Figure 1: Schematic view of the individual process steps for the production of hot-rolled strip
Figure 2: Schematic view of the individual process steps and the corresponding temperature curves
clically; the individual process steps interact via this profile. Possible deviations from the temperature profile due to disturbances are corrected by controller actions of the Integrated Temperature Model (ITM) under consideration of the plant limits and the microstructure. The coupled Microstructure Property Model (MPM) calculates the components and the mechanical properties of the hot strip as a result of its thermal and mechanical treatment in the overall process. This concept extends the possibilities to improve the desired mechanical properties with the Microstructure Properties Optimizer. The advantages of additional plant components, such as a transfer bar cooling system and compact cooling, may be analyzed and optimized quantitatively by this integrated temperature model in order to realize a gain in production and product quality. The production of hot-rolled strip takes place in individual process steps
MPT International / December 2020
which are executed one after the other. In a hot strip mill, the slabs are first pre-heated to the required processing temperature; during the process of roughing-down a specified transfer bar thickness is achieved. Subsequent rolling in the downstream finishing stands then results in the desired final geometry. The hot-rolled strip is then cooled down to a defined target temperature in the cooling section. For further processing and transport, the strip is then coiled on the coiler unit, see Figure 1. In the individual processing steps, adherence to the setpoint
values is of utmost importance. Only in this way can the desired product quality be ensured. Among other factors, the size (thickness, width) and temperature must be precisely set. For this purpose, prediction models are used which – based on physical and empirical equations – determine the energy and work as well as the coolant flow rate for the individual process steps required to obtain a certain product with the desired size and temperature [1] – [5]. SMS uses the following models to describe the individual processing steps:
Figure 3: Illustration of problematic temperature control on the finishing mill and coiler pyrometers
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