Stockist & supplier ASTM B463 · ASME SB-463
Alloy 20 Plates — ASTM B463 UNS N08020
Alloy 20 plate is a nickel-iron-chromium alloy plate designed for sulphuric acid service. Teshi Group stocks and supplies ASTM B463 / ASME SB-463 UNS N08020 plate, sheet and strip. Quotes are sent in 24–48 hours.
Also called: Alloy 20 plate, Carpenter 20 plate, 20Cb-3 plate, UNS N08020 plate
What is an Alloy 20 Plate?
Alloy 20 (UNS N08020), often sold under trade names such as Carpenter 20 or 20Cb-3, is an austenitic nickel-iron-chromium alloy with additions of molybdenum and copper, stabilised with niobium (columbium). The copper and molybdenum give resistance to hot sulphuric acid, and the high nickel resists chloride stress-corrosion cracking. Niobium stabilisation limits carbide precipitation during welding. It is used for sulphuric acid plant, pickling equipment, chemical process vessels, and synthetic rubber and pharmaceutical production.
Key features
- Stockist and supplier — sourced from nickel alloy mills; Teshi does not manufacture plate
- UNS N08020 to ASTM B463 / ASME SB-463
- Copper and molybdenum for sulphuric acid resistance
- Niobium (columbium) stabilised for welding
- Plate, sheet and strip; other sizes supplied against order
- Matching flanges and fittings manufactured by Teshi against order
Specification
| Supply | Stockist & supplier — Teshi Group, India |
|---|---|
| Standard | ASTM B463 / ASME SB-463 |
| Grade | UNS N08020 (Alloy 20) |
| Product forms | Plate 3/16 in (4.76 mm) and thicker; sheet and strip in thinner gauges; other sizes supplied against order |
| Condition | Stabilised annealed |
| Other plate grades stocked | Carbon / boiler: IS 2062 E250–E450, ASTM A36, A516 Gr 60 / 70, A537; Cr-Mo: ASTM A387 Gr 11, 12, 22, 91; stainless: ASTM A240 304 / 304L / 304H, 309S, 310S, 316 / 316L / 316H / 316Ti, 317L, 321 / 321H, 347 / 347H, 410, 430, 904L, 254 SMO; duplex S31803 / S32205; super duplex S32750 / S32760; nickel: Monel 400 (B127), Inconel 600 (B168), Inconel 625 (B443), Incoloy 800 / 800H / 800HT (B409), Incoloy 825 (B424), Hastelloy C276 / C22 (B575), Hastelloy B2 / B3 (B333), Alloy 20 (B463), Nickel 200 / 201 (B162); titanium Gr 1, 2, 5, 7, 12 (B265); Cu-Ni 90/10, 70/30 (B171) |
| Testing | Chemical and tensile tests per B463 |
| Documents | Mill test certificate to EN 10204 3.1; EN 10204 3.2 / third-party inspection when the order specifies |
Applications
- Sulphuric acid plant
- Pickling tanks and racks
- Chemical process vessels
- Synthetic rubber and plastics production
- Pharmaceutical equipment
Chemical composition — Alloy 20 (ASTM B463)
| UNS | C | Mn | P | S | Si | Cr | Ni | Mo | Cu | Fe |
|---|---|---|---|---|---|---|---|---|---|---|
| N08020 | 0.07 | 2.00 | 0.045 | 0.035 | 1.00 | 19.0–21.0 | 32.0–38.0 | 2.00–3.00 | 3.0–4.0 | Balance |
Maximum unless a range is shown; % by weight. Niobium (columbium) stabilisation also applies per ASTM B463.
Mechanical properties
| UNS | Tensile, min (MPa) | Yield 0.2%, min (MPa) | Elongation, min (%) |
|---|---|---|---|
| N08020 | 551 | 241 | 30 |
Per ASTM B463.
Technical data sheets
Dimensions & weights
FAQ
Alloy 20 Plate: common questions
Is Alloy 20 a stainless steel?
Alloy 20 has over 32% nickel and is covered by ASTM B463 as a nickel alloy, though it is sometimes called a stainless steel. Its UNS number is N08020.
Why is Alloy 20 used for sulphuric acid?
Its copper (3–4%), molybdenum (2–3%) and high nickel give resistance to sulphuric acid across a range of concentrations and temperatures. It also resists chloride stress-corrosion cracking.
What does 20Cb-3 mean?
It is a trade name for UNS N08020. 'Cb' refers to columbium (niobium), which stabilises the alloy against carbide precipitation. Order by UNS number to ASTM B463.
Does Teshi manufacture Alloy 20 plate?
No. Teshi Group is a stockist and supplier of Alloy 20 Plate, sourced from established mills and supplied with the original mill test certificate. Teshi is an OEM manufacturer of flanges, fittings, fasteners, valves and custom fabrications, which can be ordered with it.
Need a size or grade not listed here?
We source against your specification from approved mills, with mill test certificates and inspection before dispatch.
Send us your specificationTraceability
From mill heat to your site
- 01
Approved mill material
Received against the mill certificate; heat number registered.
- 02
Forging & machining
Heat number carried through every stage in our Indian works.
- 03
PMI, dimensional & NDT
Every lot inspected to the governing standard; TPI witness on request.
- 04
Stamped & certified dispatch
Hard-stamped pieces with EN 10204 3.1 / 3.2 certificates.
Quick RFQ
Quote for Alloy 20 Plate in 24–48 hours
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