An ingot stripped from its mould should go while hot to the soaking pit, a large furnace in which it is placed to be brought to a red or yellow heat preparatory to rolling. From the soaking pit it is transported to the rolls, known specifically as the rolling mill, where it is passed several times back and forth between heavy rolls, the pressure of which reduces its cross-section size and at the same time greatly increases its length.

This reduction is known as breaking down. Ingots rolled square or nearly so in cross section and left larger than billets are called blooms. These are used for making large forgings, such as piston rods, crank shafts, connecting rods, etc., in engine-building works. Ingots rolled flat and wide are called slabs. An ingot rolled into blooms, billets or slabs is cut into suitable lengths for reheating and further working. Mills are now constructed which handle an ingot quickly enough to roll it into finished railroad rails, structural shapes, plates, billets, etc., without reheating; but rods, bars, and similar shapes of small cross section cannot be rolled directly from a large ingot because the metal gets too cold before it can be rolled so small, and the amount of material in an ingot would stretch out too long for practical handling in one piece of small section. 9

Steel blooms which come from the rolling mill must not be confused with wrought-iron blooms or puddle balls.