Coquille (engineering)
Molds are reusable molds for casting ( die casting ) of metals and alloys. A mold can be closed when the block casting in continuous casting down or bottom open.
Molds in ingot casting
A mold for the block casting consists of a mold geometrically simply held usually made of ductile iron, which can be reused. To this end, the sides are beveled to easily detach the block after 1-30 hours setting time from the mold. These molds are used today mainly for large forging blanks. In addition, ingot casting is used in hard castable alloys and lower production volumes. The cast is ascending because of the higher quality, the metal is so filled by a delivery from below into your molds often standing as a team. When it comes falling cast by metal splashes surface defects.
Molds in continuous casting
A mold for the continuous casting other hand consists of water-cooled copper plates ( mold plate ) or copper pipe ( Mould ). Copper is used because it can derive the heat from the steel to be cast much better than, for example, steel.
In the continuously cast slabs for sheet metal products and billets are cast with round and square format for wire, rod and profile products.
When slab casting a distinction between the narrow and the broad sides. The narrow sides are for the purpose of adjusting the width to be cast slabs adjustable. The hydraulically or mechanically hired by spring force broadsides are this relaxed to allow the adjustment of the narrow sides. An adjustment of the narrow sides can therefore be carried out during the casting operation. After adjustment to the desired new width of the initial clamping force is restored.
The narrow sides are tapered, that is, stand up further apart than the bottom. This is necessary because the liquid steel is cooled so much in the mold that it forms a thin shell and contracts there. Had the narrow sides not employed conical, the string would no longer be performed in the lower region of the mold and it would no longer heat dissipation possible. The very thin shell would melt through the liquid core again and tear. In this case, the liquid core of the strand would break the strand shell and into the casting arc and thus cause system downtime from hours to days. The conicity of the narrow sides, mainly depends on the format width and the quality of steel to be cast. Simplified speaking, the broader is the format to be cast, the greater the Schmalseitenkonizität is set.
During casting the mold is oscillated vertically. This is necessary so that the strand shell which forms does not stick to the copper plates. The cast slabs have therefore - particularly on the narrow sides - the so-called oscillation marks.
To prevent sticking in the mold, will also be deposited on the steel bath in the mold mold powder ( release agent). This mold powder contains appropriate substances which prevent the sticking of the strand to the copper plates. Due to the oscillation reaches the molten mold powder between strand shell and copper plates. The mold powder also has the function to complete the liquid steel from the surrounding air, as this would react with the air and thus influences the quality of steel.
The slabs may be cast, vary in width and thickness. With conventional molds typically 200 to 400 mm are produced thick and up to 2000 mm wide slabs. Since the early 90s Dünnbrammenkokillen also be used with which slabs are poured from 45 to 90 mm thickness and up to 2000 mm width. There are also special constructions like for up to 3300 mm wide slabs at 150 mm thickness.
To improve product quality, some molds are rarely equipped with electromagnetic brakes with electromagnetic stirrers. These consist of coils with which the magnetic fields are generated, which influence the flow conditions within the steel bath in the mold. These means may either be permanently installed on the mold or may be devices that are moved up after the insertion of the mold in the molding machine to the hydraulic mold.
The mold for billet continuous casting are not adjustable, but must be replaced with format changes. The molds are symmetrical and thus on all sides tapered. The stick formats vary 130-240 mm square and 150 to 300 mm round. Furthermore, there are sometimes also intermediate formats for slab casting.
Next, as in the tube region Beam blank formats (H format ) can be used to cast for both the carrier plate area.