Infrared temperature measurement and interference analysis of magnesium alloys in hybrid laser-TIG welding process

Infrared (IR) temperature measurement, as a convenient, non-contact method for making temperature field measurements, has been widely used in the fields of welding, but the problem of interference from radiant reflection is a complicating factor in applying IR temperature sensing to welding. The object of this research is to make a deep understand about the formation of interference, explore a new method to eliminate the interfering radiation during laser-TIG hybrid welding of magnesium alloys and to obtain the distribution of temperature field accurately. The experimental results showed that the interferences caused by radiant specular reflection of arc light, ceramic nozzle, electrode and laser nozzle were transferred out of welding seam while the IR thermography system was placed perpendicularly to welding seam. And the welding temperature distribution captured by IR termography system which had been calibrated by thermocouple was reliable by using this method in hybrid laser-TIG welding process of AZ31B magnesium alloy.