How are adhesion streaks formed on cold-rolled coils? A: During bell-type annealing, the strip steel adheres to each other. When uncoiling, peeling the strip causes strain and tearing, forming arc-shaped strain streaks. This is often caused by poor strip shape, large fluctuations in coiling tension before annealing, insufficient surface roughness of the strip, or excessively rapid heating and cooling rates during annealing.
What is a tower-shaped defect? How to prevent it? A: A tower-shaped defect where the top and bottom of the coil are uneven. Prevention requires ensuring the leveling fluid is thoroughly cleaned to avoid residue affecting coiling; at the same time, standardize coiling operations, control coiling tension stably, and reduce strip deviation.
How are vibration marks generated on cold-rolled coils? A: Caused by mechanical resonance. This phenomenon is usually more severe during the initial machine startup and gradually weakens. Vibration marks are regular wavy patterns that cause variations in strip thickness along the rolling direction, affecting surface quality.
How to control edge crack defects on cold-rolled coils? A: On the one hand, strengthen the acceptance of hot-rolled incoming materials to avoid using raw materials with edge defects; on the other hand, optimize the rolling reduction system to avoid excessive reduction rate per pass; if edge cracks occur, the edges can be trimmed and the material delivered in the correct length, and in severe cases, it must be rejected directly.
What are the characteristics of roll mark defects? How can they be avoided?
A: The characteristic is irregular bumps and depressions periodically distributed on the surface of the steel strip. To avoid them, regularly inspect the rolls and other equipment in contact with the steel strip, promptly clean foreign matter adhering to the roll surface, replace rolls regularly, and properly configure the roll profile to prevent abnormal roll wear.