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Вр5 tungsten rhenium thermocouple wire

Вр5 tungsten rhenium thermocouple wire

The heat resistance of alloys ВР5 and ВР20

The advantages of the alloys are determined by tungsten and rhenium. Tungsten is one of the most difficult, refractory, hard metal. Temperature its melting point is 3410 °C, boiling point is the same as on the surface of the Sun — 6690 °C. Tungsten alloys for refractoriness and hardness in the lead among all other alloys. Slightly inferior to him rhenium, the melting point of which 3170 °C and the boiling point is equal to the 5870 °C. For the heat resistance of rhenium is far ahead of other metals, has high strength and resistance to corrosion.

The features of doping

Alloying tungsten with rhenium — 5% increases the ductility of the alloy, increasing the temperature of its recrystallization, which is especially important when it is applied to a positive electrode of the thermocouple. The use of alloy as a negative electrode to achieve the maximum thermo-EMF, require the maintenance of up to 35% rhenium.

Resistance

Tungsten-rhenium alloy is resistant to helium, dry nitrogen, hydrogen, argon. Doping of silica-alloy additives to increase its stability in two-three times at temperatures up to 2000 °C.

Sensors ВР5 and ВР20 can be operated in vacuum conditions. To ensure at temperatures of 1800 °C and above more effective work in a vacuum, it is necessary to use electrodes of larger diameter. ВР5/20 successfully used as differential thermocouple — it may be two equivalent thermocouple connected opposite each other. These thermocouples are able to measure the level of temperature difference between two junctions: conditional and work.

Thermoelectric power

Upon cooling to 1600 °C the nominal value of the thermal EMF also decreases to the level of 24.59 MB. The figure at t° 1500 °C is not more than from 23.31 mV at t°1400°C nominal thermal EMF is of 21.97 mV.

Disadvantages

Significant disadvantages of these alloys relates a poor reproducibility of the thermoelectric power, therefore you want to group thermocouples in categories A-1,2,3. The first category a-1 makes it possible to apply the alloy at the maximum temperature of 2200 °C, the mode of application of A-2 and 3 is limited to 1800 °C. it is Strictly forbidden to use wire of different parties because each of them has its «own» rate of thermal EMF. Since rhenium and tungsten are rare metals, their price is very high. Although the cost ВР5/20 much more than the cost of the thermocouples, consisting of other elements, but still less than the price of alternative instrumentation for temperature regimes in a similar industrial environment.

Application

ВР5, ВР20 used in the production processing and measuring devices, as well as TVR (contact sensors thermocouples) for measuring the highest temperatures in industrial metallurgy — liquid metals. The uncertainty of measurement up to 2500 °C is very small (±0,01°C). This makes the instruments for measuring the most accurate TVR in such an aggressive environment.

The calibration table tungsten-rhenium thermocouples VAR-5 (BP-5)/20 when the temperature of the free ends 0°C

The temperature of the working end °C T. E. D. S. mV temperature, °C
  0 10 20 30 40 50 60 70
0 0 0,121 0,246 0,373 0,504 0,637 0,772 0,910
100 1,337 1,483 1.632 1,781 1,933 2,086 2,240 2,396
200 2,871 3,032 3,193 3,355 3,518 3,682 3,847 4,012
300 4,512 4,680 4,843 5,016 5,185 5,354 5,523 5,693
400 6,203 6,373 6,543 6,714 6,834 7,065 7,225 7,396
500 7,908 8,073 8,248 8,418 8,588 8,758 8,928 9,098
600 9,605 9,774 9,943 10,111 10,280 10,448 10,615 10.783
700 11,283 11,450 11,616 11,782 11,947 12,112 12,277 12,442
800 12,933 13,096 13,259 13,422 13,584 13.746 13,907 14,068
900 14,549 14,708 14,867   15,026 15,184 15,342 15,500
1000 16,125 16,281 16,436   16,590 16,744 16,898 17,051
1100 17,659 17,810 17,960   18,110 18,260 18,409 18,557
1200 19,146 19,292 19,438   19,583 19,728 19,872 20,015
1300 20,584 20,725 20,866   21,006 21,145 21,284 21,423
1400 21,971 22,107 22,242   22,377 22,511 22,645 22,778
1500 23,306 23,436 23,566   23,696 23,825 23,953 24,081
1600 24,588 24,713 24,838   24,962 25,085 25,209 25,331
1700 25,816 25,936 26,056   26,175 26,293 26,411 26,528
1800 26,992              

Buy at best price

In stock LLC «AVEK global» in the presence of diverse range of thermocouple wire and tape at the best prices. We offer favorable conditions for the acquisition of products from alloys ВР5, ВР20 and similar. On our website you will find all the latest information. If necessary, You can always consult experienced managers who will help with this. Product quality is guaranteed by strict observance of the norms of production at all stages. Delivery times are minimal. For wholesale orders there is a reduced discount.