Simulation-aided design of hot rolling production processes of asymmetric sectioned profile and effect of cooling conditions on product properties

The fact that iron-steel consumption is one of the most important actors of the country in iron and steel production in the world and that one of the indicators of the development level of a country is iron and steel consumption increases the importance of this sector. In the recent years, where global competition has increased significantly, it has become necessary to carry out research and development activities for the hot rolling process, which is the most commonly used plastic forming method for mass production in the iron and steel industry. It is foreseen that it can compete with international competitors with the advantage of increasing quality and efficiency due to the reduction of raw materials, energy and labor losses which are the main input in hot rolling. In this thesis, the rolling pass to be used is designed with traditional methods and then controlled rolling simulations are performed by using a simulation program which calculates according to the finite element method to obtain an asymmetric profile with low carbon-micro alloy steel raw material used in ship structures. Simulation supported production studies were carried out to eliminate production defects, stress-strain curves, forces acting on rollers and torque requirements at the inlet and outlet of the rollers. In order to improve the mechanical properties of the final product, optimization of the production parameters was carried out. The production parameters obtained from the simulation supported activities were used in prototype production and after the production, the profile was applied to the production samples in order to cool down in different cooling environments. In general, the tensile strength, parallel to the cooling rate increased, while the value of the notch impact decreased. In the phase distribution of microstructure images taken from the samples; It has been observed that perlite phase which multiplies in the structure together with the change in cooling rate and mechanical values is the main factor.