Alloy 20 (Carpenter 20Cb3, UNS N08020)

Nickel-Iron-Chromium Alloy with Great Resistance to Chloride Stress Corrosion Cracking and Many Acidic Environments.

Alloy 20 UNS N08020Carpenter 20Cb3 2.4660 ASTM B462 / B468 / B479 / B473 / B 463

What is Alloy 20

Alloy 20 (UNS N08020), also known as Carpenter® 20, is a strong nickel-iron-chromium alloy. Well-known for its great resistance to chloride stress corrosion cracking and many acidic environments.

Carpenter 20 alloy works well in chemical processing areas. Its strength, durability, and resistance to harsh substances make it a top choice. Additionally, this material’s versatility extends to applications requiring stainless steel-like characteristics, but with superior corrosion resistance.

Compared with conventional stainless steels, Alloy 20 offers enhanced resistance to pitting, crevice corrosion, chloride stress corrosion cracking, and chemical attack. It is widely used in chemical processing, petrochemical, pharmaceutical, food processing, and pollution control applications.

Chemical Composition (%)

Nickel (Ni)	32.0 – 38.0
Chromium (Cr)	19.0 – 21.0
Iron (Fe)	Balance
Copper (Cu)	3.0 – 4.0
Molybdenum (Mo)	2.0 – 3.0
Manganese (Mn)	≤ 2.0
Silicon (Si)	≤ 1.0
Carbon (C)	≤ 0.07

Mechanical Properties

Tensile Strength	≥ 551 MPa
Yield Strength	≥ 241 MPa
Elongation	≥ 30%
Hardness	≤ 217 HB
Condition	Annealed

Physical Properties

Density	8.08 g/cm³
Melting Range	1357–1430°C
Thermal Conductivity	11.5 W/m·K
Specific Heat	500 J/kg·K
Elastic Modulus	195 GPa

Product Forms & Standards

Seamless Pipe	ASTM B729
Seamless Tube	ASTM B729
Welded Pipe	From ASTM B463 Plate (Fabricated)
Welded Tube	From ASTM B463 Plate (Fabricated)
Plate / Sheet	ASTM B463
Bar / Rod	ASTM B473
Forgings	ASTM B462
Fittings	ASTM B366
Flanges	ASTM B462

Typical Applications of Alloy 20

Chemical Processing

Reactors, storage tanks and process piping systems.

Heat Exchangers

Corrosion-resistant tubing and shell equipment.

Petrochemical Industry

Equipment exposed to acidic and corrosive media.

Pharmaceutical Plants

High purity and corrosion-resistant production systems.

Food Processing

Acidic product handling and storage systems.

Pollution Control

Scrubbers and chemical treatment units.

Available Alloy 20 Products

Alloy 20 Pipe

Seamless and welded pipe.

Alloy 20 Tube

Heat exchanger and instrumentation tubing.

Alloy 20 Bar

Round bar, flat bar and forged bar.

Alloy 20 Plate

Plate, sheet and strip products.

Alloy 20 Flanges

Weld neck, blind and slip-on flanges.

Alloy 20 Fittings

Elbows, tees, reducers and caps.