1. A wide choice of raw materials

Figures 1 and 2 (the latter being, in fact, an enlargement of the top of figure 1 ) clearly show the increasingly profound differences between the steel industries based on :

• iron ore (see article Ores and fluxes) ;

• scrap metal (see article Recycling of ferrous waste).

Without wishing to go into the history of this evolution, we can recall that, in the days of the Martin steelworks, we could use just about any combination of cast iron...