Overview
Inconel 625 (UNS N06625 / Werkstoff 2.4856) is a nickel-chromium molybdenum-niobium solid-solution-strengthened superalloy with a nominal composition of Ni 61%, Cr 21.5%, Mo 9%, Nb 3.6%. The combination of nickel, chromium, and molybdenum provides exceptional resistance to a wide range of corrosive environments, while the niobium content (acting in conjunction with the molybdenum) gives the alloy excellent strength without requiring precipitation-hardening heat treatment. Inconel 625 has outstanding resistance to pitting, crevice corrosion, and chloride-ion stress-corrosion cracking,making it one of the most versatile corrosion-resistant alloys available. The alloy retains high strength and toughness from cryogenic temperatures up to 980 °C, and exhibits excellent fatigue and thermal-fatigue resistance. Inconel 625 is approved for service under ASME Boiler and Pressure Vessel Code for temperatures from -268 °C to 650 °C.
Description (English)
Inconel 625 is supplied in two main conditions: Grade 1 (annealed, soft) andGrade 2 (solution annealed, AMS 5599). The alloy is non-magnetic, spark-resistant, and weldable by all conventional methods without susceptibility to cracking. It is widely used in chemical processing, marine engineering, aerospace, nuclear, oil & gas, and pollution-control applications where a combination of high strength and superior corrosion resistance is required.The alloy is especially well suited for seawater, sour service, wet chlorine,oxidizing acids, and high-purity nuclear environments.
Size Range
- Plate: thickness 0.5–100 mm × width ≤ 2400 mm × length ≤ 6000 mm
- Sheet: thickness 0.3–6.0 mm × width ≤ 1500 mm
- Strip: thickness 0.05–3.0 mm × width ≤ 600 mm (coil)
Grade Specification
| System | Value |
|---|---|
| 🇺🇸 UNS | N06625 |
| Werkstoff-Nr. | 2.4856 |
| 🇪🇺 EN | NiCr22Mo9Nb |
| ГОСТ | ХН75МБТЮ |
| 🇯🇵 JIS | NCF625 |
| 🇨🇳 GB | NS 3306 |
Chemical Composition
| Element | Value |
|---|---|
| C | ≤0.10 |
| Mn | ≤0.50 |
| Si | ≤0.50 |
| P | ≤0.015 |
| S | ≤0.015 |
| Cr | 20.0–23.0 |
| Mo | 8.0–10.0 |
| Nb+Ta | 3.15–4.15 |
| Co | ≤1.00 |
| Fe | ≤5.00 |
| Al | ≤0.40 |
| Ti | ≤0.40 |
| Ni | ≥58.0 |
Mechanical Properties
| productCenter.property | Value |
|---|---|
| Tensile strength (Rm) | 760–960 MPa |
| Yield strength (Rp0.2) | 345–490 MPa |
| Elongation at break (A50mm) | 30–50 % |
| Reduction of area | 50–60 % |
| Brinell hardness | 145–200 HB |
| Rockwell B hardnes | 85–95 HRB |
| Charpy V-notch impact (20 °C) | 100 J |
Physical Properties
| Property | Unit | Value |
|---|---|---|
| Density | g/cm³ | 8.44 g/cm³ |
| Melting range | °C | 1290–1350 °C |
| Modulus of elasticity (20 °C) | GPa | 207 GPa |
| Modulus of elasticity (315 °C) | GPa | 195 GPa |
| Modulus of elasticity (540 °C) | GPa | 180 GPa |
| Modulus of rigidity | - | 76 GPa |
Applications
- Chemical processing — sulfuric acid, phosphoric acid, nitric acid equipment
- Marine engineering — propeller blades, propeller shafts, submarine components
- Seawater service — pumps, valves, fasteners, instrument housings
- Oil & gas — downhole tubing, christmas trees, hangers, safety valves
- Sour (H₂S) service — NACE MR0175 approved
- Aerospace — ducting, exhaust systems, thrust reversers, engine shrouds
- Nuclear — reactor core and control rod components
- Pollution control — FGD scrubbers, ducting, stack liners
- Pulp and paper — digesters, bleach plants
- Pharmaceutical and food processing equipment
- Cryogenic applications — LNG, liquid nitrogen, liquid hydrogen
- Rocket engine components
- Weld overlay for carbon steel — cladding
- Heat shields and high-temperature fasteners
- Power generation — superheater tubes, FGD systems