The Role of Grain Boundary Oxidation on Surface Crack Formation under Continuous Casting Conditions

This paper represents an extended abstract of a study presented at the ESTAD 2019 conference. In this contribution, the influence of different cooling strategies on the formation of intergranular surface cracks is observed with in-situ bending experiments under continuous casting conditions. The steel composition is equal to a 0.17 wt.% C construction steel. It is investigated with and without Al deoxidation at bending temperatures of 1100 °C to 700 °C. The results show the most critical situation prevailed for each testing condition at 900 °C. A holding temperature of 1200 °C leads to a selective grain boundary oxidation and therefore to the formation of notches at the austenite grain boundaries, which are the cause for stress concentrations and easier formation of cracks during a subsequent tensile deformation at critical temperatures. The experiments reveal a partially stronger influence of this phenomenon on the steel without Al deoxidation.