Beschreibung:
The aim of the project was to set up a continuous rolling mill with a practical layout in order to determine strip properties of future rolling trains at laboratory scale. Such a rolling mill has been designed, set up and tested. The pilot mill comprises four rolling stands arranged in one line so roughing is possible with one reversing two-high stand, followed by continuous finishing with all stands. Rolling speeds of up to 20 m/s in the last stand allow deformation rates of more than 800s-1 depending on the degree of deformation. Starting with 45 mm samples, a strip with a final thickness of 1.0 to 6 mm and a width of up to 110 mm can be rolled. Samples are heated in an inductor allowing fast heating to 1 350°C. Chamber furnaces are used for temperature equalisation. The pilot rolling mill is furthermore equipped with descaler, rolling gap lubrication, inter-stand cooling, cooling line with water and air cooling, furnaces to stimulate coiling respectively. There is a coiler with heatable coilbox for simulation purposes. The other focus of the project was the investigation of the influence of rolling conditions on the properties of hot strip and derived cold strip from ULC- IF- and LC-, HSLA (LC+Nb)- and ELC (with/without Co, Cr) steel grades. The following parameters were varied to investigate their impact on strip properties: reheating temperature, finishing temperature, rolling speed, deformation rate, rolling direction (reversing and continuous), roll diameter, cooling conditions, coil temperature, and rolls with roll gap lubrication. The determined parameters were microstructure, texture and mechanical properties. An influence of the rolling technology, i.e. rolling either on a single stand or on the pilot mill, and the rolling (speed) conditions on the properties of the hot strip was observed.