Hastelloy C22 (UNS N06022) and Hastelloy C276 (UNS N10276) are two of the most widely used nickel-chromium-molybdenum alloys for highly corrosive environments. Both alloys offer exceptional resistance to pitting, crevice corrosion, stress corrosion cracking, and a wide range of aggressive chemicals.
Although they appear similar, their chemical composition, corrosion behavior, mechanical properties, and application focus differ significantly. Selecting the correct alloy can improve equipment reliability, extend service life, and reduce lifecycle costs.
This guide compares Hastelloy C22 and Hastelloy C276 in terms of chemical composition, physical properties, mechanical performance, corrosion resistance, service temperature, applications, and cost.
Quick Comparison
| Свойство | Хастеллой С22 | Хастеллой C276 |
| Номер UNS | N06022 | N10276 |
| ASTM Standards | ASTM B574, B575, B619, B622, B366 | ASTM B564, B575, B619, B622, B366 |
| Хром | 20–22.5% | 14.5–16.5% |
| Молибден | 12.5–14.5% | 15–17% |
| Вольфрам | 2.5–3.5% | 3–4.5% |
| Oxidizing Media | ★★★★★ | ★★★★☆ |
| Reducing Media | ★★★★☆ | ★★★★★ |
| Нефть и газ | ★★★★☆ | ★★★★★ |
| Химическая обработка | ★★★★★ | ★★★★★ |
Chemical Composition Comparison
| Элемент | Хастеллой С22 | Хастеллой C276 |
| Никель (Ni) | Баланс | Баланс |
| Хром (Cr) | 20.0–22.5% | 14.5–16.5% |
| Молибден (Mo) | 12.5–14.5% | 15.0–17.0% |
| Вольфрам (W) | 2.5–3.5% | 3.0–4.5% |
| Железо (Fe) | 2–6% | 4–7% |
| Кобальт (Co) | ≤2.5% | ≤2.5% |
| Марганец (Mn) | ≤0,5% | ≤1.0% |
| Кремний (Si) | ≤0,08% | ≤0,08% |
| Углерод (С) | ≤0,015% | ≤0.01% |
| Ванадий (V) | ≤0,35% | ≤0,35% |
| Фосфор (P) | ≤0.02% | ≤0.04% |
| Сера (S) | ≤0.02% | ≤0,03% |
Composition Analysis
Хастеллой С22
- Higher chromium content
- Better oxidation resistance
- Excellent resistance to wet chlorine and ferric chloride
Хастеллой C276
- Higher molybdenum and tungsten
- Superior reducing acid resistance
- Outstanding localized corrosion resistance
Сравнение физических свойств
| Свойство | C22 | C276 |
| Плотность | 8,69 г/см³ | 8,89 г/см³ |
| Диапазон плавления | 1357–1400°C | 1325–1370°C |
| Удельная теплоемкость | 410 J/kg·K | 427 Дж/кг·К |
| Теплопроводность | 11.1 W/m·K | 10.2 W/m·K |
| Электрическое сопротивление | 1.14 μΩ·m | 1.30 μΩ·m |
| Модуль упругости | 206 GPa | 205 ГПа |
| Thermal Expansion (20–100°C) | 12.4 μm/m·°C | 11.2 μm/m·°C |
Physical Property Highlights
- C276 is slightly denser because of its higher Mo and W content.
- C22 has marginally better thermal conductivity.
- Both alloys maintain dimensional stability at elevated temperatures.
Сравнение механических свойств
| Свойство | Хастеллой С22 | Хастеллой C276 |
| Предел прочности | ≥690 MPa | ≥690 MPa |
| Предел текучести (0,2%) | ≥310 MPa | ≥283 MPa |
| Удлинение | ≥45% | ≥40% |
| Твёрдость | ≤100 HRB | ≤100 HRB |
Mechanical Performance
Both alloys provide:
- Excellent toughness
- High ductility
- Outstanding weldability
- Excellent fatigue resistance
C22 generally exhibits a slightly higher yield strength than C276.
Maximum Service Temperature Comparison
| Свойство | Хастеллой С22 | Хастеллой C276 |
| Maximum Continuous Service Temperature | ≈1040°C (1900°F) | ≈1090°C (2000°F) |
| Short-Term Oxidation Resistance | Отличный | Отличный |
| Thermal Stability | Отличный | Отличный |
Temperature Analysis
Both alloys retain good mechanical properties at elevated temperatures. However:
- Хастеллой C276 is generally preferred for higher-temperature reducing environments because of its higher molybdenum and tungsten content.
- Хастеллой С22 performs exceptionally well in oxidizing atmospheres and mixed chemical environments.
Примечание: The actual maximum service temperature depends on the operating medium, mechanical load, oxidation conditions, and design code requirements. Continuous service limits should always be verified for the specific application.
Corrosion Resistance Comparison
| Среда | C22 | C276 |
| Hydrochloric Acid | ★★★★☆ | ★★★★★ |
| Серная кислота | ★★★★☆ | ★★★★★ |
| Nitric Acid | ★★★★★ | ★★★★☆ |
| Ferric Chloride | ★★★★★ | ★★★★☆ |
| Wet Chlorine | ★★★★★ | ★★★★☆ |
| Mixed Acids | ★★★★★ | ★★★★★ |
| Seawater | ★★★★★ | ★★★★★ |
| Питтинговая коррозия | Отличный | Отличный |
| Щелевая коррозия | Отличный | Отличный |
| Коррозионное растрескивание под напряжением | Отличный | Отличный |
Свариваемость
Both Hastelloy C22 and C276 have excellent weldability using GTAW, GMAW, SMAW, and PAW welding processes.
Post-weld heat treatment is generally not required when proper filler metals and welding procedures are used.
Типичные применения
Хастеллой С22
- Chemical reactors
- Pharmaceutical equipment
- Bleaching systems
- Flue Gas Desulfurization (FGD)
- Waste treatment
- Chlorination equipment
Хастеллой C276
- Нефть и газ
- Offshore platforms
- Petrochemical plants
- Pressure vessels
- Heat exchangers
- Sour service piping
- Acid processing equipment
Cost Comparison
| Элемент | Хастеллой С22 | Хастеллой C276 |
| Raw Material Cost | Выше | Ниже |
| Manufacturing Cost | Slightly Higher | Ниже |
| Market Availability | Умеренный | Отличный |
| Global Demand | Середина | Очень высокий |
| Typical Lead Time | Longer | Shorter |
Cost Analysis
Although both alloys belong to the premium nickel alloy family, Hastelloy C22 generally costs 5–15% more than Hastelloy C276, depending on market prices for nickel, chromium, molybdenum, and tungsten.
Reasons include:
- Higher chromium content
- Lower global production volume
- More specialized applications
- Smaller market demand
Hastelloy C276 benefits from larger production volumes and broader industrial use, making it easier to source and often more cost-effective.
Which Alloy Should You Choose?
| Приложение | Recommended Alloy |
| Hydrochloric Acid | ⭐ C276 |
| Серная кислота | ⭐ C276 |
| Nitric Acid | ⭐ C22 |
| Wet Chlorine | ⭐ C22 |
| Ferric Chloride | ⭐ C22 |
| Mixed Acids | ⭐ C22 |
| Нефть и газ | ⭐ C276 |
| Offshore | ⭐ C276 |
| Химическая обработка | Both |
Procurement Recommendation
Choose Хастеллой С22 when:
- Excellent resistance to oxidizing chemicals is required.
- The service involves wet chlorine, ferric chloride, or mixed acid environments.
- Maximum corrosion resistance is the primary concern.
Choose Хастеллой C276 when:
- The process involves strong reducing acids such as hydrochloric or sulfuric acid.
- The application is in oil & gas, offshore, or petrochemical industries.
- Lower procurement cost and wider availability are important.
Available Product Forms
SSMALLOYS manufactures and supplies:
- Плиты и листы
- Pipes & Tubes
- Фитинги для труб
- Фланцы
- Кованые фитинги
- Bars & Rods
- Поковки
- Крепежные элементы
Manufactured according to:
- ASTM B564
- ASTM B575
- ASTM B619
- ASTM B622
- ASTM B366
- ASME SB564
- ASME SB366
- ASME SB622
FAQs About Hastelloy C-22 vs Hastelloy C-276
Not necessarily. C22 performs better in oxidizing environments, while C276 offers superior resistance in reducing acids and remains the preferred choice for many oil & gas applications.
In some cases, yes. However, alloy selection should be based on the service medium, temperature, pressure, corrosion mechanism, and applicable design standards.
Hastelloy C22 is typically 5–15% more expensive than Hastelloy C276 because of its higher chromium content and lower production volume.
Both alloys provide excellent weldability and generally do not require post-weld heat treatment.
Hastelloy C276 is the most widely used nickel alloy in chemical processing, oil & gas, offshore, and power generation due to its versatility and availability.
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