Yingrong Lu

1. Introduction Temperature is a key parameter in industrial production, and accurate temperature measurement is significant for production process control, increasing production efficiency, and improving production safety [1]. Thermocouples are frequently used for gas temperature measurement because of their robustness, simplicity, and low cost. For R-, S-, B-, or K-type thermocouples, whose materials have good malleability, two thermocouple wires are welded together, forming a welding point.