Incoloy 825
Fasteners & Material Data
UNS N08825 · W.Nr. 2.4858
What is Incoloy 825 and its applications?
Incoloy 825 (UNS N08825) is a nickel-iron-chromium alloy with molybdenum, copper and titanium additions. It is used in acid processing, pollution control and oil-and-gas equipment for resistance to several forms of aqueous corrosion.
- Acid production: Chemical equipment handling compatible sulfuric or phosphoric acid solutions.
- Oil and gas recovery: Components selected against the actual produced fluids.
- Pollution control: Scrubbers and associated process hardware.
Choose your 825 product
Engineering Application & Selection Guide
Nickel supports resistance to chloride stress-corrosion cracking; molybdenum and copper contribute in reducing media. Titanium stabilizes against sensitization when combined with an appropriate heat treatment. These benefits do not establish immunity in every environment.
- Incoloy 825 hex bolts — For acid-handling pumps, state the stabilized condition and the installation procedure.
- Incoloy 825 stud bolts — For sour-service flanges, define environmental limits and required compliance evidence for the selected condition.
- Incoloy 825 hex nuts — For scrubber connections, check nut capacity, crevices and galvanic coupling in the complete assembly.
When comparing Incoloy 825 and Incoloy 020, use corrosion data for the actual solution and temperature. Their molybdenum ranges overlap, so a simple higher-molybdenum ranking cannot determine the better alloy.
Incoloy 825 Composition
Composition limits · wt.%
- Ni
- 38–46%
- Cr
- 19.5–23.5%
- Mo
- 2.5–3.5%
- Ti
- 0.6–1.2%
- Cu
- 1.5–3.0%
- Fe
- ≥22%
- C
- ≤0.05%
- Mn
- ≤1.0%
- S
- ≤0.03%
- Si
- ≤0.50%
- Al
- ≤0.20%
ASTM / ASME specifications by product form
Finished-product requirements
Specify the finished-fastener mechanical requirements, condition and inspection separately from the starting-stock specification.
Incoloy 825 hex bolt requirements ↗Fasteners · dimensional references
| Product | Reference |
|---|---|
| Hex bolts | ISO 4014 / ISO 4017 · ASME B18.2.1 |
| Threaded studs | DIN 976-1 · ASME B18.31.2 |
| Hex nuts | ISO 4032 · ASME B18.2.2 |
| Socket head screws | ISO 4762 · ASME B18.3 |
| Flat washers | ISO 7089 / ISO 7090 · ASME B18.21.1 |
| Custom fasteners | Customer drawing |
Raw-material specifications
| Product form / scope | Reference |
|---|---|
| Rod & bar | ASTM B425 / ASME SB425 |
| Forgings | ASTM B564 / ASME SB564 |
| Plate, sheet & strip | ASTM B424 / B906 · ASME SB424 / SB906 |
| Seamless pipe & tube | ASTM B423 / B829 · ASME SB423 / SB829 |
| Heat-exchanger tube | ASTM B163 / ASME SB163 |
| Welded tube | ASTM B704 / B751 · ASME SB704 / SB751 |
| Welded pipe | ASTM B705 / B775 · ASME SB705 / SB775 |
| Fittings | ASTM B366 / ASME SB366 |
Dimensions do not define material or finished-part compliance. Specify the grade, condition and applicable requirements.
How to specify round bar, plate, wire and strip ↗Incoloy 825 Mechanical Properties
Reference sample and condition
- Data basis
- Typical catalogue reference
- Condition
- Annealed
| Key properties | Value |
|---|---|
| Tensile strength | 690 MPa |
| 0.2% yield strength | 310 MPa |
| Elongation | 45% |
Incoloy 825 Physical Properties
| Property | Value | Unit |
|---|---|---|
| Density | 8.14 | g/cm³ |
| Melting range | 1370–1400 | °C |
Temperature curves and values
Tensile and yield strength
Annealed material · supplied reference
Approximate readings from the reference figure · not design allowables
Supplied technical reference · Scanned PDF page 13 · printed page 25Elongation vs temperature
Annealed material · supplied reference
Approximate readings from the reference figure · not design allowables
Supplied technical reference · Scanned PDF page 13 · printed page 25Procurement and application guide
Specify the material and final condition
Review chemical exposure and the required annealed condition.
Material forms in the technical reference: Round bar · Flat bar · Wire · Plate · Sheet · Strip · Pipe & tube · Forging stock · Hexagon & sections.
Define the finished-part acceptance
Include the material or bolting specification, required final condition, dimensions and quantity. State the service medium, temperature and loading where known. Agree the required tests, inspection coverage and acceptance criteria for the finished part.
Start with the information you have
Send a drawing or share the product form and dimensions. Identify any undecided requirements for review rather than copying a typical property value into the purchase order.
Upload DrawingCondition-specific data
Catalogue minimums
A5 elongation, as labelled in the supplied table.
| Reference / condition | Tensile MPa | Yield 0.2% MPa | Elongation % |
|---|---|---|---|
| ASTM B425 / ASME SB425 | ≥586 | ≥241 | ≥30 |
Technical guides
All technical articles ↗
Nickel Alloy Fasteners: Selection and Specification Guide
Nickel-Alloy Fastener Galling
MTC vs PMI vs Inspection Report: Which One Actually Proves Your Fastener Meets the Order?Selection and specification · 3
Installation and inspection · 3
Quality documents
EN 10204 3.1 MTC
Material certification and heat-number traceability
Mechanical testing
Methods and acceptance criteria follow the agreed specification
Alloy 718 laboratory report · PDF ↗Thread inspection
Sampled GO/NO-GO gauging for threaded products
Additional inspection and records
Heat-treatment records, PMI and third-party scope agreed per order
View PMI sample ↗Specify your Incoloy 825 fastener
Sources and references
- Supplied technical reference · Scanned PDF page 3 · printed page 15
- Special Metals · Incoloy Alloy 825 · Technical bulletin · identity, composition, applications and listed specifications ↗
- Supplied technical reference · Scanned PDF page 13 · printed page 25
- Special Metals - Alloy 020 · Material identity, characteristics and application context. ↗
Additional published references
- DIN 17744 / 17750–17754; ISO 6207 / 6208 / 9723–9725; BS 3072 / 3073 / 3074 / 3076 (NA16); VdTÜV 432; ASME Code Cases 1936 / N-572 Special Metals · Incoloy Alloy 825 · Technical bulletin · identity, composition, applications and listed specifications ↗
- NACE MR0175 / ISO 15156 Supplied technical reference · Scanned PDF page 13 · printed page 25