information including chemical composition, mechanical properties, standards and available dimensions.
Chemical Composition
The limits below come from ASTM B463, B473, and B729, which share one composition table for UNS N08020. Copper is the deliberate addition behind the acid performance, and the niobium range scales with the carbon content. The mill certificate governs final acceptance.
| Element | Content |
|---|---|
| Nickel (Ni) | 32.0–38.0% |
| Chromium (Cr) | 19.0–21.0% |
| Copper (Cu) | 3.0–4.0% |
| Molybdenum (Mo) | 2.0–3.0% |
| Niobium + Tantalum (Nb+Ta) | 8 × C min., 1.00% max. |
| Manganese (Mn) | 2.00% max. |
| Silicon (Si) | 1.00% max. |
| Carbon (C) | 0.07% max. |
| Phosphorus (P) | 0.045% max. |
| Sulfur (S) | 0.035% max. |
| Iron (Fe) | Balance |
Mechanical Properties
The tubular documents set one stabilised annealed condition across both the seamless and the welded routes, so one row set covers the page. Two details separate the documents, and both appear underneath.
| Product Form | Condition | Tensile Strength | Yield Strength, 0.2% Offset | Elongation | Hardness |
|---|---|---|---|---|---|
| Seamless pipe and tube, ASTM B729 | Stabilised annealed | ≥80 ksi (550 MPa) | ≥35 ksi (240 MPa) | 30% | Not specified |
| Welded pipe, ASTM B464 | Stabilised annealed | ≥80 ksi (551 MPa) | ≥35 ksi (241 MPa) | 30% | Not specified |
| Welded tube, ASTM B468 | Stabilised annealed | ≥80 ksi (551 MPa) | ≥35 ksi (241 MPa) | 30% | Not specified |
The seamless document prints 80 and 35 ksi against 550 and 240 MPa, while the welded documents round those figures to 551 and 241 MPa. Still, we print each standard exactly as written rather than forcing one number set.
The welded pipe document reaches NPS 6 with Schedule 5S, 10S, and 40S, and it allows Schedule 80S up to NPS 2. It calls for automatic welding without filler metal, plus a flattening test on every lot. Beyond that size, we quote the wall by agreement.
Physical Properties
The figures in this table are typical design values, and they are not acceptance limits. The alloy also stays non-magnetic, and instrument parts in acid circuits benefit.
| Property | Value |
|---|---|
| Density | Approx. 8.08 g/cm³ |
| Melting range | Approx. 1385–1443 °C |
| Modulus of elasticity | Approx. 193 GPa |
| Shear modulus | Approx. 76 GPa |
| Thermal conductivity at 20 °C | Approx. 12.3 W/m·K |
| Electrical resistivity at 20 °C | Approx. 1.08 µΩ·m |
| Specific heat at 20 °C | Approx. 500 J/kg·K |
| Thermal expansion, 25–100 °C | Approx. 14.7 µm/m·K |
| Magnetic response | Essentially non-magnetic |
| Strengthening route | Cold work only |
Standards
Four ASTM documents cover the tubular routes, and the ASME editions govern once a pressure code applies. In addition, no SAE aerospace specification reaches UNS N08020. The European and Chinese designations below serve cross-reference only.
| Standard | Product or Application |
|---|---|
| ASTM B729 / ASME SB729 | Seamless pipe and tube |
| ASTM B464 / ASME SB464 | Welded pipe |
| ASTM B468 / ASME SB468 | Welded tube |
| ASTM B366 / ASME SB366 | Factory-made wrought fittings for the same grade |
| NACE MR0175 / ISO 15156-3 | Sour service qualification for oil and gas |
| UNS N08020 | Unified Numbering System designation |
| W.Nr. 2.4660 / NiCr20CuMo | European designation |
| GB/T 15007 NS1403 | Chinese designation |
| SAE AMS | No aerospace specification covers this grade |
20Cb-3 and Carpenter 20 are trademarks of Carpenter Technology, and Incoloy is a trademark of Special Metals Corporation. We quote those names for reference only, and our deliveries follow the ASTM and ASME documents listed above.
The standard text from ASTM International settles any acceptance question.
Dimensions
Because each tubular document prints its own scope, the ranges below follow those texts rather than one house rule. For that reason, state the form and the ordered size on the enquiry.
| Product Form | Typical Supply Range |
|---|---|
| Seamless tube and pipe | Outside diameter 6–219 mm to ASTM B729 |
| Welded pipe | NPS 1/8 to 6 in Schedule 5S, 10S, and 40S to ASTM B464 |
| Welded pipe, light wall | NPS up to 2 in Schedule 80S to ASTM B464 |
| Welded tube | Outside diameter 3.2–88.9 mm to ASTM B468 |
| U-bend tube | Bent to the bundle drawing from seamless or welded stock |
| Coiled tube | Coil lengths quoted to the order |
Wall thickness runs from 0.5 mm up to 12 mm across the seamless range, and heavier wall moves to a quoted basis. Therefore, give the outside diameter and the wall on the enquiry so we price the right document.
Surface Finishes
Finish follows the operation that comes next rather than a catalogue default. In short, we agree the surface with your order.
| Surface Condition | Typical Use |
|---|---|
| Stabilised annealed and pickled | Standard delivery for acid and chloride service |
| Bright annealed | Scale-free bore for instrument and clean circuits |
| Cold drawn | Close wall control with a smoother bore and outside surface |
| Polished bore | Reduced roughness for product-contact hygienic lines |
| U-bend stress relieved | Bends annealed after forming for exchanger service |
TECHNICAL DOCUMENTATION
Download Technical Datasheet
Get detailed information including specifications, standards, dimensions and material properties.
HOW TO START
Start Your Order in 8 Simple Steps
Eight steps carry an enquiry from the first message to the delivered bundle. Therefore, send the duty and the size list first, and the rest follows.
1
Give the Medium and Grade
State the acid, its concentration, the working temperature, and the pressure class.
2
Fix the Form
Tell us whether the line needs seamless tube, welded pipe, or welded tube.
3
List the Sizes
Outside diameter, wall, and length go on the enquiry in one table.
4
Settle the Test Level
We agree hydrostatic, eddy current, or flattening checks against the standard and your specification.
5
Review the Offer
Price, lead time, and the certificate package reach you together.
6
Confirm the Order
Grade, size, inspection level, and delivery terms go on the record.
7
Run and Test the Heat
The mill takes the lot through drawing, annealing, quenching, and release testing.
8
Track the Bundle
Finally, the desk follows the shipment and mails the paperwork before it lands.
What Our Clients Say
Feedback from buyers and engineers who source nickel alloy materials from Southerly Alloy.
★★★★★
“The bundle arrived with the anneal chart attached, so the client's corrosion review closed in one session.”
★★★★★
“Seamless tube held its wall tolerance through the whole order, and the second batch matched the first.”
★★★★★
“In short, cooling coils in UNS N08020 replaced a 316L set and ran three campaigns without a leak.”
CERTIFICATIONS & QUALITY DOCUMENTATION
Certifications & Quality Documentation
Our production and inspection processes are certified to international standards, and every delivery ships with EN 10204 3.1 mill test certificates.
ISO 9001:2015
Quality Management System
PED 2014/68/EU
Pressure Equipment Directive
ASTM / ASME
Material Standards Compliance
EN 10204 3.1
Mill Test Certificates
FAQ
Frequently Asked Questions
Which ASTM specifications cover Alloy 20 pipe and tube?
ASTM B729 covers seamless pipe and tube, B464 covers welded pipe, and B468 covers welded tube.
What is the seamless size range?
Seamless tube runs from 6 to 219 mm outside diameter, with wall thickness from 0.5 up to 12 mm.
Why does welded pipe stop at NPS 6?
ASTM B464 prints its scope as NPS 6 with Schedule 5S, 10S, and 40S. Therefore, we quote larger sizes and heavier wall by agreement instead.
How does Alloy 20 tube compare with C-276 tube?
C-276 tolerates stronger acid and higher chloride levels, and it costs considerably more. Alloy 20 covers dilute acid duty at a lower price.
Which filler metal suits Alloy 20 tube welding?
ER320LR for TIG and MIG, and E320LR for stick welding. Both are low-residual grades that resist hot cracking.
What is your MOQ for Alloy 20 pipe and tube?
One length covers most stock sizes, and a short cut is enough for a trial.
What are your trade terms for Alloy 20 pipe and tube?
We quote mainly on FOB terms, and EXW or CIF follow on request.
How is the price of Alloy 20 pipe calculated?
Price follows the outside diameter, the wall, the length, and the test level. We quote per metre or per piece on request.
What is the lead time for Alloy 20 pipe and tube?
Stock sizes ship in 7-15 days, and made-to-order tube runs about 25 days.
Do you provide EN 10204 3.1 or 3.2 certificates?
Yes. Every heat ships with an EN 10204 3.1 certificate, and we arrange 3.2 endorsement on request.
REQUEST FOR QUOTATION
Need A Custom Alloy Solution?
Give us the outside diameter, the wall thickness, and the medium. We answer with price, lead time, and the certificate package in one message. Because welded pipe stops at the schedule the standard prints, state the wall you need.
A short trial length costs very little, so one tube settles the question before a plant-wide order.
