What are the differences between Hastelloy B3 and Hastelloy C-276?
What are the differences between Hastelloy B3 and Hastelloy C-276?
Hastelloy B-3 performs exceptionally well in non-oxidizing acids such as hydrochloric acid and possesses excellent thermal stability; while Hastelloy C-276 is a versatile "C-type" alloy rich in chromium and molybdenum, exhibiting broad corrosion resistance in both oxidizing and reducing environments. Therefore, B-3 is ideal for strongly reducing environments, while C-276 is suitable for a wide range of mixed chemical processes. The main difference between the two lies in their respective strengths: B-3 excels in resisting reducing acids, while C-276 is suitable for general corrosion resistance applications in various corrosive media (typically oxidizing media).
Is Hastelloy C276 resistant to hydrochloric acid corrosion?
C-276 alloy exhibits excellent corrosion resistance to sulfuric acid, hydrochloric acid, formic acid, acetic acid, chlorides, solvents, wet chlorine gas, hypochlorites, and chlorine solutions. C-276 alloy also demonstrates excellent corrosion resistance to phosphoric acid at all temperatures below the boiling point and at concentrations below 65%.
Hastelloy B-3 is a nickel-molybdenum alloy (nickel-based superalloy) whose core characteristic is its excellent corrosion resistance in reducing acid media (especially non-oxidizing acids such as hydrochloric acid, sulfuric acid, and phosphoric acid) and high-temperature chloride environments. It also significantly improves resistance to intergranular corrosion and thermal stability, addressing the processing brittleness issues of earlier B-2 alloys. It is designed for the most demanding corrosive conditions in chemical equipment, pharmaceutical industries, pickling equipment, and high-temperature reducing environments, making it one of the top material choices for handling strong reducing acid media.
Hastelloy C-276 is a nickel-molybdenum-chromium-tungsten superalloy (Hastelloy) whose core advantage is its almost universal corrosion resistance. It effectively resists strong oxidizing and reducing acids, mixed acids, chlorides, wet chlorine gas, and harsh acidic salt solutions, exhibiting exceptional performance in resistance to pitting corrosion, crevice corrosion, and stress corrosion cracking. It is designed for the most challenging corrosive industrial environments such as hydrometallurgy, chemical and pharmaceutical industries, flue gas desulfurization, waste incineration, and marine engineering, making it one of the top engineering materials with the broadest corrosion resistance range among commercially available alloys.
Chemical composition of Hastelloy C276 and Hastelloy B3
| Element | Hastelloy C-276 (wt%) | Hastelloy B-3 (wt%) |
|---|---|---|
| Nickel (Ni) | Balance | Balance |
| Molybdenum (Mo) | 15.0 - 17.0 | 24.5 - 26.5 |
| Chromium (Cr) | 14.5 - 16.5 | 1.0 - 3.0 |
| Iron (Fe) | 4.0 - 7.0 | 1.0 - 3.0 |
| Tungsten (W) | 3.0 - 4.5 | ≤ 0.50 |
| Cobalt (Co) | ≤ 2.5 | ≤ 3.0 |
| Manganese (Mn) | ≤ 1.0 | ≤ 3.0 |
| Carbon (C) | ≤ 0.01 | ≤ 0.01 |
| Silicon (Si) | ≤ 0.08 | ≤ 0.10 |
| Phosphorus (P) | ≤ 0.04 | ≤ 0.03 |
| Sulfur (S) | ≤ 0.03 | ≤ 0.01 |
| Vanadium (V) | ≤ 0.35 | ≤ 0.20 |
| Aluminum (Al) | - | ≤ 0.50 |
| Copper (Cu) | - | ≤ 0.20 |
Mechanical properties of Hastelloy C276 and Hastelloy B3
| Property | Hastelloy C-276 (Annealed Condition) | Hastelloy B-3 (Annealed Condition) |
|---|---|---|
| Tensile Strength (Ultimate) | 690 MPa (100 ksi) min | 760 MPa (110 ksi) min |
| Yield Strength (0.2% Offset) | 283 MPa (41 ksi) min | 350 MPa (51 ksi) min |
| Elongation (in 2 in / 50 mm) | 40% min | 40% min |
| Hardness (Rockwell B) | Rb 100 max | Rb 100 max |
| Modulus of Elasticity (Young's) | 205 GPa (29.7 x 10⁶ psi) | 205 GPa (29.7 x 10⁶ psi) |
| Density | 8.89 g/cm³ (0.321 lb/in³) | 9.22 g/cm³ (0.333 lb/in³) |
| Impact Energy (Charpy V-Notch) | Typically High (e.g., >100 J) | Typically High (e.g., >100 J) |
Hastelloy B3 vs. C276 Comparison – Corrosion Resistance
Both Hastelloy B3 and C276 exhibit excellent corrosion resistance. However, they each have advantages in different corrosive environments. Hastelloy B3 has particularly strong resistance to reducing acids and is often used in applications involving sulfuric and hydrochloric acids. Its cobalt content also enhances its resistance to certain types of localized corrosion, such as pitting and crevice corrosion. On the other hand, the higher molybdenum and tungsten content of Hastelloy C276 makes it perform better in terms of resistance to oxidizing acids, especially nitric acid. This alloy is often the ideal choice for applications involving oxidizing media or mixed acid environments.
Hastelloy B3 vs. C276 Comparison – Machinability and Weldability
Both Hastelloy B3 and C276 can be processed using a variety of techniques, including hot working, cold working, machining, and welding. However, their weldability varies depending on the specific alloy composition and welding conditions. Hastelloy B3 generally has good weldability, with minimal sensitization and carbide precipitation during welding. This allows for the production of strong and corrosion-resistant welds. Hastelloy C276 also has good weldability, but may require more stringent welding procedures and post-weld heat treatment to ensure optimal corrosion resistance.
Applications of Hastelloy B3 and C276 alloys
| Industry/Field | Hastelloy C-276 Applications | Hastelloy B-3 Applications |
|---|---|---|
| Chemical Processing | Reactors, columns, heat exchangers, and piping for sulfuric, hydrochloric, phosphoric acids and mixed acid/chloride streams. | Equipment for handling reducing acids like hydrochloric, sulfuric (especially in reducing conditions), and acetic acids. |
| Pollution Control | Flue gas desulfurization (FGD) systems, scrubbers, ducting, and stack liners exposed to wet chlorine and acidic condensates. | Scrubbers, piping, and vessels in chemical waste treatment and acid recovery systems. |
| Oil & Gas | Downhole tubing, casing, liners, valves, and fittings in sour gas (H₂S, CO₂, chlorides) environments. | Components for hydrochloric acid handling in acid stimulation (fracking) and pickling operations. |
| Pharmaceutical | Reaction vessels, piping, and heat exchangers where high purity and corrosion resistance are critical. | Equipment for the production and handling of aggressive pharmaceutical intermediates and concentrated acids. |
| Pulp & Paper | Digesters, bleach washers, and piping in chlorine dioxide and chlorinated environments. | Equipment exposed to concentrated sulfuric acid and chloride-containing liquors in pulp processing. |
| General Industry | Marine engineering components, industrial waste treatment systems, and pickling tanks. | Heat exchangers, evaporators, and piping for aggressive chemical services where reducing acids are predominant. |
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.