Abstract
When surface cracks on continuous casted slab were observed by a microscope, internal oxidation layers were sometimes present along the cracks. These layers that were called subscales were paid attention. The subscale was formed in steam atmosphere in laboratory for considering of the generated mechanism of the surface crack.
The results are summarized as follows,
(1) The subscale was the internal oxidation layer where the generated rate of scale was greatly reduced.
(2) The thickness of the subscale depended on the temperature and the time, and that was calculated by the internal oxidation theory.
(3) The type and the diameter of particles in the subscale also depended on the temperature.
(4) Therefore, the surface crack formed temperature and position in the continuous caster were able to decide by the observation of the subscale.
