Hastelloy C-22 UNS N06022

Hastelloy C-22, also known as alloy C-22, is a versatile nickel alloy with enhanced resistance to pitting, crevice corrosion and stress corrosion cracking. The high chromium content provides good resistance to oxidizing media while the molybdenum and tungsten content give good resistance to reducing media. This nickel steel alloy also has excellent resistance to oxidizing aqueous media including wet chlorine and mixtures containing nitric acid or oxidizing acids with chlorine ions. Other corrosives Hastelloy C-22 has resistance to are oxidizing acid chlorides, wet chlorine, formic and acetic acids, ferric and cupric chlorides, sea water, brine and many mixed or contaminated chemical solutions, both organic and inorganic. This nickel alloy also offers optimum resistance to environments where reducing and oxidizing conditions are encountered in process streams. This is beneficial in multi- purpose plants where such "upset" conditions occur frequently.
HASTELLOY C-22 alloy is a versatile nickel-chromium- molybdenum-tungsten alloy with better overall corrosion resistance than other Ni-Cr-Mo alloys available today, including HASTELLOY C-276 and C-4 alloys and alloy 625. C-22 alloy has outstanding resistance to pitting, crevice corrosion, and stress corrosion cracking. It has excellent resistance to oxidizing aqueous media including wet chlorine and mixtures containing nitric acid or oxidizing acids with chloride ions. Also, C-22 alloy offers optimum resistance to environments where reducing and oxidizing conditions are encountered in process streams. Because of such versatility it can be used where "upset" conditions are likely to occur or in multi-purpose plants.
C-22 alloy has exceptional resistance to a wide variety of chemical process environments, including strong oxidizers such as ferric and cupric chlorides, chlorine, hot contaminated solutions (organic and inorganic), formic and acetic acids, acetic anhydride, and seawater and brine solutions. C-22 alloy resists the formation of grain-boundary precipitates in the weld heat-affected zone, thus making it suitable for most chemical process applications in the as-welded condition.

Product Forms
C-22 alloy is available in most common product forms: plate, sheet, strip, billet, bar, wire, covered electrodes, pipe, and tubing.

Wrought forms of this alloy are furnished in the solution heat-treated condition unless otherwise specified.

Applications
Some of the areas of use for C-22 alloy are:
---- Acetic Acid/Acetic Anhydride
---- Acid Etching
---- Cellophane Manufacturing
---- Chlorination Systems
---- Complex Acid Mixtures
---- Electro-Galvanizing Rolls
---- Expansion Bellows
---- Flue Gas Scrubber Systems
---- Geothermal Wells
---- HF Furnace Scrubbers
---- Incineration Scrubber Systems
---- Nuclear Fuel Reprocessing
---- Pesticide Production
---- Phosphoric Acid Production
---- Pickling Systems
---- Plate Heat Exchangers
---- Selective Leaching Systems
---- SO2 Cooling Towers
---- Sulfonation Systems
---- Tubular Heat Exchangers
---- Weld Overlay-Valves

Field Test Program
Samples of C-22 alloy are readily available for laboratory or inplant corrosion testing. Analysis of corrosion resistance of the tested material can also be performed and the results provided to the customer as a free technical service. Test C-22 alloy and compare. Contact any of the convenient locations shown on the back cover of this brochure for test coupons and information.

Specifications
HASTELLOY C-22 alloy is covered by ASME Section VIII, Division I. Plate, sheet, strip, bar, tubing, and pipe are covered by ASME specifications SB-574, SB-575, SB-619, SB-622 and SB-626 and by ASTM specifica-tions B-574, B-575, B-619, B-622, and B-626. DIN specification is 17744 No. 2.4602 (all forms), TUV Werkstoffblatt 479 (all forms). NACE specification is MR-01-75. C-22 alloy falls within the range of UNS number N06022 but has a more restricted composition for improved performance. These improvements are of such significance that it has been widely patented throughout the world.

Material Safety Data Sheets
For information concerning material safety data, ask for Material Safety Data Sheets H2071 and H1072.

Nominal Chemical Composition, Weight Percent
Ni Co Cr Mo W Fe Si Mn C V
-------------------------------------
56a 2.5** 22 13 3 3 0.08** 0.50** 0.010** 0.35**

*The undiluted deposited chemical composition of C-22 alloy covered electrodes has 0.02% carbon and 0.2% Si.
** Maximum a As balance

Base Metal Preparation
The joint surface and adjacent area should be thoroughly cleaned before welding. All grease, oil, crayon marks, sulfur compounds, and other foreign matter should be removed.

Filler Metal Selections
Matching composition filler metal is recommended for joining C-22 alloy. For gas-tungsten-arc and gas-metal-arc welding, C-22 filler wire (ER NiCrMo-10) is recommended. For shielded metal arc welding, C-22 covered electrodes (ENiCrMo-10; UNS W86022) are recommended. Detailed fabricating information for C-22 alloy is available in the booklet, Fabrication of HASTELLOY® Corrosion- Resistant Alloys (H-2010) and C-22® Alloy Welding Information (H-2066).

This nickel alloy resists the formation of grain-boundary precipitates in the weld heat-affected zone, thus making it suitable for most chemical process applications in the as-welded condition.

Alloy C-22 should not be used in service temperatures above 1250F due to the formation of detrimental phases which form above this temperature.

Although ductile enough to be formed by cold working, intermediate annealing may be necessary due to work hardening. Forging should be performed between 1750-2050F followed by rapid cooling. Annealing can be performed at a temperature range between 2020-2150F followed by a rapid quench. Cooling at an accelerated rate avoids the formation of detrimental phases which form between 1400-1800F. Welding can be done by gas tungsten-arc, gas metal-arc and shielded metal-arc processes.