A development of the principal of using Small Working Rolls are illustrated by
the Four - Roll Arrangement " Fig 1 D " in which the metal passes between the two
smaller rolls, which are supported by the two large rolls. The most popular type
in rolling is the first.
Steel or Non-Ferrous metals are sheets of Metal varying in thickness from
0.25 in down to 0.02 in or less in width from 2 ft or 4 ft in various length.
Sheet Rolling as opposed to Strip is rolled in separate pieces or sheets of
2 ft width metal and is rolled from Coils, Roll Strip as wide as 4 ft and wider
in coils, from which flattened metal is cut to length in sheets.
In " Fig 1 C " three rolls are shown in an arrangement known as "3 High".
This provides for Reversible working and commonly adopted for Section and Bar Mills
also Cold Rolling long length of strip in coils.
The centre roll in a 3 High Assembly is smaller diameter than the top and bottom
rolls, thereby obtaining the technical advantages resulting from using a roll of
minimum diameter, the load due to the resistance of the metal to deformation by
the larger top and bottom rolls.
A further elaboration of this system is given by the next three diagrams " Fig 1 E”
showing the Six Rolls or "CLUSTER" Mill.
" Fig 1 F " the 12 Rolls or "ROHN" Mill.
" Fig 1 J" the SENDZIMIR assembly which has a 12 Rolls Arrangement with the final
" back up " Eight Lines of Roller Bearings.
Long continuous stock is frequently rolled in trains of mills in the as " TANDEM "
or " CONTINUOUS " as illustrated in " Fig 1 H ", this diagram shows a Three Stands
Mill each stand being of the 2 High, 3 High and 4 High types.