Eigenspannungen am Betonstahl

In many thermomechanical manufacturing processes, residual stresses arise in the material that are present without any external load. These residual stresses can significantly influence the mechanical properties of a component and therefore also its service life. It is therefore of great importance to gain a precise understanding of the stress distribution in the components. In this thesis, a reinforcing steel sample from Marienhütte Graz is examined in order to analyse the residual stresses and the hardness of the material. These residual stresses are released using the sectioning method on samples from different process points. Samples are cut using a specific cutting technique. The sections show the subsequent distortion and displacements that occur due to the residual stresses. The cantilever beam calculation can be used to draw conclusions about the residual stresses. The results of the sectioning process show that the various process steps such as rolling the rib mould, coiling and straightening lead to deformations and thus residual stresses in the samples. Hardness mapping can be used to analyse the hardness distribution of the reinforcing steel across the surface. The results show an increased hardness in the outer edge area of the samples, while the core has a lower hardness.