HPO

Impol Seval orders revamp of its hot rolling mill

Impol Seval Valjaonica Aluminijuma Sevojno, Serbia, has placed an order with SMS for a comprehensive revamp of the aluminum hot rolling mill supplied by Schloemann in 1972. The main objectives of the revamp are an increase in production and improvement in quality of the rolled strips as regards thickness and shape tolerances.

Thanks to the integration of the entry-side coiler into the production process, in future it will be possible to work with three coiling passes rather than only one as previously, thus enhancing the efficiency. To enable the mill to also roll large ingots, the entry and exit sections will be completely rebuilt. The positions of both coilers will be shifted and raised, to allow larger coil diameters to be wound. On both sides, the belt wrappers, pinch rolls and side guards will be renewed and adapted. At the exit end, a new trimming shear will be installed. It will be coordinated with the higher exit speed resulting from the reduced final gage of down to 3.5 mm.

The scope of supply includes a new X-ray measuring unit, which will measure the strip gage and shape over the strip width. The measured data will be used as the input variables for the technological control systems. In the millstand itself, new cooling headers will be installed, partly for the purpose of ensuring roll-gap lubrication and partly for allowing optimum distribution of the rolling emulsion for cooling the work rolls. The adjustable cooling patterns are an important actuator for achieving constant strip shape. The capacity of the emulsion system will be increased by approx. 30 %. In future, negative bending of the work roll, i. e. a convex setting of the roll gap, will be possible thanks to the installation of additional bending cylinders in the chocks of the backup rolls. Optimum strip geometry can thus be achieved, even in case of an increasing thermal crown of the work rolls. For cleaning the rolls, a high-pressure system is to be installed as a replacement for the rotating roll brushes used hitherto. Emulsion will be sprayed onto the rolls at a pressure of up to 1,000 bar, which ensures that deposits and adhering aluminium residues are reliably removed from the roll surfaces.

The heart of the new mill will be the new automation system, AluControl. It will comprise the technological control systems and the level 2 process models. Via a link to the existing production planning system, level 2 will receive all of the product data and, depending on the thermal condition, calculate the optimum pass schedule and mill setting values in each case. The level 1 control systems ensure that the specified close tolerances for strip gage and shape will be achieved. All plant data and process information will be displayed in the new visualization system in a user-friendly manner. AluControl has been developed at SMS over the past few years as an automation package that is specially suited to the requirements of hot and cold rolling of aluminum. AluControl has proven its value in more than 20 installations since 2012, in new plant projects and revamps alike, and enhancements to the system have been consistently implemented in practical application.

The hot rolling mill will be revamped in two stages. An initial plant shutdown in the spring of 2017 will be followed by a second shutdown after six months of interim operation. When commissioning takes place at the end of 2017, the mill will be changed over completely to the new AluControl system.

(Source: SMS group)

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