At the beginning of a steelprofile’s production stands the continous casting of a steel melt into a vertical placed formative pipe-, block- or slab moulds amde of copper. The mould pipe is cooled form the outside. Thereby the mould is constructed in a manner that the outgoing profile is bent in a circuit of 6-10 m and therefore can be directed over rolls into a horizontal position. The length of the mould whose shaping of the fluent melt is already hard on the outer steel profile is preferably between 500 and 1000m.
The steel is even shrinking already in the solid area. It would loose its contact to the cooled mould wall and risk the breaking of the thin and hard outer skin if this wasn’t compensated by the inner room’s conicity of 1,1%.
Through retracting of the starting chain the Cu-mould pipe gets damaged on the lower areas so much that is has to be worked off again after a certain idle time.
For specific measurements, for example small square shapes (130 * 130 mm) a mending is not quite profitable. Those are produced cost-efficient in higher piece numbers as “disposable mould”. Mendings are possible here but not quite profitable.
If the dimension is larger, however, and the design more complicated a mending galvanization has proved to be beneficial. The damaged mould is dechromed and purged and, afterwards, activated and galvanized inside until the copper layer is 2-5 mm thick. Partial damages are “refilled” and after a mechanical treatmeant the mould has its original contour again.
In this manner we also already achieved changes of geometry (e.g. octagon to round mould).
This process can be repeated many times as long as changes on base mould or main material don’t get into the way.
Another advantage of mending a mould is the fact that it has already its thermal final state. Erratic geometric changes as well as “driven into” moulds just don’t happen anymore.
Galvano-T conducts this kind of mending for more than 10 years now and we believe to have reached a rather high process reliability.