36-C22

Invar 36 (UNS K93600）

Hastelloy C-22 (UNS N06022)

Summary

A nickel-iron low-expansion alloy containing 36% nickel. It maintains nearly constant dimensions over the range of normal atmospheric temperatures, and has a low coefficient
of expansion from cryogenic temperatures to about 500°F (260℃). The alloy also retains good strength and toughness at cryogenic temperatures. Used for standards of length, measuring devices, laser components, bi-metal thermostat strip, thermostat rods, and tanks and piping for storing and transporting liquefied gases.

By virtue of its contents of chromium, molybdenum, and tungsten and controlled iron, this alloy exhibits excellent resistance to both oxidizing and reducing acid environments as well as those containing mixed acids. It is particularly useful for resistance to pitting and crevice corrosion in acid-halide environments. Applications include the chemical processing, pollution control, flue gas desulfurization, waste incineration, and pulp and paper processing industries.

Standard
Product Forms

Pipe, tube, sheet, plate, round bar, forging stock and wire.

Sheet, strip, plate, round bar, flat bar, forging stock, hexagon and wire.

Limiting Chemical Composition, %

	Min.	Max.		Min.	Max.		Min.	Max.
Ni	35.0	37.0	Cu			C		0.05
Cr		0.5	Co			Si		0.3
Fe	Remainder		Al			P		0.02
Mo		0.5	Ti			S		0.02
W			Mn		0.2	N

	Min.	Max.		Min.	Max.		Min.	Max.
Ni	Remainder		Cu			C		0.015
Cr	20.0	22.5	Co		2.5	Si		0.08
Fe	2.0	6.0	Al			P		0.02
Mo	12.5	14.5	Ti			S		0.02
W	2.5	3.5	Mn		0.5	V		0.35

Physical
Constants

Density,g/cm3							8.11
Melting Range,℃							1430

Density,g/cm3							8.61
Melting Range,℃							1351-1387

Typical
Mechanical
Properties

(Annealed)
Tensile Strength, ksi			71
	Mpa		490
(Yield Strength 0.2% Offset), ksi			35
		Mpa	240
Elongation,%			42

Microstructure

In the annealed condition Invar 36 exhibits an austenitc structure.

Hastelloy C-22 has a face-centered-cubic structure.

Characters

Invar 36 is an austenitic binary iron-nickel alloy with a particularly low coefficient of expansion. It is characterized by:
1. Extremely low coefficient of thermal expansion between -250 and 200℃;
2. Good ductility and toughness;
3. Good fatigue and mechanical properties at cryogenic temperature.

Hastelloy C-22, as the same as the alloy C-276, is a nickel-chromium-molybdenum alloy containing tungsten and with extremely low carbon and silicon contents. Hastelloy C-22 has the same characters as the alloy C-276:
1. Excellent resistance to a wide range of corrosive media, under oxidising and reducing condition;
2. Outstanding resistance to pitting,crevice corrossion, and stress-corrosion cracking.

Corrosion Resistance

Invar 36 is corrosion resistant in dry atmospheres at room temperature. Under unfavourable conditions, i.e., in humid or moist atmospheres, corrosion can occur in the form of rust.

Hastelloy C-22 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.

Applications

Invar 36 was developed for applications requiriing the lowest possible thermal expansion.
1. Production, storage and transportation of liquefied gases;
2. Equipment to indicate and control temperatures below 200℃, i.e., thermostats;
3. Bushings for screw or bolt connections between different metals;
4. Bimetallic components and thermostat metals, where Invar 36 constitutes the passive component；
5. TV shadow masks;
6. Molds for the production of carbon fiber reinforced plastic (CFRP) components;
7. Frames for electronic control units for satellites and space crafts at temperatures down to -200℃;
8. Mountings for electronmanetic lens systems in laser control devices.

Some of the areas of use for C-22 alloy are:
1.Acetic Acid/Acetic Anhydride；
2.Acid Etching；
3.Cellophane Manufacturing；
4.Chlorination Systems；
5.Complex Acid Mixtures；
6.Electro-Galvanizing Rolls；
7.Expansion Bellows；
8.Flue Gas Scrubber Systems；
9.Geothermal Wells；
10.HF Furnace Scrubbers；
11.Incineration Scrubber Systems ；
12.Nuclear Fuel Reprocessing；
13.Pesticide Production；
14.Phosphoric Acid Production；
15.Pickling Systems；
16.Plate Heat Exchangers；
17.Selective Leaching Systems；
18.SO2 Cooling Towers；
19.Sulfonation Systems；
20.Tubular Heat Exchangers；
21.Weld Overlay-Valves.

Shanghai Fengqu Superalloy Co., Ltd.　 Tel:+86-21-69155998 　
Sales:+86-21-69155989/69151848 　 Consulting Tel:13817961313　Fax:+86-21-69151848
Add：101#,Boxue Rd, Jiading District, Shanghai,China Zip：201801 　E-mail:Sales@superalloy.com.cn