ASTM E839 : 96

1.1 These are test methods for sheathed thermocouple material and assemblies.

1.2 The tests are intended to assure quality control and to evaluate the suitability of sheathed thermocouple material or assemblies for specific applications. Some alternative test methods to obtain the same information are given, since in a given situation an alternative test method may be more practical. Service conditions are widely variable and so it is unlikely that all the tests described will be appropriate for a given thermocouple application. A brief statement is made following each test description to indicate when it might be used.

1.3 The tests described herein include test methods to measure the following properties of sheathed thermocouple material and assemblies.

1.3.1 Insulation Properties:

1.3.1.1 Compaction-absorption method and tension method,

1.3.1.2 Thickness, and

1.3.1.3 Resistance-room temperature and elevated temperature.

1.3.2 Sheath Properties:

1.3.2.1 Integrity-water test (two test methods) and mass spectrometer,

1.3.2.2 Dimensions-length, diameter, and roundness,

1.3.2.3 Wall thickness,

1.3.2.4 Surface-gross visual, finish, defect detection by dye penetrant, and cold-lap detection by tension test,

1.3.2.5 Metallurgical structure, and

1.3.2.6 Ductility-bend test and tension test.

1.3.3 Thermoelement Properties:

1.3.3.1 Calibration,

1.3.3.2 Homogeneity,

1.3.3.3 Drift,

1.3.3.4 Thermoelement diameter, roundness, and surface appearance,

1.3.3.5 Thermoelement spacing,

1.3.3.6 Thermoelement ductility, and

1.3.3.7 Metallurgical structure.

1.3.4 Thermocouple Assembly Properties:

1.3.4.1 Dimensions-length, diameter, and roundness,

1.3.4.2 Surface-gross visual, finish, reference end seal, and defect detection by dye penetrant,

1.3.4.3 Electrical-continuity, loop resistance, and connector polarity,

1.3.4.4 Insulation resistance-room temperature, and elevated temperature,

1.3.4.5 Radiographic inspection,

1.3.4.6 Thermoelement diameter,

1.3.4.7 Thermal response time, and

1.3.4.8 Thermal cycle.