Modernized medium section mill for Hyundai Steel

Magazine3 Min

After having been in operation for more than 25 years, SMS group upgraded the existing medium section mill at Hyundai Steel at the Pohang site to make sure that the old plant also meets today’s requirements – particularly the high standards of Hyundai Motor regarding quality and precision.

To achieve this, the intermediate and finishing stand group has been equipped and rebuilt with four new hydraulically adjusted stands and associated automation and control system. In addition to that, the profile measuring device PROGAUGE has been integrated and new roll changing units were installed.

The semi-continuous medium section mill comprises furnace, high-pressure descaler and downstream breakdown mill stand. During reversing rolling, the positioning of rolled material into various roll grooves is realized by a displacement and bloom reversing device.

Modernization experts of SMS group have analyzed the entire process and developed an investment-friendly solution for Hyundai. Only the last four of the twelve finishing stands had to be replaced by HCS stands (Hydraulic Compact Stand) with hydraulic adjustment to assure that the required tolerance values of Hyundai Motor are attained. Due to customized engineering the base plates could be reused to keep foundation costs as small as possible.

The intermediate and finishing stand group in operation for more than 25 years consists of a total of twelve stands. For maximum flexibility, stands in UD design – i.e. usable as universal and two-high stands – as well as tilting stands are employed.

With four new and eight remaining stands Hyundai Steel operates the plant in five rolling modes for the production of H-beams, unequal and equal-sided angles, tank-track elements and precision round bars. After the upgrade, especially the rounds reveal a dimensional accuracy corresponding to one fourth of the specified DIN tolerance range.

Compliance with the tolerances and the surface quality is scanned completely by means of non-contact PROGAUGE laser technology. Up to 500 scans per second are done. PROGAUGE controls the hydraulic adjustments of stands 11 and 12 in closed loops fully automatically to compensate deviations in the rolled material within fractions of a second. In addition to that, PROGAUGE provides a system for surface flaw detection called SurfTec.