Tungsten wire: It is used to make tungsten-rhodium thermocouples and fast-coupled heads, sapphire-bonded wires, and electrodes for large lasers. It is also used to make high-performance filaments and tube cathodes. In 2005, the multi-purpose tungsten-rhenium alloy wire developed by our company was listed as a national key new product by the Ministry of Science and Technology.
Tungsten-rhenium thermocouple wire has a melting point of 3120-3360 °C and can be used up to 3000 °C. It is the most resistant metal thermocouple. It has the advantages of good linear relationship between temperature and electromotive force, reliable thermal stability and low price. It is matched with the display instrument. The temperature that can be directly measured is currently measured at a temperature above 1600 °C. The non-contact method is often used. However, the error of this method is large. For example, the contact temperature can accurately measure the true temperature. In high-temperature thermocouples, precious metal thermocouples (platinum-rhodium thermocouples) are expensive and the maximum temperature can only be below 1800 °C, while tungsten-rhodium thermocouples not only have a high temperature limit but also good stability, therefore, tungsten-rhodium thermocouples It is widely used in metallurgy, building materials, aerospace, aviation and nuclear energy industries. Its maximum operating temperature can reach 2800 ° C, but at more than 2300 ° C, the data is dispersed. Tungsten-rhenium thermocouples are also highly oxidizable, so they can be used in a vacuum, reduction, or inert atmosphere at temperatures ranging from 0 to 2300 °C. Tungsten bismuth couples with special protective tubes can also be used for a long time in an oxidizing atmosphere at 1600 ° C. They are cheaper than platinum-rhodium thermocouples and cannot be used in carbon-containing atmospheres (such as in hydrocarbon-containing atmospheres, temperatures exceed 1200 ° C is subject to corrosion). Tungsten or tungsten ruthenium tends to form stable carbides in a carbon-containing atmosphere, so that its sensitivity is lowered and brittle fracture is caused, and in the presence of hydrogen, carbonization is accelerated. The company specializes in the production of anti-oxidation tungsten-rhodium thermocouples. The ideal temperature range is 0-1500 °C. The structure is double-layer or three-layer (not commonly used) protection tube. The outer protection tube of double protection tube structure is ultra-pure corundum tube. The inner protection tube is a molybdenum silicide tube, and the outer protection tube of the three sleeve is a recrystallized silicon carbide tube or a special pure corundum tube, the middle tube and the inner protection tube are the same as the double tube type, and the tube filling material is a high temperature insulating material (may be Long-term use below 1800 °C), vacuum sealing and cold-end sealing (sealing adhesive can be used at temperatures below 300 °C for a long time) to ensure no residual oxygen in the tube. This product is suitable for use in vacuum, reduction and other inert gases (0~1650 °C) The ideal temperature measurement in the oxidizing atmosphere is 0 to 1500 °C. Time constant: ≥180 s