Introduction

Incoloy 825 Alloy (UNS N08825 / W.Nr. 2.4858) is a nickel-iron-chromium-molybdenum alloy with copper and titanium additions, offering outstanding corrosion resistance across both reducing and oxidizing environments. This nickel iron chromium alloy contains 38–46% nickel, 19.5–23.5% chromium, 2.5–3.5% molybdenum, 1.5–3.0% copper, and 0.6–1.2% titanium—with titanium stabilization preventing intergranular corrosion in the as‑welded condition. This corrosion resistant Incoloy 825 delivers exceptional sulfuric acid resistance (useful up to 40% at boiling, 60% at 176°F) and phosphoric acid resistance, plus excellent resistance to pitting, crevice corrosion, and chloride‑induced stress corrosion cracking, making it the preferred material for chemical processing, oil and gas, heat exchangers, pressure vessels, pickling equipment, and offshore applications. Available in Incoloy 825 plate, sheet, seamless pipe, tube, bar, round bar, wire, flanges, fittings, fasteners, and forgings, in hot rolled, cold rolled, cold drawn, annealed, and solution annealed conditions.

Chemical components （%）

Mechanical properties

Physical properties

Incoloy 825 Available Products and Standard

1. GB/T 15007 (Nickel and Nickel Alloy Plate, Strip, and Foil)

Domestic Grade: NS142 (GB/T 15007) / Incoloy 825 equivalent

Type: Wire / Strip / Bar / Sheet / Seamless Tube / Pipe / Forgings

Size Range:

• Incoloy 825 Wire: 0.1 – 15.0 mm dia

• Incoloy 825 Strip: 0.05 – 5.0 mm thick × 5 – 500 mm wide

• Incoloy 825 Round Bar: 8 – 355 mm dia

• Incoloy 825 Sheet / Plate: 0.5 – 180 mm thick

• Incoloy 825 Seamless Tube / Pipe: Custom sizes available

Surface: Annealed, Bright, Pickled, Ground

Testing: Chemical analysis, mechanical test (tensile strength, yield strength, elongation), hardness test, intergranular corrosion test, pitting corrosion test, dimensional inspection

2. ASTM B423 (Standard Specification for Nickel-Iron-Chromium-Molybdenum-Copper Alloy Seamless Pipe and Tube)

Grade: UNS N08825 / Incoloy 825 / Alloy 825 / W.Nr. 2.4858

Type: Seamless Pipe / Seamless Tube / Heat Exchanger Tube

Size Range:

• Incoloy 825 Seamless Pipe: 6 – 610 mm OD × 1 – 50 mm wall thickness

• Incoloy 825 Seamless Tube: Custom sizes

Surface: Annealed, Pickled, Bright

Testing: Chemical analysis, mechanical test (tensile, yield, elongation), hydrostatic test, eddy current test, corrosion test (sulfuric acid), dimensional inspection

3. ASTM B424 (Standard Specification for Nickel-Iron-Chromium-Molybdenum-Copper Alloy Plate, Sheet, and Strip)

Grade: UNS N08825 / Incoloy 825 / Alloy 825

Type: Sheet / Plate / Strip

Size Range:

• Incoloy 825 Sheet / Plate: 0.5 – 180 mm thick (hot rolled or cold rolled)

• Incoloy 825 Strip: 0.05 – 5.0 mm thick × up to 500 mm wide (coils)

Surface: Annealed, Pickled, Bright, Polished

Testing: Chemical analysis, mechanical test (tensile, yield, elongation), hardness test, intergranular corrosion test, pitting corrosion test, dimensional inspection

4. ASTM B425 (Standard Specification for Nickel-Iron-Chromium-Molybdenum-Copper Alloy Rod and Bar)

Grade: UNS N08825 / Incoloy 825 / Alloy 825

Type: Round Bar / Rod / Wire

Size Range:

• Incoloy 825 Round Bar: 8 – 355 mm dia (hot rolled or cold drawn)

• Incoloy 825 Wire: 0.1 – 15.0 mm dia (coils or straight)

Surface: Annealed, Pickled, Ground, Turned, Bright

Testing: Chemical analysis, mechanical test (tensile, yield, elongation), hardness test, ultrasonic test, dimensional inspection

Applications

1. Chemical Processing & Acid Production

• For reactors, heat exchangers, and piping systems handling sulfuric acid, phosphoric acid, and nitric acid, Incoloy 825 for chemical processing delivers exceptional resistance across wide concentration and temperature ranges. This acid resistant Incoloy 825 is especially effective in sulfuric acid pickling plants, with useful resistance to boiling acid up to 40% concentration.

• For sulfuric acid pickling plants, components such as heating coils, tanks, crates, baskets, and chains benefit from Alloy 825's corrosion resistance. The alloy's titanium stabilization ensures stress corrosion cracking resistant alloy performance in the as‑welded condition.

• For phosphoric acid production and acid production facilities, UNS N08825 seamless pipe handles aggressive process streams with minimal maintenance.

• For distillation columns, reactor vessels, and pressure vessels in aggressive acid environments, Incoloy 825 plate and sheet combine strength, fabricability, and outstanding corrosion resistance.

2. Oil & Gas / Offshore Equipment

• For sour gas service (H₂S/CO₂ environments) and oil and gas well piping, Incoloy 825 for oil and gas is specified for downhole tubing, flowlines, and topside process piping. The high nickel content (38–46%) ensures chloride resistant nickel alloy performance with immunity to chloride‑induced stress corrosion cracking.

• For offshore platforms and subsea equipment, Alloy 825 pipe and tube withstand seawater corrosion, chloride attack, and the corrosive effects of produced fluids in demanding offshore environments.

3. Heat Exchangers & Pressure Vessels

• For shell‑and‑tube heat exchangers, condenser tubing, and reboiler bundles, Incoloy 825 for heat exchanger offers high thermal conductivity with outstanding resistance to localized attack in aggressive chemical service.

• For ASME‑coded pressure vessels in corrosive service, ASTM B424 Incoloy 825 plate combines high strength, fabricability, and crevice corrosion resistant alloy performance.

4. Pollution Control & Nuclear Industry

• For pollution control equipment including flue gas desulfurization scrubbers and stack‑gas reheaters, Incoloy 825 sheet and plate withstand low‑pH, high‑chloride environments.

• For nuclear fuel reprocessing and radioactive waste handling, UNS N08825 tube provides the corrosion resistance and radiation stability required for demanding nuclear applications.

5. Marine Engineering & Pharmaceutical Equipment

• For marine engineering applications and seawater‑exposed systems, Incoloy 825 for marine engineering resists pitting and crevice corrosion in warm, high‑chloride environments.

• For pharmaceutical equipment requiring high purity and corrosion resistance, Incoloy 825 bar and tube maintain surface integrity in clean‑in‑place systems and API synthesis lines.

FAQ – Incoloy 825 Alloy

Q: What is the difference between Incoloy 825 and Inconel 625?

A: Incoloy 825 alloy is a nickel-iron-chromium alloy with 38–46% nickel and significant iron content, optimized for sulfuric and phosphoric acid resistance at moderate temperatures up to ~550°C. Inconel 625 has higher nickel content (58% min) with niobium addition, providing higher tensile and creep strength at elevated temperatures, but lower ductility at room temperature. For corrosion resistant Alloy 825 in acid handling applications, choose Incoloy 825; for extreme high‑temperature strength, choose Inconel 625.

Q: Is Incoloy 825 suitable for sulfuric acid service?

A: Yes. ASTM B424 Incoloy 825 plate and Alloy 825 seamless pipe offer useful resistance to boiling sulfuric acid up to 40% concentration, 60% concentration at 176°F (80°C), and all concentrations up to 150°F (66°C). The alloy's molybdenum and copper additions provide outstanding resistance to reducing environments such as sulfuric and phosphoric acids.

Q: Can Incoloy 825 be welded without post‑weld heat treatment?

A: Yes. Incoloy 825 sheet and pipe can be welded using TIG, MIG, and other standard processes. Titanium stabilization (0.6–1.2% Ti) prevents sensitization and intergranular corrosion in the as‑welded condition. The alloy is supplied in the stabilized annealed condition to resist intergranular corrosion as‑welded, eliminating the need for post‑weld heat treatment in most applications.

Q: What industries commonly use Incoloy 825?

A: Chemical processing (sulfuric and phosphoric acid plants, reactors, heat exchangers), oil and gas (sour gas well piping, offshore equipment, downhole tubing), pollution control (FGD scrubbers, waste treatment), nuclear (fuel reprocessing, radioactive waste handling), marine engineering (seawater systems, offshore platforms), pickling equipment, acid production facilities, and pharmaceutical equipment.

We are a trusted Incoloy 825 Supplier and Incoloy 825 Manufacturer, China‑based, serving chemical processors, oil and gas contractors, heat exchanger fabricators, pollution control equipment builders, and nuclear industry suppliers worldwide. All products comply with ASTM B424 / ASTM B423 / ASME SB424 with EN 10204 3.1 mill certificates, PMI verification, and dimensional inspection reports. We offer Incoloy 825 plate, sheet, seamless pipe, tube, bar, round bar, rod, wire, flanges, fittings, fasteners, and forgings in custom sizes, with cut‑to‑size and precision machining services. Contact us at info@monokj.com for size chart, pricing, or custom requirements.