Invar 36,Alloy 36 ,UNS K93600,E FORU

British Specs:，American Specs: ASTM F1684 MIL-S-16598 Tooling plate ASTM B388 Sheet & strip ASTM B753 K93050 Free-cut Invar，German Specs:WS 1.3912

### **Technical Data Sheet: Invar 36 / Alloy 36 (UNS K93600)** #### **1.0 Product Overview** Invar 36 (also known as Alloy 36), designated as **UNS K93600**, is a nickel‑iron controlled expansion alloy renowned for its extremely low coefficient of thermal expansion (CTE) at room temperature. This unique property makes it indispensable for applications requiring dimensional stability across temperature variations, particularly in precision instruments, aerospace components, and scientific equipment. --- #### **2.0 Chemical Composition (wt%)** | Element | Content (%) | Function | |---------|-------------|----------| | **Ni** | 35.0–37.0 | Primary control of thermal expansion | | **Fe** | Balance | Base element | | **Mn** | 0.35–0.65 | Deoxidizer and improves workability | | **Si** | 0.20–0.40 | Deoxidizer and enhances fluidity | | **C** | ≤ 0.05 | Impurity control | | **P** | ≤ 0.025 | Impurity control | | **S** | ≤ 0.025 | Impurity control | | **Cr** | ≤ 0.25 | Impurity control | | **Cu** | ≤ 0.25 | Impurity control | --- #### **3.0 Physical Properties** | Property | Value (Metric) | Value (Imperial) | Condition | |----------|----------------|------------------|-----------| | Density | 8.11 g/cm³ | 0.293 lb/in³ | 20°C | | Melting Point | 1427°C | 2600°F | – | | Thermal Conductivity | 10.5 W/m·K | 72.7 Btu·in/(hr·ft²·°F) | 20°C | | Mean CTE | 1.3 ×10⁻⁶/°C | 0.72 ×10⁻⁶/°F | 20–100°C | | Electrical Resistivity | 0.82 μΩ·m | 31.8 μΩ·in | 20°C | | Modulus of Elasticity | 141 GPa | 20.5 ×10⁶ psi | 20°C | | Curie Temperature | 230°C | 446°F | – | | Specific Heat | 0.52 J/g·°C | 0.124 Btu/lb·°F | 20°C | --- #### **4.0 Mechanical Properties** **4.1 Typical Room Temperature Properties (Annealed)** - **Tensile Strength**: 448–552 MPa (65–80 ksi) - **Yield Strength (0.2% Offset)**: 276–345 MPa (40–50 ksi) - **Elongation**: 30–40% - **Reduction in Area**: 65–75% - **Hardness**: 65–80 HRB - **Modulus of Elasticity**: 141 GPa (20.5 ×10⁶ psi) **4.2 Cold Worked Properties** - **Tensile Strength**: Up to 827 MPa (120 ksi) - **Yield Strength**: Up to 758 MPa (110 ksi) - **Elongation**: 5–15% (depending on cold work level) --- #### **5.0 Product Forms & Specifications** **5.1 Available Product Forms** - Sheet & Strip: 0.1 mm to 6.0 mm thickness - Plate: 6 mm to 100 mm thickness - Bar & Rod: 1.0 mm to 300 mm diameter - Wire: 0.1 mm to 12.0 mm diameter - Forgings and custom components **5.2 Thermal Expansion Characteristics** | Temperature Range | CTE (×10⁻⁶/°C) | CTE (×10⁻⁶/°F) | |-------------------|----------------|----------------| | 20–100°C | 1.3 | 0.72 | | 20–200°C | 4.0 | 2.22 | | 20–300°C | 6.5 | 3.61 | --- #### **6.0 Heat Treatment** **6.1 Stress Relieving** - **Temperature**: 425–540°C (800–1000°F) - **Time**: 1–2 hours - **Cooling**: Air cool - **Purpose**: Relieve stresses from machining or cold working **6.2 Annealing** - **Temperature**: 790–870°C (1450–1600°F) - **Time**: 30–60 minutes - **Cooling**: Air cool or faster - **Purpose**: Recrystallization and softening --- #### **7.0 Applications** **7.1 Precision Instruments** - Surveying equipment frames - Laser system components - Optical measuring devices - Watch and clock components - Precision scale parts **7.2 Aerospace & Defense** - Aircraft control systems - Satellite structural components - Radar waveguides - Gyroscope components - Aerospace instrumentation **7.3 Industrial & Scientific** - LNG tanker inner membranes - Television shadow masks - Metrology equipment - Scientific instrument frames - Mold tools for composites --- #### **8.0 International Standards** | Standard | Organization | Description | |----------|--------------|-------------| | **ASTM F1684** | ASTM | Standard Specification for Iron-Nickel Alloys for Low Thermal Expansion Applications | | **UNS K93600** | ASTM | Unified Numbering System | | **DIN 1.3912** | DIN | German Material Number | | **AMS 7725** | SAE | Bars, Forgings, and Rings | | **JIS CCMA 8** | JIS | Japanese Industrial Standard | | **GB 4J36** | China | Chinese National Standard | --- #### **9.0 Fabrication Characteristics** **9.1 Machining** - Good machinability in annealed condition - Use sharp tools with positive rake angles - Recommended speed: 25–40 m/min - Use soluble oil coolants - Work hardening requires careful handling **9.2 Forming** - Good cold formability in annealed condition - Minimum bend radius: 2T (where T = thickness) - Can be deep drawn with proper tooling - Stress relieve after severe forming **9.3 Welding** - Good weldability using common processes - Recommended methods: GTAW, GMAW, SMAW - Matching filler metals recommended - Post-weld heat treatment often required --- #### **10.0 Special Characteristics** **10.1 Unique Properties** - Lowest thermal expansion of all metals at room temperature - Maintains dimensional stability over wide temperature ranges - Good strength and toughness at cryogenic temperatures - Excellent fatigue resistance **10.2 Performance Advantages** - Minimal thermal stress in temperature-varying environments - Consistent performance in precision applications - Long-term dimensional stability - Reliable performance in critical applications --- #### **11.0 Quality Assurance** **11.1 Testing & Certification** - Chemical analysis per ASTM E1473 - Mechanical testing per ASTM E8 - Thermal expansion testing per ASTM E228 - Non-destructive testing as required - Certification to EN 10204 3.1/3.2 **11.2 Quality Standards** - ISO 9001 Quality Management Systems - AS9100 Aerospace Quality Standards - NADCAP Accreditation for special processes --- #### **12.0 Packaging & Handling** **12.1 Storage Requirements** - Store in clean, dry conditions - Protect from mechanical damage - Avoid contact with corrosive substances - Maintain identification and traceability **12.2 Special Considerations** - Handle with clean gloves to prevent contamination - Protect finished surfaces from damage - Proper support for long lengths to prevent bending - Clean before use in precision applications --- Invar 36/Alloy 36 (UNS K93600) remains the premier material for applications requiring exceptional dimensional stability across temperature variations. Its unique near-zero thermal expansion characteristics, combined with good mechanical properties and fabrication versatility, make it essential for precision instruments, aerospace components, and scientific equipment where thermal stability is critical to performance and reliability.

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 2391 gallon liquid totes Special package is available on request.