Abstract: New generation of steel casting processes allow to increase the production rate but they cause some imperfections instance. The main detrimental defects of metallurgical products generally occur during their solidification and cooling. The thermomechanical loadings undergone by the steel form the liquid state must be consequently considered with care. In this context, it is necessary to design some thermomechanical tests that dedicate to study the defectology products and the hot brittleness of steels. Hot mechanical tests use some notched axisymetric specimens and are able to reproduce the real material history. The analyses mainly allow to generate objectives thermomechanical stresses of the strand casting product and know some sensibility parameters on the failure instance. Contributions are relative to the hot ductility and micro or macrosegregation bonds and effects of strain during solidification on the cracks instances. The present results have been obtained from two types of procedure: tensile strain and contraction tests. These procedures are used to determine behaviour of continuous casting steels and cooling rate effects. Contributions are mainly relative to the hot ductility.

Key words: Hot ductility, Continuous casting, In situ solidification, Tensile test, Contraction test