Abstract: Based on the detonation characteristics in a new double vertical explosive welding process, the R-δ-Type weldability window of double vertical explosive welding with static parameters is established, by studying the boundary conditions including, lower limit, upper limit, critical initiation thickness, critical collision angle, the critical plate thickness, etc. The R-δ-type weldability window reflects the relevance between the material properties and explosive characteristics, which are the two most important welding parameters of explosive welding. The R-δ-type weldability window for copper, stainless steel, aluminum and other materials can be directly utilized in engineering practice. A welding experiment between 304L and Q235b has been done with the ultra-low charge of 15 millimeter thickness based on the R-δ-type weldability window for double vertical explosive welding. The bonding quality of 304L/Q235b composites after welding is good with small wavy combination on the interfaces, which indicates that the proposed window can be used to determine the process parameters of double vertical explosive welding.