Alloy 22

Alloy 22

Alloy 22 (UNS N06022; W. Nr. 2.4602; NiCr21Mo14W) is a fully austenitic advanced corrosion-resistant alloy that offers resistance to both aqueous corrosion and attack at elevated temperatures. This alloy provides exceptional resistance to general corrosion, pitting, crevice corrosion, intergranular attack, and stress corrosion cracking.

Alloy 22 has found numerous applications in the chemical/petrochemical processing, pollution control (flue gas desulfurization), power, marine, pulp and paper processing, and waste disposal industries. Alloy 22 is nickel-base and typically contains 22% chromium, 14% molybdenum, and 3% tungsten. Iron is normally limited to less than 3%. The alloy’s high content of chromium gives it good resistance to wet corrosion by oxidizing media (e.g., nitric acid and ferric and cupric salts). Its contents of molybdenum and tungsten give the alloy resistance to wet reducing media (e.g., sulfuric and hydrochloric acids). Alloy 22 exhibits excellent resistance to corrosive attack by seawater under stagnant and flowing conditions.

Alloy 22 (UNS N06022; W. Nr. 2.4602; NiCr21Mo14W)

At elevated temperatures, the high chromium level of INCONEL alloy 22 helps it resist oxidation, carburization, and sulfidation. Since it is nickel-base, alloy 22 resists high-temperature attack by halides (e.g., chlorides and fluorides). With these attributes, the alloy is widely used to protect steel tubes and other components in coal-fired and waste-to-energy boilers.

INCONEL alloy 22 products are covered by ASTM, ASME and ISO specifications. Alloy 22 is approved for the construction of pressure vessels and components under the ASME Boiler and Pressure Vessel Code Section VIII, Division 1 for service up to 1250°F (677°C). The alloy is also approved by VdTÜV under Werkstoffblatt 479. The alloy is equivalent to and directly competes with Hastelloy® C-22® and Nicrofer® 5621hMoW alloys.

Chemical Composition

Weight %

Alloy 22

Bal

20-22

12.5-14.5

2-6

2.5-3.5

2.5 max

0.35 max

0.015 max

0.50 max

0.02 max

0.08 max

0.02 max

Alloy 22 (UNS N06022) is the most versatile Nickel-Chromium-Molybdenum-Tungsten alloy with controlled Iron. Due to Alloy 22’s content, this alloy exhibits excellent resistance to both oxidizing and reducing acid environments as well as those containing mixed acids. Alloy 22 is particularly useful for resistance to pitting and crevice corrosion in acid-halide environments. Alloy 22 is used in pickling chlorination, sulphonation plants, pollution control, chemical processing, marine and nuclear fuel reprocessing.

Typical Mechanical Properties

Material

Yield Strength (0.2% Offset)

Tensile Strength

Elongation

(%)

KSI

MPa

KSI

MPa

Alloy 22 Bar

379

115

793

Available Products and Specifications

INCONEL alloy 22 is designated as UNS N06022 and Werkstoff Nr. 2.4602. Standard product forms include sheet, strip, plate, round bar, flat bar, forging stock, hexagon, and wire. The products are available in a wide range of sizes.

Rod, Bar, Wire and Forging Stock -ASTM B 462 (Rod, Bar and Forging Stock), ASTM B 564 & ASME SB 564 (Forgings), ASTM B 574 & ASME SB 574 (Rod, Bar and Wire), ASME Code Case 2226, ASME Code Case N-621, ISO 9723, ISO 9724, DIN 17752 (Rod & Bar), DIN 17753 (Wire), DIN 17754 (Forgings)

Plate, Sheet and Strip – ASTM B 575/B 906 & ASME SB 575/SB 906, ASME Code Case 2226, ASME Code Case N-621, ISO 6208, DIN 17750

Pipe and Tube – ASTM B 619/B 775 & ASME SB 619/SB 775 (Welded Pipe), ASTM B 622/B 829 & ASME SB 622/SB 829 (Seamless Tube), ASTM B 626/B 751 & ASME SB 626/SB 751 (Welded Tube), ASME Code Case 2226, ASME Code Case N-621, ISO 6207, DIN 17751

Welding Products – INCONEL Filler Metal 622 – AWS A5.14 / ERNiCrMo-10, INCONEL Welding Electrode 622 – AWS A5.11 / ENiCrMo-10 Other

Product Forms – ASTM B 366 & ASME SB-366 (Fittings)

Composition – DIN 17744