1. How to control processing losses of cold-rolled coils from the raw material stage?
A: Selecting hot-rolled raw material coils with high dimensional accuracy, good shape, and few beginning and end defects can reduce uncoiling and cutting losses. Agreeing on reasonable weight tolerances and width allowances with suppliers avoids increased trimming due to excessively wide raw materials or excessive camber. Simultaneously, customizing the raw material coil weight according to order requirements reduces unnecessary beginning and end shearing caused by weight mismatch.
2. How can rolling process parameters be optimized to reduce losses?
A: Employ automatic thickness control (AGC) and strip shape control systems to reduce scrap due to thickness deviations. Optimize the pass reduction ratio distribution to avoid edge cracks or strip breakage caused by excessive rolling force. Use online crown detection to adjust bending roll force in a timely manner to prevent forced edge cutting due to poor strip shape. In addition, rationally set emulsion spray parameters to reduce surface scratches caused by insufficient lubrication.
3. How to control width loss during the trimming process?
A: Accurately calculate the trimming amount based on the order's width requirements to avoid excessive trimming in a "one-cut" manner. For intermediate rolls with good sheet shape, a "less trimming or zero trimming" strategy can be adopted (provided the customer allows for rough edges upon delivery). Simultaneously, regularly calibrate the disc shear gap and overlap to prevent edge cracks caused by poor shearing quality, which would force secondary trimming and increase losses.
4. How to reduce length loss caused by head and tail shearing?
A: Utilize weld tracking and head/tail defect detection systems to achieve precise positioning during shearing, avoiding excessive cutting. Optimize welding processes to reduce hardness and thickness fluctuations in the weld area, minimizing the length that must be cut before and after the weld. For continuous annealing or galvanizing units, the head and tail speeds can be reduced, and in conjunction with an online shape meter, only scrap sections will be cut.
5. What production management measures can be taken to systematically reduce losses?
A: Implement a full-process "yield assessment" system, breaking down loss indicators to each process (pickling, rolling, finishing). Use the MES system to record the weight of the cut ends and edges of each steel coil, and regularly analyze the causes of abnormal losses. Simultaneously, utilize surplus materials, such as classifying and recycling the cut strips to downstream enterprises, or selling the short ends of coils as trial molding materials or raw materials for small-sized orders.