Alloy 20 Plates | UNS N08020 Sulfuric Acid Workhorse for Process, Marine & Power Assets
Table of Contents:
A large fertiliser and speciality‑chemicals complex had already upgraded several storage and transfer lines from 316L to rubber‑lined carbon steel to handle mixed sulfuric, phosphoric and chloride‑bearing streams, but liners blistered, weld seams failed and tank repairs were eating into shutdown budgets every year. When the reliability team redesigned key tank bottoms, nozzles, agitator covers and acid header spools in Alloy 20 Plates (UNS N08020), they moved from 304/316L with minimum tensile strengths around 515 MPa into plate with typical minimum tensile around 551 MPa and yield around 241 MPa, backed by corrosion data showing very good resistance to sulfuric, phosphoric, nitric acids and chloride salt solutions while strongly resisting pitting and chloride stress‑corrosion cracking, and inspection records over successive campaigns confirmed that metal loss and leak incidents had dropped dramatically.
A large fertiliser and speciality‑chemicals complex had already upgraded several storage and transfer lines from 316L to rubber‑lined carbon steel to handle mixed sulfuric, phosphoric and chloride‑bearing streams, but liners blistered, weld seams failed and tank repairs were eating into shutdown budgets every year. When the reliability team redesigned key tank bottoms, nozzles, agitator covers and acid header spools in Alloy 20 Plates (UNS N08020), they moved from 304/316L with minimum tensile strengths around 515 MPa into plate with typical minimum tensile around 551 MPa and yield around 241 MPa, backed by corrosion data showing very good resistance to sulfuric, phosphoric, nitric acids and chloride salt solutions while strongly resisting pitting and chloride stress‑corrosion cracking, and inspection records over successive campaigns confirmed that metal loss and leak incidents had dropped dramatically.
High-quality Alloy 20 Plates ready for industrial use.
Specification Overview
| Supplier & Role | Aurico Alloys LLP – Alloy 20 Plates supplier, stockist, exporter in India to abroad |
|---|---|
| Alloy Description | Nickel–iron–chromium alloy with copper, molybdenum and niobium, designed specifically for sulfuric acid and aggressive chemical service |
| UNS / Werkstoff | UNS N08020, WNR 2.4660; often marketed as Alloy 20, Carpenter 20 or Incoloy 20 |
| Main Plate Standards | ASTM B463 / ASME SB‑463 for rolled Alloy 20 plate, sheet and strip, supplying material in stabilised‑annealed condition |
| Thickness Range | 4.75 mm – 150 mm |
| Corrosion Focus | Very good resistance to sulfuric acid; suitable resistance to phosphoric, nitric acids and aqueous salt solutions; strong resistance to pitting, crevice attack and chloride stress‑corrosion cracking compared with 304/316L |
Equivalent Grades & Standards
| Property | Value |
|---|---|
| UNS number | N08020 |
| Werkstoff / EN number | 2.4660 |
| EN designation | — |
| Density | 8.08 g/cm3 |
| Plate, sheet and strip specification | ASTM B463 |
Identifiers and physical constants for Alloy 20. A dash means no such designation is published for this grade.
Stock & Product Availability
As an Alloy 20 Plates stockist, Aurico Alloys LLP can supply plates in thicknesses suitable for acid storage tanks, reactor and scrubber shells, tube sheets, channel covers, structural panels and acid handling equipment in chemical, oil & gas, marine, pharma and power applications, within the dimensional ranges specified in ASTM B463 for rolled plates and sheets. Material is normally delivered in stabilised‑annealed condition to achieve the required corrosion performance and mechanical properties, and cut‑to‑size, profile cutting and edge preparation help fabricators and OEMs minimise machining and weld preparation time while preserving heat and batch traceability.
Chemical Composition
| Element | Min (%) | Max (%) |
|---|---|---|
| Carbon (C) | — | 0.07 |
| Manganese (Mn) | — | 2.00 |
| Phosphorus (P) | — | 0.045 |
| Sulfur (S) | — | 0.035 |
| Silicon (Si) | — | 1.00 |
| Chromium (Cr) | 19.0 | 21.0 |
| Nickel (Ni) | 32.0 | 38.0 |
| Molybdenum (Mo) | 2.00 | 3.00 |
| Copper (Cu) | 3.00 | 4.00 |
| Niobium (Nb) | — | 1.00 (8×C min) |
Composition limits for Alloy 20. 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 20 |
|---|---|
| Ultimate Tensile Strength | Minimum ≈80 ksi (≈551 MPa) |
| Yield Strength (0.2% offset) | Minimum ≈35 ksi (≈241 MPa) |
| Elongation | Typical ≈30% |
| Hardness | Maximum around 217 HB in many product tables |
| Melting Range | Approximately 1385–1443 °C in supplier data |
| Corrosion Behaviour | Very good resistance to sulfuric acid, plus suitable resistance in phosphoric and nitric acids and salt solutions; strong resistance to pitting, crevice corrosion and chloride SCC compared with 304/316L |
Applications & Benefits
- Chemical & Oil & Gas: Alloy 20 plates are used in sulfuric‑acid pickling equipment, acid storage tanks, agitator covers, reactor linings, heat‑exchanger plates and piping components in chemical and petrochemical plants, especially where sulfuric acid and mixed chloride/acid environments have defeated conventional stainless steels.
- Marine & Power Generation: In coastal power plants, offshore topsides and marine chemical dosing systems, UNS N08020 plates provide corrosion resistance against acid condensates, polluted seawater and salt‑laden atmospheres while maintaining adequate mechanical strength for structural and pressure‑retaining parts.
- Pharma & Food Industries: Alloy 20 plate is used in pharmaceutical and food‑grade chemical systems, including production of certain preservatives and intermediates, owing to its resistance in phosphoric and nitric acid plus chloride‑bearing media and its ability to be supplied with full documentation.
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 20 Plates from Aurico Alloys LLP, supplied to UNS N08020 / WNR 2.4660 chemistry limits and ASTM B463 mechanical property requirements, give chemical, oil & gas, marine, pharma and power‑generation users a sulfuric‑acid‑optimised, chloride‑resistant plate option that bridges the gap between 316L stainless and high‑nickel alloys in both performance and cost are your most critical acid tanks, scrubbers, manifolds and structural plates still relying on less suitable materials instead of optimised Alloy 20 plates?