Phenomenon: 

A change in the properties of certain metal and alloys (such as steel) that occurs at ambient or moderately elevated temperatures after a hot working heat treatment or cold working operation.  Typical properties impacted are: hardness, yield strength, tensile strength, ductility, impact value, formability, magnetic properties, etc. See also Non-aging.

Phenomenon:  

Change of surface texture colour. Normally for black colour.

Cause: 

Heavy contact with table and other equipment during process Rubbing both surface each other during transfer of material. This cause coating powder to peel off.

Phenomenon: 

Curvature in the plane of sheet or plate in the rolling direction. Usually caused by unbalanced stresses between the top and bottom surfaces of the rolled product. One type is coil curvature.

Cause :  

1.Excessive pressing down of masher roller

2.High Burr.

Clearance to small cause contact of upper and lower cutter. This cause surface cutter rough. 3.Large different in pass line height and cause to wear off. Cause by wear off of   bridle roller and defector roller

Phenomenon: 

A curvature across the width of the strip at a 90-degree angle to the direction in which the strip has been rolled or uncoiled.

 A more severe case can result in a center buckle.

Phenomenon: 

Built up edge or roughness on the bottom of the strip resulting from slitting or shearing.

Phenomenon: 

The layer in the inner diameter is deformed. Normally one defect is found if coil is buckling  

Cause : 

Excessive high winding tension A rise of temperature than the 40 to 50C temperature.

Phenomenon: 

Camber is the deviation of a side edge from a straight edge. Measurement is taken by placing a straight edge on the concave side of a sheet and measuring the distance between the sheet edge and the straight edge in the center of the arc. Camber is caused by one side being elongated more than the other.  

Phenomenon: 

A condition in the band of steel where the center (in the direction of rolling) is longer than the edges and has a wave or buckle

Cause : 

Excessive high winding tension

Phenomenon: Gradual chemical or electrochemical attack on a metal by atmosphere, moisture or other agents.

Phenomenon:  

Parallel and same width measure from the edge. Normally is same as cutter width.

Cause : 

Rubber ring diameter is too big. To much vertical movement due to internal diameter of rubber ring too big. 

Arbor bent gap between the cutter inside diameter and cutter shaft.

Phenomenon: 

 A sharply defined surface impression on the metal which may be caused by a blow from another object.

Cause : 

When place directly on unclean flooring or foreign objects.

Mishandling when transferring.

Phenomenon:  

Deformed into shape of ellipse

Cause : 

Poor winding tension

Phenomenon: 

Red rust found at the edge

Cause :

Coil is expose to high humidity due to poor storage area.

No oil or less anti-rusty is apply.

Coil is not cover with warpper.

Phenomenon:

Separation of the coating from the base material.

Phenomenon: 

Fine dot line along or across the width of coils

Cause :

Poor cleaning process by the mill.

The tension of coil is too loose

Phenomenon:

A coil that has not wound properly whose sidewall protrudes out. Tension problems or a bad start on the exit reel causes this condition

Cause :

Poor winding tension

Stopping in the middle of slitting process.

Poor separator width setting

Phenomenon:

A term used to describe a quality defect in which the edge of the strip is wavy.

Phenomenon: 

A coating metal oxide, such as zinc oxide, which develops when the oxygen in the atmosphere mixes with the coating material (such as galvanized coating).