Although tungsten-rhenium thermocouples have excellent ultra-high temperature resistance and thermal stability, improper use environment, over-temperature operation and non-standard maintenance in overseas industrial projects will still cause various failures such as data deviation, sensitivity attenuation, wire embrittlement and fracture. Summarizing common failure causes of tungsten-rhenium thermocouples and formulating targeted preventive maintenance strategies can effectively reduce equipment failure rate, extend product service life, reduce overseas customer maintenance costs, and improve after-sales satisfaction of foreign trade products.
Atmospheric corrosion failure is the most common fault of tungsten-rhenium thermocouples in overseas projects. Tungsten-rhenium alloys are extremely susceptible to oxidation in high-temperature oxidation atmospheres without protective measures. Long-term oxidation will form dense oxide layers on the sensor surface, destroying the thermoelectric conversion structure, resulting in decreased measurement sensitivity and inaccurate data. In carbon-containing atmospheres above 1000℃, carburization reaction occurs inside the alloy to generate hard carbides, causing wire embrittlement. Slight equipment vibration will lead to wire fracture and signal interruption, directly causing equipment shutdown failure.
Over-temperature operation is the main cause of data dispersion and performance attenuation. Many overseas users blindly pursue high-temperature measurement range and long-term operate tungsten-rhenium thermocouples above 2300℃. In ultra-high temperature environments exceeding the stable limit, the internal structure of the alloy is unstable, and the thermoelectric potential changes irregularly, resulting in discrete measurement data and poor repeatability. Long-term over-temperature operation will accelerate material thermal fatigue, cause irreversible performance attenuation, greatly shorten the product service life, and increase the frequency of equipment replacement.
Improper protective measures also lead to frequent equipment failures. In oxidation atmosphere scenarios, many users do not configure special high-temperature resistant protective tubes according to requirements, resulting in direct contact between the sensor and oxygen and rapid oxidation failure. In vacuum and inert atmosphere working conditions, poor equipment sealing leads to air leakage and mixed oxygen, causing local oxidation of the sensor. In addition, improper installation such as excessive bending and vibration extrusion will cause hidden damage to the thermocouple wire, inducing early failure.
Targeted preventive maintenance measures can effectively avoid the above failures. First, strictly control the working temperature, and limit the long-term operating temperature within 2000℃ to ensure stable data and performance. Second, standardize environmental matching, use special protective tubes in oxidation atmospheres to isolate oxygen, and completely avoid carbon-containing working environments. Third, strengthen daily sealing inspection of vacuum and inert atmosphere equipment to prevent air leakage and oxidation. Finally, standardize installation operations to avoid violent bending and vibration damage, and regularly clean and inspect the sensor surface to ensure stable thermoelectric performance. Scientific maintenance can maximize the service life of tungsten-rhenium thermocouples and create greater economic benefits for overseas users.
