Slitting serves three purposes :
• HR coils are available in widths which are wider than
the required for Cold Rolling. The trimming / slitting is
done with the HR Slitter.
• The HR coils available may have width variation of the
order of up to 20 mm, so to get the uniform width
these coils are slitted.
• The edges of HR coils may get damaged during
transportation because of poor packaging and/or
improper handling. In order to remove these damaged
edges the HR coils are trimmed /slitted.
• Slitting is a process of cutting larger width coils into
narrower width coils with repetitive accuracy at a high
• The process begins with the fitting of large steel coils
onto an uncoiler drum whereby it is uncoiled and fed
through a leveller to be flattened. Subsequently, the
sheets are fed through a slitter to slit the sheets into
strips of specific width.
• After slitting, the strips are relayed through tension
pads or synchrony-wind rolls to provide tension prior
to the recoiling process. The tensed strips are then
recoiled using a recoiler to form slitted coils.
• Pickling is a metal surface treatment used to
remove impurities, such as stains, inorganic
contaminants, rust or scale from ferrous
metals, copper, precious metals and
aluminium alloys using HCL acid.
Cold Roll Milling
6 Hi Mill – 2 No's
4 Hi Mill – 3 No's
Width Range – 250 – 1300 mm
The primary function of Cold Rolling is to reduce the thickness
of Hot Rolled Pickled strip at room temperature. During the
operation overall max reduction of up to 90 % in thickness of the
HR Coil can be achieved. Cold rolling occurs with the metal
below its recrystallization temperature (usually at room
temperature), which increases the strength via strain hardening
up to 20%. It also improves the surface finish and holds tighter