What Is The Difference Between Hastelloy B2&B3

Differences in chemical composition of Hastelloy B2 & B3

Hastelloy B3 has a higher nickel content than Hastelloy B2, which makes it much more resistant to a broader spectrum of corrosive chemicals. Hastelloy B3 includes up to 69% nickel compared to Hastelloy B2’s 65% nickel composition. Hastelloy B3 also contains molybdenum, making it more resistant to pitting and crevice corrosion.

Hastelloy B3 and Hastelloy B2 are two high-performance nickel alloys known for their excellent corrosion resistance in various aggressive media. Both alloys contain nickel, molybdenum, chromium, tungsten, iron, manganese and copper as primary alloying elements. The major difference between these two alloys is that Hastelloy B3 typically contains higher Niobium levels, improving its corrosion resistance properties in certain oxidizing environments. In addition to this increased Niobium content, the composition of both alloys varies slightly concerning amounts of Nickel (Ni), chromium (Cr), Molybdenum (Mo) and Cobalt (Co).

Hastelloy B3 and B2 are two types of nickel-base alloys used in various manufacturing applications. Both contain molybdenum, chromium, tungsten, and alloying elements like iron or carbon. Hastelloy B3 is highly resistant to hydrochloric acid in all concentrations and temperatures, while Hastelloy B2 has higher resistance against hydrofluoric acid. They also have very good thermal stability withstanding up to 1,000° Fahrenheit (537 °C). The main difference between the two is their composition; Hastelloy B3 has slightly lower oxidation resistance than the more corrosion-resistant Hastelloy B2. Both can be formed into round bars for use in heat exchangers, pressure vessels, chemical reactors pump and valve components, among other uses.

Differences in the properties of Hastelloy B2 & B3

Machinability:

Hastelloy B3 may be difficult to machine due to its high nickel content, which causes it to work harden quickly. Hastelloy B2, on the other hand, is more machinable and has better formability than Hastelloy B3. Hastelloy B2 is considered the most machinable of all Hastelloy grades due to its relatively soft nature. It can be easily drilled, cut, and tapped without losing strength or corrosion resistance properties. In comparison, Hastelloy B3 is not as machinable as B2 but still offers a satisfactory cutting response and good ductility when heated during machining operations. Both materials demonstrate superior performance in terms of hardness, creep-rupture strength, stress-corrosion cracking, intergranular corrosion resistance, and oxidation resistance at high temperatures.

Temperature Resistance:

This is where Hastelloy B2 stands out. It can perform up to 1,200 °C (2,200 °F), making it an ideal choice for high-temperature applications. Hastelloy B3 can handle temperatures up to 1,070 °C (1,950 °F), a bit lower than Hastelloy B2.

Hastelloy B3 and Hastelloy B2 offer excellent temperature resistance for high-temperature applications. In the 30-40°C range, both metals have been tested to resist oxidation without deformation or discolouration. The main difference between them is that Hastelloy B3 has superior corrosion resistance and mechanical strength compared to Hastelloy B2, making it a better choice for environments with frequent temperature changes in this temperature range.

Resistance to Corrosion:

Both alloys are corrosion-resistant, but Hastelloy B3 offers better resistance to a broad spectrum of chemicals such as hydrochloric acid, sulfuric acid, and phosphoric acid. In contrast, Hastelloy B2 is ideal for use in reducing environments like hydrogen chloride gas, hydrofluoric acid, and acetic acid. Hastelloy B2 exhibits exceptional resistance to non-oxidizing acids like sulphuric, hydrochloric acid, and reducing media. The main difference between Hastelloy B3 and B2 is their corrosion resistance. Hastelloy B3 has superior corrosion resistance in hydrochloric acid at all concentrations and temperatures, compared to the moderate resistance of Hastelloy B2. In addition, Hastelloy B3 has a higher dissolved molybdenum content than its counterpart, which provides better protection against pitting and crevice corrosion in oxidizing media. When comparing hastelloy series alloys for corrosive environments, try to match the specific chemical environment with the appropriate alloy, as both have clear advantages depending on your application.

In terms of fabrication characteristics, both alloys exhibit good formability and machinability—through hardness values may vary depending on heat treatment methods used during fabrication. For example, some Hastelloy B2 has been known to achieve Rockwell Hardness values up to 44 HRC when hardened at temperatures above 1050°F (566°C). In comparison, some grades of Hastelloy B3 have been known to reach Rockwell Hardness values up to 41 HRC in their annealed condition—making them easier to machine while still providing excellent strength and wear resistance properties.

Another key difference between these two alloys is their melting point. While both alloys have relatively high melting points (B2 has a melting point of 2467°F and B3 has a melting point of 2510°F), the higher melting point of Hastelloy B3 makes it better suited for welding operations that require high levels of heat input or long hold times at elevated temperatures (e.g., annealing). Additionally, because the melting point is so close to the operating temperature range for both alloys, they can be welded without preheating or post-welding heat treatments—making them ideal for use in many industrial applications.

In summary, Hastelloy B2 and Hastelloy B3 are both excellent choices for corrosion-resistant applications, particularly in highly acidic environments. Hastelloy B3 provides enhanced resistance to hydrochloric acid and has better performance at higher temperatures. On the other hand, Hastelloy B2 offers superior resistance to sensitization. The choice between these alloys depends on the specific corrosive environment and the required mechanical properties for the application. It is advisable to consult with material specialists or engineers to determine the most suitable alloy for a particular application.