Mini-factories

The phenomenon of "mini-mills" is relatively recent: until the decade beginning in 1950, the expansion of the steel industry was based on :

• a single scheme:

  Iron ore

  .

  Blast furnace

  .

  Steelworks

  (mainly based on the Martin furnace, but also on the Thomas converter — especially in Western Europe — and then switching to oxygen);

• steady growth, both in the unit capacities of blast furnaces and steelmaking reactors, and in the plants themselves, rising rapidly to 1 Mt/year, then 5, and now reaching, or even exceeding, 10 Mt/year.

  It was against this backdrop that mini-factories gradually sprang up, first in 1950 and then more rapidly thereafter:

• with the :

  Scrap metal

  .

  Electric arc furnace

  .

  Lamination

• and often...