Hastelloy C276 vs. Alloy 20: Which is better?
Hastelloy C276 vs. Alloy 20: Which is better?
The choice between Hastelloy C276 and Alloy 20 depends on the specific corrosive environment. C276 generally performs better in highly corrosive, reducing, or mixed acid environments (such as wet chlorine, hydrochloric acid, and sulfuric acid), while Alloy 20 performs excellently in strong oxidizing acids (nitric acid and phosphoric acid) and has good resistance to pitting/crevice corrosion in weak chloride/sulfuric acid environments. It also offers good weldability and cost-effectiveness, making it suitable for a wider range of chemical and food processing applications. C276 offers extremely high corrosion resistance but is more expensive; Alloy 20 performs well in specific, less corrosive environments and has better machinability.
What is the difference between Hastelloy C276 and alloy C22?
Hastelloy C276 can withstand temperatures up to 1900°F (1037°C), while Hastelloy C22 can withstand temperatures up to 1250°F (676°C). This superior thermal stability and resistance to grain boundary precipitation make Hastelloy C276 a popular choice for high-temperature applications.
What is Hastelloy C-276?
Hastelloy C-276 (UNS N10276) is the first forged nickel-chromium-molybdenum alloy. Its extremely low carbon and silicon content effectively alleviates concerns during welding. Therefore, it is widely used in the chemical and related industries and boasts a 50-year track record of excellent performance in numerous corrosive chemical environments.
What is Nickel Alloy 20 (UNS N08020)?
Nickel Alloy 20, also known as UNS N08020, is a low-carbon, niobium-stabilized austenitic nickel-iron-chromium alloy with added molybdenum and copper. It exhibits excellent corrosion resistance in chemical environments containing phosphoric acid, nitric acid, chloride, and sulfuric acid. Furthermore, it maintains good mechanical properties at both room and high temperatures.
Hastelloy Alloy C-276 vs Nickel Alloy 20 Chemical Composition
| Element | Hastelloy C-276 Content (%) | Alloy 20 Content (%) |
|---|---|---|
| Nickel | Balance | 32–38 |
| Molybdenum | 15.0–17.0 | 2–3 |
| Chromium | 14.5–16.5 | 19–21 |
| Iron | 4.0–7.0 | ~35 |
| Tungsten | 3.0–4.5 | – |
| Cobalt | ≤ 2.5 | – |
| Manganese | ≤ 1.0 | ≤ 2 |
| Carbon | ≤ 0.01 | ≤ 0.07 |
| Vanadium | ≤ 0.35 | – |
| Phosphorus | ≤ 0.04 | ≤ 0.045 |
| Sulfur | ≤ 0.03 | ≤ 0.035 |
| Silicon | ≤ 0.08 | ≤ 1 |
| Copper | – | 3–4 |
| Niobium | – | ≤ 1 |
Comparison of Corrosion Resistance between Hastelloy C-276 and Nickel-Based Alloy 20
Nickel-based alloys inherently possess excellent corrosion resistance; therefore, both Hastelloy C-276 and Nickel-Based Alloy 20 exhibit excellent performance in corrosive environments.
Alloy 20 has a higher chromium content than C-276, thus enhancing its oxidation resistance. Therefore, compared to Alloy C-276, Alloy 20 exhibits superior oxidation resistance.
Comparison of Mechanical Properties between Hastelloy C-276 and Nickel-Based Alloy 20
In contrast, Hastelloy C-276 relies on solid solution strengthening with tungsten and molybdenum. Due to the large atomic radii of tungsten and molybdenum, they significantly improve the strength of Hastelloy C-276.
Alloy 20 exhibits good mechanical properties at both room temperature and high temperatures (up to approximately 500°C) and can be easily processed using conventional industrial processes.
| Alloy 20 | Hastelloy C-276 | |
|---|---|---|
| Density, g/cm³ | 8.10 | 8.89 |
| Density, lb/in.³ | 0.291 | 0.321 |
| Melting Range, °F | 2520-2600 | 2415-2500 |
| Melting Range, °C | 1385-1443 | 1323-1371 |
Hastelloy C276 and Alloy 20 Applications:
Alloy 20: Commonly used in the chemical industry, especially in the manufacture of equipment that comes into contact with sulfuric acid, as well as in food processing, pharmaceuticals, and pollution control systems.
Hastelloy C276: Commonly used in more demanding environments, such as chemical plants, marine environments, aerospace, and power generation-highly corrosive and high-temperature environments. It is widely used in the manufacture of reactors, heat exchangers, and other critical components.
Hastelloy C-276 and Nickel-Based Alloy 20: Key Standards
Hastelloy C-276: Key Standards
Seamless Tubes: ASTM B622, ASTM B983
Fittings: ASTM B366, ASTM B462
Bars: ASTM B574
Forgings: ASTM B564, ASTM B462
Plates, Sheets and Strips: ASTM B575
Nickel-Based Alloy 20: Key Standards
Seamless Tubes: ASTM B729, ASTM B829
Fittings: ASTM B462
Bars: ASTM B472
Forgings: ASTM B462
Plates, Sheets and Strips: ASTM B463, ASTM B906, ASTM A240
Summary of differences between Hastelloy C276 and Alloy 20:
| Property | Alloy 20 | Hastelloy C276 |
|---|---|---|
| Composition | Nickel, chromium, molybdenum, copper, iron | Nickel, molybdenum, chromium, tungsten |
| Corrosion Resistance | Good for sulfuric, nitric acids, and others | Excellent for wide range of acids and chlorides |
| Temperature Resistance | Up to 1000°F (537°C) | Up to 1040°C (1900°F) |
| Mechanical Properties | Good strength, suitable for most conditions | Superior strength, high-temperature resistance |
| Applications | Chemical, food, pharmaceutical industries | Chemical processing, marine, aerospace, high-temperature environments |
| Cost | More affordable | More expensive due to higher nickel content |
Gnee Steel is a professional manufacturer of various nickel-based alloys, including Nickel 201, Nickel 202, Hastelloy C-276, Hastelloy C-22, Hastelloy B, Hastelloy C-4, Inconel Alloy 600, Inconel 625, Inconel 718, Inconel X-750, Incoloy Alloy 800, Incoloy 800H/HT, Incoloy 825, Monel Alloy 400, Monel K500, and high-temperature alloys. We specialize in the production and sales of alloy materials. Gnee Steel's products are widely used in aerospace, chemical, power, automotive, and nuclear energy industries, and we can provide customized alloy material solutions according to customer needs. For alloy material price inquiries or to request customized alloy material solutions, please feel free to contact us at ru@gneesteelgroup.com for a quote.