Real-time heat input monitoring towards robust GMA brazing

Gas metal arc (GMA) brazing of thin sheets requires active control of heat input, filler alloy deposition and temperature field on sheet surface. A novel attempt is presented here for a rapid synchronous real-time monitoring of current and voltage transients, filler alloy depositions and temperature field using, respectively, a high-frequency recorder, high-speed videography and two thermal infrared cameras during GMA brazing of galvanized steel sheets. For heat inputs from 100 to 200 J mm ⁻¹ , the peak temperature varied from 1500 to 1700 K. The high-speed videography showed consistent filler deposition and bead profile. The methodology and results presented here depict a promising resource for real-time monitoring and feedback control of GMA brazing.