This process consists essentially of the following steps, viz.:

(1) Melting pig iron in a form of reverberatory furnace called a puddling furnace, and burning out the impurities principally by oxygen supplied from iron oxides.

(2) Subjecting the product of the furnace, after its removal therefrom and while in a hot and plastic state, to mechanical treatment to press out furnace slag.

(3) Cutting into short pieces the bars of impure iron resulting from the preceding step, binding together, re-heating, then hammering or rolling. This eliminates more slag, welds the several pieces of the mass thoroughly, and shapes it into plates or bars for market.

Carbon and other impurities are seldom entirely removed, but are merely greatly reduced in quantity. It is impossible to burn out carbon and other impurities without also burning some of the iron.