UNS N06625 Nickel Alloy Round Bar Diameter 10 - 300mm Hot Rolled Custom Cutting in Length
UNS N06625 (also widely recognized as Inconel® 625) is a premium nickel-chromium-molybdenum alloy renowned for its exceptional corrosion resistance, high-temperature strength, and excellent fabricability. The hot-rolled round bars of this alloy, with a diameter range of 10mm to 300mm and customizable length cutting, are widely used in demanding industries such as aerospace, oil and gas, chemical processing, and marine engineering. Below is a detailed overview of its key attributes, specifications, and product details:
1. Chemical Composition
The superior performance of UNS N06625 stems from its precisely controlled chemical composition, which is compliant with international standards. The typical elemental ranges (by weight percentage) are as follows:
| Element | Content Range (%) | Primary Function |
| Nickel (Ni) | 58.0 min | Base metal; provides fundamental corrosion resistance and alloy stability. |
| Chromium (Cr) | 20.0 - 23.0 | Enhances resistance to oxidation, sulfidation, and aqueous corrosion. |
| Molybdenum (Mo) | 8.0 - 10.0 | Boosts resistance to pitting, crevice corrosion, and stress corrosion cracking. |
| Niobium (Nb) | 3.15 - 4.15 | Forms precipitates (e.g., Ni₃Nb) to strengthen the alloy at high temperatures. |
| Iron (Fe) | 5.0 max | Improves workability without compromising corrosion resistance. |
| Carbon (C) | 0.10 max | Minimized to reduce carbide precipitation and avoid intergranular corrosion. |
| Silicon (Si) | 0.50 max | Controls melting and casting properties; kept low to prevent oxide inclusions. |
| Manganese (Mn) | 0.50 max | Aids in deoxidation during production; limited to maintain alloy purity. |
| Phosphorus (P) | 0.015 max | Reduced to avoid brittleness and improve weldability. |
| Sulfur (S) | 0.015 max | Minimized to prevent hot cracking and enhance corrosion resistance. |
2. Mechanical Properties
UNS N06625 hot-rolled round bars exhibit outstanding mechanical strength at both room and elevated temperatures, making them suitable for load-bearing applications in harsh environments. The following properties are typical for the hot-rolled (annealed) condition:
| Property | Test Standard | Typical Value (Room Temperature) |
| Tensile Strength | ASTM B446 | ≥ 795 MPa (115 ksi) |
| Yield Strength (0.2% offset) | ASTM B446 | ≥ 345 MPa (50 ksi) |
| Elongation (in 50mm) | ASTM B446 | ≥ 30% |
| Hardness (Brinell) | ASTM E10 | ≤ 220 HB |
| Impact Strength (Charpy V-notch) | ASTM A370 | ≥ 100 J (74 ft-lb) |
Note: At elevated temperatures (e.g., 650°C/1200°F), the tensile strength remains above 480 MPa, and yield strength above 275 MPa, demonstrating excellent high-temperature stability.
3. Similar Grades
UNS N06625 is standardized globally under different designations, ensuring compatibility with international procurement and engineering requirements. The key equivalent grades are listed below:
| Standard System | Grade Designation | Region/Organization |
| UNS (USA) | UNS N06625 | ASTM (American Society for Testing and Materials) |
| DIN (Germany) | W. Nr. 2.4856 | DIN EN (Deutsches Institut für Normung) |
| EN (Europe) | NiCr22Mo9Nb | CEN (European Committee for Standardization) |
| JIS (Japan) | NCF625 | JIS (Japanese Industrial Standards) |
| GB (China) | NS3306 | GB/T (National Standard of the People’s Republic of China) |
| ISO | ISO 6208: NiCr22Mo9Nb | ISO (International Organization for Standardization) |
4. Product Standards
The manufacturing, testing, and quality control of UNS N06625 hot-rolled round bars adhere to strict international standards to ensure consistency and reliability. The primary applicable standards are:
- ASTM B446: Standard Specification for Nickel-Chromium-Molybdenum-Columbium Alloy (UNS N06625) and Nickel-Chromium-Molybdenum-Silicon Alloy (UNS N06219) Rod and Bar
- ASTM B564: Standard Specification for Nickel and Nickel Alloy Forgings (covers forging processes if applicable)
- ASME SB-446: Boiler and Pressure Vessel Code (BPVC) version of ASTM B446, for pressure-containing applications
- EN 10088-3: European standard for stainless steels and nickel alloys; specifies requirements for bars and rods
- DIN EN 10088-3: German adoption of EN 10088-3, with additional regional quality controls
5. Product Specifications & Customization
- Diameter Range: 10mm to 300mm (inclusive). For diameters outside this range (e.g., <10mm or >300mm), custom manufacturing is available upon request.
- Processing Method: Hot-rolled. Hot rolling enhances the alloy’s grain structure, improves mechanical strength, and ensures uniform density across the bar cross-section.
- Length Customization: Standard lengths include 2000mm, 3000mm, and 6000mm. Custom cutting is offered to any length (e.g., 500mm, 1500mm) with a tolerance of ±1mm, eliminating the need for secondary cutting by customers and reducing material waste.
- Surface Finish: Hot-rolled surface (mill finish) with a smooth, scale-free appearance. Optional surface treatments (e.g., pickling, polishing) are available for applications requiring enhanced corrosion resistance or aesthetic appeal.
6. Packaging & Shipping
To ensure the round bars remain protected from damage, corrosion, and contamination during storage and transportation, the following packaging measures are implemented:
- Inner Protection: Each round bar is individually wrapped in moisture-resistant kraft paper or plastic film to prevent rusting.
- Outer Packaging: Bars are bundled into wooden crates or steel pallets (depending on diameter and quantity) for stability. Crates are reinforced with steel straps to avoid shifting during transit.
- Labeling: Each package is clearly labeled with key information: alloy grade (UNS N06625), diameter, length, heat number, batch number, weight, and manufacturer’s logo. This facilitates traceability throughout the supply chain.
- Shipping Options: Available via sea freight (for bulk orders), air freight (for urgent orders), or land transportation (for regional deliveries). Custom packaging for specific shipping requirements (e.g., export compliance) is also supported.
7. Key Applications
Leveraging its corrosion resistance, high-temperature strength, and weldability, UNS N06625 hot-rolled round bars are used in:
- Aerospace: Engine components, turbine blades, and structural parts.
- Oil & Gas: Downhole tools, wellhead equipment, and pipelines (resistant to sour gas and seawater).
- Chemical Processing: Reactors, heat exchangers, and valve stems (resistant to acids and alkalis).
- Marine Engineering: Propeller shafts, hull components, and offshore platform structures.
- Power Generation: Boiler tubes, steam turbine parts, and nuclear reactor components.
In summary, UNS N06625 hot-rolled round bars (10-300mm diameter, custom length) offer a balance of performance, versatility, and quality, making them a preferred choice for critical applications in extreme environments.
