An internship assignment by Camile Hol, Hai Wu, Jan de Roo, and Nanda Mandagi
Tata Steel has many continuous processing lines to produce coated and un-coated strip products for many demanding markets worldwide. Figure 1 shows an example of the processing lines where the strip passes through the furnace section in multiple passages guided by the transport rolls positioned alternately at the top and at the bottom. The strip is transported under high tension in order to maintain the position of the strip at the centre of the rolls. For the same purpose, the rolls with a certain profile (Figure 2) are used in the lines. The profiles are chosen such that they generate centring forces when the strip is under the tension.
A drawback of the convex roll profile is that the centring force can become excessive and cause unwanted buckling effects. It happens often in the furnace at the elevated temperatures, therefore called heat buckles as shown in Figure 3. The magnitude of this centring force is determined by the convexity of the profile, the process conditions such as applied tension and temperatures, and the strip properties such as dimensions and material properties. It is important during the production to maintain the balance between having an adequate tracking control and avoiding the formation of buckles. To improve the understanding and control results, a numerical buckling model has been developed in Tata Steel to calculate the pre-buckling stress distribution with the aforementioned parameters as the model input. The model needs to be validated.
The aim of this assignment is to design a test method to study the buckling behaviour of the steel strip and to collect the data to validate the model. An overview of the planned activities is as follow:
The assignment is intended for an internship of three months. Following works on modelling and industrial application are foreseen upon review.
 Chang Tiezhu, Zhang Qingdong, Analysis and simulation of strip transverse buckling in CAPL, Rev. Met. Paris, Vol. 106, N°6 (June 2009), pp. 257-263
Research & Development – Rolling, Finishing and Measurement
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