Tungsten-rhenium alloys WR5 and WR20
WR5 and WR20 – a tungsten-rhenium alloy. In WR5 alloy contains 95% tungsten and 5% rhenium and WR20 contains 80% tungsten and 20% rhenium. The alloys are produced in the form of wire, and to improve the stability of the thermocouple WR5 alloy doped SILICA components: Al2O3 0,1-0,5%, SiO2 0,1-0,5%, KCl 0,1-0,5%. This connection is – VAR 5/20.
The main characteristics of the alloy is determined rhenium and tungsten.
Rhenium has a melting point of 3170 ° C and a boiling point of 5870 ° C, while it is very heat resistant and corrosion resistant. Tungsten rhenium and a little more than a refractory, hard and heavy metal. It has a melting point of 3410 ° C and boils at 6690 ° C. The alloys of tungsten and rhenium are among the most solid and refractory to all known.
The alloy used as a negative electrode of the thermocouple for maximum thermoelectromotive force. Metallurgy used rhenium in the alloy is not more than 20%, which gives the maximum temperature to 2500 ° C, using a tungsten-rhenium thermocouple. The alloy is very resistant to helium, hydrogen, dry nitrogen and argon.
The disadvantage is the fact that rhenium – a very rare metal, and this increases the cost and the price VR5 / 20 greatly exceeds the price of thermocouples of other metals. It does not use an alloy wire from different parties, because each party wire your indicator of thermoelectric power.
Alloys WR5 and WR20 are used for the manufacture of contact sensors thermocouples that measure the highest temperature measurement devices, which may only be measured using a thermocouple. Thermocouples measure, such as the temperature of the molten metal. Tungsten-rhenium thermocouple is a better gauge of high temperatures in corrosive environments.
Alloy WR5 / 20 is used for the manufacture arrange that can operate even in a vacuum at a temperature of 1800 ° C.
Strapping Table tungsten-rhenium thermocouples WAR-5 (WR-5) / WR-20.
Table Nominal static characteristics of conversion WR (A) -1
|
The temperature of the working end ° C |
T.e.d.s.mV for 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 |
Main technical data
| Temperature ° C | 1600 | 1500 | 1400 |
| Nominal value teds, mV | 24,59 | 23,31 | 21,97 |
| Teds deviation from nominal, mV | ±102 | ±99 | ±96 |