Hastelloy Pipe

Hastelloy is a family of nickel-based superalloys developed by Haynes International, engineered for extreme corrosion resistance in both oxidizing and reducing environments. Hastelloy pipes are specified when stainless steel, duplex, and even Inconel grades cannot withstand the corrosive media.

The two most common Hastelloy pipe grades are C-276 (the industry workhorse) and C-22 (improved resistance to oxidizing media).

Hastelloy Grades Compared

Property	C-276	C-22	B-3
UNS	N10276	N06022	N10675
Ni (%)	57 (bal.)	56 (bal.)	65 (bal.)
Cr (%)	14.5-16.5	20-22.5	1-3
Mo (%)	15-17	12.5-14.5	27-32
W (%)	3-4.5	2.5-3.5	-
Fe (%)	4-7	2-6	1-3
Yield (min, annealed)	283 MPa (41 ksi)	310 MPa (45 ksi)	283 MPa (41 ksi)
Tensile (min, annealed)	690 MPa (100 ksi)	690 MPa (100 ksi)	690 MPa (100 ksi)
ASTM pipe (seamless)	B622	B622	B622
ASTM pipe (welded)	B619	B619	B619
Primary strength	Universal corrosion resistance	Oxidizing + reducing media	HCl, H2SO4 (reducing)

Hastelloy C-276: The Workhorse

C-276 is often called the “universal alloy” because it resists an unusually broad range of corrosive chemicals:

• Sulfuric acid (all concentrations, including hot dilute)
• Hydrochloric acid (up to 50°C in all concentrations)
• Phosphoric acid (with impurities)
• Wet chlorine gas and hypochlorite solutions
• Ferric and cupric chloride solutions (highly oxidizing)
• Acetic, formic, and other organic acids

This versatility makes C-276 the default choice when the process involves mixed or variable chemical compositions.

Hastelloy C-22: Enhanced Oxidizing Resistance

C-22 improves on C-276 in oxidizing environments due to its higher chromium content (20-22.5% vs. 14.5-16.5%). It resists:

• Oxidizing acids with chlorides better than C-276
• Mixed acid environments (nitric + HCl, sulfuric + HCl)
• Pharmaceutical process streams with aggressive cleaning chemicals

Hastelloy B-3: Reducing Acid Specialist

B-3 contains 27-32% molybdenum and minimal chromium, making it the best choice for reducing acids without oxidizing contaminants:

• Hydrochloric acid at all concentrations up to boiling
• Sulfuric acid in reducing (deaerated) conditions
• Acetic acid and other organic acids

Common Mistake

Hastelloy B-3 has poor resistance to oxidizing media (ferric chloride, nitric acid, wet chlorine). If oxidizing contaminants enter a B-3 system, rapid attack occurs. For mixed environments, C-276 or C-22 is the safer choice.

Applications

• Chemical processing reactors and piping
• Pharmaceutical manufacturing
• Flue-gas desulfurization (FGD) systems in power plants
• Waste treatment (incineration off-gas scrubbing)
• Pulp and paper bleaching
• Pesticide and herbicide production

Cost and Procurement

Material	Approximate Cost Multiple (vs. CS)
Carbon steel (A106 Gr. B)	1x
316L stainless	3-4x
Inconel 625	10-15x
Hastelloy C-276	15-25x
Hastelloy C-22	18-28x

Lead times for seamless Hastelloy pipe typically range from 20-30 weeks. Early procurement planning is essential. For large diameters where seamless is unavailable, welded pipe per ASTM B619 (with solution annealing) is specified.

Read the full guide to pipe types