Hastelloy C-276
Material grade: Hastelloy C-276
US grade: UNS N10276
German grade: W.Nr.2.4819
1. Overview of Hastelloy C-276 (N10276, 2.4819):
Hastelloy C-276 is a nickel-chromium-molybdenum alloy containing tungsten, with very low silicon and carbon content.
1. Characteristics of Hastelloy C-276 (N10276, 2.4819):
(1) Excellent corrosion resistance to most corrosive media in both oxidizing and reducing environments.
(1) Outstanding resistance to pitting, crevice corrosion, and stress corrosion cracking.
2. Grades and standards of Hastelloy C-276 (N10276, 2.4819):

3. Chemical composition of Hastelloy C-276 (N10276, 2.4819): %

4. Physical properties of Hastelloy (N10276, 2.4819):
(1) Density of Hastelloy C-276 (N10276): ρ=8.9g/cm3,
(2) Melting temperature range of Hastelloy C-276 (N10276): 1325～1370℃,
(3) ISO-V notch test of Hastelloy C-276 (N10276):
Average ≥120J/cm2 Room temperature ≥120J/cm2 -196℃.
5. Metallographic structure of Hastelloy (N10276, 2.4819): Hastelloy C-276 has a face-centered cubic lattice structure, and its chemical composition ensures metallographic stability and resistance to sensitization.
6. Corrosion resistance of Hastelloy (N10276, 2.4819):
The high molybdenum and chromium content allows Hastelloy C-276 to resist corrosion from various chemical media, including reducing media such as phosphoric acid, hydrochloric acid, sulfuric acid, chlorine gas, and organic or inorganic chlorine-containing media. Due to its high nickel content, Hastelloy C-276 effectively resists stress corrosion cracking caused by chlorine, even in hot chloride solutions.
Time-temperature-sensitization curve (carbon content 0.008%, reference ASTM G28 Method A)

2.Processing characteristics of Hastelloy C-276 (N10276, 2.4819):
1. Processing and heat treatment of Hastelloy C-276 (N10276):
(1) Hastelloy C-276 alloy can be manufactured and processed using traditional production methods.
(2) The workpiece should always be kept clean and uncontaminated before and during heat treatment.
(3) The sensitivity of this alloy to sensitization during rapid cooling between 1000℃ and 600℃ should be fully considered.
(4) During the heat treatment process, it should not come into contact with sulfur, phosphorus, lead, and other low melting point metals, otherwise it will damage the performance of the alloy. Attention should be paid to removing contaminants such as marking paint, temperature indicating paint, colored crayons, lubricating oil, and fuel.
(5) The lower the sulfur content in the fuel, the better. The sulfur content in natural gas should be less than 0.1%, and the sulfur content in heavy oil should be less than 0.5%.
(6) The furnace gas in the heating furnace should be neutral to slightly oxidizing, and fluctuations between oxidizing and reducing atmospheres should be avoided. The heating flame should not be directed at the workpiece.
2. Heating of Hastelloy C-276 (N10276) alloy:
Before and during heat treatment, the workpiece should always be kept clean and free of contamination. During the heat treatment process, it should not come into contact with sulfur, phosphorus, lead, and other low melting point metals, otherwise the Nicrofer 6616 hMo alloy will become brittle. Attention should be paid to removing contaminants such as marking paint, temperature indicating paint, colored crayons, lubricating oil, and fuel. The lower the sulfur content in the fuel, the better. The sulfur content in natural gas should be less than 0.1%, and the sulfur content in heavy oil should be less than 0.5%. Electric furnace heating is a better choice because it can control the temperature precisely, and the furnace gas is clean. If the gas furnace has sufficiently pure gas, it can also be chosen. The furnace gas in the heating furnace should be neutral to slightly reducing, and fluctuations between oxidizing and reducing atmospheres should be avoided. The heating flame should not be directed at the workpiece.
3. Hot working of Hastelloy C-276 (N10276) alloy:
(1) The hot working temperature range for Hastelloy C-276 is 1200℃ to 950℃, and the cooling method is water cooling or rapid air cooling.
(2) To ensure optimal corrosion resistance, heat treatment should be performed after hot working, and the workpiece should be directly placed into the preheated heat treatment furnace.
4. Cold working of Hastelloy C-276 (N10276) alloy:
(1) The work hardening rate of Hastelloy C-276 is greater than that of austenitic stainless steel, so the processing equipment needs to be selected accordingly. The workpiece should be in a solution heat-treated state, and intermediate annealing should be performed during cold rolling.
(2) If the cold rolling deformation exceeds 15%, a secondary solution treatment is required for the workpiece.
5. Heat treatment of Hastelloy C-276 (N10276) alloy:
(1) The solution treatment temperature range for Hastelloy C-276 is 1100℃ to 1160℃.
(2) The cooling method is water quenching, and materials with a thickness of less than 1.5mm can also use rapid air cooling. If air cooling is used, it should cool from 1000℃ to 600℃ within 2 minutes.
(3) During the heat treatment process, the workpiece must be kept clean.
6. Descaling of Hastelloy C-276 (N10276) alloy:
(1) The adhesion of surface oxides and welding slag around the weld of Hastelloy C-276 is stronger than that of stainless steel, so it is recommended to use fine-grained sand belts or fine-grained grinding wheels for polishing.
(2) Before pickling with a mixed acid of HNO3/HF, sandblasting or grinding must be done to break the oxide film.
7. Machining of Hastelloy C-276 (N10276) alloy: Due to sensitivity to work hardening, it is advisable to use low cutting speeds and heavy feed to machine below the cold-work-hardened surface.
8. Welding of Hastelloy C-276 (N10276) alloy: When welding nickel-based materials, the following procedures should be followed:
(1) Work area: The work area should be separated or have sufficient distance from the carbon steel processing area, kept as clean as possible, with partitions to avoid ventilation between the two areas.
(1) Clean gloves made of fine-grained leather and clean work clothes should be worn.
(2) Tools and machinery should have dedicated tools for nickel-based alloys and nickel-chromium steel. Steel wire brushes should be made of stainless steel, and machines such as shears, punch presses, and rolling mills should be covered with felt, cardboard, or plastic to prevent iron and carbon metals from falling onto the machine surface and causing contamination.
(3) Cleaning: The materials to be welded should be in a solution-treated state, with oxides, oil stains, and various marking residues removed, and the base metal and filler alloy (such as welding rods) in the welding area should be cleaned with acetone. Note that trichloroethylene (TRI), perchloroethylene (PER), and tetrachloride (TETRA) should not be used.
(4) Edge preparation: It is best to use machining, such as turning, milling, or planning, and plasma cutting can also be performed. If the latter is used, the cutting edge (welding surface) must be ground clean and flat, allowing for no overheating during finishing.
(5) Groove angle: Compared to carbon steel, the physical properties of nickel-based alloys and special stainless steels mainly include low thermal conductivity and high expansion coefficients, which should be considered during the preparation of the welding groove, including widening the bottom gap (1-3mm). Due to the viscosity of molten metal, a larger groove angle (60-70°) should be used for butt welding to compensate for material shrinkage.
(6) Arc initiation: The arc should not be initiated on the surface of the workpiece but on the welding surface to prevent the arc initiation point from causing corrosion.
(7) Welding process: Hastelloy C-276 is suitable for any traditional welding process, such as tungsten electrode inert gas shielded welding, plasma arc welding, manual submerged arc welding, metal inert gas shielded welding, and flux-cored arc welding. The filler metal for Hastelloy C-276, welding rod: ENiCrMo-4, welding wire: ERNiCrMo-4.
Four,Application of Hastelloy C-276 (N10276, 2.4819) alloy:
1. Application fields: It has been widely used in the chemical and petrochemical fields, such as in components and catalytic systems that come into contact with chlorinated organic substances. This material is particularly suitable for use in high-temperature environments mixed with impurities, inorganic acids, and organic acids (such as formic acid and acetic acid), as well as in seawater corrosion environments. Other application fields include: pulp and paper industry, such as cooking and bleaching vessels; washing towers, reheaters, and wet gas fans in FGD systems; equipment and components operating in acidic gas environments; reactors for acetic acid and acidic products; sulfuric acid condensers; methylene diphenyl diisocyanate (MDI); production and processing of impure phosphoric acid.
2. Application scope: Hastelloy C-276 has been widely used in most chemical fields and high-temperature environments. Typical application areas include: flue gas desulfurization systems, pickling and acid regeneration plants, acetic acid and agricultural chemical production, titanium dioxide production (chloride process), and electroplating.
五、Hastelloy C-276 (N10276, 2.4819) specifications and supply status of Hastelloy alloy:
1. Variety classification: Hastelloy C-276 seamless pipes, Hastelloy C-276 steel plates, Hastelloy C-276 round bars, Hastelloy C-276 forgings, Hastelloy C-276 flanges, Hastelloy C-276 rings, Hastelloy C-276 welded pipes, Hastelloy C-276 steel strips, Hastelloy C-276 wires and matching welding materials.
2. Delivery status: Seamless pipes: solution + acid white, length can be customized; plates: solution, acid washing, edge cutting; welded pipes: solution acid white + RT% flaw detection, forgings: annealed + turned; bars in forged state, surface polished or turned; strips delivered in cold-rolled, solution soft state, and descaled; wires delivered in solution acid-washed coil or straight bar form, solution straight bar fine polished state.