Abstract: This paper attempts to briefly discribe the boundary conditions of explosive welding parameters obtained with a semi-cylinder method. The range of the weldability window and the reasonable charge for explosive welding copper to steel have been determined through tests. The details of interface bond strength, bond area fraction, size of interracial waves and melting area for different welding perameters arc noted. Furthermore, we have established a compact weldability window from the energy point of view for various flyer plate thicknesses. We have proposed a new method for establishing such windows. The relation between the initial welding parameters and the dynamic parameters are given in the window. The bend angle of the flyer plate was determined by flash X-ray photography during explosive welding and the value coincides with that obtained in the semicylinder test. The adiabatic exponential K of 2^# nitroaniline explosive was estimated from the lateral flying angle φ obtained from the X-ray photographs and was introduced into the formula for calculating flyer plate velocities to modify and improve the Gumey equation. The flyer plate velocities Vp given by the semicylinder test, the X-ray photography and the improved Gurney equation are shown graphically. Our tests and investigations reveal that the semi-cylinder method may be used as a tool for predicting optimum welding parameters.