Hastelloy, as an expensive alloy with greater strength and toughness than stainless steel, occupies a very important position in the high-end manufacturing field. It can maintain good strength in high-temperature environments, is not easy to deform, and has strong resistance to oxidation and reduction, meeting the needs of use in various extreme environments. Below we will provide a systematic explanation of this material.
What is hastelloy
Hastelloy is a high-performance corrosion-resistant alloy based on nickel metal, with the addition of chromium, molybdenum, and tungsten, fused uniformly at a high temperature of about 1000°C. The natural color of the metal is silver-white, but after high-temperature treatment or other specific processing, a dark golden tiger-pattern oxide layer will form on the surface. Hastelloy materials are mainly divided into three categories: B, C, and G. It is mainly used in strongly corrosive environments where iron-based Cr-Ni or Cr-Ni-Mo stainless steel and non-metallic materials cannot be used. It has been widely applied abroad in petroleum, chemical, environmental protection, and many other fields.
How to Manufacture Hastelloy
The manufacturing process of Hastelloy usually begins with the strict selection of high-purity raw materials such as nickel, chromium, and molybdenum. These are then subjected to vacuum induction melting (VIM) at approximately 1450–1550°C (vacuum level about 10⁻³–10⁻⁴ Torr). If necessary, vacuum arc remelting (VAR) is used for further refining, with the aim of reducing impurity content and improving structural uniformity.
After melting, the alloy is cast into ingots, then forged at about 1200–1250°C (forging ratio generally ≥4:1), followed by hot rolling or hot extrusion to refine grains and improve density. Subsequently, solution treatment is carried out at 1050–1150°C (holding for about 30–60 minutes and rapidly cooled for annealing). Some grades also require aging treatment to precipitate strengthening phases. Finally, surface cleaning and inspections of chemical composition, mechanical properties, and corrosion resistance are performed to ensure the alloy meets application standards.
Hastelloy composition
Hastelloy uses three categories of grades: B/C/G, because their material composition ratios differ to meet the needs of different environments.
Hastelloy B-2 (N10665)
B-2 is a typical high-molybdenum, low-chromium nickel-based alloy, with nickel (about 70%) as the matrix, very high molybdenum content (26%–30%), and extremely low chromium content (≤1%). This composition gives it excellent corrosion resistance in strongly reducing environments (such as hydrochloric acid), but relatively weaker performance in oxidizing environments. The overall characteristic is “high Mo, low Cr”.
Hastelloy B-3 (N10675)
B-3 is an optimized version based on B-2, with about 65% nickel + high molybdenum (28%–32%), while appropriately increasing chromium (1%–3%) and improving alloy element control. Its advantages lie in better thermal stability and stronger resistance to intergranular corrosion, making it suitable for more complex working conditions. Overall, it is an “improved high-Mo alloy”.
Hastelloy C-276 (N10276)
C-276 is a typical multi-element synergistic corrosion-resistant alloy. Based on nickel (about 57%), it adds relatively high chromium (14.5%–16.5%), molybdenum (15%–17%), and tungsten (3%–4.5%). This combination gives it excellent corrosion resistance in both oxidizing and reducing environments, especially outstanding resistance to pitting and crevice corrosion. Hastelloy C276 is one of the most widely used general-purpose corrosion-resistant grades.
Hastelloy C-22 (N06022)
Hastelloy C22 is a further improved version based on Hastelloy C276. It features higher chromium content (20%–22.5%) + medium molybdenum (12.5%–14.5%) + tungsten. This adjustment significantly enhances its corrosion resistance in strongly oxidizing media while maintaining good resistance to localized corrosion. It belongs to the “C-series alloy optimized for oxidizing environments”.
Hastelloy G-30 (N06030)
G-30 is characterized by high chromium (30%–35%) + medium-low molybdenum (5%–7%) + added copper (2%–3%), with relatively low nickel content (about 43%). This composition design gives it excellent performance in strongly oxidizing acids (especially nitric acid and fluorine-containing environments). The addition of copper improves its adaptability to certain acidic media, making it a typical “high-Cr oxidation-resistant alloy”.
In one sentence summary: Hastelloy B series is designed for strong reducing corrosion resistance (such as hydrochloric acid), Hastelloy C series achieves a balance of corrosion resistance in both oxidizing and reducing environments, and G series Hastelloy performs excellently in oxidizing environments.
Hastelloy properties
Physical properties:
Density: Usually between 8.6–9.2 g/cm³, belonging to high-density metal materials. This means it has a dense structure and high strength, making it more stable in high-pressure, sealing, and corrosion-resistant equipment, but it also increases component weight.
Melting point: Approximately 1325–1418°C, reflecting good high-temperature resistance. A high melting point means the material is not easily softened or failed under high-temperature conditions (such as chemical reactors and heat exchange equipment).
Thermal conductivity: About 9–11 W/(m·K) at room temperature, increasing to about 18–19 W/(m·K) as temperature rises. This indicates moderate to low thermal conductivity, helping to slow rapid heat transfer in high-temperature corrosive environments and improve system stability.
Specific heat capacity: About 370–425 J/(kg·K), slightly increasing with temperature. The material heats up more slowly after absorbing heat, which helps buffer temperature fluctuations and provides good thermal stability.
Electrical resistivity: About 1.2–1.37 μΩ·m (or about 137 μΩ·cm), belonging to relatively high-resistance materials. This indicates poor electrical conductivity, but it can be advantageous in certain corrosion-resistant electrical or heating applications.
Elastic modulus: About 200–217 GPa, slightly decreasing as temperature rises. The material has high rigidity and small deformation under stress.
Coefficient of thermal expansion: About 10.3–12.4×10⁻⁶/K, with little change as temperature increases. This means the material undergoes small dimensional changes with temperature variation, helping maintain dimensional stability and sealing performance in thermal cycles.
Mechanische Eigenschaften:
Tensile strength: Generally between 690–960 MPa. The higher the value, the stronger the load-bearing capacity, making it suitable for high-pressure and high-load conditions.
Yield strength (0.2% offset): Usually in the range of 283–417 MPa, indicating good structural stability.
Elongation (A5): About 40%–53%. It has good plasticity and toughness, allowing large deformation before fracture, making it less prone to brittle failure and suitable for complex processing and impact-resistant conditions.
Hardness: Approximately HBW 90–110 HRB. Medium hardness, providing wear resistance while retaining good machinability (such as cold working and welding).
Electrical properties:
The electrical properties of Hastelloy vary slightly depending on the grade, but overall it exhibits relatively high resistivity (about 1.2–1.4 μΩ·m or equivalent) and low conductivity, significantly lower than copper and aluminum but better than ordinary stainless steel. Its resistivity increases slightly with temperature, showing good high-temperature stability. At the same time, in strongly corrosive environments such as strong acids, alkalis, and chlorine-containing media, its electrical properties change very little and can remain stable for long periods. Therefore, it is suitable for electrical connections, sensors, and functional components in high-temperature and strongly corrosive conditions.
Korrosionsbeständigkeit
Different series of Hastelloy have their own focus in corrosion resistance:
B series (such as B-2, B-3) has extremely strong corrosion resistance to strong reducing media such as hydrochloric acid and hydrofluoric acid, but performs relatively weakly in oxidizing environments;
C series has the strongest comprehensive performance, among which C-276 is suitable for a variety of mixed oxidizing and reducing environments, C-22 is better in strongly oxidizing media, and C-2000 has top-level corrosion resistance in both oxidizing and reducing environments;
G series (such as G-30), under the action of high chromium, shows outstanding corrosion resistance to oxidizing mixed acids such as phosphoric acid and sulfuric acid.
Overall, Hastelloy relies on elements such as Cr, Mo, and W to form a stable protective film, which can effectively resist uniform corrosion, pitting corrosion, crevice corrosion, and stress corrosion cracking. The specific selection needs to be determined comprehensively according to the medium properties, temperature, and concentration.
Common forms of Hastelloy
The initial processed form of Hastelloy is ingots, which are then made into plates, pipes, bars, and other shapes through rolling, forging, extrusion, and drawing for subsequent processing and use. The following are common forms of Hastelloy:
1. Bars & Profiles
Round Bars : This is the most common form of Hastelloy. With high strength and resistance to acid, alkali, and corrosion, it is used to manufacture core transmission components such as pump shafts and valve stems, as well as high-strength bolts, nuts, and other fasteners and electrodes.
Special-shaped Bars : Including hexagonal, square, and rectangular cross-sections, designed to meet specific assembly and structural requirements, reducing subsequent machining. Commonly used for manufacturing heavy-duty nuts, valve handles, keys, sliders, and special supporting structural components.
Wire : Usually supplied in coil form, with excellent flexibility and welding continuity. It is used as welding wire to ensure that the weld seam has the same corrosion resistance as the base material. It is also used to manufacture precision springs, wire meshes, and filter elements in strongly corrosive environments.
2. Plates, sheets & Strips
Plates (Hastelloy Sheets): Thickness 0.5mm-150mm, Hastelloy thin plates and medium-thick plates, surface treated by pickling, grinding or polishing. Hastelloy metal plates can provide corrosion-resistant barriers and are used in reactor shells and heads, heat exchanger tube sheets and shells, tank linings, chimney linings, as well as heavy flanges and piping systems.
Hastelloy Strips : Narrow and thin Hastelloy coils, mainly used for bellows or stamped parts. With good flexibility and dimensional accuracy, suitable for continuous stamping processing, mainly used to manufacture metal bellows (expansion joints), sealing gaskets, spring washers, cable sheaths and various precision stamped structural parts.
Hastelloy Foil : Extremely thin Hastelloy foil (usually less than 0.1mm), used in precision instruments. With ultra-thin characteristics and high specific surface area, the surface is free of pinholes and has good smoothness. Commonly used for trace medium isolation or high-precision sensing. Used in high-temperature/strong corrosion environments for sealing foils, precision sensor diaphragms, battery current collectors, electromagnetic shielding layers and isolation layers in the nuclear industry.
3. Pipes & Tubes
Seamless Pipes : Made from solid Hastelloy billets through hot extrusion and cold rolling, with no weld seams throughout the entire length and a uniform and dense structure. Seamless Hastelloy pipes are used in high-pressure pipelines in chemical plants, nuclear cooling systems, deep-sea oil and gas, and boilers, often paired with hastelloy pipe fitting.
Welded Pipes : Hastelloy welded pipes are formed by rolling steel plates or strips and then longitudinally welded using processes such as plasma or laser welding. Compared with seamless pipes, they offer higher production efficiency, cost advantages, and more flexible dimensions, allowing large-diameter pipes, and are commonly used with hastelloy fittings.
Capillary Tubes : Hastelloy capillary tubes are high-precision hastelloy tubing with an outer diameter of about 0.2–6mm and extremely thin walls. They require precision drawing, grinding, cleaning and inspection processes, featuring high dimensional accuracy and excellent inner wall smoothness. Materials (such as C-276) have excellent corrosion resistance, high temperature and high pressure resistance, and resistance to pitting, enabling stable operation in strongly corrosive environments.
4. Forgings & Semi-finished
These are usually raw materials used for further processing.
Forgings : Manufactured through forging processes, with better density and strength, commonly used to produce key components such as flanges, elbows, valve bodies, etc.
Ingots & Billets : Primary shapes after smelting, used for subsequent rolling or forging, and can also be used for cnc machining to customize more reliable parts.
5. Special forms
Wire Mesh : Hastelloy wire mesh (such as C-276, B-2, C-22) is woven in plain or twill weave, which can effectively intercept fine particles and block electromagnetic interference. Used in filtration and screening in the chemical and petroleum industries, protection of flue gas desulfurization and denitrification equipment, filtration systems in nuclear facilities and precision filtration in biopharmaceuticals, ensuring separation performance in extreme environments.
Powder : Hastelloy powder (common grades such as Hastelloy X, Hastelloy C-276, Hastelloy C-22) is produced by advanced atomization processes, with high purity, good fluidity and sphericity, specially designed for additive manufacturing (3D printing) and powder metallurgy. Used in high-temperature components of aerospace engines, complex flow channel parts in the chemical field and customized components in the nuclear industry, enabling rapid forming and repair of high-performance alloys under extreme conditions.
To help you understand more intuitively, the following table is organized:
| Shape Category | Specific Forms | Typische Anwendungen |
| Hastelloy bars | Round bars, hex bars, ground bars | Bolts, nuts, washers, pump components, valve stems |
| Hastelloy plates | Sheets, medium/thick plates, strips | Chemical vessel linings, heat exchangers, reactors |
| Hastelloy tubes | Seamless tubes, capillary tubes | Fluid pipelines, instrumentation tubing |
| Hastelloy forgings | Flanges, elbows, fittings | Pipe connectors, high-pressure valve components |
| Other forms of hastelloy | Wire mesh, powders | Filters, complex 3D printed parts |
Supplement: Hastelloy (such as C-276, B-2, C-22, etc.) is relatively difficult to machine and is prone to work hardening. Therefore, when purchasing or designing, in addition to focusing on shape, attention should also be paid to the delivery condition of the material (such as solution annealed state), which directly affects subsequent machining performance.
Applications of Hastelloy:
Medical devices: Hastelloy has excellent resistance when exposed to oxidizing environments at high temperatures for long periods. Common medical applications include stents, bone drill bits, cerclage cables, guide rods, orthopedic cables and heart valves.
Petrochemical and marine engineering: Used for the transport and processing equipment of media such as concentrated acids, concentrated alkalis and mixed acids, such as pipelines, valves and reactor supporting components, and also suitable for harsh working conditions such as flue gas desulfurization, high chlorine media treatment and auxiliary systems in the nuclear industry. In the oil and gas field, it is commonly used in drilling equipment, downhole tools, oil and gas pipelines and separators; in marine engineering, it is applied in seawater desalination devices, offshore platform structural components, ships and deep-sea oil extraction equipment.
Luft- und Raumfahrt: Manufacture key hot-end components of engines. For example, turbine blades, turbine disks, combustion chambers and engine exhaust system components; used for high-strength fasteners such as bolts, screws, nuts and washers for engines and fuel systems, as well as some structural components of wings and fuselage.
Pharmaceutical and food industry: Hastelloy is widely used in the pharmaceutical and food industries, and can be used in pharmaceutical machinery, bioreactors and pipelines and valves in high-purity medium transport systems, and is also suitable for cleanroom equipment and food-grade reactors and piping systems and other sanitary accessories, which can ensure the cleanliness and safety of the production process.
What can Weldo machining help
Choosing a professional and reliable Hastelloy machining supplier is equally important. Weldo provides CNC-Bearbeitung, extrusion, grinding, and sheet metal fabrication services. With over ten years of production experience, we can handle most manufacturing challenges while ensuring machining accuracy and delivering finished products to customers as quickly as possible. If you have any needs, feel free to Kontaktieren Sie uns for the latest quotation and a remote factory tour.
Hastelloy Precision Machining Project
bellow is our custom design hastelloy component,it is used for base part usage,Our customer required the production of 500 Hastelloy base components, with a wall thickness of 4 mm, a length of 16 mm, a hole diameter of 2.5 mm, a precision requirement of 0.01 mm, and a tolerance not exceeding 0.015 mm.
Based on the customer’s requirements, we selected Hastelloy tubing with a wall thickness of no less than 5 mm. By integrating CNC turning and 5-axis HAAS machining, we ensured roundness tolerance and multi-position drilling features, while avoiding cumulative errors caused by multiple clamping operations.
At the same time, we implemented full inspection, checking depth, diameter, and precision against the drawings, and used a CMM (Coordinate Measuring Machine) to verify the relative position and diameter of the holes, ensuring all production requirements were met.
A total of 503 parts were produced, of which 500 were fully qualified. The order was delivered to the customer within the agreed timeframe and received positive feedback.
