Delta Steel Technologies Inc.

American Steel

Some say that the American steel industry is dead. Not Joseph Savariego, President at Delta Steel Technologies Inc. in Irving, Texas. For more than 55 years, the manufacturing company, which is now run by the second generation, has been building and repairing machinery for steel mills across the country, and that will not change in the future. On the contrary: In the past ten years, entirely new types of mini and micro mills have been established – factories that Delta Stell is busy equipping as well.

During a recent project, however, Delta Steel was facing difficulties. After winning the bid on a so-called roller leveller, Savariego and his design team found that the gear units in a critical assembly had to be placed closer together than they liked. They knew that this arrangement would make it difficult for their customer to service the machine in the future, and therefore decided to reach out to electromechanical solution provider NORD DRIVESYSTEMS for help.

Customer profile

Premium processing
Delta Steel Technologies has 120 employees. Some of them have worked at Delta Steel for more than 40 years, and all are proud of contributing to the American steel industry. In a 21,000 m2 facility, the company develops and manufactures a wide range of customer-specific products, including stretch levellers, rotary shears, temper mills and cut-to-length lines. They all serve to convert rough steel coils into flat, precision-cut material that can be used by manufacturers of cars, household appliances and other sheet metal components and assemblies.

The company also refurbishes, remanufactures and retrofits older systems, offers custom machining and manufacturing, repairs cylinders and gear units, and offers ready-for-use systems from its system portfolio. Many of these systems are highly automated and use state-of-the-art technology to achieve maximum performance. There is more, but to put it simply: Delta Steel aims to deliver whatever the customer needs to process steel efficiently and economically.

This requires strong supplier partnerships. Savariego says that their company has worked with NORD DRIVESYSTEMS for a few years now and have always found the NORD team to be amenable, helpful and creative in their solutions. “Most companies just give you a catalogue and say ‘Pick one of these. If it works, great! If it does not, we are sorry – then we cannot be of any help.’ NORD, on the other hand, has always tried to understand our needs and helped us find a product solution – no matter what problems we were facing.”

Project requirements

Confined space
As the name already implies, the roller leveller uses a series of offset, rotating rollers to make coil steel flat. The material is fed into one end of the machine that alternately bends the sheet in gradually decreasing “waves”. These “waves” serve to reduce metallurgical stress and flatten the steel as it passes. In Delta Steel’s design, there are eleven rollers in total: Five above the sheet and six below it. Each roller is connected to an input shaft and each input shaft is connected to a gear unit driven by its own motor with a power of 110 kW.

The problem with this particular project was twofold. As already mentioned, the Delta Steel designers had to stack the usually two rows of components on top of each other to fit everything into the confined space. This restricted the access to the bottom row of drive components, so the designers developed a slide mechanism that allowed the technicians to easily disconnect each gear unit/motor combination from the input shaft and simply pull it back and out of the way for servicing.

Despite this space-saving arrangement, a compact but powerful gear unit would still be required. For this purpose, they reached out to the local NORD DRIVESYSTEMS representative, Steve Hunter, who put them in touch with application engineer Jeff Wittrock. He recommended an SK 5207 series MAXXDRIVE® large industrial gear unit in axis-parallel arrangement and 14:1 drive ratio. With its one-piece UNICASE™ housing, symmetrical design and extremely high power density considering its size, the gear unit would provide high torque along with the performance and service life required for this demanding application.

Application solution

Meeting challenges

“There were definitely some challenges,” Savariego said. “For example, we asked ourselves what would happen if one of the bottom gear units was to be damaged. How would you access it without having to remove the one above it? Even the best gear unit and the best motor requires regular maintenance, which would have been extremely difficult if we had chosen the less flexible design. This led us to the sliding mechanism mentioned before. However, this meant that we had to reduce the angle of the input shaft, which in turn required that we keep everything close together. NORD was very helpful and provided support throughout the entire process until we reached the optimal design.”

Every project is different, Savariego added, noting that such details often have to be worked out after the customer has already accepted the preliminary quote. Only as designers delve into all the requirements, they can understand any potential challenge. It is therefore especially important to work together with suppliers that provide a wide range of component options backed by experienced support and applications employees.

“NORD was able to help us transmit a large torque into a fairly small device assembly,” Savariego said. “They also helped us determine the best way to arrange the gear units. It is not like there are no other good gear unit manufacturers out there, but in certain applications, NORD’s service and support surpasses that of the rest. It was a pleasure to work with NORD and we will continue to do so.”