What is Hastelloy B3 and where is it used?
Nickel alloys have been in demand for quite some time now. These alloys are widely used due to their properties. In this blog, we will take a look at one such nickel alloy called Hastelloy B3. Read on to learn more about Hastelloy B3.
What is Hastelloy B3?
Hastelloy B3 is a member of the nickel-molybdenum family. It features thermal stability, which is better than alloys like Hastelloy B2 and Hastelloy c276. Hastelloy B3 has great resistance to pitting, corrosion, and cracking due to stress corrosion. This alloy of nickel also features an extraordinary resistance to acids like hydrochloric acid. It has resistance properties at different concentrations and temperature ranges.
Hastelloy B3 Chemical composition
Hastelloy B3 is an alloy made from nickel and molybdenum. It is considered a super-alloy due to its strength and various other characteristics. Here is the Hastelloy B3 chemical composition. This alloy contains around 65% nickel and 28% molybdenum, It also has elements like iron, manganese, tungsten, and cobalt. This alloy is commonly called Hastelloy B-3. However, it is also universally designated as UNS N10675. B3 Alloy is known for its resistance to acids like sulfuric, acetic, formic, and hydrochloric acids. This alloy is also known for its good thermal stability. This alloy of nickel has extremely good structural stability as compared to previous B-type alloys. This helps eliminate concerns during fabrication and welding.
Fabrication and Heat Treatment
The Hastelloy B3 alloy is an ideal option for cold-working techniques while forming components. This nickel allow hardens instantly during cold working. This leads to more stages of cold-working and annealing. The cold working process can further reduce Hastelloy B3’s resistance to stress corrosion cracking.
Characteristics of Hastelloy B3
- Corrosion Resistance
Hastelloy B3 is resistant to non-oxidizing acids. These acids include hydrochloric, sulfuric, and phosphoric acids. However, this alloy has a low chromium content. Thus, it should not be used in oxidizing acids or salts. Due to the presence of molybdenum, B3 alloy features resistance to chloride-containing localized corrosion. This includes chloride stress corrosion cracking and chloride-induced pitting and corrosion. If you want a corrosion-resistant alloy, you should opt for Hastelloy B3 alloy.
- High-Temperature Resistance
Hastelloy B3 does not have good oxidation resistance. Thus, it is limited to a maximum temperature of 427°C. Alloy B3 can be forged or hot worked, considering that it is held at 2250°F. This alloy is a low-carbon alloy. So, it may be necessary to use the lower hot finishing temperature to get the desired grain size control. This alloy can also be formed by cold working. This Hastelloy embrittles very quickly while heat treating. It normally takes several hours to turn brittle. Alloy B3 has a strong resistance to pitting stress-corrosion cracking.
- Mechanical Properties
This nickel alloy is provided in the low-strength annealed condition. This alloy maintains excellent toughness at cryogenic temperatures. Thus, it is recommended that alloy B3 should be used at cryogenic temperatures. This alloy possesses overall good forming and welding characteristics. A low carbon content allows Hastelloy B3 to be used in the welded state.
- Heat Treatment
This nickel alloy cannot be strengthened by heat treatment. This alloy is typically annealed at 1065°C. It is then followed by rapid cooling. Hastelloy, reportedly, should not be exposed to temperatures in the range of 593°C to 815°C for extended periods.
Alloy B3 can be cold-worked or hot-worked through standard methods using common techniques. This material is prone to rapid work hardening. To attain optimum corrosion resistance, it is important that solution annealing should be conducted after cold working.
Applications of Hastelloy B3
Hastelloy B3 is used in the chemical process industry. This is used to handle concentrated acids and other aggressive media. Some of the other uses include heat-treating fixtures, food processing, oil & gas, aerospace, and even nuclear power generation. Hastelloy B3 has several industrial applications.