2. Metamorphoses in steelmaking since 1950

Between 1950 and 2009, global steel production increased more than 6-fold, from 190 Mt/year to 1,225 Mt/year, after peaking at 1,351 Mt in 2007. Figure 5 shows the evolution of annual world production: total and for each of the 4 families of processes used during this period, i.e. :

• fours Martin ;

• electric arc furnaces ;

• air-cooled converters ;

• oxygen converters.