The new high-performance hot strip mill supplied by SMS at HBIS Laoting Iron & Steel Co. Ltd. in China has successfully started operation. With HBIS Laoting, the HBIS Group, which is one of the leading steel producers in China, has built a new state-of-the-art production facility for flat products at its site in Laoting.
The high-performance hot strip mill supplied by the SMS Group has an annual capacity of 4.1 million tons and produces hot rolled coils with widths of up to 1,900 millimeters. The range of final thicknesses is between 1.20 and 25.40 millimetres.
In addition to low-alloy carbon steels, the broad product range also includes high-strength automotive grades, weather-resistant structural and container steels, tube grades, boiler and pressure vessel steels as well as steels for use in shipbuilding and bridge construction.
The main units of the hot strip mill are a roughing mill scale washer, a slab upsetting press, a duo reversing roughing stand, a quarto reversing roughing stand with upsetting device, a mandrel-less coil box, a cropping shear, a finishing mill scale washer, the finishing train with seven finishing stands and a laminar cooling system. Three underfloor coilers wind the finished hot-rolled strip straight up on edge. For the high demands of winding thick, high-strength strips, reel no. 3 is a particularly efficient device.
The system configuration described allows HBIS Laoting maximum planning and manufacturing flexibility. For example, the slab upsetting press in the inlet area of the hot strip roughing train allows a width reduction of 350 millimeters. The two high-performance roughing stands allow a high degree of flexibility in stitch distribution. The finishing stands have rolling forces of 52 MN (F1-F4) and 40 MN (F5-F7). To achieve the tightest thickness tolerances, all stands are equipped with hydraulic adjustments.
The precise adjustment of strip profile, contour and flatness is achieved by means of the proven CVCplus system (Continuously Variable Crown) with integrated work roll bending. In the outlet area of the finishing line there is a laminar cooling line of the latest generation. Due to its high flexibility and wide range of cooling rates, the required mechanical properties for all materials and dimensions can be set within narrow tolerances.
The controlled and flow-monitored higher water quantities in the rear area of the cooling section also enable improved production of multiphase steels. HBIS Laoting Iron & Steel is very satisfied with the speedy start-up and the excellent quality of the hot strip mill.