If you have a square "Hot-Rolled Billet" and a square "Hot-Rolled Bar" of the same cross section dimensions, what are the actual differences between the two? Is it a question of length? Does one have more work in it than the other?
The difference boils down to the work reduction ratio between the two product forms. In some applications you can have strand cast bars with little work reduction needed. In other cases you have bars made from billets that are typically produced from ingots so you can have more work reduction.
PogoGo:
A steel billet is a less worked precursor, with a larger cross-sectional sized than the finished rolled bar. The rolling process reduces the billet cross-sectional area, while increasing the length of the volume of steel. Finished bars of many sizes and shapes are made this way.