A specially designed 76‐mm cannon was used to drive small metal plates (copper, 3.175 mm thick) against metal target plates (steel, 6.250 mm thick) in order to study the fundamental parameters involved in the high‐velocity impact‐welding process. This method of study allowed experimental examination of the influence of each variable separately, in the classical mode. The results of these experiments were analyzed to define the required impact conditions for welding. A line of optimum weldability was identified and shown to be characterized by invariance in the metallic jet velocity. The analysis was also used to identity conditions applying to the transition zone between laminar and wavy interfaced welds.