Thermography measurements allow to detect the defects that may appear on a joint at welding of components. Energy pulse generated by a xenon lamp with adequate power in a short period of time is sufficient for thermal excitation and enables to register the temperature distribution using the thermography high resolution camera FLIR SC7000. The impulse with 6kJ energy and 6ms time generate sufficient power to measure the temperature distribution on the surface of the weld tested. During cooling the temperature of the area with defect changes more slowly than in the areas without defects, because of to the less intense heat dissipation. This allows the registration of defects in welds "on-line" at the production process. Material used for analysis detection of defects in the welded joints is Inconel 718, stainless steel 410 and stainless steel 321. The peak energy which flow throw the samples with defects in the welded joints its completely or partially blocked. It cause different temperature distribution on the surface in the places where the connection discontinuity take place.