C22 vs C276: The Ultimate Guide to Selecting Hastelloy C Series Grades

C276 and C22 both belong to the Hastelloy C series. C22 and C276 are their respective grades. The standard for C22 is UNS N06022, and the standard for C276 is UNS N10276.

Comparison of the Chemical Composition of C22 VS C276

Elements	Hastelloy C-22 (N06022)	Hastelloy C-276 (N10276)
Nickel (Ni)	Balance (approximately 56%)	Balance (approximately 57%)
Chromium (Cr)	20.0 – 22.5	14.5 – 16.5
Molybdenum (Mo)	12.5 – 14.5	15.0 – 17.0
Tungsten (W)	2.5 – 3.5	3.0 – 4.5
Iron (Fe)	2.0 – 6.0	4.0 – 7.0
Cobalt (Co)	≤ 2.5	≤ 2.5
Carbon (C)	≤ 0.015	≤ 0.01

From the table, you can see that the chromium content of C22 is significantly higher than that of C276, while the molybdenum content of C276 is higher than that of C22. The high content of chromium element is conducive to the formation of oxide film, indicating that C22 has good resistance to pitting corrosion. High molybdenum content indicates that C276 is more suitable for reducing environments and can inhibit chloride ions. Tungsten element can make alloys relatively stable at high temperatures, and the tungsten content of the two is comparable.

Comparison of Corrosion Resistance Between C22 VS C276

Oxidative Environment

In an oxidizing environment, C22 alloy has a greater advantage and better corrosion resistance.

Restoring Environment

In a reducing environment, C276 has better corrosion resistance than C22, but when the solution concentration is higher, C22’s corrosion resistance surpasses C276.

Chloride Environment

Characteristic	Hastelloy C-22	Hastelloy C-276
Oxidizing chlorides	Excellent corrosion resistance	Slightly weaker than the C22
Reducing environment	Excellent corrosion resistance	Slightly weaker than the C22
Critical crevice corrosion temperature	High (approximately 80°C)	Lower (approximately 55°C)
Wet chlorine resistance	Highest	High

In chloride environments, C22 exhibits excellent corrosion resistance, while C276 is somewhat weaker than C22.

High-temperature Thermal Stability

Characteristic	Hastelloy C-22	Hastelloy C-276
Phase Stability	Extremely high stability	Easily leads to precipitation of weld heat-affected zone
Welding status	Better corrosion resistance in the welded state	Further processing is required after welding.
Maximum operating temperature	Approximately 677–1000℃	Approximately 1038℃

Overall, C22 has better high-temperature thermal stability.

Stress Corrosion Cracking

If your application environment contains a lot of oxidizing media or requires frequent welding, then choose C22; if your application environment is a strong reducing environment, then choose C276.

Machining Properties of C22 VS C276

Characteristic	Hastelloy C-22	Hastelloy C-276
Processing difficulty	High processing difficulty	Basically equivalent to C22
Work hardening	Cold work hardens quickly	A hardened layer will form on the surface.
Heat conduction	Poor thermal conductivity	Poor thermal conductivity
Tool wear	Due to its high chromium content, wear is noticeable.	The tool wears out quickly.
Robustness	very good	Slightly weaker than the C22

In general, the machining process for C276 is more mature, but C22 has better machining performance and is more expensive.

Industry Applications of Hastelloy C22 VS C276

Applications of Hastelloy C22

Because of its high chromium content, C22 exhibits exceptional resistance to pitting and crevice corrosion. Its most common applications include:

Biopharmaceutical Engineering

C22 is a material frequently used in the pharmaceutical industry. It has excellent corrosion resistance and can prevent the formation of “red rust”.

Nuclear Industry

C22 alloy is frequently used in fuel processing systems in the nuclear industry because it can withstand corrosion from media such as high-concentration nitric acid.

Food Industry

C22 alloy is also frequently used in certain food processing equipment with high salt or acid content due to its superior corrosion resistance.

Marine Engineering

C22 alloy is also frequently used in marine engineering in areas where gaps are extremely sensitive.

Applications of Hastelloy C276

Environmental protection

C276 alloy is typically used in scrubbers and heat exchangers in incinerators, as well as in flue gas desulfurization systems. It is widely used in FGD systems.

Traditional chemical industry

Most applications are in pesticide production, organochlorine synthesis, and treatment of acidic media containing chloride ions.

Paper industry

C276 is often used in bleaching equipment and can withstand corrosion from strong oxidizing substances and chlorides.

Oil and gas extraction

C276 Hastelloy is frequently used in downhole casing and core components of acidic oil and gas wells.

Cost and Life Cycle of C22 VS C276

Unit price of raw materials:

Typically, C22 is more expensive than C276, costing 1.1 to 1.3 times more.

Comparison of processing costs:

The welding material for C22 is more expensive than that for C276, but due to the greater difficulty in processing, the processing efficiency of C22 is not as good as that of C276, which also increases the processing cost.

Lifespan Comparison:

Although C22 is more difficult to process than C276, C22 has a longer lifespan because its welding performance is much better than that of C276.

Conclusion

Overall, Hastelloy C22 VS C276 each have their advantages. If you are looking for high cost-effectiveness and your application environment is primarily reducing, then C276 is the best choice; if you are looking for better performance and your application environment is strongly oxidizing or complex oxidizing, then C22 can meet your requirements.

FAQ

How Did Hastelloy Get its Name?

The name Hastelloy is an abbreviation of the formula used to develop it. In 1922, the Haynes Company developed this nickel-based corrosion-resistant alloy.

Hastelloy C22 vs C276, Which one is More Expensive?

The answer is C22. Both the raw materials and processing costs of C22 are higher than those of C276.

C22 vs C276, Which Has a Longer Lifespan?

C22 has a longer lifespan because of its good machinability.

What is the Hastelloy C22 vs C276 Chemical Composition?

The difference in nickel content between the two is not significant; the main differences lie in the content of chromium, molybdenum, tungsten, and iron.

Chromium content: 20.0-22.5% in C-22, 14.5-16.5% in C-276.

Molybdenum content: 12.5-14.5% in C-22, 15.0-17.0% in C-276.

Tungsten content: 2.5-3.5% in C-22; 3.0-4.5% in C-276.

Iron content: 2.0-6.0% in C-22; 4.0-7.0% in C-276.

Do C22 VS C276 have the same density?

They are different. The density of C22 is approximately 8.69 g/cm³, while the density of C276 is approximately 8.89 g/cm³, making C276 slightly heavier.