Inconel vs Hastelloy

Nickel superalloys.
Different strengths.
Aerospace vs chemistry.

Both Inconel and Hastelloy are nickel-based superalloys. Both resist high temperature and corrosion. But they're optimized for different priorities: Inconel typically for aerospace strength-at-temperature, Hastelloy for aggressive chemical environments.

Get a Quote DFM guide

01 · At a glance

Side-by-side summary.

Option A

Inconel 718

Precipitation-hardened nickel superalloy. 1035 MPa yield strength. Service to 650°C. Aerospace workhorse — rocket engines, jet engine hot section, high-stress + temperature applications.

Option B

Hastelloy C-276

Solid-solution nickel-molybdenum-chromium alloy. 355 MPa yield. Exceptional corrosion resistance to 1100°C. Chemical processing standard — handles aggressive chemistries other alloys cannot.

02 · Detailed comparison

Feature-by-feature breakdown.

Attribute	Inconel 718	Hastelloy C-276
Nickel content	50-55%	57%
Main alloying	Fe, Cr, Mo, Nb, Ti, Al	Mo, Cr, W, Fe
Yield strength	1035 MPa (STA)	355 MPa (annealed)
Hardening mechanism	Precipitation	Solid solution
Service temperature	650°C (aged)	1100°C (short-term)
Oxidation resistance	Good	Excellent
HCl resistance	Poor	Excellent
H2SO4 resistance	Moderate	Excellent
Chloride pitting (PREN)	~50	~65
Cost per kg	$50-80	$60-100
Machinability	Difficult (work hardening)	Difficult
Weldability	Good (post-weld age)	Excellent

03 · Decision guide

When to choose each.

Choose Inconel 718 when:

Aerospace structural hot section (650°C)
Rocket engine components
High-strength at temperature required
Standard aerospace engine supplier qualification
Cost-sensitive high-temp applications
NACE sour service for oil and gas

Choose Hastelloy C-276 when:

Severe chemical processing (HCl, H2SO4)
Oxidizing + reducing environments
Highest corrosion + temperature combined
Pharmaceutical reactor linings
Pulp and paper processing
Flue gas handling (wet)

FAQ

Common questions.

Inconel 718 combines: (1) High strength at temperature (1035 MPa yield to 650°C). (2) Good fatigue life for rotating components. (3) Weldability. (4) Established supplier base. (5) Moderate cost vs other superalloys. It's the workhorse for gas turbine discs, rotating engine parts, and aerospace fasteners. Variants: Inconel 625 (solid solution, similar temperature), Inconel X-750 (older precipitation-hardened grade).

C-276 handles combinations of oxidizing and reducing environments — most alloys favor one or other. Plus: high chloride resistance (PREN 65), tolerates wet chlorine, handles sulfuric, hydrochloric, and phosphoric acids, stress corrosion cracking resistant. For process plants with mixed or uncertain chemistry, C-276 is the catch-all alloy. Premium cost but single material solves multiple problems.

Inconel 625: solid solution strengthened, not heat-treatable. Better corrosion resistance than 718. Used for: welded assemblies (no post-weld aging needed), oil and gas sour service (NACE-qualified), chemical processing. Inconel 718: precipitation hardened (aged), higher strength (1035 vs 460 MPa yield), harder to weld. Used for: structural aerospace, rotating engine parts. Generally: 625 for chemistry, 718 for mechanical.

Both are notoriously difficult. Work hardening (stainless behavior but worse), low thermal conductivity (heat concentrates at tool), sticky chips. Techniques: sharp carbide tooling (change often), slow cutting speeds (20-30 m/min), heavy feed to stay ahead of work hardening, flood coolant, rigid setup essential. Machining cost 3-5× equivalent steel. Ceramic or CBN tooling economical for production volumes. Plan extra machining time and cost in quoting.

Inconel 718: $50-80/kg. Hastelloy C-276: $60-100/kg. Compare to: stainless 316L $5-8/kg. Duplex 2507 $15-20/kg. Ti-6Al-4V $60-80/kg. Pure nickel 200: $25-35/kg. Monel 400: $30-50/kg. Specify nickel superalloys only when performance justifies — often 5-10× stainless cost. Review carefully whether duplex stainless or specialty steel would serve application.

Rene 41, Waspaloy: very high temperature aerospace (700-900°C). Haynes 230: oxidation resistance to 1150°C, gas turbine combustor. Haynes 25 (L605): cobalt-base for very high temp. MP35N: non-magnetic high strength + corrosion. Nimonic 90: older British aerospace alloy. For specific extreme applications, consult specialty superalloy supplier — many niche alloys for specific needs. Inconel and Hastelloy cover 80% of superalloy applications.