9th ECCC European Continuous Casting Conference – ECCC 2017

For the casting of Nb-mikroalloyed steels with C- content >0.09 mass-% the transverse crack formation on the slab surface is a big problem. The production practice at voestalpine shows that these crack formation is dependent on the content of microlalloyed elements like Nb, Al, B, V and N -content. Higher content of micro alloyed element causes more crack formation. In the present work, precipitation behavior like Nb(C,N) , B(N) and AlN in Nb-alloyed steel slabs has been systematically investigated with the help of the dissolution technology which is developed at voestalpine. The Investigation shows that the distribution of precipitate in slabs is different from broad side to narrow side, from slab surface to slab center. The influence of steel composition on the precipitation is identified. In order to understand the precipitation behavior, the numerical simulation was applied to understand the precipitation mechanism, especially about distribution of the precipitate in the casting slab.