Hastelloy B2 is a nickel-based alloy containing elements such as chromium, molybdenum, and iron. It is known for its excellent corrosion resistance. Below, we will detail the corrosion resistance of Hastelloy B2 and explain why it is widely used in various industrial fields.
Hastelloy C-276 belongs to nickel-molybdenum-chromium-iron-tungsten nickel-based alloy, which is one of the most corrosion-resistant modern metal materials.
Hastelloy X is a nickel-based superalloy known for its exceptional high-temperature strength and oxidation resistance.
3 Key Points About Corrosion Resistance of Hastelloy B2
First of all, Hastelloy B2 has excellent acid resistance. It can withstand the erosion of strong acids, including sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, etc. Compared to other alloy materials, Hastelloy B2 exhibits higher stability and corrosion resistance in acidic environments. This makes it an ideal choice for handling strong acids in the chemical, pharmaceutical, food processing, and other industries.
Secondly, Hastelloy B2 also has outstanding resistance to chlorine and chlorides. Chlorides are one of the common corrosive substances, especially in chloride-containing environments such as seawater. The high molybdenum content of Hastelloy B2 makes it less susceptible to the adsorption and migration of chloride ions, thus effectively resisting corrosion caused by chlorides. This characteristic makes Hastelloy B2 commonly used in fields such as marine engineering, chemical plants, and seawater treatment equipment.
In addition, Hastelloy B2 also has excellent acid oxidation resistance. Few alloy materials can maintain stable performance in high-temperature and high-concentration acidic environments. However, Hastelloy B2 can maintain its mechanical properties and corrosion resistance in acidic environments, and has resistance to oxidation and erosion by strong acids such as sulfuric acid and nitric acid. Therefore, it is widely used in high-temperature acidic environments in the chemical, petroleum, metallurgical, and other industries.
It is worth mentioning that Hastelloy B2 can also resist the corrosion of various organic acids and oxidants. It performs well in organic acid solutions such as acetic acid, citric acid, and formic acid, making it suitable for applications in the food and pharmaceutical industries. In addition, it can also resist the corrosion of sulfuric acid oxidants, making it widely used in the chemical industry.
Resistance to Hydrochloric Acid
Hastelloy B-2 is specifically designed to resist corrosion in pure hydrochloric acid across all concentrations and temperatures.
- It performs exceptionally well in environments where hydrochloric acid is present, making it ideal for industries handling concentrated HCl.
- Unlike many alloys, it resists both general corrosion and pitting in hydrochloric acid.
Resistance to Reducing Environments
- Hastelloy B-2 excels in reducing conditions, where the environment lacks oxygen or other oxidizing agents.
- This includes resistance to hydrogen chloride gas, sulfuric acid, and other reducing chemicals commonly found in chemical processing.
Resistance to Localized Attack
- Hastelloy B-2 excels in reducing conditions, where the environment lacks oxygen or other oxidizing agents.
- This includes resistance to hydrogen chloride gas, sulfuric acid, and other reducing chemicals commonly found in chemical processing.
Limitations in Oxidizing Environments
While Hastelloy B-2 has superior resistance in reducing conditions, its performance in oxidizing environments is limited:
- It is not suitable for oxidizing agents, such as nitric acid or ferric chloride, which can cause rapid corrosion.
- Exposure to oxidizing contaminants in reducing acids, even in small amounts, can significantly impair its corrosion resistance.
Sensitivity to Heat
Hastelloy B-2 is sensitive to the formation of carbides and other phases in its microstructure when exposed to elevated temperatures (above 1000°F or 540°C). These phases can reduce its corrosion resistance.
- To mitigate this, Hastelloy B-2 is usually used in its solution-annealed condition, where it retains its optimal corrosion resistance.
Applications Benefiting from its Corrosion Resistance
Thanks to its corrosion-resistant properties, Hastelloy B-2 is commonly used in:
- Chemical Processing: Vessels, reactors, heat exchangers, and piping systems handling hydrochloric acid, sulfuric acid, or other reducing agents.
- Pharmaceutical Industry: Equipment exposed to highly corrosive substances.
- Pollution Control: Components exposed to acidic waste gases or liquids.
- Pickling Operations: Resistant to strong acids used in cleaning and descaling metals.
Comparison with Other Alloys
| Feature | Hastelloy B-2 | Hastelloy C-22 | 316 Stainless Steel |
|---|---|---|---|
| Corrosion Resistance (Reducing) | Exceptional (e.g., hydrochloric acid) | Moderate | Limited |
| Corrosion Resistance (Oxidizing) | Limited | Excellent | Moderate |
| Resistance to Pitting/Crevice | High | Very High | Moderate |
| Stress Corrosion Cracking (SCC) | Excellent | Excellent | Susceptible |
Key Benefits of Hastelloy B-2's Corrosion Resistance
- Specialized Performance: One of the best materials for pure reducing acid environments.
- Versatility: Suitable for handling highly corrosive processes that involve hydrochloric acid and other strong acids.
- Durability: Resistant to localized corrosion, ensuring long service life in aggressive environments.
Why Choose Huaxiao Alloy?
In summary, Hastelloy B2 is widely favored for its excellent corrosion resistance. It can resist the erosion of various corrosive substances such as acids, chlorides, and oxidants, making it widely used in the fields of chemical, pharmaceutical, food processing, and marine engineering.
Thank you for reading our article and we hope it can help you to have a better understanding of the corrosion resistance of Hastelloy B2. If you want to learn more about Hastelloy B2, we would advise you to visit Huaxiao Alloy for more information.
As a leading supplier of Hastelloy Alloys across the world, Huaxiao Alloys provides customers with high-quality Hastelloy B2, Hastelloy X alloy, Hastelloy C4, Hastelloy C-276, and Hastelloy C22 at a very competitive price.
Hastelloy C-276 belongs to nickel-molybdenum-chromium-iron-tungsten nickel-based alloy, which is one of the most corrosion-resistant modern metal materials.
Hastelloy X is a nickel-based superalloy known for its exceptional high-temperature strength and oxidation resistance.
Hastelloy B2 is a high-performance nickel-based alloy primarily composed of nickel (about 60-70%) and molybdenum (about 30%), with trace amounts of iron and other elements. It is specifically designed for excellent resistance to hydrochloric acid and other highly corrosive environments. Hastelloy B2 is often used in chemical processing industries, particularly where materials are exposed to reducing acids and aggressive conditions. Its corrosion resistance, especially in hydrochloric acid environments, makes it ideal for applications such as heat exchangers, reactors, and piping systems.
The corrosion rate of Hastelloy B2 depends on the specific environment it is exposed to. In general, Hastelloy B2 exhibits exceptional resistance to corrosion in highly reducing environments, such as hydrochloric acid and other chlorides. The corrosion rate can be extremely low (in the range of microns per year) in these conditions, but it increases when exposed to oxidizing agents. For example, in 100% HCl at ambient temperatures, the corrosion rate is typically negligible, while in mixed acid environments or in oxidizing conditions, its rate increases.
The density of Hastelloy B2 is approximately 8.89 g/cm³ (8890 kg/m³). This density is relatively high due to its high nickel and molybdenum content, which are denser elements compared to other common metals.
Hastelloy B2 has several equivalents in other alloy systems, though it is unique due to its molybdenum content and resistance to hydrochloric acid. Some equivalents include:
- Monel 400 (Nickel-Copper Alloy): In some applications where acid resistance is not as critical, Monel 400 can be used, though it has lower resistance to hydrochloric acid than Hastelloy B2.
- Inconel 600: For high-temperature applications, Inconel 600 may serve as an alternative, although it is more suited for oxidizing environments.
- Haynes 25: This alloy is also designed for aggressive chemical environments but may offer slightly different characteristics in terms of mechanical properties and corrosion resistance.
Hastelloy B2 is highly resistant to corrosion primarily due to its composition, which includes a high percentage of molybdenum. Molybdenum enhances the alloy’s resistance to pitting, crevice corrosion, and stress corrosion cracking, particularly in aggressive acid environments such as hydrochloric acid. The alloy’s nickel base also contributes to its ability to withstand a wide range of corrosive chemicals, while the minimal presence of chromium reduces the risk of oxidation and improves its resistance to reducing acids.
An acceptable corrosion rate depends on the application and the expected lifetime of the material. In general, a corrosion rate of less than 0.1 mm per year is considered acceptable for most applications in corrosive environments. For critical applications in harsh chemicals, a corrosion rate of less than 0.01 mm per year may be required to ensure the material remains functional over a long period. In environments where Hastelloy B2 is employed, the corrosion rate can often be much lower due to its excellent resistance properties.
While both Hastelloy B3 and B2 are designed for resistance to highly corrosive environments, particularly hydrochloric acid, the key differences are:
- Chemical Composition: Hastelloy B3 is a slightly modified version of B2, with a lower iron content and more carbon, improving its resistance to oxidizing environments and enhancing its resistance to stress corrosion cracking.
- Corrosion Resistance: Hastelloy B3 offers better resistance to high-temperature environments and certain oxidizing acids, whereas B2 is more resistant to reducing acids like hydrochloric acid.
- Mechanical Properties: B3 typically has better weldability and is less prone to forming the deleterious phases that can appear in B2 during welding.
- Specialized Performance: One of the best materials for pure reducing acid environments.
- Versatility: Suitable for handling highly corrosive processes that involve hydrochloric acid and other strong acids.
- Durability: Resistant to localized corrosion, ensuring long service life in aggressive environments.
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