Nickel Alloy 825 | UNS N08825 | 2.4858 | Incoloy 825

Nickel Alloy 825 | UNS N08825 | 2.4858 | Incoloy 825

Shaanxi Shangyou Stainless Steel Co., Ltd. supplies Nickel Alloy 825, also known as Incoloy 825, identified as UNS N08825 and Werkstoff 2.4858, in plate, sheet, strip, round bar, rod, seamless and welded tubing, pipe, and forging forms. Our Alloy 825 products can be supplied according to ASTM B424 / ASME SB-424 for plate, sheet and strip; ASTM B423 / ASME SB-423 for seamless pipe and tube; ASTM B425 / ASME SB-425 for bar and wire; and ASTM B564 / ASME SB-564 for forgings.

Nickel Alloy 825 is a nickel-iron-chromium alloy with additions of molybdenum, copper, and titanium, developed for very good corrosion resistance in aggressive chemical environments. The alloy combines resistance to both oxidizing and reducing acids with good mechanical strength and excellent weldability. Molybdenum and copper improve resistance to reducing environments such as sulfuric acid and phosphoric acid, while chromium contributes to resistance to oxidizing media. Titanium stabilizes the alloy against sensitization and intergranular corrosion, making the material particularly suitable for welded structures.

Actual properties depend on product form, dimensions, heat-treatment cycle, and the specified ASTM, ASME or AMS standard.

Solution Annealed

Alloy 825 is normally supplied in the solution-annealed condition. The standard annealing treatment is performed at approximately 930 – 980°C (1,706 – 1,796°F) followed by quenching in water. This treatment provides optimal corrosion resistance and ductility. The titanium stabilization ensures resistance to sensitization and intergranular corrosion.

Cold Working

Alloy 825 is not age-hardenable – strength increases only through cold working. Annealed material typically exhibits tensile strength of 80 – 109 ksi (550 – 750 MPa), with excellent formability and weldability.

Alloy 825 offers exceptional resistance to both reducing and oxidizing acids, stress-corrosion cracking, and localized attack such as pitting and crevice corrosion.

Key Corrosion Characteristics:

• Excellent resistance to sulfuric and phosphoric acids of various concentrations and temperatures
• Good resistance to nitric acid and many oxidizing media
• Excellent resistance to chloride stress-corrosion cracking due to high nickel content (38-46%)
• Superior pitting and crevice corrosion resistance compared to AISI 316L, due to higher Cr and Mo content
• Titanium stabilization prevents sensitization and intergranular corrosion in the as-welded condition
• Good resistance to wet sulfur oxide and numerous acid mixtures, especially those containing sulfuric acid
• Approved for sour service per NACE MR0175/ISO 15156 in annealed and cold-worked conditions, with no environmental limits on H₂S partial pressure

Selection Considerations:

• Superior to standard molybdenum-alloyed stainless steels such as 316L, particularly in non-oxidizing media
• For more aggressive environments requiring higher Ni and Mo content, Alloy G-3 or C-276 may be preferred
• For applications involving pure reducing acids, Alloy B-3 may offer better performance
• Final selection must consider the specific medium, concentration, temperature, and exposure conditions

• Chemical Processing: Heat exchangers, reactors, evaporators, distillation columns, and piping for aggressive acid environments; phosphoric and sulfuric acid production equipment
• Oil & Gas: Sour gas well piping, heat exchangers, transfer lines, and components for acidic environments with chlorides and hydrogen sulfide
• Pollution Control: Flue gas desulfurization scrubbers, stack liners, and environmental control equipment
• Pickling Operations: Pickling tank heaters, tanks, and equipment
• Nuclear: Fuel reprocessing, radioactive waste handling
• Marine: Propeller shafts, seawater-cooled heat exchangers

Available quality-control services include:

• Heat-number traceability
• Chemical composition verification
• Tensile, yield and elongation testing
• Hardness inspection
• Dimensional and surface inspection
• Positive Material Identification (PMI)
• Ultrasonic testing
• Dye penetrant inspection
• Heat-treatment records
• EN 10204 3.1 material certificate

For an accurate quotation, please provide:

Alloy Grade · Standard · Product Form · Dimensions · Quantity · Heat Treatment · Inspection Requirement · Application · Working Temperature · Destination Port

For corrosive environments, also provide:

Chemical Medium · Concentration · Temperature · Pressure · Oxidizing or Reducing Conditions

• Request Nickel Alloy 825 Quote
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Nickel Alloy 825 (UNS N08825), also known as Incoloy 825, is a nickel-iron-chromium alloy with molybdenum, copper and titanium additions, offering excellent resistance to both oxidizing and reducing acids, particularly sulfuric and phosphoric acids.

The UNS designation is N08825; the European Werkstoff number is 2.4858; the EN material symbol is NiCr21Mo.

ASTM B424 / ASME SB-424 applies to plate, sheet and strip; ASTM B425 / ASME SB-425 applies to bar, rod and wire.

ASTM B423 / ASME SB-423 applies to seamless pipe and tube.

No. Alloy 825 is not age-hardenable and is strengthened only through cold working.

It resists sulfuric acid, phosphoric acid, nitric acid, organic acids, chloride-containing environments, sour gas (H2S), and many acid mixtures. It also provides excellent resistance to stress-corrosion cracking and pitting.

The titanium addition stabilizes the alloy against sensitization and intergranular corrosion in the as-welded condition, making it suitable for welded structures without risk of carbide precipitation.

For pressure vessel applications, the maximum recommended temperature is 540°C (1,000°F) per ASME Code. The alloy maintains good mechanical properties up to approximately 550°C.

Yes. Alloy 825 has excellent weldability. Suitable methods include TIG/GTAW and MMA/SMAW. The low carbon content and titanium stabilization minimize the risk of intergranular corrosion in the welded condition.

Please provide the standard, product form, dimensions, quantity, heat-treatment condition, inspection requirements, application, working temperature and destination port. For corrosive environments, also specify the chemical medium and concentration.