spore: profile id: thermocouple-alloys spore_version: 0.2 family: resistance-and-thermocouple-alloys name: Thermocouple wire alloys (Types J, T, E and N) abbreviation: TC role: positive and negative legs of base-metal thermocouples category: metals type: copper-alloys summary: | A thermocouple is two dissimilar wires joined at a hot junction, and the voltage that appears across the cold ends gives the temperature. This profile covers four standard base-metal pairs. Type J is iron against constantan, Type T is copper against constantan, Type E is chromel against constantan, and Type N is Nicrosil against Nisil. The alloy datasheets read in this run give density, melting point, resistivity, strength and maximum continuous temperature for each leg, and ASTM E230 limits of error for each pair. best_for: Base-metal temperature sensing where the pair is chosen by range and atmosphere (Type N for stable readings in air above 1000 °C, per Kanthal) weakest_at: 'Each pair is limited by its atmosphere: the iron leg rusts, sulphur attacks the iron and Nisil legs, and Nicrosil cannot be used in vacuum or reducing gas (Kanthal, Isabellenhutte, Pyromation)' identity: formula: 'Four base-metal pairs, each a positive and a negative leg. Type J: iron (nominal C 0.03, Si 0.05, Mn 0.30 %, Fe balance; Kanthal) against constantan. Type T: copper (Aurubis C10200, 99.95 % minimum Cu; used here as a proxy) against constantan. Type E: chromel (nominal 90 Ni, 10 Cr; Concept Alloys) against constantan. Type N: Nicrosil (Ni balance, Cr 14.2 %, Si 1.5 %; Kanthal) against Nisil (Ni balance, Si 4.3 %, Mg 0.1 %; Kanthal). Constantan: Cu balance with Ni 43.0 to 45.0 %, Mn 0.50 to 2.00 % (Matthey CuNi44Mn1).' source: kanthal-nicrosil where: Chemical composition table of the Kanthal Nicrosil and Nisil pages; iron composition table of the Kanthal iron page; Concept Alloys chromel nominal composition; Matthey chemical composition table; Aurubis C10200 description tags: environments: [] stresses: - extreme-heat - extreme-cold applications: - thermal-control properties: - benchmark: density label: Density, iron leg (Isabellenhutte IRON) value: 7.874 unit: g/cm3 scope: material conditions: leg: iron, Type J positive leg temperature: +20 °C method: Reference value printed in the Isabellenhutte leg datasheet status: ground source: isabellen-iron where: Physical Characteristics (Reference Values), Density at +20 °C, 7.874 - benchmark: density label: Density, iron leg (Kanthal) value: 7.86 unit: g/cm3 scope: material conditions: leg: iron, Kanthal thermocouple iron temperature: not stated method: Value printed in the Kanthal physical properties table status: ground note: Isabellenhutte prints 7.874 g/cm3 for the same nominal iron leg; both are kept. source: kanthal-iron where: Physical properties table, Density (g/cm3) 7.86 - benchmark: melting_point label: Melting point, iron leg (Isabellenhutte IRON) value: 1496 unit: °C scope: material conditions: leg: iron, Type J positive leg pressure: not stated method: Reference value printed in the Isabellenhutte leg datasheet, printed as +1,496 °C status: ground source: isabellen-iron where: Physical Characteristics (Reference Values), Melting point, +1,496 - benchmark: melting_point label: Melting point, iron leg (Kanthal) value: 1535 unit: °C scope: material conditions: leg: iron, Kanthal thermocouple iron pressure: not stated method: Value printed in the Kanthal physical properties table status: ground note: The two datasheets disagree by about 39 °C (1535 against 1496). The purity of each product is not stated in the datasheet, so both values are kept. source: kanthal-iron where: Physical properties table, Melting point (°C) 1535 - benchmark: thermal_conductivity label: Thermal conductivity at 20 °C, iron leg (Isabellenhutte IRON) value: 81 unit: W/(m·K) scope: material conditions: leg: iron, Type J positive leg temperature: +20 °C method: Reference value printed in the Isabellenhutte leg datasheet status: ground source: isabellen-iron where: Physical Characteristics (Reference Values), Thermal conductivity at +20 °C, 81 W/m K - benchmark: electrical_resistivity label: Electrical resistivity at 20 °C, iron leg (Isabellenhutte IRON) value: 12 unit: µΩ·cm scope: material conditions: leg: iron, soft-annealed condition temperature: +20 °C method: Value printed in the Isabellenhutte electrical values table, printed as µΩ x cm status: ground source: isabellen-iron where: Thermoelectrical and Electrical Values in Soft-Annealed Condition, Electrical resistivity at +20 °C, 12 - benchmark: ultimate_tensile_strength label: Tensile strength, soft annealed iron leg value: 370 unit: MPa scope: material conditions: leg: iron, Type J positive leg temper: soft, annealed temperature: +20 °C dimension: 1.0 mm diameter (datasheet note) method: Value printed in the Isabellenhutte mechanical properties table status: ground source: isabellen-iron where: Mechanical Properties at +20 °C in Annealed Condition, soft, tensile strength 370 - benchmark: elongation label: Elongation, soft annealed iron leg value: 28 unit: '%' scope: material conditions: leg: iron, Type J positive leg temper: soft, annealed temperature: +20 °C method: Value printed in the Isabellenhutte mechanical properties table status: ground source: isabellen-iron where: Mechanical Properties at +20 °C in Annealed Condition, soft, elongation 28 - benchmark: max_service_temp label: Recommended maximum continuous temperature, bare iron wire 3.26 mm value: 760 unit: °C scope: material conditions: leg: iron, bare wire wire_size: 3.26 mm atmosphere: air method: Guide value printed in the Kanthal table of recommended maximum continuous operating temperatures status: ground note: Kanthal prints these as guide values only; bare wire of 0.25 mm falls to 560 °C. source: kanthal-iron where: Recommended maximum continuous operating temperature, bare wire at 3.26 mm, 760 - benchmark: cte label: Coefficient of thermal expansion, iron leg value: 11.7 unit: 10-6/K scope: material conditions: leg: iron temperature: 20 to 100 °C method: Value printed in the Kanthal physical properties table status: ground source: kanthal-iron where: Physical properties table, Coefficient of thermal expansion 20 - 100, 11.7 - benchmark: density label: Density, copper leg (Aurubis C10200, proxy) value: 8.9 unit: g/cm3 scope: material conditions: leg: copper, Type T positive leg (proxy grade) temperature: not stated method: Value printed in the Aurubis technical datasheet for C10200 status: ground note: C10200 is commercial oxygen-free copper, not a thermocouple-grade datasheet. It stands in for the Type T copper leg. source: aurubis-c10200 where: Physical properties table, Density [g/cm3] 8.90 - benchmark: melting_point label: Melting point, copper leg (Aurubis C10200, proxy) value: 1083 unit: °C scope: material conditions: leg: copper, Type T positive leg (proxy grade) pressure: not stated method: Value printed in the Aurubis technical datasheet for C10200 status: ground source: aurubis-c10200 where: Physical properties table, Melting point [C] 1083 - benchmark: thermal_conductivity label: Thermal conductivity at 20 °C, copper leg (Aurubis C10200, proxy) value: 391 unit: W/(m·K) scope: material conditions: leg: copper, Type T positive leg (proxy grade) temperature: 20 °C method: Value printed in the Aurubis technical datasheet for C10200 status: ground source: aurubis-c10200 where: Physical properties table, Thermal cond. at 20 °C [W/mK] 391 - benchmark: elastic_modulus label: Modulus of elasticity, copper leg (Aurubis C10200, proxy) value: 117 unit: GPa scope: material conditions: leg: copper, Type T positive leg (proxy grade) temperature: 20 °C method: Value printed in the Aurubis technical datasheet for C10200 status: ground source: aurubis-c10200 where: Physical properties table, Mod. of elasticity at 20 °C [GPa] 117 - benchmark: yield_strength label: Yield strength, soft copper leg (Aurubis C10200, proxy) value: 69 unit: MPa scope: material conditions: leg: copper, soft temper (proxy grade) temperature: not stated method: Nominal value printed in the Aurubis mechanical properties table status: ground source: aurubis-c10200 where: Mechanical properties, Soft, Rp0.2 nominal 69 MPa - benchmark: ultimate_tensile_strength label: Tensile strength, soft copper leg (Aurubis C10200, proxy) value: 179 value_high: 262 unit: MPa scope: material conditions: leg: copper, soft temper (proxy grade) temperature: not stated method: Range printed in the Aurubis mechanical properties table status: ground source: aurubis-c10200 where: Mechanical properties, Soft, Rm 179-262 MPa - benchmark: cte label: Coefficient of thermal expansion at 20 °C, copper leg (Aurubis C10200, proxy) value: 17.6 unit: 10-6/K scope: material conditions: leg: copper, Type T positive leg (proxy grade) temperature: 20 °C method: Value printed in the Aurubis technical datasheet for C10200 status: ground source: aurubis-c10200 where: Physical properties table, Coef. of therm exp at 20 °C [10-6/K] 17.6 - benchmark: density label: Density, constantan (CuNi44Mn1, Matthey) value: 8.9 unit: g/cm3 scope: material conditions: leg: constantan, negative leg of Types J, T and E temperature: not stated method: Value printed in the Matthey physical properties table status: ground source: matthey-cuni44 where: Physical properties, Density g/cm3 8.9 - benchmark: melting_point label: Melting point range, constantan (CuNi44Mn1, Matthey) value: 1230 value_high: 1290 unit: °C scope: material conditions: leg: constantan, negative leg of Types J, T and E pressure: not stated method: Range printed in the Matthey physical properties table status: ground source: matthey-cuni44 where: Physical properties, Melting point C 1230-1290 - benchmark: max_service_temp label: Maximum application temperature, constantan (Matthey) value: 600 unit: °C scope: material conditions: leg: constantan, strip and wire atmosphere: not stated method: Value printed in the Matthey physical properties table and the main properties text status: ground source: matthey-cuni44 where: Physical properties, Maximum application temperature 600 - benchmark: temperature_coefficient_of_resistance label: Temperature coefficient of electrical resistance, constantan value: -80 value_high: 40 unit: 10-6/K scope: material conditions: leg: constantan, CuNi44Mn1 temperature: 20 to 105 °C method: Range printed in the Matthey physical properties table status: ground note: Non-canonical property name; temperature_coefficient_of_resistance is not in the canonical property file. source: matthey-cuni44 where: Physical properties, Temperature coefficient of electrical resistance (20-105 °°C), -80 to +40 - benchmark: cte label: Linear dilatation coefficient, constantan (Matthey) value: 14.5 unit: 10-6/K scope: material conditions: leg: constantan temperature: 20 to 300 °C method: Value printed in the Matthey physical properties table status: ground source: matthey-cuni44 where: Physical properties, Linear dilatation coefficient (20-300 °°C) 14.5 - benchmark: ultimate_tensile_strength label: Tensile strength, soft annealed constantan strip (R360 temper) value: 360 value_high: 460 unit: MPa scope: material conditions: leg: constantan, strip, soft annealed (R360, H90) temperature: not stated method: Range printed in the Matthey mechanical properties table of strips status: ground source: matthey-cuni44 where: Mechanical properties of strips, R360 H90 soft annealed, Rm 360-460 N/mm2 - benchmark: density label: Density, chromel-P (Concept Alloys, Type E positive leg) value: 8.73 unit: g/cm3 scope: material conditions: leg: chromel-P, nominal 90 Ni and 10 Cr temperature: not stated method: Value printed in the Concept Alloys typical physical property data status: ground note: The Concept Alloys sheet is for Chromel-P, labelled ANSI KP. Its use as the Type E positive leg is not confirmed by a Type E source read in this run. source: concept-chromel where: Typical Physical Property Data, Density (g/cm3) 8.73 - benchmark: melting_point label: Approximate melting point, chromel-P value: 1427 unit: °C scope: material conditions: leg: chromel-P, nominal 90 Ni and 10 Cr pressure: not stated method: Value printed in the Concept Alloys typical physical property data, given there as 2600 F and 1427 °C status: ground source: concept-chromel where: Typical Physical Property Data, Approximate Melting Point 2600 F (1427 °°C) - benchmark: electrical_resistivity label: Nominal resistivity at 20 °C, chromel-P value: 70.6 unit: µΩ·cm scope: material conditions: leg: chromel-P, nominal 90 Ni and 10 Cr temperature: 20 °C unit_in_source: uOhm/cm3 method: Nominal value printed in the Concept Alloys datasheet; the sheet labels the unit as uOhm/cm3 and it is read as µΩ·cm status: ground source: concept-chromel where: Typical Physical Property Data, Nominal Resistivity (uOhm/cm3) 70.6 at 20 °C - benchmark: cte label: Coefficient of thermal expansion, chromel-P value: 13.1 unit: 10-6/K scope: material conditions: leg: chromel-P temperature: 20 to 100 °C method: Value printed in the Concept Alloys datasheet, printed as cm/cm/C E-6 status: ground source: concept-chromel where: Typical Physical Property Data, Temp. Coef. Of Expansion (cm/cm/°C) E-6 13.1 (20 to 100 °°C) - benchmark: ultimate_tensile_strength label: Tensile strength, chromel-P annealed value: 95 unit: ksi scope: material conditions: leg: chromel-P temper: annealed temperature: not stated method: Typical value printed in the Concept Alloys mechanical properties table status: ground source: concept-chromel where: Typical Mechanical Properties, Tensile Strength, annealed (ksi) 95 - benchmark: yield_strength label: Yield strength, chromel-P annealed value: 45 unit: ksi scope: material conditions: leg: chromel-P temper: annealed temperature: not stated method: Typical value printed in the Concept Alloys mechanical properties table status: ground source: concept-chromel where: Typical Mechanical Properties, Yield Strength, annealed (ksi) 45 - benchmark: density label: Density, Nicrosil (Kanthal) value: 8.53 unit: g/cm3 scope: material conditions: leg: Nicrosil, positive leg of Type N temperature: not stated method: Value printed in the Kanthal physical properties table status: ground note: Isabellenhutte prints 8.50 g/cm3 for its NP Nicrosil; both are kept. source: kanthal-nicrosil where: Physical properties, Density g/cm3 8.53 - benchmark: density label: Density, Nicrosil NP (Isabellenhutte) value: 8.5 unit: g/cm3 scope: material conditions: leg: Nicrosil NP, Cr 14.6 % and Si 1.30 % temperature: reference value method: Reference value printed in the Isabellenhutte Type N sheet status: ground source: isabellen-typeN where: Physical characteristics row, Melting point / Density, NICROSIL NP 1,394 °C / 8.50 g/cm3 - benchmark: melting_point label: Melting point, Nicrosil (Kanthal) value: 1420 unit: °C scope: material conditions: leg: Nicrosil, positive leg of Type N pressure: not stated method: Value printed in the Kanthal physical properties table status: ground note: Isabellenhutte prints 1394 °C for Nicrosil NP; both are kept. source: kanthal-nicrosil where: Physical properties, Melting point C 1420 - benchmark: melting_point label: Melting point, Nicrosil NP (Isabellenhutte) value: 1394 unit: °C scope: material conditions: leg: Nicrosil NP pressure: not stated method: Reference value printed in the Isabellenhutte Type N sheet status: ground source: isabellen-typeN where: Melting point / Density row, NICROSIL NP 1,394 °C - benchmark: electrical_resistivity label: Electrical resistivity at 20 °C, Nicrosil (Kanthal) value: 1 unit: Ω·mm2/m scope: material conditions: leg: Nicrosil temperature: 20 °C method: Value printed in the Kanthal physical properties table status: ground source: kanthal-nicrosil where: Physical properties, Electrical resistivity at 20 °C Ohm mm2/m 1.00 - benchmark: max_service_temp label: Recommended maximum continuous temperature, bare Nicrosil wire 3.26 mm value: 1100 unit: °C scope: material conditions: leg: Nicrosil, bare wire wire_size: 3.26 mm atmosphere: air method: Guide value printed in the Kanthal table of recommended maximum continuous operating temperatures status: ground note: The same table gives 1250 °C for protected Nicrosil wire of 3.26 mm. Kanthal says the sheet cannot be used in reducing or vacuum atmospheres. source: kanthal-nicrosil where: Recommended maximum continuous operating temperature, bare wire at 3.26 mm, 1100 - benchmark: ultimate_tensile_strength label: Tensile strength, Nicrosil wire 2.0 mm value: 800 unit: MPa scope: material conditions: leg: Nicrosil, wire 2.0 mm temperature: not stated method: Value printed in the Kanthal mechanical properties table status: ground source: kanthal-nicrosil where: Mechanical properties, wire 2.0 mm, Tensile strength Rm 800 - benchmark: cte label: Coefficient of thermal expansion, Nicrosil value: 17 unit: 10-6/K scope: material conditions: leg: Nicrosil temperature: 20 to 100 °C method: Value printed in the Kanthal physical properties table status: ground source: kanthal-nicrosil where: Coefficient of thermal expansion, 20 - 100, 17 - benchmark: density label: Density, Nisil (Kanthal) value: 8.585 unit: g/cm3 scope: material conditions: leg: Nisil, negative leg of Type N temperature: not stated method: Value printed in the Kanthal physical properties table status: ground source: kanthal-nisil where: Physical properties, Density g/cm3 8.585 - benchmark: density label: Density, Nisil NN (Isabellenhutte) value: 8.55 unit: g/cm3 scope: material conditions: leg: Nisil NN, Si about 4.8 % temperature: reference value method: Reference value printed in the Isabellenhutte NISIL sheet and the Type N sheet status: ground source: isabellen-nisil where: Physical Characteristics (Reference Values), Density at +20 °C, 8.55 - benchmark: melting_point label: Melting point, Nisil (Kanthal) value: 1420 unit: °C scope: material conditions: leg: Nisil pressure: not stated method: Value printed in the Kanthal physical properties table status: ground note: Isabellenhutte prints 1341 °C for Nisil NN, so the two sources differ by 79 °C. Both are kept. source: kanthal-nisil where: Physical properties, Melting point C 1420 - benchmark: melting_point label: Melting point, Nisil NN (Isabellenhutte) value: 1341 unit: °C scope: material conditions: leg: Nisil NN pressure: not stated method: Reference value printed in the Isabellenhutte NISIL sheet status: ground source: isabellen-nisil where: Physical Characteristics (Reference Values), Melting point, +1,341 - benchmark: electrical_resistivity label: Electrical resistivity at 20 °C, Nisil NN (Isabellenhutte) value: 36 unit: µΩ·cm scope: material conditions: leg: Nisil NN temperature: 20 °C method: Value printed in the Isabellenhutte electrical values table, printed as µΩ x cm status: ground source: isabellen-nisil where: Thermoelectrical and Electrical Values, Electrical resistivity at +20 °C, 36 - benchmark: thermal_conductivity label: Thermal conductivity at 100 °C, Nisil (Kanthal) value: 27 unit: W/(m·K) scope: material conditions: leg: Nisil temperature: 100 °C method: Value printed in the Kanthal physical properties table status: ground source: kanthal-nisil where: Physical properties, Thermal conductivity at 100 °C, 27 - benchmark: specific_heat label: Specific heat at 20 °C, Nisil NN (Isabellenhutte) value: 0.5 unit: J/(g·K) scope: material conditions: leg: Nisil NN temperature: 20 °C method: Reference value printed in the Isabellenhutte NISIL sheet status: ground source: isabellen-nisil where: Physical Characteristics (Reference Values), Specific heat at +20 °C, 0.50 - benchmark: ultimate_tensile_strength label: Tensile strength, Nisil wire 2.00 mm value: 680 unit: MPa scope: material conditions: leg: Nisil, wire 2.00 mm temperature: not stated method: Value printed in the Kanthal mechanical properties table status: ground source: kanthal-nisil where: Mechanical properties, wire 2.00 mm, Tensile strength Rm 680 - benchmark: max_service_temp label: Recommended maximum continuous temperature, bare Nisil wire 3.26 mm value: 1100 unit: °C scope: material conditions: leg: Nisil, bare wire wire_size: 3.26 mm atmosphere: air method: Guide value printed in the Kanthal table of recommended maximum continuous operating temperatures status: ground note: Kanthal says Nisil cannot be exposed to sulphur-containing gases. source: kanthal-nisil where: Recommended maximum continuous operating temperatures, bare wire at 3.26 mm, 1100 - benchmark: thermoelectric_emf label: Nominal EMF, Nicrosil against Nisil, at 1000 °C value: 36.256 unit: mV scope: material conditions: pair: Nicrosil against Nisil (Type N) temperature: 1000 °C reference_junction: 0 °C, ITS-90 method: Nominal EMF value printed in the Kanthal table; the Kanthal sheet lists EMF against Nisil at each temperature status: ground note: Non-canonical property name; thermoelectric_emf is not in the canonical property file. source: kanthal-nicrosil where: Thermoelectric properties, Nominal EMF values vs Nisil, 1000 °C, 36.256 mV - benchmark: thermoelectric_emf label: EMF of Nisil NN against Cu/NIST 175, at 100 °C value: -1.763 unit: mV scope: material conditions: pair: Nisil NN against copper (NIST 175) temperature: 100 °C reference_junction: 0 °C method: Value printed in the Isabellenhutte NISIL sheet status: ground note: Non-canonical property name; the EMF is against copper, not against the Nicrosil leg. source: isabellen-nisil where: Thermoelectrical values, EMF versus Cu/NIST 175 at +100 °C, -1.763 - benchmark: limit_of_error label: Limit of error, Type J, standard (ASTM E230) value: 2.2 unit: °C scope: material conditions: pair: Type J, iron against constantan temperature_range: 0 to 760 °C rule: greater of this value or 0.75 % of reading reference_junction: 0 °C method: Limit of error printed in the ASTM E230 table reproduced by Pelican Wire status: ground note: Non-canonical property name; limit_of_error is not in the canonical property file. source: pelican-tolerances where: 'ASTM E230 table, Type J row, Standard column: +/-2.2 or +/-0.75 %' - benchmark: limit_of_error label: Limit of error, Type J, special (ASTM E230) value: 1.1 unit: °C scope: material conditions: pair: Type J, iron against constantan temperature_range: 0 to 760 °C rule: greater of this value or 0.4 % of reading reference_junction: 0 °C method: Limit of error printed in the ASTM E230 table reproduced by Pelican Wire status: ground note: Non-canonical property name; limit_of_error is not in the canonical property file. source: pelican-tolerances where: 'ASTM E230 table, Type J row, Special column: +/-1.1 or 0.4 %' - benchmark: limit_of_error label: Limit of error, Type T, standard (ASTM E230) value: 1 unit: °C scope: material conditions: pair: Type T, copper against constantan temperature_range: 0 to 370 °C rule: greater of this value or 0.75 % of reading reference_junction: 0 °C method: Limit of error printed in the ASTM E230 table reproduced by Pelican Wire status: ground note: Non-canonical property name; limit_of_error is not in the canonical property file. source: pelican-tolerances where: 'ASTM E230 table, Type T row, Standard column: +/-1 or +/-0.75 %' - benchmark: limit_of_error label: Limit of error, Type T, special (ASTM E230) value: 0.5 unit: °C scope: material conditions: pair: Type T, copper against constantan temperature_range: 0 to 370 °C rule: greater of this value or 0.4 % of reading reference_junction: 0 °C method: Limit of error printed in the ASTM E230 table reproduced by Pelican Wire status: ground note: Non-canonical property name; limit_of_error is not in the canonical property file. source: pelican-tolerances where: 'ASTM E230 table, Type T row, Special column: +/-0.5 or +/-0.4 %' - benchmark: limit_of_error label: Limit of error, Type E, standard (ASTM E230) value: 1.7 unit: °C scope: material conditions: pair: Type E, chromel against constantan temperature_range: 0 to 870 °C rule: greater of this value or 0.5 % of reading reference_junction: 0 °C method: Limit of error printed in the ASTM E230 table reproduced by Pelican Wire status: ground note: Non-canonical property name; limit_of_error is not in the canonical property file. source: pelican-tolerances where: 'ASTM E230 table, Type E row, Standard column: +/-1.7 or +/-0.5 %' - benchmark: limit_of_error label: Limit of error, Type E, special (ASTM E230) value: 1 unit: °C scope: material conditions: pair: Type E, chromel against constantan temperature_range: 0 to 870 °C rule: greater of this value or 0.4 % of reading reference_junction: 0 °C method: Limit of error printed in the ASTM E230 table reproduced by Pelican Wire status: ground note: Non-canonical property name; limit_of_error is not in the canonical property file. source: pelican-tolerances where: 'ASTM E230 table, Type E row, Special column: +/-1 or +/-0.4 %' - benchmark: limit_of_error label: Limit of error, Type N, standard (ASTM E230) value: 2.2 unit: °C scope: material conditions: pair: Type N, Nicrosil against Nisil temperature_range: 0 to 1260 °C rule: greater of this value or 0.75 % of reading reference_junction: 0 °C method: Limit of error printed in the Isabellenhutte Type N sheet, which cites ASTM E230 status: ground note: Non-canonical property name; limit_of_error is not in the canonical property file. source: isabellen-typeN where: Thermoelectric standard tolerances, TYPE N acc. ASTM E230, Standard +/-2.2 °C or 0.75 % (t90) - benchmark: limit_of_error label: Limit of error, Type N, special (ASTM E230) value: 1.1 unit: °C scope: material conditions: pair: Type N, Nicrosil against Nisil temperature_range: 0 to 1260 °C rule: greater of this value or 0.4 % of reading reference_junction: 0 °C method: Limit of error printed in the Isabellenhutte Type N sheet, which cites ASTM E230 status: ground note: Non-canonical property name; limit_of_error is not in the canonical property file. source: isabellen-typeN where: Thermoelectric standard tolerances, TYPE N acc. ASTM E230, Special +/-1.1 °C or 0.4 % (t90) - benchmark: limit_of_error label: Limit of error, Type N, Class 1 (IEC 60584) value: 1.5 unit: °C scope: material conditions: pair: Type N, Nicrosil against Nisil temperature_range: '-40 to 1000 °C' rule: greater of this value or 0.4 % of reading reference_junction: 0 °C method: Limit of error printed in the Isabellenhutte Type N sheet, which cites IEC 60584 status: ground note: Non-canonical property name. The IEC 60584 classes for Types J, T and E were not read in this run and are not stored. source: isabellen-typeN where: Thermoelectric standard tolerances, TYPE N acc. IEC 60584, Class 1 +/-1.5 °C or 0.4 % (t90), -40 to 1,000 °C - benchmark: max_service_temp label: Upper limit of the usable temperature range, Type J pair value: 760 unit: °C scope: material conditions: pair: Type J, iron against constantan lower_limit: 0 °C atmosphere: vacuum, reducing or inert; oxidising with reduced life method: Upper end of the range printed in the Pyromation thermocouple types table, shown as (0 to 760) °C status: ground note: Upper limit of the pair's Pyromation range, not a single-leg property. The lower limit is in conditions. source: pyromation-types where: Type J section, Alloy Combination Iron/Constantan, Temp. Range (0 to 760) °C - benchmark: max_service_temp label: Upper limit of the usable temperature range, Type T pair value: 370 unit: °C scope: material conditions: pair: Type T, copper against constantan lower_limit: '-200 °C' atmosphere: oxidising, reducing or inert, and vacuum method: Upper end of the range printed in the Pyromation thermocouple types table, shown as (-200 to 370) °C status: ground note: Upper limit of the pair's Pyromation range, not a single-leg property. The lower limit is in conditions. source: pyromation-types where: Type T section, Alloy Combination Copper/Constantan, Temp. Range (-200 to 370) °C - benchmark: max_service_temp label: Upper limit of the usable temperature range, Type E pair value: 870 unit: °C scope: material conditions: pair: Type E, chromel against constantan lower_limit: 0 °C atmosphere: continuously oxidising or inert method: Upper end of the range printed in the Pyromation thermocouple types table, shown as (0 to 870) °C status: ground note: Upper limit of the pair's Pyromation range, not a single-leg property. The lower limit is in conditions. source: pyromation-types where: Type E section, Alloy Combination Chromel/Constantan, Temp. Range (0 to 870) °C - benchmark: max_service_temp label: Upper limit of the usable temperature range, Type N pair value: 1260 unit: °C scope: material conditions: pair: Type N, Nicrosil against Nisil lower_limit: 0 °C atmosphere: air, low oxygen (see Pyromation oxidation note) method: Upper end of the range printed in the Pyromation thermocouple types table, shown as (0 to 1260) °C status: ground note: Upper limit of the pair's Pyromation range, not a single-leg property. The lower limit is in conditions. source: pyromation-types where: Type N section, Alloy Combination Nicrosil/Nisil, Temp. Range (0 to 1260) °C corrosion: - environment: Moist air or wet storage, iron leg headline: Iron rusts readily, and Isabellenhutte says the copper coating does not protect it. effect: Isabellenhutte says the iron leg has a strong tendency to corrode and rust, and that it should be stored and used in a dry environment. Its note says the copper coating does not act as a rust protection. Kanthal says iron wire is supplied copper-coated to prevent oxidation. No rust rate or test duration is given. rating: severe conditions: environment: moist air, wet storage basis: datasheet statements; no test duration stated source: isabellen-iron where: Special Remarks on the Alloy; Notes on Treatment - environment: Oxidising air above 538 °C, iron leg headline: Iron oxidises rapidly above 538 °C, so heavy gauge wire is recommended. effect: Pyromation says iron oxidises rapidly above 538 °C and that only heavy gauge wire is recommended for high temperature use. The source gives no oxidation rate. rating: severe conditions: environment: air, above 538 °C basis: vendor statement; no test duration stated source: pyromation-types where: Type J section, oxidation warning sentence - environment: Sulphur-bearing atmospheres, iron and Nisil legs headline: Iron and Nisil cannot be exposed to sulphur-containing atmospheres. effect: Kanthal says iron cannot be exposed to sulphur-containing atmospheres, and that Nisil cannot be exposed to sulphur-containing gases. Pyromation says bare Type J elements should not be exposed to sulphurous atmospheres above 538 °C. The sources give no exposure time or concentration. rating: severe conditions: environment: sulphur-containing gas basis: vendor statements; no exposure time stated source: kanthal-iron where: Special remarks, iron cannot be exposed to sulphur-containing atmospheres; Nisil page, sulphur-containing gases - environment: Reducing, vacuum or alternating oxidising and reducing gas, Nicrosil leg headline: Nicrosil cannot be used in reducing or vacuum atmospheres. effect: Kanthal says Nicrosil cannot be exposed to reducing atmospheres, to alternating oxidising and reducing atmospheres, or to vacuum. The Nicrosil wire is for air use. No time to failure is stated. rating: severe conditions: environment: reducing gas, vacuum, alternating oxidising and reducing gas basis: vendor statement; no test duration stated source: kanthal-nicrosil where: Opening paragraph, cannot be exposed to reducing or alternatively oxidizing and reducing atmospheres or to vacuum - environment: Low-oxygen conditions, Type N pair headline: Type N has oxidation stability problems and green rot in some conditions. effect: Pyromation says Type N can replace Type K where Type K has a shorter life, but notes stability problems from oxidation and the development of green rot. Isabellenhutte says Nicrosil and Nisil show higher oxidation stability than the Type K legs because of their silicon and aluminium balance. No corrosion rate is given. rating: moderate conditions: environment: low oxygen, Type N pair basis: vendor statements; no test duration stated source: pyromation-types where: Type N section, oxidation warning sentence - environment: Moist atmosphere, copper and constantan legs headline: Type T is not subject to corrosion in moist atmospheres, according to Pyromation. effect: Pyromation says Type T thermocouples are not subject to corrosion in moist atmospheres. Matthey gives constantan good corrosion resistance and says it can be welded. No corrosion rate is given for either leg. rating: low conditions: environment: moist atmosphere basis: vendor statements; no test duration stated source: matthey-cuni44 where: Main technical properties and features, good corrosion resistance - environment: Oxidising or inert air, chromel leg headline: Chromel resists oxidation well enough for bare wire to be used across the range. effect: Concept Alloys says the superior resistance of the alloys to oxidation allows bare metals to be used throughout the useful range of the Chromel/Alumel pair, from -200 °C to 1260 °C. Pyromation says Type E is recommended for continuously oxidising or inert atmospheres. No corrosion rate is given. rating: low conditions: environment: oxidising or inert air basis: vendor statements; no test duration stated source: concept-chromel where: Opening paragraph, superior resistance of the alloys to oxidation; Pyromation Type E recommended atmospheres risks: hazards: - text: 'Airgas nickel wire and rod SDS: GHS Hazard Classification is Not Classified, with no symbol or signal word. The sheet covers a nickel wire and rod product, not a thermocouple pair.' ghs: [] source: airgas-nickel-sds where: Section 2, GHS Hazard Classification line - text: The same SDS lists manganese, nickel, chromium, chromium oxide, silicon and copper among its ingredients, with exposure limits for several of them. ghs: [] source: airgas-nickel-sds where: Section 2 ingredient list and the exposure limits table failure_risks: - mode: Rust of the iron leg in moist or wet storage trigger: Moist air or wet storage of bare or copper-coated iron wire consequence: Isabellenhutte says the iron leg has a strong tendency to corrode and rust. The source gives no rate and no effect on calibration. severity: high source: isabellen-iron where: Special Remarks on the Alloy - mode: Attack by sulphur on the iron and Nisil legs trigger: Exposure of the iron or Nisil leg to sulphur-containing gas consequence: Kanthal says the leg cannot be exposed to sulphur-containing gases, and Pyromation says bare Type J elements should not be exposed to sulphurous atmospheres above 538 °C. No failure time is given. severity: high source: kanthal-iron where: Opening statement on sulphur-containing atmospheres - mode: Use of Nicrosil in vacuum or reducing gas trigger: Vacuum, reducing atmosphere or alternating oxidising and reducing gas consequence: Kanthal says the sheet cannot be exposed to these atmospheres. The source gives no failure time. severity: high source: kanthal-nicrosil where: Opening paragraph, cannot be exposed to reducing or alternatively oxidizing and reducing atmospheres or to vacuum - mode: Green rot and oxidation of the Type N pair trigger: Oxidation and low-oxygen conditions at high temperature consequence: Pyromation reports stability problems from oxidation and the development of green rot. No drift value is given. severity: moderate source: pyromation-types where: Type N section, oxidation warning sentence - mode: Rapid oxidation of bare iron above 538 °C trigger: Bare iron wire in air above 538 °C consequence: Pyromation says iron oxidises rapidly above 538 °C and recommends heavy gauge wire. No rate is given. severity: moderate source: pyromation-types where: Type J section, oxidation warning sentence side_effects: - text: The Airgas SDS says welding fumes can affect the eyes, skin and respiratory system, and lists pancreas and liver effects, from the fume produced when welding nickel-base wire. affects: Handling of fume from grinding or welding nickel-containing legs source: airgas-nickel-sds where: Section 2, Hazards line on welding fumes and gases handling: - text: Keep the iron leg dry and store it in a dry environment (Isabellenhutte). source: isabellen-iron where: Special Remarks on the Alloy - text: Keep iron and Nisil away from sulphur-containing gas (Kanthal). source: kanthal-iron where: Opening statement on sulphur-containing atmospheres - text: Keep the iron leg above zero degrees C; Kanthal says iron cannot be exposed to temperatures below zero. source: kanthal-iron where: Opening statement on temperatures below zero - text: Keep Nicrosil out of vacuum and reducing gas (Kanthal). source: kanthal-nicrosil where: Opening paragraph mitigations: [] uses: - application: thermal-control device: Type N thermocouple, Nicrosil and Nisil example: Isabellenhutte's Type N sheet lists use in exhaust systems, turbochargers, casts, furnaces and nuclear power stations. source: isabellen-typeN where: Application notes table - application: thermal-control device: Type J thermocouple, iron and constantan example: Pyromation says Type J suits vacuum, reducing or inert atmospheres, and oxidising atmosphere with reduced life, and that iron oxidises rapidly above 538 °C. source: pyromation-types where: Type J section, use and atmospheres - application: thermal-control device: Type T thermocouple, copper and constantan example: Pyromation says Type T works in oxidising, reducing or inert atmospheres, and in vacuum, and that it is not subject to corrosion in moist atmospheres. source: pyromation-types where: Type T section, use and corrosion sentences supply: - subject: Iron producers: - country: China share_percent: 63.8 year: 2025 - country: India share_percent: 7.5 year: 2025 - country: Japan share_percent: 4.5 year: 2025 - country: Russia share_percent: 3.6 year: 2025 critical_lists: - list: USGS 2025 List of Critical Minerals listed: false recycling: 'USGS iron and steel chapter: recycling is covered in the Iron and Steel Scrap chapter, which is not read in this run.' substitutes: - 'USGS: iron and steel compete with lighter materials such as aluminum and plastics in the automotive industry.' source: usgs-iron-steel where: World Production table, pig iron 2025e (world total 1,300 million t, rounded; shares calculated by Space Mushroom against that total); Substitutes; the USGS 2025 list has no iron entry (see usgs-critical-2025) - subject: Copper producers: - country: Chile share_percent: 23 year: 2025 - country: Congo (Kinshasa) share_percent: 13.9 year: 2025 - country: Peru share_percent: 11.7 year: 2025 - country: China share_percent: 7.8 year: 2025 critical_lists: - list: USGS 2025 List of Critical Minerals listed: true recycling: 'USGS: copper recovered from scrap contributed about 30 % of the U.S. copper supply in 2025.' substitutes: - 'USGS: aluminum substitutes for copper in radiators, tube, electrical equipment and power cable; titanium and steel are used in heat exchangers.' source: usgs-copper where: World Mine Production and Reserves table, 2025e (world total 23,000 thousand t, rounded; shares calculated by Space Mushroom against that total); Recycling; Substitutes; the 2025 list adds copper - subject: Nickel producers: - country: Indonesia share_percent: 66.7 year: 2025 - country: Philippines share_percent: 6.9 year: 2025 - country: Russia share_percent: 5.1 year: 2025 - country: Canada share_percent: 3.6 year: 2025 critical_lists: - list: USGS 2025 List of Critical Minerals listed: true recycling: 'USGS: most secondary nickel is the nickel content of stainless-steel scrap; nickel recovered from scrap was about 60 % of apparent consumption in 2025.' substitutes: - 'USGS: low-nickel, duplex or ultrahigh-chromium stainless steels can replace austenitic grades; titanium alloys can substitute for nickel-base alloys in corrosive environments.' source: usgs-nickel where: World Mine Production and Reserves table, 2025e (world total 3,900,000 t; shares calculated by Space Mushroom against that total); Recycling; Substitutes - subject: Chromium producers: - country: South Africa share_percent: 45.1 year: 2025 - country: Turkey share_percent: 17.6 year: 2025 - country: Kazakhstan share_percent: 13.7 year: 2025 - country: India share_percent: 5.9 year: 2025 critical_lists: - list: USGS 2025 List of Critical Minerals listed: true recycling: 'USGS: recycled chromium in stainless-steel scrap accounted for 21 % of apparent consumption in 2025.' substitutes: - 'USGS: chromium has no substitute in stainless steel, the leading end use, or in superalloys.' source: usgs-chromium where: World Mine Production and Reserves table, 2025e (world total 51,000 thousand t, rounded; shares calculated by Space Mushroom against that total); Recycling; Substitutes documents: - title: 'Kanthal: Nicrosil thermocouple wire datasheet (updated 2024-09-05)' type: datasheet url: https://www.kanthal.com/en/products/datasheets/material-datasheets/wire/thermocouple-wire/nicrosil/ year: 2024 - title: 'Kanthal: Nisil thermocouple wire datasheet (updated 2021-02-04)' type: datasheet url: https://www.kanthal.com/en/products/datasheets/material-datasheets/wire/thermocouple-wire/nisil/ year: 2021 - title: 'Kanthal: thermocouple iron datasheet (updated 2021-02-04)' type: datasheet url: https://www.kanthal.com/en/products/material-datasheets/wire/thermocouple-wire/thermocouple-iron - title: 'Isabellenhutte: NISIL data sheet (issue 17-April-2019)' type: datasheet url: https://www.isabellenhuette.com/hubfs/Files/Data-sheets/LE/Thermo/NISIL.pdf year: 2019 - title: 'Isabellenhutte: Thermocouples type N / extension leads type NX data sheet (issue 27-March-2020)' type: datasheet url: https://www.isabellenhuette.com/hubfs/Files/Data-sheets/LE/Thermo/Thermocouples%20type%20N_NX.pdf year: 2020 - title: 'Isabellenhutte: IRON data sheet (issue 30-September-2022)' type: datasheet url: https://www.isabellenhuette.com/hubfs/Files/Data-sheets/LE/Thermo/IRON.pdf year: 2022 - title: 'Concept Alloys: Chromel-P technical data sheet (Rev. 12-23-09)' type: datasheet url: https://conceptalloys.com/wp-content/uploads/2013/10/Chromel-PGMVdatasheet091223.pdf year: 2009 - title: 'Matthey: CuNi44Mn1 constantan technical data sheet' type: datasheet url: https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi44Mn1_v22E.pdf - title: 'Aurubis: Technical datasheet C10200 (Cu-OF)' type: datasheet url: https://www.aurubis.be/en/dam/jcr:90029b00-b968-486e-bde0-ce56f16022cd/c10200-cu-of-us.pdf - title: 'Pelican Wire: Thermocouple tolerances (ASTM E230 table)' type: database url: https://pelicanwire.com/resources/thermocouple-wire-resources/thermocouple-tolerances/ - title: 'Pyromation: Thermocouple types' type: datasheet url: https://www.pyromation.com/products/Thermocouple/Thermocouple-Types.aspx - title: 'USGS Mineral Commodity Summaries 2026: Iron and Steel' type: report url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-iron-steel.pdf year: 2026 - title: 'USGS Mineral Commodity Summaries 2026: Copper' type: report url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-copper.pdf year: 2026 - title: 'USGS Mineral Commodity Summaries 2026: Nickel' type: report url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf year: 2026 - title: 'USGS Mineral Commodity Summaries 2026: Chromium' type: report url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf year: 2026 - title: 'USGS: About the 2025 List of Critical Minerals' type: report url: https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals year: 2025 - title: 'Airgas: Nickel Wire and Rod safety data sheet (approval 2-1-2016)' type: sds url: https://www.airgas.com/msds/005727.pdf year: 2016 gaps: - IEC 60584 classes for Types J, T and E are not stored. The Rangdong tolerance chart refused connection in this run, and the search snippets were not used. Only the Type N IEC Class 1 value is stored, from the Isabellenhutte sheet. - The iron leg has two melting points (1535 °C from Kanthal and 1496 °C from Isabellenhutte), and two densities (7.86 and 7.874 g/cm3). Both are kept. The purity of each product is not stated, and the Kanthal page says the material is magnetic. - Nicrosil and Nisil also differ between Kanthal and Isabellenhutte. Nicrosil density is 8.53 against 8.50 g/cm3, Nicrosil melting point 1420 against 1394 °C, Nisil melting point 1420 against 1341 °C, and the composition is Cr 14.2 against 14.6 % and Si 1.5 against 1.30 %. Every value is kept with its source. - The copper leg is a proxy. Aurubis C10200 is commercial oxygen-free copper with 99.95 % minimum Cu, not a thermocouple-grade copper datasheet. A datasheet for the Type T positive leg was not read in this run. - The chromel sheet is for Chromel-P, labelled ANSI KP, with nominal 90 Ni and 10 Cr. Its use as the Type E positive leg is not confirmed by a Type E source read in this run. - No corrosion rate, oxidation weight gain, drift per hour or test duration was found for any of the four pairs. The corrosion entries are qualitative statements from datasheets and the Pyromation pages. - Designations (UNS, EN and DIN codes) are not stored in this file, because a designation belongs to one grade. The constantan leg has UNS C72150 and EN 2.0842 in the Matthey sheet, and they belong in constantan.yaml. - The Type J and Type E output in microvolts per degree was not stored, because no datasheet read in this run gives it. - The iron Curie or magnetic transition temperatures were not read in a fetched page. Only a search snippet gave 770 °C and 900 °C, so they are not stored. - Hazard data rest on one SDS, the Airgas nickel wire and rod sheet, which covers a nickel product. No SDS was read for iron, copper, constantan or chromel thermocouple wire, and PubChem was not read. - Supply shares for iron are calculated against the rounded world pig iron total of 1,300 million t, and the USGS iron chapter read here gives pig iron, not iron ore. The EU critical raw materials list was not checked for any of the four metals. - Non-canonical benchmark names are used for limit_of_error, thermoelectric_emf and temperature_coefficient_of_resistance. They are listed in the property notes so the import can map them. sources: kanthal-nicrosil: title: 'Kanthal: Nicrosil thermocouple wire datasheet' url: https://www.kanthal.com/en/products/datasheets/material-datasheets/wire/thermocouple-wire/nicrosil/ kind: datasheet year: 2024 license: Manufacturer datasheet (cited, not reproduced) kanthal-nisil: title: 'Kanthal: Nisil thermocouple wire datasheet' url: https://www.kanthal.com/en/products/datasheets/material-datasheets/wire/thermocouple-wire/nisil/ kind: datasheet year: 2021 license: Manufacturer datasheet (cited, not reproduced) kanthal-iron: title: 'Kanthal: thermocouple iron datasheet' url: https://www.kanthal.com/en/products/material-datasheets/wire/thermocouple-wire/thermocouple-iron kind: datasheet year: 2021 license: Manufacturer datasheet (cited, not reproduced) isabellen-nisil: title: 'Isabellenhutte: NISIL data sheet' url: https://www.isabellenhuette.com/hubfs/Files/Data-sheets/LE/Thermo/NISIL.pdf kind: datasheet year: 2019 license: Manufacturer datasheet (cited, not reproduced) isabellen-typeN: title: 'Isabellenhutte: Thermocouples type N / extension leads type NX' url: https://www.isabellenhuette.com/hubfs/Files/Data-sheets/LE/Thermo/Thermocouples%20type%20N_NX.pdf kind: datasheet year: 2020 license: Manufacturer datasheet (cited, not reproduced) isabellen-iron: title: 'Isabellenhutte: IRON data sheet' url: https://www.isabellenhuette.com/hubfs/Files/Data-sheets/LE/Thermo/IRON.pdf kind: datasheet year: 2022 license: Manufacturer datasheet (cited, not reproduced) concept-chromel: title: 'Concept Alloys: Chromel-P technical data sheet' url: https://conceptalloys.com/wp-content/uploads/2013/10/Chromel-PGMVdatasheet091223.pdf kind: datasheet year: 2009 license: Manufacturer datasheet (cited, not reproduced) matthey-cuni44: title: 'Matthey: CuNi44Mn1 constantan technical data sheet' url: https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi44Mn1_v22E.pdf kind: datasheet license: Manufacturer datasheet (cited, not reproduced) aurubis-c10200: title: 'Aurubis: Technical datasheet C10200 (Cu-OF)' url: https://www.aurubis.be/en/dam/jcr:90029b00-b968-486e-bde0-ce56f16022cd/c10200-cu-of-us.pdf kind: datasheet license: Manufacturer datasheet (cited, not reproduced) pelican-tolerances: title: 'Pelican Wire: Thermocouple tolerances' url: https://pelicanwire.com/resources/thermocouple-wire-resources/thermocouple-tolerances/ kind: web license: Supplier web page (cited, not reproduced) pyromation-types: title: 'Pyromation: Thermocouple types' url: https://www.pyromation.com/products/Thermocouple/Thermocouple-Types.aspx kind: web license: Supplier web page (cited, not reproduced) usgs-iron-steel: title: Mineral Commodity Summaries 2026, Iron and Steel url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-iron-steel.pdf year: 2026 kind: report license: public domain (USGS) usgs-copper: title: Mineral Commodity Summaries 2026, Copper url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-copper.pdf year: 2026 kind: report license: public domain (USGS) usgs-nickel: title: Mineral Commodity Summaries 2026, Nickel url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf year: 2026 kind: report license: public domain (USGS) usgs-chromium: title: Mineral Commodity Summaries 2026, Chromium url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf year: 2026 kind: report license: public domain (USGS) usgs-critical-2025: title: 'USGS: About the 2025 List of Critical Minerals' url: https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals year: 2025 kind: report license: public domain (USGS) airgas-nickel-sds: title: Safety Data Sheet, Nickel Wire and Rod (Airgas) url: https://www.airgas.com/msds/005727.pdf year: 2016 kind: datasheet license: Supplier safety data sheet (cited, not reproduced) license: CC-BY-4.0 updated: '2026-10-26' review: status: draft method: assistant checked_values: 61 unreachable: 1 caveats: 5 note: 'Values were read by an AI assistant on 2026-10-26 from the pages and PDFs named in each entry. Unreachable in this run: the Rangdong IEC 60584 tolerance chart (connection refused), so IEC classes for Types J, T and E are not stored, and the Kanthal iron page was read through a fetch tool, not the browser. Caveats: the copper leg is a commercial oxygen-free copper proxy; the iron and Nicrosil/Nisil values disagree between Kanthal and Isabellenhutte, and both are kept; Chromel-P is labelled KP and is used as the Type E positive leg without a Type E source; supply shares are calculated against rounded world totals.' story: risk_groups: - title: For people lead: The four pairs are alloys of iron, copper, nickel and chromium. The only hazard source read is the Airgas nickel wire and rod SDS, which is Not Classified under GHS. level: 1 verdict: No pair-level hazard classification found points: - label: Supplier classification line: The Airgas nickel wire and rod SDS is classified as Not Classified under GHS and has no signal word. It covers a nickel wire and rod product, not a thermocouple pair. - label: Fume line: The same SDS lists manganese, nickel, chromium and silicon among its ingredients, so grinding or welding these legs can produce fume with those metals. - title: If it fails lead: The failure routes in the sources are atmosphere, moisture and temperature. The sources give limits but no failure rates for any pair. points: - label: Rust line: Isabellenhutte says the iron leg has a strong tendency to rust and should be stored dry. - label: Sulphur line: Kanthal says the iron and Nisil legs cannot be exposed to sulphur-containing gas. - label: Vacuum and reducing gas line: Kanthal says Nicrosil cannot be used in vacuum or reducing gas. - title: Handling and storage points: - label: Keep iron dry line: Store the iron leg in a dry environment, as Isabellenhutte says. - label: Keep it above zero line: Kanthal says the iron leg cannot be exposed to temperatures below zero. why: A thermocouple pair is two dissimilar wires joined at a hot junction, and the voltage across the cold ends gives the temperature. This profile covers four base-metal pairs. Type J uses iron against constantan, Type T uses copper against constantan, Type E uses chromel against constantan, and Type N uses Nicrosil against Nisil. The pairs are chosen by atmosphere more than by range, because the legs fail differently in air, moisture, sulphur and vacuum. uses: - where: Type N in furnaces and exhaust systems line: Isabellenhutte lists Type N use in exhaust systems, turbochargers, casts, furnaces and nuclear power stations. - where: Type J in vacuum or reducing gas line: Pyromation says Type J suits vacuum, reducing or inert atmospheres, and oxidising atmosphere with reduced life. - where: Type T in moist or vacuum service line: Pyromation says Type T works in oxidising, reducing or inert atmospheres and in vacuum, and is not subject to corrosion in moist atmospheres. can_do: - label: Stay within a standard limit value: 2.2 °C standard limit for Type J benchmark: limit_of_error line: Pelican gives the Type J standard limit as 2.2 °C or 0.75 %, over 0 to 760 °C (ASTM E230). - label: Hot in air, Type N value: 1100 °C bare wire benchmark: max_service_temp line: Kanthal gives 1100 °C as the guide maximum continuous temperature for 3.26 mm bare Nicrosil and Nisil wire. - label: Stable resistance, constantan value: '-80 to 40 10-6/K' benchmark: temperature_coefficient_of_resistance line: Matthey gives constantan a temperature coefficient of electrical resistance of -80 to +40 10-6/K over 20 to 105 °C. compare: Compared on the same benchmarks, the copper leg melts at 1083 °C, the constantan leg at 1230 to 1290 °C (Matthey), chromel at 1427 °C (Concept Alloys), and the Nicrosil and Nisil legs at 1420 °C each in the Kanthal sheets. These are leg values, not a ranking of the pairs. compare_rows: - label: Density benchmark: density - label: Melting point benchmark: melting_point - label: Electrical resistivity benchmark: electrical_resistivity handling: - Keep the iron leg dry and out of sulphur-containing gas (Isabellenhutte and Kanthal). - Keep Nicrosil out of vacuum and reducing gas (Kanthal). - Keep bare Nicrosil and Nisil wire at or below the guide values in the Kanthal table (1100 °C at 3.26 mm). good_for: - Type N in air at high temperature, with a guide maximum of 1100 °C for 3.26 mm bare Nicrosil and Nisil wire (Kanthal) and standard limit of error 2.2 °C (ASTM E230). - Type T in moist air and in vacuum, with copper and constantan legs (Pyromation). - Type E in continuously oxidising or inert atmospheres (Pyromation), with a pair range of 0 to 870 °C. watch_out: - Iron rusts readily, and the copper coating does not protect it (Isabellenhutte). - Iron and Nisil cannot be exposed to sulphur-containing gas (Kanthal). - Nicrosil cannot be used in vacuum or reducing gas (Kanthal). - The iron melting point differs by 39 °C between Kanthal and Isabellenhutte, and the Nisil melting point differs by 79 °C. verdict: The four pairs cover base-metal sensing, and each pair is limited by its atmosphere. Type N suits high temperature in air, Type T suits moist air and low temperature, Type J needs dry and sulphur-free service, and Type E suits oxidising or inert air. The sources give tolerance and range figures, but no corrosion rates or drift data for any pair. recipe: line: Thermocouple wire is a pair of legs, not one alloy. The four pairs are iron against constantan (Type J), copper against constantan (Type T), chromel against constantan (Type E) and Nicrosil against Nisil (Type N). Constantan is a copper-nickel alloy with manganese (Matthey CuNi44Mn1). Iron, copper and chromel are supplied as wire, and Nicrosil and Nisil as wire, strip or rod (Kanthal, Isabellenhutte). parts: - name: Iron symbol: Fe share: balance, with nominal C 0.03 %, Si 0.05 % and Mn 0.30 % (Kanthal) role: Positive leg of Type J. - name: Copper symbol: Cu share: balance in constantan (Matthey); 99.95 % minimum in C10200 (Aurubis, used as a proxy) role: Positive leg of Type T, and the base of constantan. - name: Nickel symbol: Ni share: 43.0 to 45.0 % in constantan (Matthey); nominal 90 % in chromel (Concept Alloys); balance in Nicrosil and Nisil (Kanthal) role: Base of the chromel, Nicrosil and Nisil legs, and the nickel content of constantan. - name: Chromium symbol: Cr share: nominal 10 % in chromel (Concept Alloys); 14.2 % in Nicrosil (Kanthal) role: Gives the chromel and Nicrosil legs their high-temperature stability in air. - name: Silicon symbol: Si share: 1.5 % in Nicrosil and 4.3 % in Nisil (Kanthal) role: Gives Nicrosil and Nisil their thermoelectric stability and oxidation resistance. - name: Manganese symbol: Mn share: 0.50 to 2.00 % in constantan (Matthey) role: Minor addition to constantan, the negative leg of Types J, T and E.