In this article we will discuss skin pass and defects.
Rolling is used to reduced the thickness and to make the thickness uniform.
Skin pass is another type of rolling process.
Skin pass rolling is defined as a process in which fine structure give to the newly generated grain
After annealing process so that it become useful for forming operation.
In case of skin rolling also known as a skin pass having less reduction around 0.5-1 %.
It produced smooth surface, uniform thickness, and reduced the yield point.
It is used where ductility is required.
DUCTILITY is a material that can be stretched thin wire when tensile stress is applied.
Skin pass rolling is done for following parameters:
To achieve the optimum mechanical properties
(Hardness, YS, —–)
To prevent occurrence of stretcher strains in annealed steel
To impart desired surface finish – “matte” on the strip surface
To improve strip shape
To reduced the yield point
Mechanical Properties are controlled by regulating the % elongation during skin passing
% Elongation depends on the grade of the CR steel.
Stretcher Strain removal is achieved through suppression of the yield point elongation during
SKIN PASS AND DEFECTS
- Hole mark
- Roll mark
- Edge cut
- Pick up mark(use of rubber pad)
- Seam line
- CBL(COIL BRAKE LINE)
- RIS(ROLLED IN SLAG)