The iron-clad barrel is curled and deformed during rolling. The design of the sealing wheel must make the crimping process step by step and minimize the deformation resistance, otherwise it will lead to deformation.

Barrel objects made of iron can be used to hold liquids and solids. They are usually cylindrical and have a bottom. The bottom is closed with iron sheet, and the top has iron handle, which is convenient to carry. Iron drums first appeared in the Xia Dynasty in ancient China. Another kind of iron drum, which only has a small mouth at the top and a closed bottom, is generally used for transporting oil and the like, and appeared in modern times.