Hastelloy is a family of nickel-based superalloys, made up of iron, chromium and molybdenum. It is the only wrought, nickel-chromium-molybdenum material to have such low levels of carbon and silicon, which makes it easy to form and weld.
Hastelloy C-276 is the most widely used Hastelloy and the first of its kind. It offers excellent corrosion resistance in a wide range of environments and media, including chlorides, sulfuric acid, and other hot acids. Its strength and versatility make it suitable for a variety of applications, such as chemical processing, power generation, oil and gas production, flue gas desulfurization (FGD) systems, pollution control systems, nuclear fuel reprocessing plants, pharmaceutical manufacturing equipment and more.
Its high chromium content gives Hastelloy excellent stress corrosion cracking resistance in chloride-bearing media while its molybdenum content provides great pitting resistance. The nickel content also imparts good ductility which makes Hastelloy easier to form into intricate shapes. In addition to its excellent corrosion resistance properties Hastelloy is highly resistant to heat, oxidation and carburization making it an optimal choice for components that are exposed to high temperatures or flame hardening.
The low levels of carbon and silicon found in Hastelloy make it much easier to weld than other alloys without sacrificing integrity or performance. This is an important factor when welding Hastelloy parts because the welding process often causes metal fatigue resulting in weakened structural integrity over time. By using Hastelloy C-276 alloy with low levels of carbon and silicon this risk can be significantly minimized.
What is Hastelloy material?
Hastelloy is a family of nickel-based superalloys, renowned for its excellent corrosion resistance, ductility and high-temperature strength.
Is Hastelloy Stainless Steel?
No, Hastelloy is not stainless steel. Hastelloy is a family of nickel-based superalloys that are made up of iron, chromium and molybdenum. It offers superior corrosion resistance compared to most stainless steels in a wide range of environments and media, including chlorides, sulfuric acid and other hot acids. Unlike stainless steels, Hastelloy has low levels of carbon and silicon which make it easier to form and weld without sacrificing integrity or performance. Furthermore, Hastelloy also offers high levels of heat resistance and oxidation resistance making it ideal for components exposed to high temperatures or flame hardening. Additionally, Hastelloy molybdenum content gives it excellent pitting resistance while its chromium content provides great stress corrosion cracking resistance in chloride-bearing media.
Are Hastelloy and Inconel the same?
No, Hastelloy and Inconel are not the same. Both are nickel-based superalloys, but Hastelloy contains iron, chromium, and molybdenum while Inconel is composed of nickel and chromium. Inconel offers superior corrosion resistance in oxidizing environments while Hastelloy has a higher resistance to chloride stress corrosion cracking and pitting. Hastelloy’s low levels of carbon and silicon make it easier to form and weld without sacrificing integrity or performance, whereas Inconel’s high nickel content makes it ductile but prone to crevice corrosion in some environments. Both Hastelloy and Inconel have excellent heat resistance and oxidation resistance; however, Hastelloy is better suited for components exposed to high temperatures or flame hardening due to its higher thermal conductivity. Furthermore, Hastelloy has better fatigue strength than Inconel due to its lower coefficient of thermal expansion. In summary, Hastelloy is ideal for applications that require corrosion resistance in highly acidic environments while Inconel is best suited for those that need more ductility with oxidizing media.
What grade is Hastelloy?
Hastelloy is available in a wide variety of grades, each with its own unique combination of corrosion resistance, ductility and temperature strength. The most popular grade of Hastelloy is Hastelloy C-276 alloy (UNS N10276). This particular grade contains a high amount of chromium (over 20%) which gives it excellent stress corrosion cracking resistance in chloride-bearing media and pitting resistance due to its molybdenum content. It also has low levels of carbon and silicon which makes Hastelloy easier to form into intricate shapes and weld without sacrificing integrity or performance. Other Hastelloy grades include Hastelloy B2 (UNS N10665), Hastelloy X (UNS N06002) and Hastelloy G30 (UNS N06030). Hastelloy B2 is widely used in highly acidic environments such as hydrochloric acid plants because it resists localized attack even at high temperatures. Moreover, Hastelloy X offers enhanced oxidation resistance up to 1290°C making it suitable for use in furnace components, combustors, exhaust systems and other high-temperature applications. Finally, Hastelloy G30 is the most economical grade owing to its lower cost while still retaining its excellent corrosion resistance capabilities. Overall, Hastelloy alloys offer superior corrosion resistance compared to most stainless steels across a wide range of environments and media including chlorides, sulfuric acid and other hot acids. They are also much easier to form into intricate shapes than stainless steel due to their low levels of carbon and silicon content. Combined with their exceptional heat resistance at high temperatures or flame hardening, Hastelloy alloys have become an essential part of many industries such as chemical processing, oil refining, power generation and various others where corrosive materials are present.
Nominal Composition
Hastelloy Material is a family of nickel-based superalloys, renowned for its excellent corrosion resistance, ductility and high-temperature strength. It is composed of a combination of nickel, molybdenum, chromium and iron, with low levels of carbon and silicon to facilitate welding capabilities.
Resistance to Pitting and Crevice Corrosion
Hastelloy Material is a family of nickel-based superalloys, known for its excellent corrosion resistance, ductility and high-temperature strength. It is made up of a combination of nickel, chromium, molybdenum and iron, with low levels of carbon and silicon to facilitate welding characteristics.
Resistance to Stress Corrosion Cracking
Hastelloy C-276 alloy is particularly well known for its resistance to stress corrosion cracking (SCC). This type of corrosion is caused by a combination of tensile stress, environment, and corrosive agents and can be extremely damaging if not addressed. Hastelloy C-276 has an exceptional ability to resist SCC due to
Resistance to Seawater Crevice Corrosion
Hastelloy C-276 alloy is renowned for its resistance to seawater crevice corrosion, making it ideal for use in marine environments where crevice corrosion can be a major issue. Its combination of nickel, chromium, molybdenum and iron makes Hastelloy extremely effective at preventing the formation of anodic pits which can lead to crevice corrosion. The low levels of carbon and silicon also allow Hastelloy to retain its strength even when exposed to temperatures up to 1000°F (537°C). Hastelloy has also been found to perform well in acidic and alkaline solutions, as well as brine and other aggressive fluids, giving it superior protection over other materials like stainless steel which are prone to pitting and crevice corrosion in such environments.
Corrosion Resistance of Welds
Hastelloy C-276 alloy is known to provide superior corrosion resistance and weldability. This makes Hastelloy an ideal choice for components that require welding in corrosive environments. The low carbon and silicon content of Hastelloy makes it highly resistant to heat, oxidation and carburization during the welding process, while still providing excellent structural integrity. This reduces the risk of welds deteriorating due to corrosion over time, which can be an issue when welding other metals due to increased porosity or other defects. Additionally, Hastelloy’s high molybdenum content further enhances its ability to resist a wide range of corrosives including acids, alkalis, organic compounds and chloride-bearing solutions which are especially prone to causing stress corrosion cracking. Furthermore, Hastelloy C-276 alloy is also extremely resistant to seawater crevice corrosion, making it the perfect choice for components that require thorough protection from harsh marine environments.
Physical Properties
Hastelloy C-276 alloy has excellent physical properties, making it an ideal material for a variety of applications. It has a high melting point of 1370°C (2498°F) and an ultimate tensile strength of up to 895 MPa (130 ksi). It also has a good modulus of elasticity, which is the measure of how much a material will return to its original shape after being bent or stretched. The alloy is highly resistant to thermal shock, making it well-suited for extreme temperatures and environmental conditions. Hastelloy C-276 can be machined with standard tools at room temperature and still maintain its superior characteristics. It also offers good formability and weldability due to its low carbon and silicon levels. The Hastelloy alloy is non-magnetic and retains its mechanical properties over a wide range of temperatures, allowing it to excel in many different applications.
Impact Strength
Hastelloy C-276 alloy is known for its superior impact strength which makes it an ideal choice for components subject to high levels of stress and strain. The alloy can resist deformation and crack even under extreme temperatures, and the presence of molybdenum helps to further enhance its impact resistance. Studies have shown that Hastelloy can withstand up to 1,059 J/m2 (58 ft. lbs/in2) in Charpy tests, making it one of the strongest alloys available on the market today.
Tensile Strength and Elongation
Hastelloy C-276 alloy is well known for its excellent tensile strength and elongation properties. It has a yield strength of 276 MPa (40 ksi) and a tensile strength of up to 515 MPa (74.9 ksi), which is higher than many other superalloys. The alloy also boasts an impressive elongation of 50%. This means Hastelloy can be stretched to more than twice its original length, making it an ideal choice for applications where flexibility and resilience are paramount, such as components in chemical processing plants. Furthermore, Hastelloy high tensile strength allows it to resist deformation under load, meaning Hastelloy parts remain strong and durable even after long-term usage.
Hardness
Hastelloy C-276 alloy is known for its superior hardness, which makes it suitable for use in applications where strength and durability are paramount. The hardness of Hastelloy can range from 35 HRC up to 45 HRC, depending on the composition and heat treatment used. This high level of hardness is due to the presence of molybdenum and chromium in Hastelloy chemical composition. As a result, Hastelloy has exceptional wear resistance and can withstand high mechanical loads without deformation or damage. Moreover, Hastelloy’s superior corrosion resistance also helps to protect against surface fatigue as Hastelloy also resists cracking, pitting and other forms of degradation in corrosive environments.
Welding and Fabrication
Hastelloy C-276 alloy is well suited for welding and fabrication due to its excellent corrosion resistance, ductility, and high-temperature strength. Welding Hastelloy does not require any special precautions as long as proper welding techniques are used. The low carbon and silicon content ensures that the welds remain resistant to metal fatigue and cracking. When welding Hastelloy, it is important to use the correct type of filler metals such as nickel-based alloys. Hastelloy can also be machined using conventional tools such as drills, taps, and dies. It has good machinability characteristics compared to other nickel-based alloys and can be easily fabricated into complex shapes.
