Particularly large diameter drills which are widely used in industry are produced from two different steels. Drill shanks are made of carbon steels, whereas drill bodies are made of high speed steels. Flash butt welding is usually used for joining of these types of bimetallic tools in many countries. In this work, flash butt welded C45-HS 6-5-2 dissimilar steel joints were made. The weld zone of the weldments was examined using scanning electron microscopy energy dispersive X-ray analysis, and wavelength dispersive X-ray analysis. Diffusion phenomena in the weld zone of the joints are also explained. (C) 1997 The Institute of Materials.