UNS Number N08020

Incoloy Alloy 20 is a nickel-iron-chromium austenitic alloy that was developed for maximum resistance to acid attack, specifically sulfuric acid. This superalloy has excellent resistance to general corrosion, pitting, and crevice corrosion in chemicals containing chlorides and sulfuric, phosphoric, and nitric acids. It also contains niobium for stabilization against sensitization and resultant intergranular corrosion. Carpenter 20 combines excellent corrosion resistance with elevated mechanical properties and relatively easy fabrication. Although originally designed for use in sulfuric acid related industries, Alloy 20 is now a popular choice for a wide variety of industries including the chemical, food, pharmaceutical, and plastics industries. In addition, this superalloy is used in heat exchangers, mixing tanks, metal cleaning and pickling equipment, and piping.

Available Forms of Alloy 20 at Rooplaxmi Steels:

•           Sheet
•           Plate
•           Bar
•           Pipe & Tube (welded & seamless)
•           Fittings
•           Wire

Characteristics of Alloy 20:

•           Excellent general corrosion resistance to sulfuric acid
•           Excellent resistance to chloride stress corrosion cracking
•           Excellent mechanical properties and fabricability
•           Minimal carbide precipitation during welding
•           Excels in resisting corrosion to hot sulfuric acids

Alloy 20 Chemical Composition, %:

Ni	Fe	Cr	Cu	Mo	Nb	C	Mn
32.0-38.0	Balance	19.0-21.0	3.0-4.0	2.0-3.0	8XC-1.0 max	0.07 max	2.0 max

 

P	S	Si
0.045 max	0.035 max	1.0 max

 

Application of Alloy 20:

•           Synthetic rubber manufacturing equipment
•           Processing of pharmaceuticals, plastics and organic and heavy chemicals
•           Tanks, piping, heat exchangers, pumps, valves, and other process equipment
•           Acid cleaning and pickling equipment
•           Chemical process piping, reactor vessels
•           Bubble caps
•           Petrochemical process equipment
•           Food and dye production

Machining and Fabrication with Alloy 20:

 

Alloy 20 ASTM Specification:

Pipe Smls	Pipe Welded	Tube Smls	Tube Welded	Sheet / Plate	Bar	Forging	Fitting
B729	B464	B729	B468	B463	B473	B462	B366

 

Welding Wire Designations:
AWS A5.14 – ER320

Mechanical Properties of Alloy 20:

Annealed Material:

Product form	Tensile (ksi) Min	0.2 % Yield (ksi)	Elongation (%)
Bar (hot or Cold Finished)	80	35	30
Sheet/Plate	80	35	30