4.1 million tons per year for a wide range of quality flat products

by Hans Diederichs

HBIS Laoting successfully commissions high-performance hot strip mill

The new high-performance hot strip mill supplied by SMS group has successfully started production at HBIS Laoting Iron & Steel Co. Ltd. in China. With this facility, HBIS Group, a leading steel producer in China, has set up a new, ultra-modern production facility for flat products at the Laoting location.

The high-performance hot strip mill has an annual capacity of 4.1 million tons and produces hot coils with widths of up to 1,900 millimeters. Final thicknesses range between 1.2 and 25.4 millimeters. The product mix includes besides low-alloy carbon steels, high-strength automotive grades, weather-resistant structural and container steels, pipe grades, boiler and pressure vessel steels and steels for use in ship and bridge construction.

The hot strip mill comprises as main equipment a roughing mill descaler, a slab-sizing press, a two-high reversing roughing mill, a four-high reversing roughing mill with attached edger, a mandrel-less coilbox and a crop shear, and at the finishing end a descaler, a seven-stand finishing mill and a laminar cooling system. Three downcoilers produce straight-edged coils of finished hot strip. Downcoiler No. 3 has been specifically designed for the challenging task of coiling thick, high-strength strips.

The described system configuration provides HBIS Laoting maximum flexibility in planning and production. For example, the slab sizing press in the entry area of the hot-strip roughing mill enables a width reduction of up to 350 millimeters.

The two high-performance roughing stands allow a high degree of flexibility in the distribution of pass reductions. The finishing stands come with rolling forces of 52 MN (F1-F4) and 40 MN (F5-F7). All stands - equipped with hydraulic roll gap adjustment – achieve tightest tolerances. For optimum profile, contour and flatness of the strip, the stands are equipped with the proven CVC®plus system (Continuously Variable Crown) with integrated work roll bending.

A laminar cooling line of the latest generation in the exit area of the finishing mill provides high flexibility and a wide range of cooling rates in setting the required mechanical properties for all grades and dimensions within narrow tolerances. The higher flow rates in the rear part of the cooling section also facilitate the production of multi-phase steels.

HBIS Laoting Iron & Steel is very satisfied with the rapid commissioning process and the excellent quality of the hot strip mill.

Source and photo: SMS group

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