Haynes 625 alloy,1

### **Haynes® 625 Alloy (UNS N06625) - Nickel-Chromium-Molybdenum-Niobium Superalloy** #### **Overview** **Haynes® 625 Alloy** is a nickel-chromium-molybdenum-niobium superalloy renowned for its exceptional combination of high strength, excellent fatigue resistance, and outstanding corrosion resistance. This versatile alloy derives its strength from the stiffening effect of molybdenum and niobium in its nickel-chromium matrix, providing excellent mechanical properties from cryogenic temperatures to 1800°F (980°C). The alloy exhibits remarkable resistance to a wide range of severe corrosive environments and maintains good fabricability and weldability. --- #### **Chemical Composition (Weight %)** | Element | Content (%) | Function | |---------|-------------|-----------| | **Nickel (Ni)** | **≥ 58.0** | **Base element providing corrosion resistance and matrix stability** | | **Chromium (Cr)** | **20.0-23.0** | **Oxidation and corrosion resistance through Cr₂O₃ scale formation** | | **Molybdenum (Mo)** | **8.0-10.0** | **Solid solution strengthening and pitting resistance** | | **Niobium (Nb)** | **3.15-4.15** | **Forms gamma prime and gamma double prime strengthening phases** | | **Iron (Fe)** | **≤ 5.0** | **Controlled impurity** | | **Aluminum (Al)** | **≤ 0.40** | **Controlled impurity** | | **Titanium (Ti)** | **≤ 0.40** | **Controlled impurity** | | **Carbon (C)** | **≤ 0.10** | **Controlled for carbide formation** | | **Manganese (Mn)** | **≤ 0.50** | **Deoxidizer** | | **Silicon (Si)** | **≤ 0.50** | **Controlled impurity** | | **Phosphorus (P)** | **≤ 0.015** | **Controlled impurity** | | **Sulfur (S)** | **≤ 0.015** | **Controlled impurity** | --- #### **Physical Properties** | Property | Value / Description | |----------|---------------------| | **Density** | **8.44 g/cm³ (0.305 lb/in³)** | | **Melting Range** | **1290-1350°C (2350-2460°F)** | | **Electrical Resistivity** | **1.29 μΩ·m** | | **Thermal Conductivity** | **9.8 W/m·K (at 100°C)** | | **Coefficient of Thermal Expansion** | **12.8 μm/m·°C (20-100°C)** | | **Specific Heat Capacity** | **410 J/kg·K** | | **Magnetic Permeability** | **< 1.001 (essentially non-magnetic)** | --- #### **Mechanical Properties (Annealed Condition)** | Temperature | Tensile Strength | Yield Strength (0.2%) | Elongation | |-------------|------------------|---------------------|------------| | **Room Temperature** | **830 MPa (120 ksi)** | **415 MPa (60 ksi)** | **50%** | | **650°C (1200°F)** | **655 MPa (95 ksi)** | **275 MPa (40 ksi)** | **45%** | | **815°C (1500°F)** | **450 MPa (65 ksi)** | **345 MPa (50 ksi)** | **50%** | --- #### **High-Temperature Capabilities** | Property | Performance | |----------|-------------| | **Oxidation Resistance** | **Excellent up to 1800°F (980°C)** | | **Creep Strength** | **Outstanding at elevated temperatures** | | **Thermal Fatigue** | **Excellent resistance** | | **Cyclic Oxidation** | **Superior performance** | --- #### **Corrosion Resistance Performance** | Environment | Performance | Temperature Limit | |-------------|-------------|-------------------| | **Chloride Ion Stress Corrosion** | **Excellent** | **All temperatures** | | **Pitting & Crevice Corrosion** | **Outstanding** | **Severe environments** | | **Organic Acids** | **Excellent** | **Up to boiling points** | | **Seawater** | **Superior** | **All temperatures** | | **Oxidizing Salts** | **Excellent** | **Molten salt conditions** | --- #### **Key Characteristics & Applications** **Key Characteristics:** - **Exceptional Strength-Toughness Combination**: Maintains properties across wide temperature range - **Outstanding Corrosion Resistance**: Superior performance in diverse corrosive media - **Excellent Fabricability**: Good weldability and formability - **High Fatigue Resistance**: Superior performance under cyclic loading - **Good Oxidation Resistance**: Suitable for high-temperature service - **Versatile Strengthening Mechanism**: Solid solution and precipitation hardening capabilities **Typical Applications:** - **Aerospace Industry**: Engine exhaust systems, thrust reversers, spray bars - **Marine Engineering**: Propeller blades, submarine fittings, seawater components - **Chemical Processing**: Reactors, heat exchangers, distillation columns - **Power Generation**: Gas turbine components, heat exchangers, boiler parts - **Oil & Gas**: Downhole equipment, wellhead components, flow lines - **Pollution Control**: Flue gas desulfurization systems, scrubbers - **Nuclear Industry**: Fuel element assemblies, core components --- #### **International Standards & Specifications** | Standard | Designation | Description | |----------|-------------|-------------| | **UNS** | **N06625** | **Unified Numbering System** | | **ASTM** | **B443** | **Plate, Sheet, and Strip** | | **ASTM** | **B444** | **Bar and Shapes** | | **ASTM** | **B446** | **Rod** | | **ASTM** | **B704** | **Welded Tube** | | **ASTM** | **B705** | **Welded Pipe** | | **ASTM** | **B366** | **Fittings** | | **AWS** | **A5.14** | **Welding Electrodes and Rods** | | **AMS** | **5599** | **Sheet, Strip, and Plate** | | **AMS** | **5666** | **Bar, Forgings, and Rings** | | **AMS** | **5837** | **Welding Wire** | --- #### **Manufacturing & Processing** **Available Forms:** - **Plate and Sheet**: 0.5 mm to 150 mm thickness - **Bar and Rod**: 3 mm to 400 mm diameter - **Pipe and Tube**: 6 mm to 1200 mm diameter - **Wire and Strip**: Various sizes for specialized applications - **Forgings and Fittings**: Custom components **Processing Guidelines:** - **Hot Working**: 1150-1200°C (2100-2190°F) - **Cold Working**: Good capability with intermediate annealing - **Annealing**: 1100-1150°C (2000-2100°F) with rapid cooling - **Welding**: Excellent weldability using AWS A5.14 ERNiCrMo-3 - **Machining**: Similar to other nickel-based superalloys --- #### **Quality Control & Testing** - **Chemical Analysis**: Per ASTM E1473 - **Mechanical Testing**: Per ASTM E8/E8M - **Corrosion Testing**: ASTM G28, G48, G61 methods - **Non-Destructive Testing**: UT, RT, PT, ET as required - **Metallographic Examination**: Per ASTM E3 --- #### **Comparison with Competitive Alloys** | Property | Alloy 625 | Alloy 825 | Alloy C-276 | Stainless 316 | |----------|-----------|-----------|-------------|---------------| | **Strength Level** | **High** | Medium | High | Low | | **Corrosion Resistance** | **Excellent** | Very Good | Excellent | Good | | **Temperature Capability** | **980°C** | 540°C | 1090°C | 870°C | | **Cost Effectiveness** | **High** | Medium | High | Low | --- #### **Summary** **Haynes® 625 Alloy (UNS N06625)** represents one of the most versatile and widely used nickel-based superalloys, offering an exceptional balance of high strength, outstanding corrosion resistance, and excellent fabricability. Its comprehensive standardization across multiple ASTM, AMS, and AWS specifications ensures consistent quality and reliable performance across diverse applications. The alloy's unique combination of solid solution strengthening from molybdenum and precipitation hardening from niobium provides robust mechanical properties from cryogenic temperatures to 980°C. Supported by extensive service experience and rigorous quality standards, Alloy 625 continues to be the material of choice for demanding applications in aerospace, chemical processing, marine engineering, and energy industries where reliability in severe environments is paramount.

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 3244 gallon liquid totes Special package is available on request.