A steel producer noticed fatigue cracks and rust in the frame, supports, and piping of a walking beam furnace at its hot strip mill. This led to an increase in leaks and emergency repairs, which negatively impacted reliability. As a result, the steel producer decided to replace the walking mechanism of the furnace with an improved version.
About the project
In the walking beam furnace of a hot strip mill – 40 meters long – steel slabs alternate between resting on moving and stationary rails. The moving rails lift the steel slabs and place them further down the furnace. Step by step, the slabs essentially “walk” through the furnace. With this operating principle, it is necessary to cool the rails and supports with cooling water. After years of use, replacement became essential. The steel producer opted not for a one-to-one replacement but for a redesign that offered more opportunities for cleaning and maintenance work. The entire walking frame, including hydraulics, electrical installation, and piping, was replaced. Vicoma was called in to contribute to the project.
Role of Vicoma
Vicoma’s role initially involved engineering the cooling water piping. A 3D scan was used to map the current situation. This was followed by a CFD analysis of the original design of the supports. Vicoma also performed pipe stress calculations for the piping between the supports to ensure they would not break. Thanks to the CFD analysis, Vicoma was able to improve the original design.
Several departments and specialties from Vicoma were involved in the project. The mechanical department provided support for the piping. The weight, the diameter of the piping (DN300), and the limited space presented additional challenges. A new design led to an improved assembly method between the supports and the frame.
The Electrical & Instrumentation (E&I) department streamlined the electrical installation. They were responsible for new terminal boxes with nearly 2,150 terminals, proper cable routing, and assembling the control cabinets for the hydraulic drive of the walking mechanism.
Finally, machine safety was enhanced with machine guarding in accordance with the latest safety standards.
Result
The hot strip mill successfully put a state-of-the-art walking beam furnace into operation, meeting the latest regulations. Significant attention was also given to improving the conditions for cleaning and maintenance activities.
The collaboration with both the client and other engineering partners (Stemar, responsible for the walking frame, and Pentacon, responsible for the water tanks and clash controls between the three engineering firms) went very well. The parties saw each other not as competitors but as partners. Thanks to clash control, weekly meetings, and the trust of the client, decisions could be made quickly. This contributed to a successful project. The project team was even invited for a tour and a small celebration to mark the successful completion.