TYPE J (Iron vs Constantan) is used in vacuum, oxidizing, inert or reducing atmospheres. Iron element oxidizes rapidly at temperatures exceeding 538'C, and therefore heavier gauge wire is recommended for longer life at these temperatures.
1. Chemical Composition
Material | Chemical composition (%) |
Ni | Cu | Si | Iron | Al |
JP(Iron) |
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| 100 |
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JN(Constantan) | 45 | 55 |
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2. Physical properties and Mechanical properties
Material | Density (g/cm3) | Melting point (℃) | Tensile Strength (Mpa) | Volume resistivity (μΩNaN) | Elongation rate (%) |
JP(Iron) | 7.8 | 1402 | >240 | 12.0(20℃) | >20 |
JN(Constantan) | 8.8 | 1220 | >390 | 49.0(20℃) | >25 |
3. EMF Value range at different temperature
Material | EMF value (μV) |
100℃ | 200℃ | 300℃ | 400℃ | 500℃ | 600℃ |
JP-JN | 5187~5351 | 10696~10862 | 16244~16410 | 21760~21936 | 27281~27505 | 32962~33242 |
EMF value Vs Pt(μV) |
700℃ | 750℃ | 760℃ | 800℃ | 900℃ | 1000℃ |
38958~39306 | 42089~42473 | 42725~43113 |
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