Invar 36,Alloy 36 Pipe,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 Pipe (UNS K93600)** #### **1.0 Product Overview** Invar 36 Pipe (also known as Alloy 36 Pipe), designated as **UNS K93600**, is a nickel‑iron controlled expansion alloy manufactured in tubular form. This specialized product maintains an extremely low coefficient of thermal expansion at ambient temperatures, making it essential for cryogenic systems, precision instruments, and aerospace applications where dimensional stability across temperature variations is critical. --- #### **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 | --- #### **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 Properties (Annealed Condition)** - **Tensile Strength**: 448–552 MPa (65–80 ksi) - **Yield Strength (0.2% Offset)**: 276–345 MPa (40–50 ksi) - **Elongation**: 30–40% - **Hardness**: 65–80 HRB - **Bursting Pressure**: 2.5 × working pressure **4.2 Pressure-Temperature Ratings** - **Maximum Working Pressure**: 100 bar (1450 psi) at 20°C - **Temperature Limit**: 425°C (800°F) for continuous service - **Pressure Derating**: Required above 300°C (570°F) --- #### **5.0 Product Specifications** **5.1 Standard Pipe Sizes** - **Outside Diameter**: 6 mm to 150 mm (0.25" to 6.0") - **Wall Thickness**: 0.5 mm to 12 mm (0.020" to 0.50") - **Length**: 500 mm to 3000 mm (20" to 118") - **Tolerance**: Per ASTM B774 for thin wall tubing - **Straightness**: 1 mm per 300 mm maximum **5.2 Manufacturing Methods** - Seamless cold drawing - Welded and redrawn - Centrifugal casting (special sizes) - Machined from solid bar (custom applications) --- #### **6.0 Manufacturing Processes** **6.1 Production Methods** - Cold drawing over mandrel for seamless tubing - Pilger milling process for precise wall thickness - Annealing in controlled atmosphere - Final sizing and straightening operations - Non-destructive testing and inspection **6.2 Quality Control** - Eddy current testing for defect detection - Hydrostatic pressure testing - Dimensional verification - Surface quality inspection - Ultrasonic thickness measurement --- #### **7.0 Heat Treatment** **7.1 Stress Relieving** - **Temperature**: 425–540°C (800–1000°F) - **Time**: 1–2 hours - **Cooling**: Air cool - **Application**: After bending or forming operations **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 Cryogenic Systems** - LNG transfer lines - Cryogenic fluid piping - Superconducting magnet housings - Liquid nitrogen transfer systems - Cryogenic instrument housings **8.2 Aerospace & Defense** - Satellite fuel lines - Space telescope structural tubing - Aircraft instrumentation piping - Radar cooling systems - Missile guidance system components **8.3 Scientific & Research** - Particle accelerator beam tubes - Nuclear magnetic resonance probes - Laboratory cryostat components - Vacuum chamber piping - Precision measurement instrument frames --- #### **9.0 International Standards** | Standard | Organization | Description | |----------|--------------|-------------| | **ASTM F1684** | ASTM | Iron-Nickel Alloys for Low Thermal Expansion | | **ASTM B774** | ASTM | Thin-Wall Seamless Pipe and Tube | | **UNS K93600** | ASTM | Unified Numbering System | | **DIN 1.3912** | DIN | German Material Number | | **AMS 7725** | SAE | Bars, Forgings, and Rings | | **MIL-I-23011** | U.S. Military | Sealing Alloys | --- #### **10.0 Fabrication & Installation** **10.1 Machining & Processing** - Good machinability in annealed condition - Use carbide tools with positive rake angles - Recommended cutting speed: 25–40 m/min - Suitable for turning, boring, and facing operations - EDM machining possible for complex features **10.2 Welding & Joining** - Good weldability using GTAW process - Recommended filler: Matching composition wire - Pre-heat not required for thin wall sections - Post-weld stress relief recommended **10.3 Bending & Forming** - Can be cold formed with proper tooling - Minimum bend radius: 2 × OD for thin wall tubing - Mandrel bending recommended for tight radii - Stress relieve after severe forming operations --- #### **11.0 Performance Characteristics** **11.1 Thermal Performance** - Exceptionally low thermal expansion around room temperature - Minimal thermal stress during temperature cycling - Stable dimensional characteristics from cryogenic to elevated temperatures - Excellent thermal shock resistance **11.2 Cryogenic Performance** - Maintains toughness at cryogenic temperatures - Low thermal conductivity reduces heat transfer - Excellent dimensional stability in cryogenic service - Suitable for LNG and other cryogenic applications --- #### **12.0 Quality Assurance** **12.1 Testing & Certification** - **Pressure Testing**: Hydrostatic or pneumatic per applicable standards - **Non-Destructive Examination**: Eddy current, ultrasonic, or radiographic - **Dimensional Inspection**: To ASTM B774 or customer specifications - **Material Certification**: EN 10204 3.1 with full traceability - **Surface Finish**: Per customer requirements and application needs **12.2 Marking & Identification** - Material grade (K93600) - Size and wall thickness - Manufacturer's identification - Heat number for traceability - Compliance markings as required --- Invar 36/Alloy 36 Pipe (UNS K93600) provides exceptional performance in applications requiring minimal thermal expansion and dimensional stability across temperature variations. Its unique near-zero thermal expansion characteristics make it indispensable for cryogenic systems, precision instruments, and aerospace applications where conventional materials would fail due to excessive thermal movement or inadequate dimensional stability.

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 2394 gallon liquid totes Special package is available on request.