1.What problems can occur due to inter-roll pressure and friction?
Problem: When roll materials are stacked horizontally (especially too high), the bottom rolls bear enormous pressure. During transport and bumps, minute but high-frequency relative sliding and friction occur between the rolls.
Result: This friction can wear down, scratch, and even "crush off" the coating on the outside of the roll. The peeling often manifests as large, directional scratches or abrasions.
2.What are the consequences of edge collisions and "scratches"?
Problem: The edges of the steel coils are very hard. If not properly secured during transport, collisions between coils or between coils and the vehicle body can cause these hard edges to cut or crush the coating of adjacent coils like knives.
Result: This leads to linear or dot-like cracking and peeling of the coating at the point of impact, eventually causing it to detach.
3.What are the consequences of interlayer adhesion and delamination?
Problem: In high-temperature environments (such as containers or warehouses exposed to the summer sun), when the roll material is tightly wound, the coating surface (especially the smooth film surface) may experience slight adhesion under pressure and heat.
Result: When the roll is unwound, the adhered areas are forcibly pulled apart, causing the coating to be partially "ripped off." This often manifests as dot-like or small patchy peeling.
4.What are the consequences of improper hoisting and strangulation?
Problem: Using substandard cables or lifting equipment (such as damaged or angular ones), or improper lifting angles, causes the cables to dig directly into the membrane, creating excessive pressure in a localized area.
Result: This results in the coating being crushed, cut, or even the substrate deformed, leading to detachment.
5.How can we determine if the detachment is related to the stacking during transport?
Location Characteristics:
Damage mostly occurs on the outermost layer of the roll material (3-10 turns).
It often occurs on the sides or edges of the roll material, i.e., at the points of contact with other roll materials or fixtures.
The damage to the bottom layer of the roll material is more severe than that to the top layer.
Morphological Characteristics:
There are obvious mechanical scratches and abrasion marks, oriented in the same direction as the circumference of the roll material.
There are regular, repetitive indentations or puncture marks.
Traces of compression and deformation of the metal substrate are visible at the point of detachment.