Hastelloy B3 Round Bars vs Hastelloy B2 – What’s the Difference

Hastelloy B3 and Hastelloy B2 are two commonly used nickel-based alloys that offer excellent resistance to corrosion and high-temperature applications. While both of them share similar attributes, they have some distinct differences that set them apart from each other. This blog explores the differences between Hastelloy B3 round bars and Hastelloy B2 and highlights their unique advantages. Let’s dive into the details.

What is Hastelloy B3 Round Bar and Hastelloy B2?

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.

Difference Between Hastelloy B3 Round Bar vs Hastelloy B2

Chemical Composition:

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).

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 Round Bars 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.


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.


Due to its high resistance to chemical environments and its ability to handle contaminants and sulfuric acids, Hastelloy B3 is used for chemical processing, chemical storage, and pharmaceutical and food processing applications. At the same time, Hastelloy B2 is used for handling and transporting fluids in the chemical and petrochemical processes and seawater.


Hastelloy B3 Round Bars and Hastelloy B2 are excellent nickel-based alloys with unique benefits. Hastelloy B3 offers better resistance to a broader range of chemicals, while Hastelloy B2 handles high-temperature applications better. Choosing between the two alloys mainly depends on the substances to be handled and the environment in which they will be used. So, it’s essential to consult with experts before choosing the best one for specific applications. With these differences in mind, you can now decide when selecting which alloy to use for your application.

Hastelloy B3 Round Bars vs Hastelloy B2 – What’s the Difference

by AB Steel time to read: 3 min