Invar 36,Alloy 36 Bar(Round bar, Flat bar),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 Bar (Round Bar & Flat Bar) UNS K93600** #### **1.0 Product Overview** Invar 36 Bar (also known as Alloy 36 Bar), designated as **UNS K93600**, is a nickel‑iron controlled expansion alloy supplied in both round bar and flat bar configurations. These product forms maintain an extremely low coefficient of thermal expansion at ambient temperatures, providing excellent machinability and fabrication versatility for components requiring exceptional dimensional stability in precision instruments, aerospace systems, 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 machinability | | **C** | ≤ 0.05 | Impurity control | | **P** | ≤ 0.025 | Impurity control | | **S** | ≤ 0.025 | 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 Annealed Condition (Typical)** - **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 Condition** - **Tensile Strength**: 620–758 MPa (90–110 ksi) - **Yield Strength**: 550–690 MPa (80–100 ksi) - **Elongation**: 15–25% - **Hardness**: 85–100 HRB --- #### **5.0 Product Specifications** **5.1 Round Bar Specifications** - **Diameter Range**: 3.0 mm to 200 mm (0.125" to 8.0") - **Length**: 1000 mm to 3000 mm (39" to 118") - **Diameter Tolerance**: h9 for precision applications - **Straightness**: 0.5 mm per 300 mm maximum - **Surface Finish**: Centerless ground, turned, or hot rolled **5.2 Flat Bar Specifications** - **Thickness**: 3.0 mm to 50 mm (0.125" to 2.0") - **Width**: 10 mm to 200 mm (0.375" to 8.0") - **Length**: 1000 mm to 3000 mm (39" to 118") - **Flatness**: 0.1 mm per 100 mm maximum - **Edge Condition**: Sheared, sawn, or ground --- #### **6.0 Manufacturing Processes** **6.1 Production Methods** - Hot rolling from forged billets - Cold drawing for improved surface finish - Centerless grinding for tight tolerances - Annealing in controlled atmosphere - Precision sawing and cutting **6.2 Quality Control** - Ultrasonic testing per ASTM A388 - Dimensional verification - Surface quality inspection - Mechanical property testing - Chemical analysis verification --- #### **7.0 Heat Treatment** **7.1 Stress Relieving** - **Temperature**: 425–540°C (800–1000°F) - **Time**: 1–2 hours - **Cooling**: Air cool - **Application**: Recommended after heavy machining **7.2 Annealing** - **Temperature**: 790–870°C (1450–1600°F) - **Time**: 30–60 minutes - **Cooling**: Air cool or faster - **Purpose**: Recrystallization and softening --- #### **8.0 Applications** **8.1 Round Bar Applications** - Precision instrument shafts - Laser system optical mounts - Metrology machine components - Watch and clock arbors - Scientific instrument frames **8.2 Flat Bar Applications** - Optical bench bases - Measuring machine rails - Composite mold bases - Instrument platform plates - Cryogenic support structures **8.3 Industry Specific Uses** - **Aerospace**: Satellite frames, aircraft instruments - **Defense**: Guidance system components, radar bases - **Scientific**: Laboratory equipment, research instruments - **Industrial**: Precision machinery, measurement systems --- #### **9.0 International Standards** | Standard | Organization | Description | |----------|--------------|-------------| | **ASTM F1684** | ASTM | Iron-Nickel Alloys for Low Thermal Expansion | | **AMS 7725** | SAE | Bars, Forgings, and Rings | | **UNS K93600** | ASTM | Unified Numbering System | | **DIN 1.3912** | DIN | German Material Number | | **JIS CCMA 8** | JIS | Japanese Industrial Standard | | **GB 4J36** | China | Chinese National Standard | --- #### **10.0 Machining & Fabrication** **10.1 Machining Characteristics** - Good machinability in annealed condition - Use carbide tools with positive rake angles - Recommended cutting speed: 25–40 m/min - Use soluble oil or chemical coolants - Moderate work hardening tendency requires sharp tools **10.2 Turning & Milling** - **Roughing**: Depth of cut 2–5 mm, feed 0.2–0.5 mm/rev - **Finishing**: Depth of cut 0.5–1.5 mm, feed 0.1–0.3 mm/rev - **Surface Speed**: 30–45 m/min for carbide tools **10.3 Grinding & Cutting** - Suitable for surface and cylindrical grinding - Abrasive cutting effective for bar stock - EDM machining possible for complex shapes - Laser and waterjet cutting available --- #### **11.0 Performance Characteristics** **11.1 Thermal Expansion Performance** - Exceptionally low CTE around room temperature - Minimal dimensional changes with temperature fluctuations - Stable performance from cryogenic to elevated temperatures - Excellent for precision applications requiring thermal stability **11.2 Special Features** - Near-zero thermal expansion at room temperature - Good strength and toughness at cryogenic temperatures - Excellent fatigue resistance - Reliable long-term dimensional stability --- #### **12.0 Quality Assurance** **12.1 Testing & Certification** - Chemical composition analysis - Thermal expansion coefficient verification - Mechanical property testing - Ultrasonic testing for internal quality - Dimensional accuracy certification **12.2 Documentation & Traceability** - Mill Test Certificates per EN 10204 3.1 - Full material traceability from melt to finished bar - Heat treatment records and certifications - Compliance with customer and industry specifications --- Invar 36/Alloy 36 Bar (UNS K93600) in both round and flat configurations provides manufacturers with versatile raw materials for producing precision components that require exceptional dimensional stability across temperature variations. The availability in different bar forms enables efficient manufacturing of components for precision instruments, aerospace systems, and scientific equipment where near-zero thermal expansion and reliable performance are critical requirements.

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 2393 gallon liquid totes Special package is available on request.