Hastelloy C276 Superalloy (UNS N10276)

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Hastelloy C276 (ASTM B574, 2.4819, AMS 5750)

Hastelloy C276 is a nickel-molybdenum-chromium alloy with tungsten. It fights corrosion in many tough places. The nickel and molybdenum make it strong against pitting and crevice corrosion. The chromium helps it stand up to oxidizing agents. This mix makes it useful in chemical plants, marine jobs, and industrial work. Big Hastelloy C276 makers and suppliers, like Supreme Engineering Limited, lead the market in making this strong metal.

The alloy has low carbon, which stops carbide buildup when welded. This keeps its corrosion resistance even after joining. It also stops grain buildup in welded spots, so it stays tough. That is why it works well in chemical process work, even when welded. Of all the Hastelloy types, C276 is the most used. It gives great strength, heat stability, and corrosion safety. This makes it a top pick for modern engineering and industrial use.

Features of Hastelloy C276:

Excellent Corrosion Resistance Hastelloy C276 resists many strong chemicals. It performs well in both oxidizing and reducing conditions. It stands strong against pitting, crevice corrosion, and cracking. It also handles harsh acids like hydrochloric and sulfuric acid.
Works in Harsh Environments This alloy stays strong in hot and corrosive areas. It resists chlorine gas, oxidizers, and acid chlorides. It performs well under high pressure and temperature.
Easy to Weld and Form Hastelloy C276 is easy to weld using standard methods. It does not form carbide during welding. It needs no post-weld heat treatment
High Strength and Long Life The mix of nickel, molybdenum, chromium, and tungsten gives great strength. It lasts long even in extreme conditions. It resists wear, heat, and corrosion for years.
Wide Range of Uses It is used in chemical plants, power stations, and marine systems. It also suits paper, pulp, and pollution control units. Its flexibility makes it ideal for many industries.
Strong Against Localized Attack It resists pitting and crevice corrosion in stagnant or salty conditions. This makes it safe for chemical handling and waste systems.
Heat Resistant Hastelloy C276 keeps its strength at high temperatures. It is reliable for heat exchangers, reactors, and scrubbers.
Low Maintenance and Cost-Effective Its corrosion resistance gives long service life. It reduces repair costs and downtime. This makes it a cost-effective material choice.

Performance Profile:

1. Outstanding Corrosion Resistance

Hastelloy C276 resists many harsh chemicals. It performs well in both oxidizing and reducing conditions. Nickel and molybdenum protect against pitting and crevice corrosion. Chromium adds strength against oxidizing agents. This balance makes the alloy ideal for aggressive environments.

2. Excellent Resistance in Chemical Processing

The alloy works well in chemical plants and refineries. It resists strong acids like hydrochloric, sulfuric, and phosphoric acid. It also stands strong against chlorine gas, hypochlorite, and chlorine dioxide. This makes it perfect for reactors, heat exchangers, and scrubbers.

3. High Mechanical Strength

Hastelloy C276 stays strong under stress and heat. It keeps good toughness and ductility even at high pressure. It does not crack or deform easily. This strength makes it reliable for pressure vessels and pipelines.

4. Superior Weldability and Fabrication

The alloy is easy to weld and shape. It can be welded by TIG, MIG, or arc methods. It forms little carbide during welding, keeping its corrosion resistance intact. It can be rolled, bent, or pressed into many forms without losing quality.

5. Thermal Stability and Oxidation Resistance

Hastelloy C276 performs well under high heat. It resists oxidation and scaling at high temperatures. It stays stable even when conditions change quickly. This makes it ideal for hot and corrosive systems.

6. Long Service Life and Low Maintenance

The alloy lasts long and needs little care. Its corrosion resistance cuts down wear and tear. This helps reduce plant downtime and repair costs. It gives steady performance for many years.

7. Proven Use Across Industries

Hastelloy C276 is used in chemical, marine, and power industries. It is also found in wastewater treatment and pollution control plants. It is trusted for pipes, fittings, heat exchangers, and pressure vessels. Its performance makes it a dependable choice for extreme environments.

Common Applications

Hastelloy C276 is used in many industries that face strong chemicals and heat. It works well in both oxidizing and reducing conditions. Below are the main uses of this alloy.

1. Chemical Processing Industry

Hastelloy C276 is common in chemical plants. It is used to make reactors, heat exchangers, scrubbers, and evaporators. It handles acids like hydrochloric, sulfuric, and phosphoric acid. The alloy also resists chlorine and other harsh chemicals.

2. Pollution Control Systems

This alloy is used in air and water treatment plants. It works well in stack liners, scrubbers, and ducts that carry hot gases. It stands strong against acid fumes and chemical vapors. Hastelloy C276 helps extend equipment life in flue gas systems.

3. Marine and Offshore Engineering

Hastelloy C276 performs well in seawater and salty air. It is used in heat exchangers, pumps, and pipelines near the ocean. The alloy resists pitting and crevice corrosion caused by seawater.

4. Pulp and Paper Industry

In paper plants, Hastelloy C276 is used in bleach systems and chemical recovery units. It resists chlorine dioxide and sodium hypochlorite. This helps reduce rust and keeps machines clean.

5. Power Generation

Power plants use Hastelloy C276 in boilers, scrubbers, and cooling systems. It handles acidic steam and hot gases. The alloy stays strong under high pressure and temperature.

6. Pharmaceutical and Food Processing

This alloy is used in mixers, tanks, and pipes. It resists cleaning chemicals and keeps surfaces smooth. It helps maintain hygiene and prevents contamination.

7. Waste Treatment and Environmental Systems

Hastelloy C276 is ideal for waste plants. It resists acid waste, chlorine gas, and chemical effluents. It reduces wear and extends equipment life in harsh environments.

8. Aerospace and Defense

In aerospace, Hastelloy C276 is used in engines and exhaust ducts. It resists high heat and oxidation. The alloy ensures safe and stable performance in extreme conditions.

Hastelloy C276 is a trusted material for harsh working conditions. It offers strength, safety, and long service life across many industries.

Specifications:

Hastelloy® C-276
Alloy C-276
Nickel Alloy C-276
Inconel® C-276 (generic reference
Nicrofer 5716 hMoW
NS 334
W.Nr. 2.4819
NiMo16Cr15W
UNS N10276
AMS 5750
ASTM B574 / B575 / B622 / B619 / B626 (Product Standards)

Chemical Composition (WT %):

Element	Symbol	Weight % (Typical Range)	Function / Role
Nickel	Ni	Balance (≈ 57%)	Provides overall corrosion resistance and strength.
Molybdenum	Mo	15.0 – 17.0%	Improves resistance to pitting and crevice corrosion.
Chromium	Cr	14.5 – 16.5%	Enhances oxidation and corrosion resistance.
Iron	Fe	4.0 – 7.0%	Present as an impurity; contributes to structural stability.
Tungsten	W	3.0 – 4.5%	Adds resistance to strong oxidizing environments.
Cobalt	Co	≤ 2.5%	Minor strengthening element.
Manganese	Mn	≤ 1.0%	Helps improve hot-working properties.
Vanadium	V	≤ 0.35%	Increases hardness and wear resistance.
Carbon	C	≤ 0.01%	Low carbon prevents carbide precipitation during welding.
Silicon	Si	≤ 0.08%	Controlled for improved oxidation resistance.
Phosphorus	P	≤ 0.04%	Kept low to avoid brittleness.
Sulfur	S	≤ 0.03%	Limited to prevent hot cracking and corrosion.

Physical Properties:

Property	Metric (SI Units)	Imperial (US Units)	Description / Notes
Density	8.89 g/cm³	0.321 lb/in³	Indicates high strength and stability under mechanical and thermal stress.
Melting Point	1325–1370 °C	2417–2498 °F	Shows strong thermal endurance suitable for high-temperature environments.
Specific Heat Capacity	427 J/kg·K	0.102 Btu/lb·°F	Reflects the alloy’s ability to absorb and transfer heat efficiently.
Thermal Conductivity (at 20 °C)	10.6 W/m·K	73.6 BTU·in/hr·ft²·°F	Moderate heat conduction helps maintain temperature balance in chemical systems.
Electrical Resistivity	1.29 µΩ·m	50.8 µΩ·in	Ensures consistent electrical resistance under stress and corrosion.
Modulus of Elasticity (Tension)	205 GPa	29.7 × 10³ ksi	Provides rigidity and resistance to deformation under mechanical loads.
Poisson’s Ratio	0.31	0.31	Defines the ratio of lateral strain to axial strain, showing good ductility.
Mean Coefficient of Thermal Expansion (20–100 °C)	10.9 µm/m·°C	6.06 µin/in·°F	Displays stability under temperature fluctuations with low expansion rate.
Magnetic Permeability (at 200 Oersted)	1.0006 (Approx.)	1.0006 (Approx.)	Non-magnetic in annealed condition, suitable for sensitive chemical environments.
Curie Temperature	Below -196 °C	Below -321 °F	Remains non-magnetic at cryogenic temperatures.
Hardness (Rockwell B)	89 HRB	89 HRB	Shows high surface hardness with good machinability.
Melting Range	1325–1370 °C	2415–2500 °F	Offers wide solidification range, improving weld quality and structural consistency.
Thermal Expansion (20–1000 °C)	13.2 µm/m·°C	7.33 µin/in·°F	Ensures dimensional stability under prolonged heating conditions.
Modulus of Rigidity (Shear Modulus)	84 GPa	12.2 × 10³ ksi	Measures resistance to shearing deformation.

Mechanical Properties

Property	Metric Value	Imperial Value	Test Condition / Notes
Density	8.89 g/cm³	0.321 lb/in³	At 20°C (68°F)
Melting Point	1325 – 1370°C	2415 – 2500°F	—
Tensile Strength (Ultimate)	760 MPa	110,000 psi	Annealed condition
Yield Strength (0.2% Offset)	355 MPa	51,500 psi	Annealed condition
Elongation at Break	60%	60%	In 50 mm (2 in) gauge length
Modulus of Elasticity	205 GPa	29.7 × 10³ ksi	At 20°C (68°F)
Hardness (Rockwell B)	90 HRB	90 HRB	Annealed condition
Impact Strength	240 J	177 ft-lb	Charpy V-Notch test
Poisson’s Ratio	0.31	0.31	At 20°C (68°F)
Thermal Conductivity	10.2 W/m·K	70.8 BTU·in/hr·ft²·°F	At 20°C (68°F)
Coefficient of Thermal Expansion	11.2 µm/m·°C	6.2 µin/in·°F	20–100°C (68–212°F)
Specific Heat Capacity	427 J/kg·K	0.102 BTU/lb·°F	At 25°C (77°F)
Electrical Resistivity	1.24 µΩ·m	49 µΩ·in	At 20°C (68°F)

Heat treatment:

Process Stage	Description	Temperature Range (°C / °F)	Atmosphere / Medium	Purpose / Effect	Recommended Cooling Method	Notes & Precautions
Solution Annealing	The alloy is heated to a specific temperature to dissolve carbides and other precipitates formed during fabrication.	1120–1175°C / 2050–2150°F	Clean, controlled furnace atmosphere or inert gas	Restores corrosion resistance and mechanical uniformity by homogenizing the structure.	Rapid quenching in water or air (depending on section thickness).	Avoid prolonged heating below 1120°C to prevent grain boundary carbide precipitation.
Stress Relief Annealing	Applied after cold working or welding to reduce internal stresses without significantly altering the microstructure.	870–900°C / 1600–1650°F	Inert or reducing atmosphere	Relieves residual stresses from forming or welding operations.	Air cool or slow furnace cooling.	Not always necessary; only used when stress levels are critical.
Stabilization Treatment	Rarely required but can be used for specific industrial applications involving extended high-temperature exposure.	980–1050°C / 1800–1920°F	Inert or vacuum atmosphere	Stabilizes grain structure and improves high-temperature performance.	Air cool.	Perform only under expert supervision; excessive time can lower strength.
Post-Weld Heat Treatment (PWHT)	Restores corrosion resistance and mechanical integrity of welded components.	1120°C / 2050°F (typical)	Controlled or inert atmosphere	Dissolves carbide precipitates formed in the heat-affected zone.	Rapid water quenching.	Mandatory for thick weld sections; use proper cleaning before and after heating.
Aging Treatment	Not recommended for Hastelloy C276 due to its stable solid-solution structure.	—	—	Alloy does not respond to aging or precipitation hardening.	—	Mechanical strength improvements achieved by cold working, not aging.
Cooling Considerations	Proper cooling after heat treatment is critical to maintain corrosion resistance and grain uniformity.	—	—	Prevents carbide formation and intergranular attack.	Rapid water quenching preferred.	Always ensure parts are clean and free from contaminants before quenching.

Frequently Asked Questions (FAQs)

What is Hastelloy C276 made of?

It is a nickel, molybdenum, and chromium alloy with tungsten. These elements give it strong resistance to rust and chemical attack. It also prevents pitting and cracking in harsh conditions.

Where is Hastelloy C276 used?

It is used in chemical plants, marine systems, pollution control units, and power plants. Common products include pipes, tanks, heat exchangers, and reactors.

Can Hastelloy C276 be welded?

Yes. It is easy to weld and form. It does not form carbide when welded, so it keeps its corrosion resistance after fabrication.

How does Hastelloy C276 handle acids?

It works well in strong acids like hydrochloric, sulfuric, and phosphoric acid. It also resists chlorine gas and other strong oxidizers.

What forms are available?

It comes in sheets, plates, bars, pipes, tubes, fittings, and flanges. Custom sizes and shapes are also available for different needs.