Research of coil break

One of the deficiency which can be seen at production of the plates after rolling is the coil breaks. Coil breaks exists at a vertically and untidy time breaks meanwhile hot rolled middle carbon contained steel coils at the cutting lines. The aim of this thesis is to emphasize the reasons for the existence of coil breaks and to show how effective is the grain growth on the coil breaks. This work contains SEM tests and finite elements analysis. By the help of the comparing results of SEM analysis and grain size, grain growth has been observed at the inner part of the coil which is effected by the high temperature. Since the parts which have bigger grain size will be exposed to more deformation breaks at lower stress, it is more often possible to see coil breaks at the inner side of the coil. There is an inverse ratio between the coil radius and cooling time so an increase of coil radius has an inverse effect on cooling time. As a result, by the exposure of high temperature within a more time an growth will be observed at the grain radius so the risk of coil break appearance increases. Key Words : Coil, break