Preheating of Colliding Plates by a Shock-Compressed Gas during Explosive Welding

Abstract—The parameters of the shock-compressed gas that forms between plates under their collision during explosive welding are investigated. A photosensor is used to determine the shock wave front velocity at a contact point velocity V_c = 1900–2600 m/s; this velocity is found to be ≈1.3V_c, which is higher than that calculated using a Hugoniot adiabat (≈1.2V_c). Ultrafine (50–200 nm) metallic particles, which form from a dispersed cumulative jet in the welding gap, are found to affect the shock wave front velocity substantially. Low-inertia thermopiles were used to determine the heat flow (≈0.24 GW/m²) induced by the action of the shock-compressed gas on the plate surface before a collision at a distance of 0.4–1.3 m from the beginning of welding, which made it possible to calculate the temperature of heating the surface layers of the plates before a collision.