Customer case

New scrap steel containers save time and US$140,000/year in operating costs

November 14, 2022 6 min read

SSAB Scrap steel container

Case details

Country Sweden
Company SSAB
Industry Steel distributors and stockholders

The SSAB strip-rolling facility in Borlänge, Sweden produces heavy steel scrap as a by-product of converting steel slabs into coils and plates of cold- and hot-rolled high-strength steel. The heavy steel scrap was collected at the mill and loaded into a railroad gondola wagon — a heavy-duty, open-top car. The train would then take the scrap to SSAB’s mill in Luleå, in northern Sweden, to be recycled into new steel slabs.

The previously used railroad wagon — a high-walled, open-topped gondola car — for carrying the heavy scrap steel.

Case details

Country Sweden
Company SSAB
Industry Steel distributors and stockholders

Developing a more efficient scrap unloading process

SSAB logistics department wanted to improve the scrap steel unloading process at the Luleå mill. The existing method required a crane to move the scrap from the railroad wagon onto a dump truck (container lorry), that then moved the cargo to mill’s scrapyard. This process consumed 33 worker hours every week.

The goal was to eliminate the need for the crane and dump truck and instead use the mill’s existing forklifts to unload new, railcar-mounted scrap containers that could then be directly tipped into the Luleå scrapyard.

Design challenges for the new scrap steel containers

  • Weight: The weight of each new container had to be as light as possible to maximize the amount of scrap steel transported — yet the design had to be robust to withstand steel-on-steel impact.
  • Compatibility: To mechanically secure the containers onto the rail wagon, the containers’ frames had to be compatible with the stopper and ISO-lock configurations on the existing, standard Green Cargo flatbed rail cars.
  • Compatibility, part 2: The scrap containerss had to be compatible with the existing forklift truck attachments used to move the containers on and off the rail wagon and around both mills.
  • The shape of the containers had to maximize their tipping angle and have their center of gravity to the containers’ angled front wall to facilitate unloading and minimize carry back.
  • Dimensions of the containers must fit within the factory gates of the Luleå mill.

Design for manufacturing was key. Welds and the number of parts needed had to be minimized. The design also needed to optimize the use of each steel plate to reduce scrap. And the design had to be robust — but also economical. 

The SSAB Product Engineering assignment was to deliver manufacturing and assembly drawings with comprehensive details that, in turn, could be sent out for request for quotes (RFQs) for the containers’ steel fabrication.

With both railway wagons the same length, the three-container per rail car design turned out to hold more steel scrap than the four-container approach.

The scrap containers’ development and engineering process

As with all projects — whether for internal or external customers — Product Engineering used its own innovation workshop methodology, based on the SSAB ONE lean principles, to comprehensively gather and structure input from all stakeholders. This included the operators at the location where the scrap was generated, gathered, and put onto railway cars, as well as operators at the receiving end, where the containers were taken off the rail wagons and unloaded in the scrapyard. Green Cargo, the rail company, was also a key participant in the design input process.

SSAB Product Engineering explored two different design approaches: 1) Making three containers as large as possible for a rail car and 2) making four containers that would also fit on the same length rail car. It was mutually decided to go with the three-container approach since that maximized the load capacity.

Product Engineering’s first concept underwent several iterations to meet all of the project’s requirements, including finite element method (FEM) analysis for four different load scenarios.

Finite element method analysis for the steel scrap containers under one of four different load scenarios.

The front wall of the container was modified to optimize the tipping process. Next, the container’s frame was adapted to Green Cargo’s specifications for the rail wagon. After some iterations, Product Engineering chose a frame structure made of rectangular tubes for its simplicity and lower center of gravity. 

Two frame concepts explored prior to settling on the final design — see next images.

Left image: final frame design. Right image: detail of container’s forklift pocket.

To withstand the impact of the heavy steel scraps, Hardox® 500 Tuf wear plate was chosen for the containers’ walls. The design was adapted to use 8 mm steel plate for all of its components, reducing the number of plates needed to build each container and simplifying ordering and inventory.

Drawings of the final, assembled, heavy-duty container for scrap steel.

View of the back and side walls. The economical containers maximize freight handling efficiency, both at the mills and on the railroad.

Fully documented container engineering speeds fabrication

From initial sketch of the container to fully documented engineering for fabricating quotes took less than six weeks. Through constant two-way communication with all stakeholders, SSAB Product Engineering was able to completely gather all the necessary details, saving both time and the need for engineering rework. 

Stock availability for prototyping was secured by Product Engineering, who also gave technical support to the procurement team during the quotation process and the manufacturing of the container. 

The container kits were manufactured by the SSAB Steel Service Center Oborniki, Poland. Product Engineering’s fully detailed manufacturing documentation, combined with the Oborniki Center’s high expertise and state-of-the-art fabricating equipment, enabled all components to be made within tight tolerances and in a timely fashion. The container kits were then sent to a fabricator in Poland for final assembly and welding using Product Engineering’s assembly documents.

New containers save $140,000/year and enable faster turnaround

“The scrap steel-handling process from railroad wagon to the Luleå scrapyard went from 33 hours/week to 7 hours/week, while eliminating the need for a crane and a dump truck,” notes Hans O. Andersson, SSAB Procurement/Strategic. “Savings are estimated to be US$140,000 per year. The new containers also free-up a Luleå crane for other uses.”

“Because unloading the scrap steel is so much quicker, wagons arriving in the morning can rejoin the return train the same evening, minimizing their round-trip time.”

- Hans O. Andersson, SSAB Procurement/Strategic

“The transport container concept can be used for materials other than scrap,” says Andersson. “It is equally suitable for transporting glow plugs for recycling and many other by-products of the SSAB Borlänge mill.”

Discrete Element Method for optimized container flowrates

SSAB Product Engineering has fully developed and engineered numerous scrap recycling containers, for both light and heavy materials, for a variety of customers. To further improve our offerings, we are deploying Discrete Element Method (DEM) to optimize container flowrates and reduce wear points.

Accelerate your innovation and product development

SSAB Product Engineering works within the OEM’s perspectives to find potential steel product portfolio improvements. Early-stage cooperation and SSAB’s unique development methods give your steel products a head start that reduces their costs and time-to-market.