Hastelloy® C-276

What is Hastelloy® C-276 ?

Hastelloy C276 is a nickel-molybdenum-chromium superalloy with an addition of tungsten designed to have excellent corrosion resistance in a wide range of severe environments. The high nickel and molybdenum contents make the nickel steel alloy especially resistant to pitting and crevice corrosion in reducing environments while chromium conveys resistance to oxidizing media. The low carbon content minimizes carbide precipitation during welding to maintain corrosion resistance in as-welded structures. This nickel alloy is resistant to the formation of grain boundary precipitates in the weld heat-affected zone, thus making it suitable for most chemical process application in an as welded condition.

Hastelloy® C-276 Products Form

• Seamless & welded pipe
• Seamless & welded tube
• Bar
• Wire
• Sheet
• Plate
• Forgings
• Pipe fittings
• Flanges
• Weld Rod

Applications for Hastelloy® C-276

• Digesters and bleach plants in the paper industry.
• Components exposed to sour gas.
• Equipment for flue-gas desulfurisation plants.
• Evaporators, heat exchangers, filters and mixers used in sulfuric acid environments.
• Sulfuric acid reactors.
• Organic chloride process equipment.
• Equipment for processes utilizing halide or acid catalysts.

Equivalents of Hastelloy® C-276

STANDARD	WERKSTOFF NR.	UNS	JIS	GOST	EN	OR
Hastelloy C276	2.4819	N10276	NW 0276	ХН65МВУ	NiMo16Cr15W	ЭП760

Chemical Composition

GRADE

Cr

Mn

Co

Fe

Mo

W

C

V

P

S

Si

Ni

HASTELLOY  C-276

MIN

14.5

–

–

4

15

3

–

–

–

–

–

–

MAX

16.5

1

2.5

7

17

4.5

0.01

0.35

0.04

0.03

0.08

Remainder

Mechanical Properties

Element	Density	Melting Point	Tensile Strength	Yield Strength (0.2%Offset)	Elongation
Hastelloy C276	8.89 g/cm3	1370 °C (2500 °F)	Psi – 1,15,000 , MPa – 790	Psi – 52,000 , MPa – 355	40 %

Physical Properties

DENSITY	8.89 g/cm 3 / 0.321 lb/in 3
MELTING POINT	1325 -1370 (°C) / 2415 – 2500 (°F)
SPECIFIC HEAT @ 70°F	0.102 Btu/lb/°F
THERMAL CONDUCTIVITY @ 70°F	67.9 Btu•in/h/ft2/°F
YOUNG’S MODULUS 103KSI	29.8
SHEAR MODULUS 103KSI	11.4
PERMEABILITY (15.9 KA/M)	1.0002 (200 oersted)
POISSON’S RATIO	0.307
ANNEALED	1121 (°C) / 2050 (°F)
QUENCH	Rapid Air/Water

Corrosion Resistance

Considered one of the most versatile corrosion resistant alloys available, Hastelloy C-276 exhibits excellent resistance in a wide variety of chemical process environments including those with ferric and cupric chlorides, hot contaminated organic and inorganic media, chlorine, formic and acetic acids, acetic anhydride, seawater, brine and hypochlorite and chlorine dioxide solutions. In addition, alloy C-276 resists formation of grain boundary precipitates in the weld heat affected zone making it useful for most chemical processes in the as-welded condition. This alloy has excellent resistance to pitting and stress corrosion cracking.

Fabrication and Heat Treatment

Alloy C-276 material can be forged, hot-upset and impact extruded. All of the common methods of welding can be used, although the oxyacetylene and submerged arc processes are not recommended when the fabricated item is for use in corrosion service.

HASTELLOY C-276 alloy can be hot forged, hot rolled, hot upset, hot extruded, and hot formed.  Although the alloy tends to work-harden, you can have it successfully spun, deep-drawn, press formed or punched.

However, it is more sensitive to strain and strain rates than the austenitic stainless steels, and the hot working temperature range is quite narrow. For example, Hot forming should be between 1600 and 2250°F (870 and 1230°C), with all heavy forming above 2000°F (1090°C).

HASTELLOY C-276 alloy work hardens more readily than most austenitic stainless steels, and may require several stages of cold work, with intermediate anneals. INCONEL alloy C-276 is normally annealed at 2100-2150°F (1150-1175°C) and rapidly cooled such as by water quenching

Hot Working

Super alloy HASTELLOY(r) C276 is capable of being extruded or hot formed. After the hot forming process, this alloy should be solution heat treated.

Cold Working

Conventional cold working procedures are used for cold working HASTELLOY(r).

FORGING

The alloy is forged between 2250/1750ºF (1230/955ºC) following a soak at forging temperature of 30 minutes per inch of billet or ingot section thickness. Forging should be started immediately the stock is removed from the reheat furnace and 25/40% reductions help to retain as much internal heat as possible. For optimum corrosion resistance, forged parts should be subsequently annealed. See Heat Treatment.

MACHINABILITY

The alloy is considered moderate to difficult to machine, but can be machined using conventional methods. The alloy has a high work hardening rate, and efficient machining requires rigid and overpowered machines, sharp tools, preferably carbide-tipped, and heavy, constant feeds.

Welding

Gas tungsten-arc welding, gas metal-arc welding, shielded metal-arc (coated electrode) welding, or resistance welding may be used. Minimum heat input consistent with adequate penetration reduces the chance of hot-cracking. Oxyacetylene welding should be avoided due to possibility of carburization. Hastelloy C-276 can be used in the as-welded condition in most chemical and petrochemical process equipment.