SMS Group (Düsseldorf, Germany):

Wiens O., Dr. Eng., e-mail: oviver.wiens@sms-group.com
Moβner W.

Defects of the surdace of continuously cast billets (e.g. longitudinal cracks) have very negative effect on product quality and can cause breakage of continuous caster. Solidification processes occurring in a mould are characterized by complicated and dynamic features, because many phases originate depending on steel grade. It is established that the materials using in moulds should have both high thermal conductivity and high hardness in optimal combination. It can be solved by choice of the most efficient coatings for moulds. The mould coatings described in this article allow to decrease substantially mould surface wear. Service life of wide plates has increased by 2.5 times and more, while resistance of narrow plates — by 3.5 times in average. It was shown that wear of the experimental plates was not complete. It is concluded that it is expedient to use Uniguard metal ceramic coating in slab continuous casters for critically hard steel grades. It is based on the fact that surface layer solidifies according to the constant procedure and in uniform mode along the mould perimeter, and that lowers compression stresses and forming of longitudinal cracks.

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