Shape Defects
Beveling
Process Stages: Pickling, rolling, finishing
Description: Angled edges on steel coils or strips after edge trimming
Sickle Bending
Process Stages: Cold rolling, smoothing, leveling
Causes: Unbalanced rolling force across strip width, delayed response in force adjustment, uneven roll gap settings, or inconsistent material density and hardness
Wave Patterns (including unilateral wave, bilateral wave, center wave, oblique wave)
Process Stages: Cold rolling, smoothing, leveling
Causes: Non-uniform material density/hardness, slow response in rolling force/bending force adjustments, excessive tension fluctuations, significant diameter difference between top and bottom rolls
Buckling
Process Stages: Hot rolling, cold rolling, smoothing, leveling
Causes: Uneven density or hardness through material thickness, resulting in differential plasticity between top and bottom surfaces
Coil Configuration Defects
Telescoping
Process Stage: Coiling operation
Bulging
Process Stage: Coiling operation
Cause: Excessive edge thinness leading to coil expansion during continuous winding
Drum Ears
Process Stage: Coiling operation
Cause: For galvanized coils, overly thick edges can cause end protrusions during coiling
Dimensional Defects
Thickness Deviation
Process Stage: Rolling process
Cause: Inaccurate rolling control parameters
Width Shortfall
Process Stage: Trimming operation
Causes: Improper trimming settings or pre-existing edge defects in raw material
Length Deviation
Process Stage: Slitting operation
Cause: Control system inaccuracy
