1.What are the main risks of using overhead cranes to transport cold-rolled coils?
The main risk is injury from falling steel coils, especially during human-machine coordination.
Cold-rolled coils are heavy (a single coil can weigh 20-30 tons), have a smooth surface, and are prone to rolling. If they detach or sway during hoisting, the consequences could be disastrous. Accident statistics show that locations with frequent human-machine contact have the highest risk. For example, an accident occurred at a steel company: the crane operator, while hoisting a steel coil into a train car, failed to confirm that the crane operator was in a safe position and blindly operated the crane, causing the coil to collide with and crush the operator's chest, resulting in his death. This serves as a warning: effective safety checks must be performed before crane operation, and operation without proper evacuation of personnel is strictly prohibited.
Furthermore, loosely secured steel coils or improper control of turning speed can also cause them to roll off during hoisting or transportation.
2.What type of lifting equipment should be used when using a crane to transport cold-rolled coils?
Specialized lifting equipment must be used; direct lifting with ordinary steel wire ropes is strictly prohibited.
Cold-rolled coils require extremely high surface quality. Direct lifting with ordinary steel wire ropes can easily damage the edges of the coils and even the inner coils. Industry standards clearly require the use of specialized lifting equipment to avoid damaging the steel coils.
3.What checks and confirmations are required before overhead crane operation?
The "three checks and one test" system is mandatory; none can be omitted.
Based on accident lessons and industry standards, the following confirmations must be completed before hoisting:
Check the condition of the lifting equipment: Inspect the lifting slings for wear and cuts; check the hook for cracks and deformation; ensure the anti-disengagement device is intact.
Check the steel coil packaging: Confirm that the binding steel straps are free from rust and breakage; ensure the edge protection (corner guards) is intact.
Check personnel positioning: Confirm that all personnel have evacuated to a safe location; no one is allowed to remain below the hoisting path or in the direction where the steel coil may tip over.
Test hoist confirmation: Before the formal hoisting, lift the steel coil 200-300mm off the ground and hover for 10-15 seconds to check the stress on the lifting equipment and the balance of the steel coil. Only after confirming there are no abnormalities can work continue.
4.What operating procedures should be followed during overhead crane operations?
The core principles are "stability, slowness, clarity, and prevention."
**Stableness:** Smooth lifting: Lifting and lowering should be done smoothly, avoiding sudden acceleration or stopping to prevent the steel coil from swaying and damaging the slings or colliding with surrounding equipment.
**Slowness:** Controlled speed: The crane speed should not be too fast during lifting, especially when passing through narrow areas or approaching the landing point; slow and fine adjustments are necessary.
**Clearness:** Ensure the lifting route is free of obstacles and personnel; if the steel coil is large and obstructs visibility, ground personnel should be deployed for coordination if necessary.
**Prevention:** Preventing swaying: Experience from Hebei Iron & Steel Logistics shows that reducing the sling length from 6 meters to 4 meters significantly reduces the swaying amplitude of the steel coil and improves lifting stability. Additionally, ropes can be used to protect and secure the steel coil to prevent rolling or collisions during lifting.
5.What are the emergency and protective measures for hoisting operations?
Work Area Isolation: During hoisting operations, a warning zone should be established within the work radius, and unauthorized personnel are strictly prohibited from entering. For locations with narrow hoisting areas, poor visibility, and frequent human-machine contact, process optimization or hardware improvement measures must be studied to reduce risks.
Double Confirmation Mechanism: A clear signal confirmation system must be established between the crane operator and the ground-based crane operator. The crane operator must receive clear instructions from the crane operator and confirm that personnel have been evacuated before operating the crane.
Emergency Preparedness: Emergency rescue equipment (such as hydraulic rescue supports, slings, etc.) should be available at the work site, and operators should be familiar with basic emergency response procedures. In the event of steel coil tipping or malfunction of the lifting equipment, work should be stopped immediately, personnel evacuated, and the situation handled by qualified personnel.
Safety Belt Wearing: If ground workers need to perform hooking or unhooking operations at heights (such as inside the vehicle), they must wear safety belts correctly to prevent falls.