Each electrode exchange causes idle time for the EAF, and the crane is occupied for an even longer duration. Watch out if the crane is already highly utilized. Bucket charging transports may be delayed, further increasing the unproductivetime of the EAF. 

Offline Column Extend
Take out the hot column and place it in the jointing station. Extend it with a new piece and put it back in the electrode arm of the EAF.

EAF idle time: 8.5 min | Crane working time: 10 min | Benefit, no cool down and reheating of the column

Offline Column Swap

Take out the hot column and place it in the jointing station. Move to the storage rack, take a ready-prepared column, and put it back in the electrode arms of the EAF. Extend the hot column in the jointing station when there is time and place it in the storage rack.

EAF idle time: 6.5 min | Crane working time: 12 min (7.5 + 4.5 min) | Benefit: Less idle time for the crane and no special equipment necessary.

Online Two Hook Swap

When the crane is equipped with two auxiliary hooks, pick up an extended cold column from the storage rack and move to the EAF. With the second auxiliary hook, pull the hot electrode and place the cold electrode in the EAF’s electrode arm. Move the hot column to the jointing station and place it there. Extend the hot column in the jointing station when there is time and place it in the storage rack.

EAF idle time: 3.5 min | Crane working time: 8 min | Benefit: Very fast, but the crane must be equipped with two auxiliary hooks.

Online Robot Extend

Pick up the loaded vertical automatic addition device—aka robot—and travel to the EAFplatform to connect the supply lines. Move to the EAF electrode, mount the device, and join the new piece. After slipping the electrode, move back to the EAF floor and disconnect the supply lines. Transport the device to the electrode up-ending table, load a new piece in the device, and unmount at the standby position.

EAF idle time: 3.5 min | Crane working time: 7.5 min | Benefit: Very fast, but may not be applicable due to space constraints.

Send me an email at office@fesios.com to send you the Excel file with the detailed step by step break down for each method and further assumptions made. 

‍