Product Details
Product Description
Type J Thermocouple Bare Wire (SWG30/SWG25/SWG19)
Product Overview
Type J thermocouple bare wire, a high-precision temperature-sensing
element crafted by Huona New Material, consists of two dissimilar
alloy conductors—iron (positive leg) and constantan (copper-nickel
alloy, negative leg)—engineered for accurate temperature
measurement in moderate-temperature environments. Available in
three standard wire gauges: SWG30 (0.305mm), SWG25 (0.51mm), and
SWG19 (1.02mm), this bare wire eliminates insulation interference,
making it ideal for custom thermocouple assembly, high-temperature
calibration, and applications requiring direct contact with
measured media. Leveraging Huona’s advanced alloy smelting and
drawing technologies, each gauge maintains strict dimensional
tolerance and stable thermoelectric properties, ensuring
consistency across batches.
Standard Designations
- Thermocouple Type: J (Iron-Constantan)
- Wire Gauges: SWG30 (0.315mm), SWG25 (0.56mm), SWG19 (1.024mm)
- International Standards: Complies with IEC 60584-1, ASTM E230, and
GB/T 4990
- Form: Bare wire (uninsulated, for custom insulation/protection)
- Manufacturer: Huona New Material, certified to ISO 9001 and
calibrated to national temperature standards
Key Advantages (vs. Insulated J-Type Wires & Other Thermocouple
Types)
This bare wire solution stands out for its versatility, accuracy,
and gauge-specific adaptability:
- Gauge-Tailored Performance: SWG30 (thin gauge) offers high
flexibility for tight-space installations (e.g., small sensors);
SWG19 (thick gauge) provides enhanced mechanical strength for
industrial environments; SWG25 balances flexibility and durability
for general-purpose use.
- Superior Thermoelectric Accuracy: Generates a stable electromotive
force (EMF) with a sensitivity of ~52 μV/°C (at 200°C),
outperforming Type K in the 0-500°C range, with Class 1 accuracy
(tolerance: ±1.5°C or ±0.25% of reading, whichever is larger).
- Bare Wire Versatility: No pre-applied insulation allows users to
customize protection (e.g., ceramic tubes, fiberglass sleeving)
based on specific temperature/corrosion requirements, reducing
waste from mismatched pre-insulated wires.
- Cost-Effective: Iron-constantan alloy is more affordable than
precious metal thermocouples (Types R/S/B) while delivering higher
sensitivity than Type K, making it ideal for mid-range temperature
measurement (0-750°C) without overspending.
- Good Oxidation Resistance: Performs reliably in oxidizing
environments up to 750°C; iron conductor forms a protective oxide
layer that minimizes drift, extending service life vs. unalloyed
iron wires.
Technical Specifications
| Attribute | SWG30 (0.315mm) | SWG25 (0.56mm) | SWG19 (1.024mm) |
|---|
| Conductor Material | Positive: Iron; Negative: Constantan (Cu-Ni 40%) | Positive: Iron; Negative: Constantan (Cu-Ni 40%) | Positive: Iron; Negative: Constantan (Cu-Ni 40%) |
| Nominal Diameter | 0.305mm | 0.51mm | 1.02mm |
| Diameter Tolerance | ±0.01mm | ±0.015mm | ±0.02mm |
| Temperature Range | Continuous: 0-700°C; Short-term: 750°C | Continuous: 0-750°C; Short-term: 800°C | Continuous: 0-750°C; Short-term: 800°C |
| EMF at 100°C (vs 0°C) | 5.268 mV | 5.268 mV | 5.268 mV |
| EMF at 750°C (vs 0°C) | 42.919 mV | 42.919 mV | 42.919 mV |
| Conductor Resistance (20°C) | ≤160 Ω/km | ≤50 Ω/km | ≤15 Ω/km |
| Tensile Strength (20°C) | ≥380 MPa | ≥400 MPa | ≥420 MPa |
| Elongation (20°C) | ≥20% | ≥22% | ≥25% |
Product Specifications
| Item | Specification |
|---|
| Surface Finish | Bright annealed (oxide-free, Ra ≤0.2μm) |
| Supply Form | Spools (length: 50m/100m/300m per gauge) |
| Chemical Purity | Iron: ≥99.5%; Constantan: Cu 59-61%, Ni 39-41%, impurities ≤0.5% |
| Calibration | Traceable to NIST/China National Institute of Metrology (CNIM) |
| Packaging | Vacuum-sealed in argon-filled bags (to prevent oxidation); plastic
spools in moisture-proof cartons |
| Customization | Cut-to-length (minimum 1m), special alloy purity (high-purity iron
for calibration), or pre-tinned ends |
Typical Applications
- Custom Thermocouple Assembly: Used by sensor manufacturers to
fabricate probes with application-specific protection (e.g.,
ceramic-sheathed probes for furnaces, stainless steel-sheathed
probes for liquids).
- Industrial Temperature Sensing: Direct measurement in food
processing (oven baking, 100-300°C) and plastic molding (melt
temperature, 200-400°C)—SWG25 is preferred for balance of
flexibility and strength.
- Calibration Equipment: Reference elements in temperature
calibrators (SWG30 for compact calibration cells).
- Automotive Testing: Monitoring engine block and exhaust system
temperatures (SWG19 for vibration resistance).
- Laboratory Research: Thermal profiling in material science
experiments (0-700°C) where custom insulation is required.
Huona New Material subjects every batch of Type J bare wire to
rigorous quality testing: thermoelectric stability tests (100
cycles of 0-750°C), dimensional inspection (laser micrometry), and
chemical composition analysis (XRF). Free samples (1m per gauge)
and calibration certificates are available upon request. Our
technical team provides tailored guidance—including gauge selection
for specific applications and soldering/ welding best practices—to
ensure optimal performance in custom thermocouple setups.
Company Profile
Huona (Shanghai) New Material Co., Ltd. Was established in 2008,
currently have three divisions: Magnesium Division, Thermal Spray
Division and Functional Material Division.
Magnesium Division produces magnesium metal products. Various
models of high-quality magnesium alloy plate, magnesium rods,
high-purity magnesium, magnesium plate, magnesium die casting,
magnesium extrusion profiles and other metal magnesium and deep
processing products.
Thermal spray wire Division offers a wide variety of pure metal and
metal alloy wires, including nickel-, iron-, aluminum-, and
zinc-based wires for thermal spray projects.
Fuctional Material Division supply electronic packaging
COMPONENTS(GTMS, CTMS), soft magnetic alloys and bimetal strip.
Our company is certified by ISO9001 quality system and ISO14001
environmental protection system.
Mission Statement
We try our best to understand and utilize information within the
environment. With this competency, we assist customers to create
added value and contribute to the development of industry and
healthy living.
We strive for "Best, " welcome challenges, and are relentless till
we deliver products and solutions.