Alloy 725，Inconel 725 Tube，UNS N07725，EFORU

British Specs:，American Specs:ASTM B805，German Specs:

### **Product Introduction: Alloy 725 / Inconel 725 Tube (UNS N07725)** #### **Overview** **Alloy 725 Tube** (commercially known as **Inconel® 725 Tube**) is a high-performance nickel-chromium-molybdenum-niobium alloy tubing product specifically engineered for severe corrosive service conditions requiring exceptional corrosion resistance combined with high strength. This precipitation-hardenable alloy maintains outstanding performance in aggressive environments including sour gas (H₂S-containing) wells, acidic solutions, and chloride-containing media, while providing excellent mechanical properties at temperatures up to 650°C (1200°F). The tube is manufactured through precision processes to ensure consistent wall thickness, superior surface finish, and reliable performance in critical oil and gas, chemical processing, and marine applications. The alloy's enhanced characteristics are achieved through a sophisticated precipitation-hardening mechanism involving gamma prime [γ'] and gamma double prime [γ''] phase formation, providing an optimal balance of strength and corrosion resistance for demanding tubing applications. --- #### **Chemical Composition** The chemical composition of Alloy 725 Tube (UNS N07725) is carefully balanced for optimal performance: | Element | Content (%) | | :--- | :--- | | **Nickel (Ni)** | 55.0 - 59.0 | | **Chromium (Cr)** | 19.0 - 22.5 | | **Molybdenum (Mo)** | 7.0 - 9.5 | | **Iron (Fe)** | 5.0 - 9.0 | | **Niobium (Nb)** | 2.75 - 4.00 | | **Titanium (Ti)** | 1.0 - 1.7 | | **Aluminum (Al)** | 0.35 - 0.75 | | **Manganese (Mn)** | ≤ 0.35 | | **Silicon (Si)** | ≤ 0.20 | | **Carbon (C)** | ≤ 0.03 | | **Sulfur (S)** | ≤ 0.010 | | **Copper (Cu)** | ≤ 0.20 | | **Phosphorus (P)** | ≤ 0.015 | *The optimized composition provides excellent corrosion resistance while enabling effective precipitation hardening through gamma double prime [γ'' Ni₃Nb] phase formation.* --- #### **Physical Properties** Critical properties for tube design and application engineering: | Property | Metric Value | Imperial Value | | :--- | :--- | :--- | | **Density** | 8.31 g/cm³ | 0.300 lb/in³ | | **Melting Range** | 1320 - 1360 °C | 2410 - 2480 °F | | **Specific Heat (20°C)** | 442 J/kg·K | 0.106 Btu/lb·°F | | **Thermal Conductivity (20°C)** | 10.8 W/m·K | 75.0 Btu·in/hr·ft²·°F | | **Thermal Expansion Coefficient (20-100°C)** | 12.9 μm/m·°C | 7.2 μin/in·°F | | **Modulus of Elasticity** | 206 GPa | 29.9 x 10⁶ psi | | **Electrical Resistivity** | 1.28 μΩ·m | - | --- #### **Mechanical Properties** Enhanced mechanical properties achieved through optimized heat treatment: **Solution Annealed + Aged Condition:** * **Ultimate Tensile Strength:** 1100-1240 MPa (160-180 ksi) * **Yield Strength (0.2% Offset):** 760-895 MPa (110-130 ksi) * **Elongation:** 15-25% * **Hardness:** 30-40 HRC **Pressure Performance:** * **Maximum Working Temperature:** 650°C (1200°F) * **Minimum Cryogenic Service:** -196°C (-321°F) * **Burst Pressure:** Excellent resistance to internal pressure failure --- #### **International Standards** Alloy 725 Tube conforms to several international specifications: **ASTM Standards:** * **ASTM B829:** Standard Specification for Seamless Nickel and Nickel Alloy Pipe and Tube * **ASTM B751:** Standard Specification for Nickel-Alloy Seamless and Welded Tube * **ASTM B880:** General Requirements for Chemical Check Analysis Limits **NACE Standards:** * **NACE MR0175/ISO 15156:** Suitable for use in H₂S-containing environments * **NACE MR0103:** Resistance to sulfide stress cracking **Other Standards:** * **ISO 6207:** Nickel and nickel alloy tubes * **DIN 17751:** Nickel and nickel alloy tubes - Technical delivery conditions * **ASME SB829:** Specification for Seamless Nickel and Nickel Alloy Pipe and Tube --- #### **Product Applications** Alloy 725 tubes serve critical functions across multiple high-performance industries: **Oil & Gas Industry:** * **Downhole Instruments:** Instrument protection tubing, control line conduits * **Subsea Systems:** Chemical injection lines, hydraulic control tubing * **Surface Equipment:** Pressure gauge lines, sensor tubing, sample lines * **Well Completion:** Control line tubing for downhole valves **Chemical Processing:** * **Heat Exchangers:** Tube bundles for corrosive service heat exchangers * **Process Instrumentation:** Analyzer sample lines, pressure sensing tubes * **Reactor Systems:** Thermocouple wells, instrument protection tubes * **Acid Services:** Tubing for hydrochloric, sulfuric acid handling **Marine & Offshore:** * **Seawater Systems:** Heat exchanger tubes, condenser tubes * **Offshore Platforms:** Hydraulic control lines, instrument tubing * **Desalination Plants:** Evaporator tubes, heat recovery tubing **Power Generation:** * **FGD Systems:** Absorber tower spray tubes, mist eliminator wash pipes * **Chemical Injection:** Ammonia injection tubes, amine solution lines * **Heat Recovery:** Waste heat boiler tubes, economizer sections --- #### **Key Advantages** * **Exceptional Corrosion Resistance:** Superior performance in sour gas and chloride-containing environments * **High Strength:** Excellent mechanical properties maintained in corrosive conditions * **Outstanding Stress Corrosion Cracking Resistance:** Superior resistance to SCC in chloride environments * **Excellent Pitting Resistance:** High resistance to pitting and crevice corrosion * **Excellent Fabricability:** Can be bent, flared, flanged, and welded using standard techniques * **Outstanding Fatigue Performance:** Superior resistance to vibration and pressure cycling * **Wide Temperature Capability:** Performs reliably from cryogenic to high-temperature service * **Pressure Integrity:** Maintains structural integrity under high internal and external pressures **Available Forms & Sizes:** * **Seamless Tubes:** OD from 1.6mm to 100mm (0.062" to 4") * **Welded Tubes:** OD from 6mm to 50mm (0.25" to 2") * **Wall Thickness:** 0.5mm to 10mm (0.020" to 0.394") * **Lengths:** Standard random lengths or cut-to-size **Surface Conditions:** * **Annealed and Pickled:** Clean, scale-free surface * **Bright Annealed:** Smooth, shiny surface finish * **Cold Drawn:** Precision dimensional control * **Special Coatings:** Custom surface treatments available **Heat Treatment Specifications:** * **Solution Treatment:** 980-1010°C (1800-1850°F) followed by rapid cooling * **Aging Treatment:** 620-650°C (1150-1200°F) for 8-12 hours, air cool * **Stress Relieving:** Available for cold worked and welded tubes **Corrosion Performance:** * **Critical Pitting Temperature (ASTM G48):** > 85°C (185°F) * **Critical Crevice Temperature (ASTM G48):** > 65°C (150°F) * **Sulfide Stress Cracking:** Resistant per NACE MR0175 **Note:** *Inconel® is a registered trademark of Special Metals Corporation. Alloy 725 tubes are available in seamless and welded construction, with various sizes and wall thicknesses to meet specific application requirements. Proper cleaning and passivation are recommended after fabrication to maintain corrosion resistance. Comprehensive certification including chemical analysis, mechanical properties, and corrosion testing reports are provided for critical applications.*

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 1810 gallon liquid totes Special package is available on request.