Hastelloy is an important alloy to consider if you are looking for exceptional corrosion resistance and withstanding harsh conditions such as nuclear radiation. This article elaborates on the meaning of Hastelloy, its features, manufacturing process and applications.
What is Hastelloy material?
As the name suggests Hastelloy is an alloy like steel. To be more specific, it is a nickel-based alloy. Nickel is alloyed with molybdenum and chromium to form Hastelloy.
Hastelloy is further categorised into grades depending on the percentage of molybdenum and chromium. One of the most popular grades of Hastelloy is C276.
Some key features of the Hastelloy include:
- Corrosion resistance: Steel’s corrosion resistance abilities are limited, while Hastelloy features excellent corrosion resistance. The material can even withstand acids and aggressive chemicals. Additionally, it is resistant to pitting, crevice corrosion and stress corrosion.
- Fabricability: Hastelloy can easily be formed or fabricated with various techniques including welding, machining, etc.
- Resistant to high temperatures: Hastelloy can withstand high temperatures and hence can be used in harsh temperatures such as aerospace, chemical processing, oil & gas industry and so on.
- Magnetic permeability: Hastelloy is known for its non-magnetic features. This characteristic is advantageous in certain applications.
Here are some of the important properties of Hastelloy.
|Tensile strength||655 MPa|
|Yield strength||275 MPa|
How is Hastelloy made?
Hastelloy is normally made using the following method. The manufacturing method may vary depending on the manufacturer, grade, technology used and so on. However, the following is the commonly used method.
- Choosing raw materials: The first step is to choose the right quality raw materials. As mentioned earlier, Hastelloy mainly contains nickel, chromium and molybdenum. Broadly speaking, percentages of these raw materials are 1% and 25% chromium, between 5% and 30% molybdenum. It may or may not contain iron. Moreover, depending on the grade, other materials such as carbon, tungsten, vanadium, titanium, etc., can also be used to make Hastelloy.
- Melting: Once the raw material is gathered, they are melted in the furnace. Depending on the manufacturer, an electric arc furnace or vacuum induction furnace is used.
- Casting: Like steel casting, Hastelloy also undergoes casting. When the materials are melted and well combined, the next step is casting. According to requirements, molten Hastelloy is cast in the form of billets, bars, sheets or any other form.
- Heat treatment: As per the requirement, Hastelloy undergoes heat treatment. It improves the mechanical properties of the metal.
- Other treatments: Making Hastelloy may also involve other treatments such as annealing, surface finish, cutting and machining, and so on.
- Testing and inspection: The final step of Hastelloy making is testing and inspecting the product if meets all required standards.
Like steel and stainless steel, Hastelloy is also made in several grades. Here are some of the popular Hastelloy grades:
|Hastelloy C276 (UNS N10276)||Excellent resistance to a variety of corrosive chemicals, radiation resistance|
|Hastelloy B2 (UNS N10665)||Resistant to hydrochloric acid at high concentrations and temperatures|
|Hastelloy B3 (UNS N10675)||Improved thermal stability compared to B2, highly resistant to hydrochloric acid and other strong acids|
|Hastelloy X (UNS N06002)||High-temperature strength and oxidation resistance.|
|Hastelloy C-22 (UNS N06022)||Resistance to a wide range of chemicals, including aggressive oxidizers and reducing acids, resistance to pitting and crevice corrosion|
|Hastelloy G30 (UNS N06030)||Resistant to sulfuric and phosphoric acids|
|Hastelloy N (UNS N10003)||Resistance to both oxidizing and reducing environments|
|Hastelloy C-2000 (UNS N06200)||Excellent resistance to a wide range of chemicals and corrosive environments|
Hastelloy C276: Chemical composition
Hastelloy C276 alloy is also known as UNS N10276. The chemical composition of C276 includes nickel, chromium, and molybdenum. As a result, it offers exceptional resistance to chloride stress cracking and pitting corrosion. This remarkable resistance is primarily attributed to its elevated levels of chromium and molybdenum.
One of the most important features of C276 grade is radiation resistance. As a result, it is used in nuclear applications.
Applications of Hastelloy
Here are some of the common applications of Hastelloy.
Since Hastelloy is resistant to a wide range of chemicals and chemical processing, it is widely used in the chemical industry. It is commonly used for handling corrosive acids, strong oxidizers, and aggressive chemicals. Hence it is commonly used to handle sulfuric acid, acetic acid, and hydrochloric acid. Moreover, it is also used in reactors, heat exchangers, and piping systems. Additionally, it is used in the agrochemical industry to handle agricultural chemicals and pesticides.
Oil & gas industry
Hastelloy is typically deployed in offshore and onshore applications. It is also widely used in gas exploration and production as it is resistant to sour gas and corrosive environments.
It is yet another industry that needs corrosive-resistant materials. Like stainless steel, Hastelloy is also widely used in the pharma industry. It is mainly used for various equipment such as reaction vessels and storage tanks where high purity and corrosion resistance are critical.
Hastealloy is capable of handling high temperatures and harsh environments. Therefore, it is commonly used for making aerospace components such as engine parts.
Marine industry and desalination plants
Since Hastelloy does not corrode in saltwater, it is an important material to be used in the marine industry and desalination plants.
Some of the other industries that use Hastelloy include:
- Power generation – For flue gas desulfurization (FGD) systems, heat exchangers, and other components
- Pollution control – For scrubbers used in neutralising acidic gases
- Food & beverage processing – In equipment that need to withstand highly acidic or corrosive cleaning solutions.
- Electronics – For making components.