Hastelloy C-276 — The Ultimate Nickel Alloy for Extreme Environments
When hydrochloric acid, sulphuric acid, wet chlorine gas, or ferric chloride solutions are involved — when stainless steel, duplex, and even titanium fail — Hastelloy C-276 stands alone. This nickel-chromium-molybdenum-tungsten alloy resists the most aggressive chemical environments known to industrial processing. As an industrial raw material supplier in Gujarat and specialist in exotic alloys, Creative Metal Industries sources C-276 in pipes, plates, bars, fittings, and flanges for India's chemical, pharmaceutical, and pollution control industries.
Why Hastelloy C-276 is Chosen for Aggressive Chemical Exposure
Most corrosion-resistant alloys work in either oxidising OR reducing environments — but not both. SS 316L handles mild oxidising conditions. Hastelloy B-2 excels in pure reducing acids but fails if any oxidant is present. Titanium works in oxidising acids but dissolves in HCl.
Hastelloy C-276 uniquely bridges both worlds. Its combination of 16% Chromium (for oxidation resistance) + 16% Molybdenum and 4% Tungsten (for reducing acid resistance) in a 57% Nickel matrix creates an alloy that handles mixed oxidising-reducing environments, fluctuating process conditions, and contaminated acids that destroy single-purpose alloys. This versatility is why C-276 is often called the "universal" corrosion-resistant alloy.
Chemical Composition — Hastelloy C-276
| Element | Content (wt%) | Role in Corrosion Resistance |
|---|---|---|
| Nickel (Ni) | Balance (~57%) | Matrix — inherently resistant to chloride SCC and caustic environments |
| Chromium (Cr) | 14.5–16.5% | Oxidation resistance; passive film in oxidising media |
| Molybdenum (Mo) | 15.0–17.0% | Reducing acid resistance (HCl, H₂SO₄); pitting protection |
| Tungsten (W) | 3.0–4.5% | Synergises with Mo for reducing acid + localised corrosion resistance |
| Iron (Fe) | 4.0–7.0% | Economiser; minor role in properties |
| Cobalt (Co) | 2.5% max | Residual; contributes to hot strength |
| Carbon (C) | 0.010% max | Ultra-low — prevents carbide precipitation in HAZ |
| Vanadium (V) | 0.35% max | Grain refinement |
| Manganese (Mn) | 1.0% max | Deoxidiser |
| Silicon (Si) | 0.08% max | Kept extremely low — Si promotes intermetallic precipitation |
UNS: N10276 | ASTM: B574 (bar), B575 (plate), B622 (pipe), B366 (fittings) | EN: 2.4819
Key Properties — What C-276 Resists
| Environment | C-276 Performance | 316L Performance |
|---|---|---|
| Hydrochloric acid (all concentrations) | Excellent to boiling | Fails immediately |
| Sulphuric acid (dilute to moderate) | Excellent | Poor |
| Wet chlorine gas | Excellent | Fails |
| Ferric chloride (FeCl₃) | Excellent — no pitting | Pits instantly |
| Phosphoric acid (contaminated) | Excellent | Moderate |
| Acetic/formic acid | Excellent | Good (clean only) |
| Sodium hypochlorite (bleach) | Excellent | Crevice corrodes |
| Mixed acids (HCl + H₂SO₄ + oxidants) | Excellent — unique capability | Impossible |
| Chloride SCC | Immune (Ni-base) | Susceptible > 60°C |
| Pitting (PREN equivalent) | ~65 equivalent | ~24 |
Key Applications of Hastelloy C-276
Chemical Processing
Reactors, heat exchangers, piping, and valves handling HCl, H₂SO₄, chlorinated solvents, and mixed acid streams. The go-to alloy when process conditions fluctuate.
Pollution Control (FGD)
Flue gas desulphurisation scrubbers, ducts, and dampers in coal power plants. Handles hot, acidic, chloride-laden condensate that destroys all stainless grades.
Pulp & Paper
Bleach plant equipment — chlorine dioxide generators, washers, piping exposed to hypochlorite and ClO₂. Critical where 316L and even titanium have failed.
Pharmaceutical
Reactors and piping for synthesis involving HCl, bromides, and aggressive organic/inorganic acid combinations. Process purity + corrosion resistance.
Waste Treatment
Incineration off-gas scrubbers, hazardous waste processing, landfill leachate handling. Unknown/variable chemistry demands C-276's universal resistance.
Nuclear
Fuel reprocessing, reactor components, spent fuel handling. Resists both nitric acid (oxidising) and reducing conditions encountered in nuclear service.
Fabrication and Welding Guidelines
Hastelloy C-276 is weldable by TIG (GTAW), MIG (GMAW), and MMA (SMAW) using matching filler ERNiCrMo-4 (AWS A5.14) or ENiCrMo-4 electrode. Key considerations:
- Low heat input: Minimise to prevent segregation of Mo and W — which creates intermetallic precipitation zones susceptible to preferential corrosion
- No preheat: C-276 should never be preheated. Interpass temperature maximum 93°C (200°F)
- Stringer beads only: No weaving — rapid cooling is critical. Fast travel speed, low amperage
- Full back purge: Argon back purge mandatory to prevent oxidation on root side — even slight oxide discolouration reduces corrosion resistance
- Clean surfaces: Remove all contaminants — grease, oil, marking paint, oxide — within 25mm of the weld joint. Use dedicated stainless/nickel alloy tools
- No PWHT required: C-276 does not sensitise (ultra-low carbon 0.01% max eliminates carbide risk). Solution anneal only if intermetallics formed during prior hot working
- Machining: Work-hardens rapidly. Use sharp carbide tools, low speed, heavy cuts. Do not allow tool to rub — will work-harden surface and make subsequent passes nearly impossible
Why Source Hastelloy C-276 from Creative Metal Industries?
Exotic alloys require specialised sourcing. As a well-established industrial raw material supplier in Gujarat with global import channels, Creative Metal Industries supplies C-276 with full traceability and competitive pricing:
- Mill sources: Haynes International (USA — the original Hastelloy manufacturer), Special Metals (USA), VDM Metals (Germany), ThyssenKrupp (Germany)
- Product range: Seamless pipes (ASTM B622), plates/sheets (B575), bars (B574), fittings (B366), flanges, fasteners — complete project supply
- Matching filler metals: ERNiCrMo-4 TIG wire + ENiCrMo-4 electrodes stocked alongside parent material
- Full certification: MTC 3.1/3.2 with chemical analysis, mechanical properties, intergranular corrosion test (ASTM G28 Method A), PMI verification
- Cut-to-size: Plasma/waterjet cutting for plates, pipe cutting to length — minimising your exotic alloy wastage
- Also supplying: Complete plant material packages — combining C-276 with SS pipes, CS fittings, flanges, and gaskets as a one-stop SS pipe fittings flanges supplier in India
Frequently Asked Questions — Hastelloy C-276
What is Hastelloy C-276 used for?
C-276 is used where virtually all other alloys fail: concentrated HCl, H₂SO₄, wet chlorine gas, FeCl₃ etch, mixed acid environments. Industries: chemical processing, FGD scrubbers, pulp & paper bleaching, pharmaceutical, waste incineration, nuclear fuel reprocessing.
What makes Hastelloy C-276 special?
It uniquely resists BOTH oxidising AND reducing environments simultaneously. 16% Cr handles oxidising conditions while 16% Mo + 4% W handles reducing acids — all in a 57% Ni matrix immune to chloride SCC. No other single alloy offers this universal corrosion resistance.
How much does Hastelloy C-276 cost in India?
₹4,000-7,000/kg depending on product form and size — approximately 10-15× the cost of 316L. Justified only where no cheaper material survives. Creative Metal Industries sources from Haynes and Special Metals at competitive import pricing. Contact for current rates.
Need Hastelloy C-276?
Haynes & Special Metals sourcing. Pipes, plates, bars, fittings. Full MTC + corrosion test reports.
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