Double-jet cooling device for semicontinuous vertical casting mould
View Patent ↗The subject matter of the invention is a device for the direct cooling of a mould for the vertical semicontinuous casting of rolling ingots or extrusion billets ( 3 ) with gradual quenching by double jet ( 4 and 5 ), the first at substantially 32° and second at substantially 22°, simultaneously and delivering substantially the same flow rates and speeds from a single liquid chamber ( 2 ). Another subject of the invention is a method using said device, with or without graphite insert ( 1 ) on the working faces and in association with various bottom block configurations.
1. Device for cooling a vertical semicontinuous casting mould with direct cooling of rolling ingots or extrusion billets, comprising two rows of holes, disposed over the whole of the internal perimeter of the mould cavity, in a lower part thereof where the ingot or billet exits, each of the rows of holes being situated close to a plane perpendicular to the vertical axis of said mould, wherein:
a) the two rows of holes are connected to a single cooling-liquid chamber provided in the body of said mould, wherein said single cooling-liquid chamber does not include a valve,
b) the first row of said holes, which is highest in the vertical mould, or furthest upstream with regard to dispensing of the liquid onto the ingot surface, is connected to said chamber by channels for dispensing jets of said cooling liquid onto said ingot or billet with an angle of incidence of 32±5 degrees with respect to the vertical axis of the mould,
c) the second row of said holes, which is lowest in the vertical mould, or furthest downstream with regard to the dispensing of the liquid, is connected to said chamber by channels for dispensing jets of said cooling liquid over said ingot or billet with an angle of incidence of 22±5 degrees with respect to the vertical axis of the mould,
d) the holes in the second row, the lowest or furthest downstream with regard to the dispensing of the liquid, are disposed substantially on a bisection of a gap between two holes in the first row, which is highest and/or the furthest upstream, relative to the vertical axis of the mould,
wherein the diameters of the holes are substantially equal, on the same row and between two rows, in order to be able to simultaneously dispense said liquid with flow rates and speeds substantially equal over the two rows of holes, both during a start-up phase and during a permanent casting regime.
2. Cooling device according to one of claim 1 , wherein the two rows of holes are disposed with respect to each other so as to produce jets which, if they are straight, form, at any moment during casting, both during start-up and during permanent regime, impacts on a substantially vertical surface containing a working face of the mould, spaced apart from one another by a distance of from 10 to 40 mm in a vertical direction.
3. Cooling device according to claim 1 , wherein the diameter of each of said holes in each row is 3 mm±1 mm.
4. Cooling device according to claim 1 , wherein spacing between two adjacent holes on the same row is from 10 to 30 mm.
5. Method for using the cooling device according to claim 1 for vertical semicontinuous casting with direct cooling of rolling ingots and/or extrusion billets, said method comprising permitting total flow rate of cooling water for all the holes in the two rows, which is flow leaving the cooling liquid chamber, to be from 0.3 to 0.8 liters/minute per linear cm of mould perimeter, at the beginning of a transient casting start-up phase, which is a phase during which flow of cooling liquid and the casting speed have not reached a steady state value, and then raising flow to a required flow rate for a permanent casting regime.
6. Method according to claim 5 , wherein said flow rate of water at the beginning of the transient casting start-up phase is from 0.4 to 0.6 liters/cm/min.
7. Method according to claim 5 , wherein the cooling liquid is brought simultaneously to all the holes in the two rows during the casting start-up phase.
8. Method for using a cooling device according to claim 5 , for vertical semicontinuous casting of rolling ingots, comprising using a slab casting mould provided with a flat bottom block with edges which lie in a substantially horizontal plane.
9. Method for using a cooling device according to claim 5 , for vertical semicontinuous casting of rolling ingots, comprising using a slab casting mould provided with a curved bottom block, so that a middle portion of rolling faces of a product is, during the casting start-up phase, subjected to direct cooling by cooling liquid while regions of a rolling face furthest from the middle portion thereof have not yet left the mould.
10. Method according to claim 5 , for the vertical semicontinuous casting of rolling ingots, comprising using a casting mould provided with a flat bottom block with a curved edge, so that a middle portion of faces of products is, during the casting start-up phase, subjected to direct cooling by cooling liquid before regions of the rolling face furthest from the middle portion have left the mould.
11. Method for using a cooling device for vertical semicontinuous casting with direct cooling of rolling ingots and/or extrusion billets according to claim 5 , comprising using a casting mould provided, on a working surface thereof, with a graphite insert.
12. Cooling device according to claim 1 , wherein spacing between two adjacent holes on the same row is from 10 to 40 mm.