Steel Mill Heavy-Plate Leveler Refurbishing Project Experience

February 2, 2024

Steel mills are industrial plants from which finished steel products such as steel plates, tubes, and pipes are produced. Steelmaking is a complex process involving several steps to transform molten pig iron into refined steel products meeting the client’s specifications.

Given the importance of each step in the steelmaking process, interruptions to production caused by equipment failure at one stage of steelmaking can impact the productivity of the entire steel mill. This interruption can result in substantial economic losses, delays, production overtime, and client dissatisfaction. Equipment at steel mills must be monitored and kept in good working condition to prevent these outcomes and maintain plant productivity.

Heavy-Plate Leveler Project

Our engineers completed a refurbishing and upgrade project of a heavy-plate leveler, a machine equipped with a series of rollers and presses to remove deformities in steel plates for a global-scale steel mill in South Korea. The heavy-plate leveler is a critical component in the production of steel plates, and our engineers were retained to refurbish the heavy-plate leveler due to decreased performance and visible signs of damage to the equipment.

Existing plate mill at DKC Steel plant prior to refurbishing project — Existing Plate Mill Prior to Refurbishing

Project Scope and Outcomes

Our engineers performed an initial inspection and diagnosis of problems, the redesign and replacement of equipment parts, a final quality inspection, and recommissioning as part of the project scope. The project resulted in improved equipment performance, longer equipment lifespan, and greater maintainability. A notable outcome was that the refurbishment increased the press capacity (maximum applied force by the press) from 800 tons to 900 tons.

Major Equipment Issues Identified

Mitigating Measure Taken and Outcome

Bending of the lower base frame; the existing main frame was made of one piece and the upper plate of the frame could not be calibrated independently from the lower plate

The one-piece frame was replaced with separate upper and lower plates to eliminate bending in the frame

Breakage of the hydraulic piping line caused during operation due to the loosening of the hydraulic cylinder tie rods (bolts)

Change of cylinder tie rod (bolt) material, resulting in a 50% increase in tensile strength to allow the hydraulic cylinder to withstand increased pressures without coming apart

Inefficient operation due to a lack of control of hydraulic pumps (i.e., pumps for the hydraulic system operating presses)

Replacement of a two-stage pressure control system using two pumps with one Variable Displacement Pump with horsepower control, resulting in more efficient operation

A lack of control of the main cylinder speed

Design changes were made to the main cylinder to allow for speed control, resulting in improved equipment operability

Possibility of damage to equipment in the hydraulic system caused by pressure conditions exceeding component limits

A relief valve was installed in the hydraulic circuit to prevent high-pressure conditions from occurring

To allow the hydraulic system to withstand higher operating pressures, our team of engineers successfully proposed the replacement of the flanges in the hydraulic circuit. The refurbishing project increased the operating pressure of the system from 250 bar to 280 bar.

flanges for hydraulic ports on plate mill — Existing SSA Flange, 210 bar rating (left), New SAE Flange, 420 bar rating (right)

Engineering Services and Manufacturing Solutions for the Steelmaking Industry on US Korea Hotlink

LPR Global offers steel mill design and fabrication services including, equipment fabrication for heavy plate rolling mills, hot strip mills, and section mills.

Steel Making Plant Design & Fabrication Project References

Our steel mill equipment offerings include cut-to-length and slitting lines, forged steel rolls, large bore hydraulic cylinders, process pipe spools, and steel frames and roll change cars.

Our extensive range of steel mill products and services attests to our technical expertise; please contact us for solutions to your steel mill equipment needs.

Arvola, D. A. (2018). Grain refinement of high alloy stainless steels in sand and directionally solidified castings. Missouri University of Science and Technology Scholars’ Mine. https://scholarsmine.mst.edu/masters_theses/7793/

De Oliveira, U., de Souza, H., Menezes, C., & Rocha, H. (2023). Straightening Machine Preventive Maintenance Intervention Plan based on AHP: A case study in a steel company in Brazil. Operations Management Research, 16(3), 1577–1593. https://doi.org/10.1007/s12063-023-00368-x