Alloy 28 Plates | UNS N08028 Sour-Service & Acid-Resistant Plates for Chemical, Oil & Gas, Marine, Pharma & Power
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A sour‑gas gathering station on a coastal cluster had already replaced carbon steel spools with 316L and 904L in its wet H₂S and chlorides‑laden manifolds, yet every turnaround the UT readings told the same story: grooving around welds, pitting in dead legs and worryingly fast wall‑loss in the phosphoric‑acid injection loops. When the integrity team redesigned the most punished header plates, spool sections and absorber internals in Alloy 28 Plates (UNS N08028, WNR 1.4563), they switched to a nickel–iron–chromium alloy with around 30–32% Ni, 26–28% Cr, 3–4% Mo and 0.6–1.4% Cu which data show has excellent resistance to both oxidising and reducing acids, stress‑corrosion cracking and localised attack in sulphuric, phosphoric and chloride‑bearing service, and inspection reports over several campaigns confirmed that in areas where 316L and even 904L had struggled, the new plates remained essentially unaffected.
Alloy 28 (also marketed as Sanicro 28 and Incoloy 28) is an austenitic nickel–iron–chromium alloy with additions of molybdenum and copper, developed specifically for aggressive wet‑process phosphoric acid and other strong acid environments. The alloy is designated UNS N08028 and WNR 1.4563, and plate and sheet are commonly supplied under standards such as ASTM B709 for Alloy 28 plate and related specifications for wrought corrosion‑resistant alloys. Published data show tensile strengths typically around 500–750 MPa with yield strengths from about 220–250 MPa and elongation around 35–45% depending on product form, with Brinell hardness roughly 180 HB and a pitting resistance equivalent number (PREN) around 39, indicating strong resistance to chloride pitting and crevice corrosion.
For procurement heads, corrosion and mechanical engineers, fabricators, OEMs and hardware or industrial supply stores serving chemical, oil & gas, marine, pharma and power‑generation projects, Alloy 28 plates occupy a strategic space: more corrosion‑resistant than 316L and 904L in many contaminated acid and chloride environments, yet often more cost‑effective than fully nickel‑base alloys. Studies and datasheets highlight that Alloy 28 has very good resistance to sulphuric and phosphoric acid, including chloride‑contaminated solutions, plus excellent resistance to stress‑corrosion cracking in chloride‑bearing and H₂S‑containing conditions, making it attractive for phosphoric acid units, sour‑gas systems, FGD equipment, seawater‑cooled exchangers and nuclear fuel or pollution‑control services.
Aurico Alloys LLP can support these demanding uses as an affordable, authentic Alloy 28 Plates supplier, manufacturer and stockist in India with exports abroad, providing plate aligned with UNS N08028 / WNR 1.4563 chemistry and ASTM B709 mechanical requirements with EN 10204 certification for EPC, OEM and MRO customers worldwide.
High-quality Alloy 28 Plates ready for industrial use.
Specification Overview
| Supplier & Role | Aurico Alloys LLP – Alloy 28 Plates supplier, stockist, exporter in India to abroad |
|---|---|
| Alloy Description | Nickel–iron–chromium super austenitic alloy with molybdenum and copper, optimised for strong acids and chloride‑bearing service |
| UNS / Werkstoff | UNS N08028, WNR 1.4563; often sold as Alloy 28 or Sanicro 28 |
| Main Plate Standards | ASTM B709 for Alloy 28 plate and sheet; suppliers also list Alloy 28 products alongside other corrosion‑resistant alloys under similar plate specifications |
| Thickness Range | 4.75 mm – 150 mm |
| Maximum Recommended Service Temperature | Datasheets for UR/Alloy 28 variants commonly cite maximum service temperatures around 450–460 °C for corrosion‑limited service in aggressive media |
| Corrosion Focus | Excellent resistance to sulphuric and phosphoric acid, very good resistance to hydrochloric and mixed acids, and strong resistance to pitting, crevice corrosion and stress‑corrosion cracking in chloride and H₂S environments |
UNS & Equivalent Grades
| Property | Value |
|---|---|
| UNS number | N08028 |
| Werkstoff / EN number | 1.4563 |
| EN designation | X1NiCrMoCu31-27-4 |
| Density | 8.00 g/cm3 |
| Modulus of elasticity (20 °C) | 195 GPa |
| Thermal conductivity (20 °C) | 10 W/m·°C |
| Electrical resistivity (20 °C) | 0.99 µΩ·m |
| Specific heat (20 °C) | 460 J/kg·°C |
| Coefficient of expansion (30-100 °C) | 15 µm/m·°C |
| Magnetic permeability (relative) | 1.003 (datasheet prints this as an approximate value) |
| Plate, sheet and strip specification | ASTM B709 |
Identifiers and physical constants for Alloy 28. A dash means no such designation is published for this grade.
Stock & Product Availability
As an Alloy 28 Plates stockist, Aurico Alloys LLP can supply plate and sheet dimensions suited to absorber and scrubber shells, phosphoric‑acid heat‑exchanger plates, tube sheets, channel covers, manifolds, seawater‑cooled equipment and structural panels for chemical, oil & gas, marine, pharma and power projects, in line with thickness and width ranges typically provided under ASTM B709. Material is generally delivered in solution‑annealed condition to secure optimum corrosion resistance and mechanical properties, and services such as cut‑to‑size, contour cutting and prepared edges help fabricators and OEMs reduce machining time while retaining full heat and batch traceability.
Chemical Composition
| Element | Min (%) | Max (%) |
|---|---|---|
| Carbon (C) | — | 0.020 |
| Silicon (Si) | — | 0.70 |
| Manganese (Mn) | — | 2.00 |
| Phosphorus (P) | — | 0.030 |
| Sulfur (S) | — | 0.010 |
| Chromium (Cr) | 26.0 | 28.0 |
| Molybdenum (Mo) | 3.0 | 4.0 |
| Nickel (Ni) | 30.0 | 32.0 |
| Copper (Cu) | 0.70 | 1.50 |
| Nitrogen (N) | — | 0.10 |
Composition limits for Alloy 28. These are specification limits for the grade, not measured values for a lot; the mill test certificate supplied with your order states the actual analysis.
Mechanical & Physical Properties
| Property (Room Temperature, Typical Plate) | Typical Value – Alloy 28 |
|---|---|
| Tensile Strength (UTS) | ≈570–650 MPa typical; some plate datasheets list minimum 500–650 MPa ranges |
| Yield Strength (0.2% offset) | ≈220–250 MPa typical; some sources cite minimum 220–250 MPa |
| Elongation | ≈35–45% in representative data |
| Brinell Hardness | ≈180 HB typical, with some product limits at ≤230 HB |
| Melting Range | Solidus around 1370 °C and liquidus around 1420 °C in generic N08028 data |
| Pitting Resistance (PREN) | Indicative PREN values around 39 based on composition, reflecting high pitting resistance |
| Maximum Corrosion Service Temperature | Datasheets for Sanicro/UR 28 variants often recommend maximum corrosion‑limited service temperatures around 450–460 °C in aggressive media |
Applications & Benefits
- Chemical & Oil & Gas: Alloy 28 plates are used in wet‑process phosphoric acid plants, sulphuric‑acid systems, urea and fertiliser equipment, pickling lines and sour‑gas manifolds where they resist general corrosion, SCC and localised attack in mixed acids and H₂S‑containing environments better than 316L or 904L.
- Marine & Power Generation: In seawater‑cooled heat exchangers, FGD systems and coastal power‑plant condensers, UNS N08028 / 1.4563 plates offer high resistance to chloride‑induced pitting and crevice corrosion and good resistance in polluted seawater and acid condensates.
- Pharma & High‑Purity Plant: Alloy 28 can be selected for phosphoric‑ and sulphuric‑acid‑related intermediates, mother‑liquor handling and scrubber systems where both strong acid resistance and robust chloride SCC resistance are needed under tight cleanliness expectations.
FAQ & Search Trends
Global Export Destinations
We ship worldwide from Mumbai. See every destination we export to on our export markets page.
Domestic Supply Network
We deliver across India from our Mumbai stockyard. See every city we supply on our supply locations page.
Conclusion
Alloy 28 Plates from Aurico Alloys LLP, supplied to UNS N08028 / WNR 1.4563 chemistry limits and ASTM B709 mechanical property expectations, give chemical, oil & gas, marine, pharma and power‑generation users a super austenitic plate option that combines strong resistance to sulphuric, phosphoric and chloride‑bearing media with robust SCC and pitting performance at elevated temperatures are your most critical sour‑gas, acid and seawater‑exposed assets still relying on less resistant materials instead of optimised Alloy 28 plates?