Inconel vs Hastelloy: Key Differences, Properties, and Selection Guide for High-Performance Applications

When selecting materials for high-temperature, high-pressure, and highly corrosive industrial environments, two alloy families stand out above the rest: Inconel and Hastelloy.

Both are nickel-based superalloys used in extreme applications such as jet engines, refineries, chemical reactors, offshore platforms, and power plants.

This detailed guide from Moksh Tubes & Fittings LLP compares both alloys based on:

Chemical composition
High-temperature performance
Corrosion resistance
Mechanical strength
Weldability
Applications
Selection guide
FAQs

Understanding the Two Superalloy Families

What is Inconel?

High temperature capability
High strength
Oxidation resistance
Thermal stability
Stress handling

Common industries:

Aerospace
Power generation
Oil & gas
Furnaces & heaters

What is Hastelloy?

Extreme corrosion resistance
Acid resistance
Chemical compatibility
Works in reducing + oxidizing environments

Common industries:

Chemical processing
Acid plants
Pharmaceutical reactors
Pollution control systems

Chemical Composition Differences

Inconel 625 Composition

Nickel: 58%
Chromium: 20–23%
Molybdenum: 8–10%
Niobium: 3–4%

Hastelloy C276 Composition

Nickel: 57%
Chromium: 15–17%
Molybdenum: 15–17%
Tungsten: 3–4%

Key Differences:

Hastelloy has higher Mo + W → extreme corrosion resistance.
Inconel has higher Cr + Nb → superior high-temp strength & stability.

High-Temperature Resistance

Inconel (625 / 718 / 600):

Stable up to 1000–1200°C
Exceptional oxidation resistance
High creep strength
Ideal for turbines, jet engines, furnaces

Hastelloy (C276 / C22):

Heat resistant up to ~950°C
Loses mechanical strength above 900°C

Winner (High Temperature): Inconel

Corrosion Resistance

Hastelloy advantages:

Exceptional resistance to strong acids (HCl, H₂SO₄, HF, HNO₃)
Excellent pitting & crevice corrosion resistance
Works in oxidizing & reducing media

Inconel corrosion performance:

Excellent overall
Very strong in chlorides (625)
Strong in sulfuric acid (825)
But generally < Hastelloy in extreme acids

Winner (Corrosion): Hastelloy

Strength & Mechanical Performance

Inconel 718:

Tensile Strength: 1275 MPa
Yield Strength: 1035 MPa
Hardness: 36–44 HRC

Inconel 625:

Tensile Strength: 690 MPa

Hastelloy C276:

Tensile Strength: ~690 MPa
Yield Strength: ~283 MPa

Conclusion: Inconel 718 is significantly stronger than Hastelloy.

Oxidation & Thermal Stability

Inconel offers:

High-temperature oxidation resistance
Scaling resistance
Thermal fatigue resistance
Creep resistance

Winner: Inconel

Weldability

Inconel:

625 → Good weldability
718 → Difficult, requires PWHT

Hastelloy C276:

Excellent weldability
Lower hot cracking risk

Winner: Hastelloy C276

Cost Comparison

Typically:

Hastelloy C276 → Highest cost
Inconel 625 → Moderate
Inconel 718 → Lower than both (mass-use alloy)

Application Comparison

Where Inconel Is Better

Jet engines
Turbines
Furnace components
Exhaust systems
Nuclear systems
High-temp valves
Downhole tools

Where Hastelloy Is Better

Acid plants
Chemical reactors
Pollution control
Wet chlorine systems
Pickling lines
Pharmaceutical equipment

Summary Comparison Table

Property	Inconel	Hastelloy
High-Temp Strength	⭐⭐⭐⭐⭐	⭐⭐⭐
Corrosion Resistance	⭐⭐⭐⭐	⭐⭐⭐⭐⭐
Oxidation Resistance	⭐⭐⭐⭐⭐	⭐⭐⭐
Weldability	⭐⭐⭐	⭐⭐⭐⭐
Cost	⭐⭐⭐	⭐⭐⭐⭐
Best For	High-temperature	Extreme corrosion

Which Alloy Should You Choose?

Choose Inconel If:

High-temperature strength is required
Component faces thermal cycling
Operating temp > 850°C
Mechanical load is high
Used in aerospace, power plants, turbines

Choose Hastelloy If:

You need extreme acid resistance
Component faces HF, HCl, sulfuric acid
Operating in harsh chemical media
Pitting/crevice corrosion risk is high
Used in chemical or pharmaceutical plants

FAQ's

Which alloy is better overall?

Neither. Choose based on environment → Heat (Inconel), Corrosion (Hastelloy).

Is Hastelloy stronger than Inconel?

No. Inconel 718 is much stronger.

Which alloy is best for seawater?

Inconel 625 performs excellently. Hastelloy C276 also works, but Inconel is more cost-effective.

Which alloy handles acids better?

Hastelloy C276 → king of acid resistance.

Which alloy is cheaper?

Inconel is generally cheaper than Hastelloy.