Incoloy 825 Product Introduction
Product Overview
Incoloy 825 is a nickel-iron-chromium-based corrosion-resistant alloy developed by Special Metals Corporation (USA), specifically engineered for aggressive acidic and chloride-containing environments. Its balanced composition (high chromium for oxidative corrosion resistance, molybdenum and copper for reductive acid resistance, and titanium for stabilization) enables it to excel in resisting sulfuric acid, phosphoric acid, organic acids, and seawater. It maintains stable mechanical properties at temperatures up to 600°C, with outstanding resistance to stress corrosion cracking (SCC) and localized corrosion (pitting/crevice corrosion). Widely applied in chemical processing, oil & gas, and environmental protection industries, it is a reliable material for critical components where conventional stainless steels or low-alloy steels fail to withstand harsh corrosion.
International Grade Comparison
Standard System | Grade | Description |
ASTM (USA) | N08825 | UNS Unified Numbering System Grade |
EN (EU) | NiFe30Cr21Mo3 | EN 10088-1 Standard Grade |
JIS (Japan) | NW08825 | JIS G4902 Standard Grade |
DIN (Germany) | 2.4858 | DIN 17750 Standard Grade |
ISO (International) | NiFe30Cr21Mo3 | ISO 6363 Standard Grade |
Physical Properties (Room Temperature, Key Brief Indicators)
Property Indicator | Typical Value | Unit |
Tensile Strength | ≥550 | MPa |
Yield Strength (0.2% Offset) | ≥240 | MPa |
Elongation (50mm Gauge Length) | ≥30 | % |
Density | 8.14 | g/cm³ |
Melting Point | 1370-1400 | ℃ |
Chemical Composition (Mass Fraction, Key Elements)
Chemical Symbol | Composition Range (%) | Chemical Symbol | Composition Range (%) |
Ni | 38.0-47.0 | Cu | 1.5-3.0 |
Fe | Balance | Ti | 0.6-1.2 |
Cr | 19.5-23.5 | C | ≤0.05 |
Mo | 2.5-3.5 | Si | ≤0.5 |
|
| Mn | ≤1.0 |
|
| P/S | ≤0.03/≤0.015 |
Product Characteristics
Versatile Corrosion Resistance: Performs exceptionally well in both reductive (dilute sulfuric acid, phosphoric acid) and oxidative (nitric acid, hypochlorite) media, with strong resistance to pitting and crevice corrosion in chloride-rich environments (e.g., seawater, brine);
Stress Corrosion Cracking (SCC) Resistance: Titanium addition stabilizes the matrix, effectively preventing SCC in chloride or hydrogen sulfide (H₂S) environments, a key advantage over many nickel-based alloys;
Moderate High-Temperature Performance: Maintains mechanical stability and corrosion resistance below 600°C, suitable for medium-temperature applications such as heat exchangers and process pipelines;
Good Processability: Compatible with conventional manufacturing processes (welding, forging, rolling, machining); post-weld heat treatment is optional for most applications, simplifying production.
Metallographic Structure
At room temperature, it has a face-centered cubic crystal structure (austenitic matrix). The addition of titanium inhibits carbide precipitation at grain boundaries, avoiding intergranular corrosion and ensuring long-term microstructural stability even after exposure to high temperatures.
Product Forms and Executive Standards
Product Form | Main International Executive Standards | Application Reference |
Plates/Strips | ASTM B424, EN 10088-2 | Acid storage tank liners, chemical reactor walls |
Seamless Pipes/Tubes | ASTM B423, EN 10216-5 | Sulfuric acid transport pipelines, offshore oil & gas flowlines |
Bars/Forgings | ASTM B425, EN 10269 | Valve stems, pump casings, flange connections |
Wires | ASTM B426, EN 10250-3 | Welding filler wires for corrosion-resistant joints, precision springs |
