The Rose Corporation recently fabricated furnace charge buckets for a local specialty steel manufacturer. Charge buckets are used to load scrap into an electric arc furnace and are sized by volume and diameter. At the steel manufacturing plant, a charging bucket is transported by an overhead crane using its main hook. It uses a special lifting bale that is opened and closes by a second auxiliary hook. A charging bucket must be sized so that it fits inside the top ring of an electric arc furnace.
Below is a video of a charge bucket loading 75 tons of scrap steel into an electric arc furnace:
The buckets are designed for an even spread of scrap over the bed of the furnace. Constructed of heavy steel plate, bars, and rolled shapes. Bottom doors, fabricated of dished plate allow the bucket to sit on the floor without special auxiliary supports. Dished plate refers to a concave metal plate shaped to allow for contraction (as after welding) and to increase resistance to force applied to the convex surface.
Here is a detail of the welding on the bottom doors:
Three clamshell charging buckets were fabricated. One with 600 cubic foot capacity, 9 feet in diameter, 10 feet tall, and two charging buckets with 265 cubic foot capacity, 7 feet in diameter and 7 feet tall.
Pictured below is the largest charging bucket being machined on a Giddings & Lewis horizontal boring mill with a 7-inch spindle:
Each charging bucket required an average of 70 hours of welding, 50 hours of fitting, and 40 hours of machining each. Pictured below is a detail of the machining and welding work completed at The Rose Corporation: