There are two ways to anneal cold-rolled steel coils: batch and continuous.Batch (Box) Three to four coils are stacked on top of each other, and a cover is placed on top for up to 3 days, then heated in a non-oxygen atmosphere (to prevent rust) and slowly cooled.Continuous. Normally part of a coating line, the steel is uncoiled and run through a series of vertical loops within a heater. The temperature and cooling rates are controlled to obtain the desired mechanical properties for the steel.