Incoloy 028, also known as Alloy 28, Sanicro 28, UNS N08028 or EN 1.4563, is a high-alloy austenitic nickel-iron-chromium-molybdenum-copper stainless steel built for acid service beyond standard 316L or 904L grades. XTD stocks this grade within its incoloy seamless pipe range, supplying seamless pipe manufactured to ASTM B668 for sulfuric acid, phosphoric acid, and chloride-heavy applications across chemical processing and oil and gas industries.
Incoloy 028 Seamless Pipe Manufacturer in China
Zhejiang Xintongda Special Steel (XTD) has been manufacturing nickel alloy pipe from its Songyang County facility in Zhejiang for over four decades, holding ISO 9001, ISO 14001, and ISO 45001 certification. Annual output now exceeds 25,000 tons. Stock orders ship within a week, custom production runs take 15 to 60 days, with a minimum order quantity of 200 kg. Stocked sizes carry no MOQ.
UNS N08028 pipe, commercially known as Incoloy 028, is a high-alloy austenitic nickel-iron-chromium stainless steel built for acid and chloride service. Nominal composition runs around 31% nickel, 27% chromium, 3.5% molybdenum, and 1% copper, giving the alloy resistance across sulfuric and phosphoric acid environments that standard austenitic grades cannot match. Buyers researching this incoloy pipe grade typically land on it after standard 316L or 904L options fail under concentrated acid duty.
Before ordering, note these designations for the material: UNS N08028, W.Nr. 1.4563, EN name X1NiCrMoCu31-27-4, ISO 4563-080-28-I, SS 2584, and AFNOR Z1NCDU31-27-03. Alloy 28 and Sanicro 28 are both trade names that describe the same material. The main standards for this seamless pipe and tube are ASTM B668 and EN 10216-5.
Product Specifications
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Standard
ASTM B668, EN 10216-5
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UNS Number
N08028
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W.Nr.
1.4563
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OD, Wall and Length
On request
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Alloy 028 Seamless Pipe Manufacturing Process
Production typically starts with hot piercing to form the initial hollow shell, followed by cold pilgering or drawing to reduce the diameter to the final dimension. Each length then goes through solution annealing to restore the stable austenitic structure before pickling and surface finishing. Non-destructive testing closes out the run. For the complete production sequence, visit our manufacturing process page.
Characteristics of Incoloy 028 Seamless Pipe
UNS N08028 pipe performs well in environments where sulfuric and phosphoric acids rapidly attack most stainless grades. The figures below follow the Alleima Sanicro 28 datasheet.
- Chemical Composition (wt%): C ≤0.020, Si ≤0.7, Mn ≤2.0, P ≤0.020, S ≤0.010, Cr 27, Ni 31, Mo 3.5, Cu 1.0, N ≤0.1, Fe balance.
- Corrosion Resistance: The alloy holds up in strong sulfuric and phosphoric acid concentrations. Stress-corrosion cracking resistance stays high even in chloride-bearing media, and pitting and crevice attack remain limited compared to standard austenitic grades.
- Mechanical properties (solution annealed, wall ≤20 mm): proof strength Rp0.2 ≥220 MPa, Rp1.0 ≥250 MPa, tensile strength 550 to 750 MPa, elongation ≥40%, hardness ≤90 HRB, density 8.0 g/cm³. For wall thickness above 20 mm, minimum Rp0.2 drops to 200 MPa and Rp1.0 to 230 MPa.
- Austenitic Structure: Low carbon content, capped at 0.020%, keeps the microstructure resistant to sensitization during welding. XTD supplies every length in the solution-annealed condition.
- Workability: The alloy forms and welds well using matched filler metal, and it holds dimensional accuracy through both hot and cold processing stages.
ASTM B668 Nickel Alloy Seamless Pipe Tolerance
UNS N08028 pipe follows the permissible variation tables set out in ASTM B829, the general specification governing dimensional tolerance for seamless nickel alloy pipe and tube under ASTM B668.
| Nominal Outside Diameter | Outside Diameter Tolerance | Wall Thickness Tolerance (% of nominal) |
| Over 10 mm to 16 mm | ±0.13 mm | ±15.0% |
| 16 mm to 38 mm | ±0.19 mm | ±10.0% |
| Over 38 mm to 76 mm | ±0.25 mm | ±10.0% |
| Over 76 mm to 114 mm | ±0.38 mm | ±10.0% |
| Over 114 mm to 152 mm | ±0.51 mm | ±12.5% |
| Over 152 mm to 168 mm | ±0.64 mm | ±12.5% |
| Over 168 mm to 219 mm | ±0.79 mm | ±12.5% |
| Over 219 mm to 356 mm | +1.57 mm / -0.79 mm | +15.0% / -12.5% |
| Over 356 mm to 610 mm | +3.18 mm / -0.79 mm | +15.0% / -12.5% |
For cut lengths beyond 7.3 m, an additional over-tolerance of 3.2 mm applies for every 3 m or fraction thereof, capped at 12.7 mm total.
Incoloy 028 (UNS N08028) Equivalent Material
UNS N08028 carries parallel designations across international standards bodies, all describing the same nickel-iron-chromium-molybdenum-copper chemistry under different national numbering systems and mill trade names.
| Standard Body | Designation |
| UNS | N08028 |
| Werkstoff Number (EN) | 1.4563 |
| EN Name | X1NiCrMoCu31-27-4 |
| ISO | 4563-080-28-I |
| Swedish Standard (SS) | 2584 |
| AFNOR (France) | Z1NCDU31-27-03 |
| Trade Names | Alloy 28, Sanicro 28 |
Difference Between Incoloy 825 and Incoloy 028 (Alloy 28)
Incoloy 825 and Incoloy 028 both resist sulfuric and phosphoric acid attack, but their nickel-iron-chromium chemistry, copper content, and corrosion niche diverge across several key alloying elements.
| Property | Incoloy 825 (UNS N08825) | Incoloy 028 / Alloy 28 (UNS N08028) |
| Designation | UNS N08825 / W.Nr. 2.4858 | UNS N08028 / W.Nr. 1.4563 |
| Nickel | 38.0-46.0% | ~31% |
| Chromium | 19.5-23.5% | ~27% |
| Molybdenum | 2.5-3.5% | 3.5% |
| Copper | 1.5-3.0% | 1.0% |
| Titanium | 0.6-1.2% (stabilizing element) | Not added; low carbon controls sensitization |
| Carbon | 0.05% max | 0.020% max |
| Tensile strength | 772 MPa typical (annealed tube) | 550-750 MPa (ASTM B668 spec range) |
| Yield strength (0.2%) | 441 MPa typical (annealed tube) | 220 MPa minimum (ASTM B668 spec) |
| Corrosion focus | Sulfuric acid, phosphoric acid, sour gas, seawater, nitric acid | Sulfuric acid, phosphoric acid (flagship niche) |
The mechanical figures above sit on different footing. Alloy 28 values are ASTM B668 specification minima, while Incoloy 825 values are typical results from annealed tubing, so the two rows are not a stress-for-stress comparison. Composition marks the real distinction. Grade 825 carries more copper and nickel, while 028 carries more chromium for its acid-service niche. Buyers weighing both options can review the incoloy 825 seamless pipe range alongside this grade before finalizing a specification.
Material Certification and Inspection Package
Every Incoloy 028 pipe order ships with a documented inspection trail, giving buyers traceability from raw material through final dispatch.
- EN 10204 3.1 / 3.1B / 3.2 Material Test Certificates
- Raw Materials Certificate
- 100% Radiography Test Report
- 100% PMI (Positive Material Identification)
- Heat Treatment Charts
- Third Party Inspection Report
- Surface Roughness and Size Measurement Records
- Manufacturer Test Certificate (impact, flatten, spin, curve, hardness, intergranular corrosion, pitting corrosion tests)
- Laboratory Test Certificate from a Government-Approved Lab
Applications of Incoloy 028 Pipe
Incoloy 028 pipe earns its place in plants where acid concentration rules out standard stainless.
Phosphoric Acid and Fertiliser Plants
The alloy handles piping and acid-transfer lines in wet-process phosphoric acid production, particularly in the concentration and evaporation stages, where corrosion runs worst.
Sulfuric Acid and Chemical Processing
Acid transfer and process piping in sulfuric-acid and mixed-acid plants rely on the same resistance profile. Read more about our work in chemical processing.
Oil and Gas
Production tubing and casing see service in sour, H2S-bearing wells and chloride-heavy downhole environments. See our oil and gas application page.
Seawater and Desalination
Piping and brine lines that carry seawater benefit from the resistance of the alloy to pitting and crevice corrosion. See our desalination application page.
Frequently Asked Questions
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What is Incoloy 028 (UNS N08028)?
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Can Xintongda Special Steel supply custom sizes of Incoloy 028 seamless pipe?Zhejiang Xintongda Special Steel Manufacturing Co., Ltd produces Incoloy 028 pipe custom size orders against project drawings, adjusting outer diameter, wall thickness, and cut length to match specifications. Standard stock sizes ship within a week, while custom runs take 15 to 60 days, depending on volume. Share your required dimensions and specification standard, and the sales team will confirm feasibility and lead time.
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Where can I buy Incoloy 028 pipe?Zhejiang Xintongda Special Steel supplies Incoloy 028 pipe directly from its Songyang, Zhejiang facility, shipping stock sizes worldwide and producing custom orders to specification. To buy, submit your required dimensions, standard, and quantity through the quote request form. The sales team reviews each inquiry and responds with price and lead time based on order volume.
- Alloy 028 Seamless Pipe Manufacturing Process
- Characteristics of Incoloy 028 Seamless Pipe
- ASTM B668 Nickel Alloy Seamless Pipe Tolerance
- Incoloy 028 (UNS N08028) Equivalent Material
- Difference Between Incoloy 825 and Incoloy 028 (Alloy 28)
- Material Certification and Inspection Package
- Applications of Incoloy 028 Pipe
- Frequently Asked Questions