Hastelloy

Three check valves in corrosion-resistant Hastelloy

Hastelloy is the registered trademark name of Haynes International, Inc. The trademark is applied as the prefix name of a range of twenty two different highly corrosion-resistant metal alloys loosely grouped by the metallurgical industry under the material term “superalloys” or “high-performance alloys”.

The predominant alloying ingredient is typically the transition metal nickel. Other alloying ingredients are added to nickel in each of the subcategories of this trademark designation and include varying percentages of the elements molybdenum, chromium, cobalt, iron, copper, manganese, titanium, zirconium, aluminum, carbon, and tungsten.

The primary function of the Hastelloy super alloys is that of effective survival under high-temperature, high-stress service in a moderately to severely corrosive, and/or erosion-prone environment where more common and less expensive iron-based alloys would fail, including the pressure vessels of some nuclear reactors, chemical reactors, distillation equipment, and pipes and valves in chemical industry. Although a super alloy, Hastelloy does experience degradation due to fabricating and handling. Electropolishing or passivation of Hastelloy can improve corrosion resistance.

Types

The following Hastelloy alloys have been produced; however, production of some may have been discontinued:

Composition of various hastelloy alloys (percent)

Alloy	Co	Cr	Mo	W	Fe	Si	Mn	C	Ni	Others
B-2	1*	1*	28	–	2*	0.1*	1*	0.01*	Balance	–
B-3	3*	1.5	28.5	3*	1.5	0.1*	3*	0.01*	65 min.	Al-0.5*, Ti-0.2*
C-4	2*	16	16	–	3*	0.08*	1*	0.01*	Balance	Ti-0.7*
C-2000	2*	23	16	–	3*	0.08*	–	0.01*	Balance	Cu-1.6
C-22	2.5*	22	13	3	3	0.08*	0.5*	0.01*	Balance	V-0.35*
C-276	2.5*	16	16	4	5	0.08*	1*	0.01*	Balance	V-0.35*
G-30	2*	30	5.5	2.5	15	1*	1.5*	0.03*	Balance	Nb-0.8*, Cu-2*
N	0.2*	7	16	0.5*	5*	1*	0.8*	0.08*	Balance	Al+Ti-0.5*, Cu-0.35*
W	2.5*	5	24	–	6	1*	1*	0.12*	Balance	V-0.6*
X	1.5*	22*	9*	0.6*	18.5*	0.5*	0.5*	0.1*	Balance	-

• ¹ The undiluted deposited chemical composition of covered electrodes of some of these alloys may vary beyond the limits shown.
• ^*Maximum

See also

• Stellite
• Inconel
• Monel