If we classify the metal rolling operations according to the shape, then there are two types of metal rolling operations.
- Flat rolling and
- Shape rolling
Here I have explained both flat rolling and shape rolling of metals.
So let’s dive right into it.
What is Flat Rolling?
Flat rolling is a type of metal rolling operation in which the starting and ending material have a rectangular cross section.
As shown in the above diagram, the metal which is to be flat rolled is fed in between the two opposite spinning rollers called working rollers.
The gap between the rollers is less than the thickness of the metal which is fed between the rollers.
This causes the metal to deform when it passes through the rollers.
Also because of the reduction in thickness, the metals get elongated.
There is a lot of friction that acts between the metal surface and the roller surface. This friction causes the metals to push through the rollers.
If the amount of thickness to be reduced is more, then the roller may slip over the metal.
Using flat rolling, a metal sheet or plate can be manufactured easily.
In flat rolling operations, the rollers are subjected to more force at the center as compared to the edges.
So the thickness of the rollers plate or sheet can be more at the center and less towards the edges.
What is Shape Rolling?
Shape rolling is a type of metal rolling operation in which the forming of metal is done by using rollers of certain geometry.
The rollers are made of desired shapes which form the metal part into that specific shape.
The workpiece does not get deformed in a single pass, but it requires multiple passes for achieving the desired shape.
By using shape rolling operations, cross sections like I-beam, U-channels, L-beams, rails, etc can be manufactured.
The workpiece may experience different deformation and different reductions in different areas of its cross section.
During the shape rolling operation, if there is excessive deformation in any part, then it may lead to some rolling defects.
In shape rolling, the design for roll pass is done in such a way that rolling defects can be avoided.
Improper reductions in the workpiece leads to cracking or warpage of the material.