Alloy 20 / UNS N08020


Alloy 20 is an iron-base, austenitic alloy with excellent corrosion resistance to a number of different media and proves to be useful in a number of applications such as flue-gas desulfurization, chemical processing, food processing and storage as well as pharmaceutical applications to name a few. Application of the alloy could result in real cost savings when carefully compared to higher-cost alloys to determine if the necessary resistance is obtained in the chosen media. Applications are limited to a maximum temperature of 1000°F per ASME.

Resistance to Corrosion

Resistance to sulfuric acid is particularly exceptional but the alloy shows useful resistance in phosphoric acid, nitric acid as well as in chloride environments. Alloy 20 is an excellent option when chloride stress corrosion cracking is an issue and resists pitting and crevice corrosion.

Fabrication and Heat Treatment

Alloy 20 can be formed by either hot-working or cold-work using traditional methods. Hot forged material should be heated between 2100°F and 2250°F with careful temperature control insuring that the material not fall below 1800°F prior to forging. After hot working, anneal the material by heating to 1725°F and 1850°F for a minimum of 30 minutes per inch of thickness followed by water quench.

When stress relieving is desired, heat to a temperature below 1000°F followed by water quench after the desired time at temperature
has been established. Annealing Alloy 20 should be between 1725°F and 1850°F for 30 minutes at temperature per inch of thickness. A lower hardness can be obtained by heating to 2100°F but his may have a negative effect on the stabilization of the alloy.

Welding Alloy 20 is commonly performed via, TIG, MIG as well as submerged arc welding (SAW) using either the matching filler metal, ER320LR for TIG and MIG and E320LR for SAW. When welding to dissimilar alloys such as 316 or higher alloys such as C276 and Alloy 22, AWS ERNiCrMo-3 can be used for TIG and MIG while using ENiCrMo-3 for SAW.


N08020, ASTM B473, ASME SB473, COLD DRAWN, HOT FINISHED, EN 10204-3.1, ASME SA 240, ASME SB 366, ASME SB 463, ASTM A 240, ASTM B 366, ASTM B 463,

Common Trade Names

INCOLOY® alloy 20, Carpenter® 20 alloy, 20CB-3®

INCOLOY® is a registered trademark of the Special Metals Corporation group of companies.

Carpenter® and 20CB-3® are registered trademarks of Carpenter.

Data Sheet

Chemical Composition:

Element Nickel Chromium Molybdenum Copper Columbium + Tantalum Carbon Iron
Avg. Nominal % 32.5 - 35.0 19.0 - 21.0 2.0 - 3.0 3.0 - 4.0 1.00 Max 0.06 Max Balance


Alloy 20 Plate

Alloy 20 Plate

Alloy 20 Fittings

Alloy 20 Fittings

Alloy 20 Tubing

Alloy 20 Tubing

Alloy 20 Pipe

Alloy 20 Pipe

Alloy 20 Bar

Alloy 20 Bar

Alloy 20 Sheet

Alloy 20 Sheet

Alloy 20 Fasteners

Alloy 20 Fasteners

Alloy 20 Flanges

Alloy 20 Flanges

Alloy 20 Welding Products

Alloy 20 Welding Products

Alloy 20 Coil

Alloy 20 Coil

Alloy 20 Welded Components

Alloy 20 Welding

Alloy 20 Machined Parts

Alloy 20 Machining

Alloy 20 Forgings

Alloy 20 Forgings

Alloy 20 Custom Profiles

Alloy 20 Custom Profiles

Alloy 20 Plate Shapes

Alloy 20 Plate Shapes