1.What are the limits on the height or number of layers for stacking cold-rolled coils?
Standard practice: Stack in two layers. This is the requirement of most enterprise standards (such as Baosteel Q/BQB 400) and warehousing regulations. Larger coils should be stacked at the bottom and smaller coils at the top to avoid compression damage.
Three layers are permissible under specific conditions: If the thickness of the bottom layer of steel coils is ≥1.0mm and the weight of the upper layer of steel coils is no greater than that of the bottom layer, stacking in three layers is allowed. However, safety regulations clearly state that multi-layer stacks must be trapezoidal (i.e., each layer recedes inwards), with a height not exceeding three layers and a stack spacing greater than 0.4 meters.
Exceeding limits is prohibited: Stacking beyond three layers is strictly prohibited, otherwise there is a risk of collapse.
2.Why can't cold-rolled coils be stacked indefinitely? What are the main risks?
Collapse Risk (Most Important): Cold-rolled coils are cylindrical with a high center of gravity and a small contact area. If the stack is too high, and the bottom coils lack sufficient load-bearing capacity or the stack is tilted, a complete collapse is highly likely. Such accidents have severe consequences-the impact force when the coils roll or fall is enormous, potentially causing personal injury and equipment damage.
Product Quality Risk: Excessive pressure on the bottom coils may cause elliptical deformation (out-of-roundness), affecting subsequent uncoiling processing; it may also cause interlayer extrusion scratches, damaging surface quality.
3.Besides the number of layers, what other strict requirements are there for stacking?
Stacking Shape: Multi-layer stacking must be trapezoidal (or pyramidal) in shape, with the top layer of steel coils tucked inwards to prevent the center of gravity from shifting. Vertical alignment is strictly prohibited.
Size Order: When stacking in two layers, the largest coil should be at the bottom and the smallest at the top; when stacking in three layers, the heaviest and thickest steel coil must be placed at the bottom.
Bottom Layer Steel Coil Thickness: If stacking in three layers, the bottom layer steel coil thickness must be at least 1.0 mm; otherwise, only two layers can be stacked.
Padded and Barriers: Steel coils must not directly contact the ground; rubber pads or nylon straps must be laid underneath. Each row of stacks must be secured at both ends with triangular blocks or barriers to prevent rolling.
4.Are there differences in stacking height for cold-rolled coils of different thicknesses?
Thin sheets (< 1.0mm, 2 layers) have weak load-bearing capacity; stacking 3 layers is strictly prohibited.
< 1.0mm (2 layers): Thin sheets have weak load-bearing capacity; stacking 3 layers is strictly prohibited.
≥ 1.0mm (3 layers): Must meet the following condition: Bottom layer thickness ≥ 1.0mm + Weight of top layer ≤ Weight of bottom layer.
5.How can we ensure that stacking meets safety requirements? What should we pay attention to during routine inspections?
Pre-stacking confirmation: Check if the thickness of the bottom steel coils meets the load-bearing requirements; confirm that the larger coils are at the bottom and the smaller coils on top; ensure the padding material is intact and the triangular blocks are securely fixed in place.
During stacking monitoring: Use trapezoidal stacking, with each layer receding inwards; use lasers or lifting devices to ensure the steel coils are centered and avoid misalignment.
Daily inspection: Regularly check for stack skewing, whether the bottom steel coils show elliptical deformation; check whether the triangular blocks have shifted and whether the padding material is damaged.
Identification management: For stacks exceeding two layers, the bundled goods, weight, and other information must be clearly marked on the aisle side for easy identification and supervision.