Rotary de-scaling upstream of the tunnel furnace aims at the removal of heterogeneously distributed scale as well as residuals of casting slag.

It can be used to check the flexibility of the convection section when the feed and operation condition changes, and it can be used to design the cracking furnace of different scale and feedstocks.

On the one hand, this should suppress scale pick-up on the tunnel furnace rollers which may lead to so-called depressions on the slab bottom side.