In this paper we will try to address technological diffusion and substitution from two methodological angles. The first consists in a complete and comprehensive morphological analysis (MA) of a set of (process) technologies for a particular industry. In the second part, we use the results of our MA of the technological trajectories in the casting industry, to analyse their diffusion in two countries, France and the FRG. With respect to the results of this work, we can express two observations. First, this case study will provide valuable insights on the conditions of exit from a “lock-in” situation. Second, the MA will permit us to avoid misinterpretation concerning the asymmetrical character and discontinuities of the diffusion trajectory of the technology under consideration.