Tu 11-75. Tungsten alloy wire with rhenium annealed graded for thermocouple thermoelectrodes. Technical conditions.

Tu 11-75
GOST 18903-73
GOST 19671-91
GOST 23949-80
TU 48-19-221-83
TU 48-19-106-91
TU 48-19-527-91
TU 48-19-309-79
TU 48-19-39-85
TU 11-77
Astm C702
Astm B760
Astm B631
Astm B777
Astm E696

TECHNICAL REQUIREMENTS

1.1 Main parameters and dimensions
1.1.1 Nominal wire diameter and its limiting deviations shall be as specified in Table 1.

Table 1

Wire diameter, mm. Marginal deviation by diameter, %
0,10 ±5
50,20 ±5
0,35 ±5
0,50 ±5

1.1.2 Wire cross-section shall be round. Tolerable ovality shall not exceed diameter tolerance limits.

1.2 Characteristics of the material
1.2.1 Chemical composition of the wire of different alloy grades shall comply with Table 2.

Table 2

Alloy grade Content, %
rhenium admixtures and additives, not more tungsten
ВР-20 20±0,5 0,1 the rest
ВР-5 5±0,5 0,1 the rest
VAR-5
1.2.2 Value of thermoelectromotive force (TEF) developed by thermocouple, made from samples, taken from both ends of the same wire length at 1550°С±20°С, shall not be greater than ±50 μV.
Value of tedes developed by wires of alloy grade ВАР-5 (ВР-5) and ВР-20 in tandem at the temperature of the free ends of 0 °С, should correspond to the rated values of tedes, specified in Table 3 of these specifications and in the tables of GOST 3044-74. Permissible deviations of thermocouple readings in °С (at temperature of free ends of 0 °С) from the values indicated in calibration tables must not exceed ±5 °С (up to 1000 °С) and ±0,5 % from tabulated values of temperatures in the range of 1000-1800 °С.
Notes:
  • By agreement with the customer it is allowed to supply wire from alloy grades BAR-5 (BP-5) and BP-20, developing in the pair theedes, different from the standards specified in Table 3 of TU and the tables of GOST 3044-74.
  • The maximum temperature of thermocouple wire calibration is 1800 °C.
  • Graduation of VAR-5/VR-20 thermocouples to temperatures exceeding 1800 °C up to the maximum temperature of its possible use (3000 °C) is performed by customers or institutes of the State Standards Committee of the USSR Council of Ministers (S.F.VNIIM, Sverdlovsk).

Table 3

Temperature, °С Rated values of teds, mV, for calibrations
1 2 3
0 0 0 0
100 1,33 1,34 1,32
200 2,87 2,90 2,84
300 4,52 4,57 4,47
400 6,21 6,28 6,14
500 7,91 8,00 7,83
600 9,60 9,71 9,51
700 11,28 11,40 11,17
800 12,94 13,07 12,81
900 14,57 14,71 14,43
1000 16,15 16,31 16,00
1100 17,69 17,86 17,52
1200 19,17 19,35 19,00
1300 20,60 20,79 20,43
1400 21,99 22,19 21,80
1500 23,33 23,54 23,13
1600 24,62 24,84 24,41
1700 25,85 26,08 25,63
1800 27,03 27,27 26,80
1.2.4 Tensile strength of the wire shall not be less than 125 kgf/mm2.
1.2.5. thermocouple wire shall not break or delaminate during bending tests.
1.2.6. 0.1 mm wire shall be free of burrs and dints. Fine burrs and dints visible to the naked eye are permissible on wire of 0.2 mm diameter and above.
1.2.7. Wire shall be wound on a spool (hoop) evenly across its width without knots or loops and shall be easy to unwind from the spool. Free height of the bobbin edge after winding must be not less than 2 mm.
1.2.8. on a reel (hoop) shall be wound one piece of wire with a length of at least 15 m for diameter 0.20, 0.35 and 0.50 mm and at least 30 m for wire diameter 0.10 mm. Note. As agreed with the customer, shorter wire ends may be supplied.