Hilchenbach, July 24, 2017

ArcelorMittal Gent: New mill stands for new products

Modernization of hot strip mill

With this modernization ArcelorMittal is preparing its hot strip mill in Ghent, Belgium, to be able to meet future requirements. The most important objective is the enlargement of the product portfolio in the eld of high-strength grades and multi-phase steels. At its Ghent location, ArcelorMittal is enhancing the production of strips of the newly developed Fortiform® series which covers new steel grades for the automotive industry and comes with a considerable reduction in weight, at the same time providing an increased level of safety. In addition, ArcelorMittal is striving for more flexibility in production and wants to be able to increase its hot strip capacity at the Ghent site, if and when necessary.

The upgrade focuses on the finishing mill of the plant, which was commissioned in 1967, and comprises the installation of new finishing stands F1 and F2 as well as modifications to boost the rolling forces of mill stands F3 and F4 plus the integration of hydraulic loopers throughout the complete finishing mill. In the recent past, SMS group already strengthened the drive trains of mill stands F1 to F3 by installing new main and mill pinion gear units and powerful SIEFLEX® HT spindles (high torque spindles) and supplied a new profile, contour and flatness control system (PCFC®) for the finishing mill.

Higher rolling forces in F3 and F4

An essential reason for awarding the contract for this comprehensive and complex modernization project to SMS group was the convincing conversion concept. To keep the need for restricting the production process as little as possible and to ensure a reliable production start after completion of the conversion work, a modernization concept providing for two shutdowns was prepared.

The first shutdown was in December 2015 and lasted 14 days, as scheduled. Measures primarily focused on mill stands F3 and F4 which received new hydraulic adjustment cylinders able to produce an effective rolling force of 45 MN. The mechanical adjusting equipment was reinforced. The internal faces of the mill housings were remilled, and the housing clearance was adapted by installing new wear plates. To absorb the higher rolling forces now attainable, SMS group retrofitted oil film bearings of the SMS brand X-Roll® Oil Bearing. In the course of that shutdown, too, the electromechanical looper downstream F6 was replaced by a hydraulic one. The new hydraulic loopers for mill stands F3 to F5 will be installed in autumn 2016 during short downtimes.

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Conversion measures at a glance: The new mill stands respective components are marked in red.
Replacement of mill stands F1 and F2

The main conversion work in the hot strip mill will be performed at the end of 2016 and comprises the removal of the existing mill stands F1 and F2 and their replacement by new and stronger ones which come with powerful actuators such as hydraulic adjustment and CVC® plus, including work roll shifting and bending systems. These actuators will be integrated in the existing PCFC® model and thus permit the strip geometry to be influenced right from the first finishing stand. Thanks to a rolling force of 50 MN per mill stand, it will be possible to attain high reductions in the first mill stands even when high-strength steel grades are rolled.

ArcelorMittal performing tests in SMS group workshop

Since March, big preparations have been underway for the next conversion shutdown. To ensure minimum downtime, almost no remachining work at mill stands and a fast ramp-up, both new mill stands were pre-assembled in the SMS group’s Hilchenbach workshop and the mechanical and hydraulic equipment tested for proper functioning.

In June and July, ArcelorMittal Gent had the opportunity to test the mill stand functions such as adjustment and balancing systems or the entry and exit guides by itself. This was accomplished by involving the automation system installed at the hot strip mill and thus permitted the mechanical equipment and the automation system to be harmonized already in advance.

Once the tests will have been completed, the mill stands will be transported to Ghent and, in September, be assembled adjacent to the mill. The customer will test the equipment again before the second shutdown in mid-November. The first step will be to remove the old mill stands F1 and F2 and then to shift the pre-assembled new ones to these positions in the finishing mill. The new mill stands will be installed with a minimum number of changes to the environment and re-using existing plant components such as the media pump station. The hot strip mill is scheduled to roll its first coil at the beginning of December 2016.