Investigation of thermal processes in the gap during explosion welding

•A thermocouple method was developed for determining the heat flux from shock-compressed gas in the gap during explosion welding.•The thermal impact of the shock-compressed gas on the plate surface is constant and unaffected by the collision parameters.•The effect of shock-compressed gas preheating is commensurate with the energy released in the weld area during collision. This paper describes a thermocouple method for measuring the heat flux from the shock-compressed gas in the welding gap to the surfaces of the impacted plates during explosion welding. A set of experiments was conducted to determine the heat flux during explosion welding of copper plates at a distance of 0.4–0.6 m from the beginning of welding. The heat flux from the shock-compressed gas was found to be independent of the contact point velocity in the range of 1800–2500 m/s. As a result, the temperature of surface preheating before collision was found to be quantitatively dependent on the size and material of the welded plates. Thus, the effect of preheating the plates with shock-compressed gas in the gap can be commensurate with the energy released in the weld at the subsequent collision of the plates.