Supreme Corrosion Resistance • Chemical Processing Workhorse • Versatile Performance
Hastelloy C-276 is a nickel-molybdenum-chromium superalloy with exceptional resistance to a wide variety of chemical process environments, including strong oxidizers, chlorides, solvents, and acids. Renowned as the premier material for the most severe corrosive conditions, it combines outstanding versatility with resistance to pitting, crevice corrosion, and stress corrosion cracking.
Hastelloy C-276 is a solid-solution strengthened nickel-molybdenum-chromium alloy with excellent resistance to both oxidizing and reducing environments. Its high molybdenum content provides exceptional resistance to pitting and crevice corrosion, while chromium offers resistance to oxidizing media. The low carbon content minimizes carbide precipitation during welding, maintaining corrosion resistance in welded structures.
Hastelloy C-276 is the industry standard for chemical processing equipment due to its exceptional resistance to a broad spectrum of corrosive chemicals. It performs reliably in environments containing sulfuric acid, hydrochloric acid, phosphoric acid, acetic acid, and numerous other aggressive media. The alloy's resistance to both oxidizing and reducing conditions makes it uniquely versatile.
| Element | Weight % | Purpose |
|---|---|---|
| Nickel (Ni) | Balance (57% min) | Base metal, provides ductility and corrosion resistance |
| Molybdenum (Mo) | 15.0 - 17.0 | Superior pitting and crevice corrosion resistance |
| Chromium (Cr) | 14.5 - 16.5 | Oxidizing environment resistance and passivation |
| Tungsten (W) | 3.0 - 4.5 | Enhances corrosion resistance in reducing conditions |
| Iron (Fe) | 4.0 - 7.0 | Contributes to solid solution strengthening |
| Cobalt (Co) | ≤ 2.5 | Minor constituent (impurity limit) |
| Manganese (Mn) | ≤ 1.0 | Deoxidizer and sulfur control |
| Vanadium (V) | ≤ 0.35 | Grain refinement |
| Silicon (Si) | ≤ 0.08 | Deoxidizer (kept low) |
| Carbon (C) | ≤ 0.01 | Ultra-low to prevent sensitization |
Chemistry Advantage: The high molybdenum (15-17%) combined with chromium and tungsten creates synergistic corrosion resistance superior to alloys with higher individual element contents. Ultra-low carbon (≤0.01%) ensures weld zone corrosion resistance without heat treatment.
| Property | Metric | Imperial |
|---|---|---|
| Tensile Strength (Ultimate) | 690 MPa | 100,000 psi |
| Yield Strength (0.2% offset) | 283 MPa | 41,000 psi |
| Elongation at Break | 40% (in 50mm) | |
| Modulus of Elasticity | 205 GPa | 29.8 × 10⁶ psi |
| Rockwell Hardness | ≤ 22 HRC (typical) | |
| Brinell Hardness | ≤ 223 HB | |
| Shear Strength | 400 MPa | 58,000 psi |
| Shear Modulus | 78.6 GPa | 11.4 × 10⁶ psi |
| Poisson's Ratio | 0.306 | |
Note: Properties shown are for solution annealed condition. The alloy can be significantly strengthened by cold working. High ductility (40% elongation) provides excellent formability.
Reaction vessels, heat exchangers, evaporators, transfer piping, valves, pumps, flue gas scrubbers, acetic acid production, pesticide production, chlorination systems, phosphoric acid production, sulfuric acid coolers, and equipment handling mixed acid environments.
Flue gas desulfurization (FGD) systems, wet scrubber components, stack gas reheaters, ducting, dampers, absorber vessels, spray nozzles, mist eliminators, and waste treatment equipment handling acidic and chloride-bearing solutions.
Sour gas service components, sulfur recovery plants, hydrodesulfurization reactors, acid gas injection systems, geothermal wells, offshore drilling equipment, subsea wellhead components, and high-pressure high-temperature (HPHT) applications.
Process vessels, piping systems, pharmaceutical production equipment, bioreactors, fermentation tanks, clean-in-place (CIP) systems, and equipment requiring high purity and corrosion resistance.
Digesters, bleach plant equipment, evaporators, flash tanks, liquor heaters, and components exposed to chlorine dioxide, hypochlorite, and acidic chloride solutions.
Hazardous waste incineration systems, radioactive waste processing, toxic waste neutralization equipment, and waste treatment facilities handling aggressive chemical mixtures.
| Operation | Recommended Parameters |
|---|---|
| Turning (Roughing) | Speed: 30-60 SFM (9-18 m/min), Feed: 0.008-0.015 ipr, DOC: 0.125-0.250" |
| Turning (Finishing) | Speed: 60-90 SFM (18-27 m/min), Feed: 0.004-0.008 ipr, DOC: 0.030-0.060" |
| Milling (Face/Slab) | Speed: 40-80 SFM (12-24 m/min), Feed: 0.004-0.010 ipt, radial DOC 50-75% of cutter diameter |
| Milling (End) | Speed: 50-100 SFM (15-30 m/min), Feed: 0.003-0.008 ipt, use climb milling |
| Drilling | Speed: 15-30 SFM (4.5-9 m/min), Feed: 0.001-0.005 ipr, MANDATORY peck drilling |
| Threading | Thread milling strongly preferred, single-point only as last resort at very low speeds |
| Coolant | High-pressure flood coolant REQUIRED, sulfurized or extreme-pressure cutting oils |
Machining Success Key: Hastelloy C-276 work hardens more severely than most superalloys. The work-hardened layer from previous passes must be removed completely on each subsequent pass. Use the maximum practical depth of cut to get below the work-hardened zone. Never allow the tool to rub or dwell.
Hastelloy C-276 has excellent weldability and can be readily welded using common fusion welding processes. The alloy's low carbon content (≤0.01%) minimizes carbide precipitation, ensuring the weld zone maintains corrosion resistance without post-weld heat treatment.
One of Hastelloy C-276's key advantages is that the weld zone maintains corrosion resistance equivalent to the base metal without post-weld heat treatment. The ultra-low carbon content prevents carbide precipitation during welding, eliminating the sensitization that occurs in higher-carbon nickel alloys.
Hastelloy C-276 exhibits exceptional resistance to a wider variety of corrosive media than virtually any other commercial alloy. Its performance in both oxidizing and reducing environments, combined with outstanding resistance to localized corrosion, makes it the material of choice for the most demanding chemical processing applications.
PREN Formula: %Cr + 3.3(%Mo) + 16(%N)
Higher PREN = Better pitting resistance
C-276 typically achieves PREN of 70-75
Hastelloy C-276 is particularly valued for its resistance to mixed acid environments where both oxidizing and reducing conditions exist simultaneously. This includes sulfuric acid contaminated with chlorides, mixed sulfuric-nitric-hydrochloric acids, and other complex chemical mixtures where conventional materials fail.
Get a quote for AS9100D certified Hastelloy C-276 machining with full material traceability and chemical processing certification.