A Novel Method for Measuring Laying Head Temperature of Wire Rod

The laying head temperature (LHT) is the crucial for determining the Stelmor air cooling rate of the high-speed wire rod. However, the high ambient temperature and long distance make it challenging to measure this temperature accurately with the current approach. To address this issue, a new method has been developed that involved placing a pyrometer close to the wire rod in a location with lower ambient temperatures in front of the laying head, resulting in a smaller measuring spot. To improve accuracy, two primary issues have been investigated. Firstly, a relationship between oxidation time and emissivity of the wire rod was established. For example, when the HRB400 (8 mm) wire rod was oxidized at 1000°C for 0.625 s, its emissivity was calculated to be approximately 0.69. Secondly, a correlation was established between directional emissivity and the angle between radiation emitted from the measuring spot of the wire rod and its normal to address rapid fluctuations in measured temperature caused by wire rod vibration. As a result, measured temperature was reconstructed when changes in the angle occurred due to wire rod vibration, resulting in a significant reduction in temperature fluctuations.