Methods for weld monitoring and laser heat treatment monitoring

Methods for weld monitoring and for laser heat treatment monitoring are provided using infrared emissions. In the method for weld monitoring, an infrared (IR) signature emitted by a hot weld surface during welding is detected. The detected infrared signature is compared with a steady state infrared signature signal. The compared results are correlated with a predetermined weld parameter. The predetermined weld parameter includes at least one of a full penetration weld, a workpiece misalignment, and a workpiece contamination. In the method for monitoring a laser heat treating process, an infrared (IR) energy signal emitted by a workpiece surface during the laser heat treating process is detected. The detected energy signal is compared with a predefined voltage range. The compared results are correlated to identify a potential defect.