C 625 Nickel-Chromium-Molybdenum Alloy,UNS N06625,E FORU

### **Product Introduction: C-625 Nickel-Chromium-Molybdenum Alloy (UNS N06625)** **C-625 Nickel-Chromium-Molybdenum Alloy (UNS N06625)** is a nickel-chromium-molybdenum-niobium alloy renowned for its exceptional strength, outstanding fatigue resistance, and excellent corrosion resistance across a wide range of severe environments. This solid-solution strengthened superalloy maintains remarkable mechanical properties from cryogenic temperatures up to 980°C (1800°F), making it particularly valuable for aerospace, marine, and chemical processing applications where reliability under extreme conditions is paramount. The alloy derives its superior performance from the synergistic combination of molybdenum and niobium, which provide solid-solution strengthening and enable the material to withstand highly corrosive environments while maintaining structural integrity under significant mechanical stress. --- #### **1. Chemical Composition (Weight %)** The chemical composition of C-625 Nickel-Chromium-Molybdenum Alloy per UNS N06625 is as follows: | Element | Content (%) | Element | Content (%) | |---------|-------------|---------|-------------| | **Nickel (Ni)** | 58.0 min | **Chromium (Cr)** | 20.0 - 23.0 | | **Molybdenum (Mo)** | 8.0 - 10.0 | **Niobium (Nb)** | 3.15 - 4.15 | | **Iron (Fe)** | 5.0 max | **Titanium (Ti)** | 0.40 max | | **Aluminum (Al)** | 0.40 max | **Carbon (C)** | 0.10 max | | **Manganese (Mn)** | 0.50 max | **Silicon (Si)** | 0.50 max | | **Phosphorus (P)** | 0.015 max | **Sulfur (S)** | 0.015 max | --- #### **2. Physical & Mechanical Properties** **Physical Properties:** | Property | Metric Units | Imperial Units | |----------|-----------------|------| | **Density** | 8.44 g/cm³ | 0.305 lb/in³ | | **Melting Range** | 1290 - 1350 °C | 2350 - 2460 °F | | **Thermal Conductivity** | 9.8 W/m·K | 68.0 Btu·in/hr·ft²·°F | | **Coefficient of Thermal Expansion** | 12.8 μm/m·°C | 7.1 μin/in·°F | | **Specific Heat** | 410 J/kg·K | 0.098 Btu/lb·°F | | **Electrical Resistivity** | 1.28 μΩ·m | - | | **Modulus of Elasticity** | 207 GPa | 30.0 x 10⁶ psi | **Mechanical Properties (Annealed Condition):** | Property | Value | |----------|-----------------| | **Tensile Strength** | 930 MPa | 135 ksi | | **Yield Strength (0.2% Offset)** | 517 MPa | 75 ksi | | **Elongation** | 42.5% | | **Hardness (Rockwell B)** | 96 HRB | **Elevated Temperature Properties (at 650°C/1200°F):** | **Tensile Strength** | 725 MPa | 105 ksi | | **Yield Strength** | 400 MPa | 58 ksi | | **Creep Rupture Strength (1000h)** | 170 MPa | 25 ksi | --- #### **3. Key Characteristics & Product Applications** **Key Characteristics:** - **Excellent Corrosion Resistance**: Outstanding performance in acidic, alkaline, and saline environments - **Superior Strength Properties**: High tensile, creep, and fatigue strength across wide temperature range - **Outstanding Fatigue Resistance**: Excellent performance under cyclic loading conditions - **Good Oxidation Resistance**: Suitable for continuous service up to 980°C (1800°F) - **Excellent Fabricability**: Good weldability and formability characteristics - **Cryogenic Toughness**: Maintains ductility and strength at cryogenic temperatures **Product Applications:** C-625 Nickel-Chromium-Molybdenum Alloy serves critical functions in demanding applications: - **Aerospace & Defense**: - Gas turbine engine components - Aircraft ducting systems - Rocket motor components - Spacecraft structural parts - **Marine Engineering**: - Propeller blades and marine components - Subsea fasteners and connectors - Seawater piping systems - Offshore platform components - **Chemical Processing**: - Reactor vessels and heat exchangers - Process piping and valves - Scrubbers and pollution control equipment - Chemical storage tanks - **Power Generation**: - Gas turbine components - Heat recovery systems - Nuclear power plant components - Flue gas desulfurization systems --- #### **4. International Standards & Specifications** C-625 Nickel-Chromium-Molybdenum Alloy complies with the following international standards: **Primary Specifications:** - **UNS N06625**: Unified Numbering System - **ASTM B443**: Plate, Sheet, and Strip - **ASTM B444**: Seamless Pipe and Tube - **ASTM B446**: Rod and Bar - **ASTM B704**: Welded Tube **International Equivalents:** - **EN**: 2.4856 (NiCr22Mo9Nb) - **DIN**: 2.4856 - **JIS**: NW 6625 - **ISO**: 6207 (NW 6625) - **AMS**: 5666 (Bars, Forgings, and Rings) --- #### **Summary of Key Advantages** - **Exceptional Corrosion Resistance**: Outstanding performance in diverse corrosive environments - **Superior Mechanical Strength**: High strength maintained across wide temperature range - **Excellent Fabricability**: Good weldability and formability for complex components - **Proven Reliability**: Extensive service history in critical applications - **Versatile Performance**: Suitable for aerospace, marine, chemical, and power applications - **Comprehensive Standardization**: Meets international quality and performance standards **Technical Note**: C-625 Nickel-Chromium-Molybdenum Alloy exhibits excellent weldability using common processes including GTAW, GMAW, and SMAW with matching filler metals. The alloy is not precipitation hardenable but derives its strength from solid-solution strengthening mechanisms. For optimal corrosion resistance, a solution annealing treatment at 1095-1205°C (2000-2200°F) followed by rapid cooling is recommended. The material demonstrates exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking in chloride-containing environments. Proper cleaning after fabrication is essential to maintain optimum corrosion resistance performance. The alloy's niobium content stabilizes it against sensitization during welding and thermal processing.

Packing of Standard Packing: Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 3190 gallon liquid totes Special package is available on request.