Alloy 20 Stainless Steel

Alloy 20 (UNS N08020) is an austenitic, nickel-iron-chromium based super alloy with additions of Copper and Molybdenum which provide resistance to hostile environments, pitting, and crevice corrosion. It is also stabilized with Columbium to minimize carbide precipitation during welding. Alloy 20 appears to fall between both the stainless and nickel categories as it contains characteristics of both. It was designed for maximum resistance to acid attack and demonstrates superior resistance to stress-corrosion cracking in boiling 20% to 40% sulfuric acid, and also has excellent general corrosion resistance to sulfuric acid and to chloride stress corrosion cracking. Alloy 20 has good mechanical properties at both ambient and elevated temperatures, up to approximately 930°F (500°C) and is readily fabricated by usual industrial processes.

Specifications

	Standard	Alloy 20
1	UNS	N08020
2	Werkstoff Nr.	2.4660

Chemical Properties:

TYPE	C	Cr	Cu	Fe	Mn	Mo	Ni	P	Si	S	Nb (Cb)
Alloy 20 UNS N08020	0.07 max	min: 19.00 max: 21.00	min: 3.00 max: 4.00	Balance	2.00 max	min: 2.00 max: 3.00	min: 32.00 max: 38.00	0.045 max	1.00 max	0.035 max	8 XC min 1.00 max

Mechanical Properties:

Stabilized-Annealed Condition
Product Form	Tensile Strength, ksi (min)	Yield Strength, 0.2% offset ksi (min)	Elongation % (min)	Reduction of Area % (min)	Hardness Brinell (max)	Hardness Rockwell B (max)
Plate, Sheet	80	35	30	—	217	95
Bar	80	35	30	50	—	—

 

Density	8.1 g/cm3
Melting Point	1443 °C (2430 °F)

 

Features

• Superior corrosion, pitting and crevice resistance
• Contains Niobium for stabilization against sensitization and resultant intergranular corrosion
• Excellent mechanical properties and fabricability
• Minimal carbide precipitation during welding

Applications
Due to its high resistance to corrosion, Alloy 20 is used in chemical processing, food production, pharmaceutical, power generation and plastics applications. Valves, pumps and pressure systems are some of the most popular components where Alloy 20 is employed.