Explosion Welding And Hardening Of Metallic Materials Technology Research

The bonding boundary microstructure is detected and analyzed on the basis of explosive welding experiments between aluminium-aluminium, aluminium-steel, steel-steel and copper-steel materials by means of microscopic examination, scanning electron microscope and transmission electron microscope. In particular, it is helpful to understand the explosive welding mechnism and bonding microstates to use transmission eletron microscope to observe the bonding zone directly. In addition, an insensitive explosive suitable for explosive hardening is determined through NK-EH500 steel explosive hardening test and the hardening effectiveness is measured and analyzed. Main conclusions could be reached by theoretical analysis and experiments as follows: (1) The formulation with 90% 2 rock explosive and 10% TNT is applicable to be used as an explosive welding charge. It is in favor of detonation propagation and of higher energy. (2) ??type initiation method is proved to be optimistic which can effectively reduce the wave front curvature and improve the front shape, at the same time, is easer to operate. (3) The processing hardening effect produced in the bonding boundary is a common characteristic based on the microscopic hardness analysis after explosive welding. The hardness increase of bonding boundary indicate that the structure and properties of the bonding zone have been changed and are very different from the matrix materials. (4) Larger solid solubility between two metals leads to firm solid solution structure, stronger linkage and better welding performance between the two metals accordong to the transmission electron microscope analysis for the bonding zone contexture. (5) The surface hardness of NK-EH500 steel can be significantly improved by explosive hardening pre-processing using RDX or PBXN-5 explosives.(6) The hardening effect of two-time explosive processing is muchbetter than one-tipse processing.