Alumel Thermocouple Wire Type K - Std,ASTM E230，1

### Technical Datasheet: Alumel Thermocouple Wire (Type K Negative Leg) **Classification:** Nickel-Based Thermocouple Alloy **Type:** K Thermocouple Negative Conductor (KN) **Standard:** ASTM E230/E230M --- #### 1.0 Introduction **Alumel** is the standardized negative leg material for Type K thermocouples, one of the most widely used base metal thermocouple systems. This nickel-based alloy, when paired with the positive leg Chromel (KP), generates a predictable and reproducible electromotive force (EMF) in response to temperature changes. Alumel thermocouple wire is designed for **reliable temperature measurement** across a broad range, offering good oxidation resistance and stable performance in various industrial environments. --- #### 2.0 Chemical Composition (Weight %) | Element | Minimum | Maximum | Typical Value | Function | |---------|---------|---------|---------------|----------| | **Nickel (Ni)** | Balance | Balance | ~95% | Base element | | **Aluminum (Al)** | 1.5 | 2.5 | 2.0 | Thermoelectric properties | | **Manganese (Mn)** | 1.0 | 2.5 | 1.8 | Thermoelectric properties | | **Silicon (Si)** | 0.8 | 1.5 | 1.2 | Oxidation resistance | | **Cobalt (Co)** | - | 0.5 | 0.2 | - | | **Iron (Fe)** | - | 0.5 | 0.2 | - | | **Carbon (C)** | - | 0.10 | 0.05 | - | | **Other Elements** | - | 0.5 | 0.2 | - | *Note: Composition is carefully controlled to maintain consistent thermoelectric properties.* --- #### 3.0 Physical & Mechanical Properties | Property | Value | Condition/Notes | |----------|-------|-----------------| | **Density** | 8.6 g/cm³ | At room temperature | | **Melting Point** | 1399°C (2550°F) | - | | **Electrical Resistivity** | 0.29 μΩ·m | At 20°C | | **Thermal EMF** | -5.56 mV | At 1000°C (relative to Pt-67) | | **Temperature Range** | -200°C to 1260°C | Continuous service | | **Curie Temperature** | 163°C (325°F) | Magnetic transition point | | **Tensile Strength** | 620-690 MPa | Annealed condition | | **Elongation** | 20-30% | Annealed condition | --- #### 4.0 Thermoelectric Properties **4.1 EMF Output (Reference Junction at 0°C):** | Temperature | EMF Output | |-------------|------------| | 0°C | 0 mV | | 100°C | -3.55 mV | | 200°C | -7.32 mV | | 500°C | -20.64 mV | | 1000°C | -41.27 mV | **4.2 Accuracy (per ASTM E230):** - **Standard Grade:** ±2.2°C or ±0.75% (whichever is greater) - **Special Grade:** ±1.1°C or ±0.4% (whichever is greater) --- #### 5.0 Performance Characteristics **5.1 Advantages:** - Wide temperature range coverage - Good oxidation resistance in clean atmospheres - Linear EMF output characteristics - Cost-effective for general purpose applications - Good mechanical strength and durability **5.2 Limitations:** - Subject to aging effects at high temperatures - Vulnerable to sulfur attack - Affected by reducing atmospheres - Magnetic below 163°C - Requires protection in corrosive environments --- #### 6.0 Applications **6.1 Primary Application Areas:** - Industrial process control and monitoring - Heat treatment furnaces - Power generation equipment - Chemical processing plants - Food processing equipment - Environmental chambers - Educational and research laboratories **6.2 Typical Installations:** - Furnace temperature profiling - Engine exhaust temperature measurement - Oven and kiln temperature control - Boiler temperature monitoring - Industrial heater supervision --- #### 7.0 International Standards & Specifications **Primary Standards Compliance:** | Standard | Title | Scope | |----------|-------|-------| | **ASTM E230/E230M** | Standard Specification and Temperature-Electromotive Force (EMF) Tables for Standardized Thermocouples | Primary specification | | **IEC 60584-1** | Thermocouples - Part 1: EMF specifications and tolerances | International standard | | **IEC 60584-2** | Thermocouples - Part 2: Tolerances | Tolerance classifications | | **ANSI MC96.1** | Temperature Measurement Thermocouples | American national standard | | **BS EN 60584-1** | Thermocouples - Part 1: EMF specifications and tolerances | European standard | **7.1 Tolerance Classifications (per IEC 60584-2):** - **Class 1:** ±1.5°C from -40°C to 375°C, ±0.4% above 375°C - **Class 2:** ±2.5°C from -40°C to 333°C, ±0.75% above 333°C --- #### 8.0 Wire Specifications & Configurations **8.1 Standard Wire Sizes:** - **AWG 8** (3.25 mm) - High temperature applications - **AWG 14** (1.63 mm) - General purpose - **AWG 20** (0.81 mm) - Limited space applications - **AWG 24** (0.51 mm) - High flexibility required - **AWG 30** (0.25 mm) - Fast response applications **8.2 Insulation Types:** - PVC (up to 105°C) - Fiberglass (up to 480°C) - Ceramic fiber (up to 1260°C) - Teflon (up to 260°C) --- #### 9.0 Installation & Usage Guidelines **9.1 Best Practices:** - Use matching extension wire for long runs - Maintain clean, tight connections - Avoid mechanical stress at measurement junctions - Protect from corrosive atmospheres - Use appropriate sheathing for hostile environments **9.2 Common Pitfalls to Avoid:** - Mixing with other thermocouple types - Exposure to reducing atmospheres - Mechanical vibration and stress - Temperature cycling beyond specifications - Poor junction fabrication --- **Note:** Alumel is a registered trademark of Hoskins Manufacturing Company. Type K thermocouples are the most commonly used base metal thermocouple system worldwide. For critical applications, always verify calibration and ensure proper installation according to manufacturer recommendations and relevant industry standards. Performance may vary based on specific environmental conditions and installation practices.

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 3281 gallon liquid totes Special package is available on request.