LU86693A1 - Device and method for casting metals in plastic phase - improving grain structure and reducing segregation - Google Patents

Abstract

A device for the casting of metal in the plastic phase comprising a casting vessel contg. the liq. metal fitted with a nozzle and a continuous casting mould connected by a cooled canal that is inclined with respect to the horizontal by an angle of between 5 and 80 degs. This canal is equipped with a cooling circuit using water as the coolant. The inner section of this canal is greater than, pref. double, that of the nozzle to reduce the risk of blockage by solidified metal. At the end of the canal is a vertical pipe connected to it by an elbow, the lower end of which comprises an extension with an inner dia. (C2) that is less than the dia. (D1) of the nozzle and introduces the metal into the continuous casting mould. A means is also provided to introduce a protective gas such as argon into the canal to fill the space not occupied by the metal. The method of using this device for casting metals is also claimed.

Description

C? 375 ^ λ Λ ^ 2.5412 Q fi π M j

</ i Q “\ J — V — w- GRAND-DUCHY OF LUXEMBOURG

* Patent N * ........................................

of „December 1 st, 1986 Mr. Minister, gvpgjh of Economy and Average Classes i Title delivered ........................... .............. Intellectual Property Service

SMP LUXEMBOURG

• j "Patent Application vet ./ 'ΟΜ * ..

I. Request

The METALLURGICAL RESEARCH CENTER-CENTRUM VOOR RESEARCH (i) IN ._DE..JffiJEAI ^ JJRQJJE ^ .s5.s_ojcLlatlan_jaan5 - bnt ..... liiiica ± ii! = £ i £ eisnl1gln ^ - .. zpiidsT · winstoogmerk 47, rue Montoyer. 1040 Bruxelles.Belgique.represented) by .... Ma ..- Alain. ·· RUKAYINA, .avQC.at-avo.ué.t ...... agiss.an.t .. ..en .._ q.uall ± é__de_jnaiiiiatai deposits (nt) this premi.ex ..-. de..c.emb.r_e .__ 1.9.0Q ..... qua.t.r'e-vr .ixig.tT ^ s.Lx_ (3) at 15.00 hours, at the Ministry of the Economy and the Middle Classes, in Luxembourg: 1. this request for obtaining a patent for invention concerning: --- ---------------------------------------------------------- ---------------------------------------------------------- --------------------------- ~ (4) "Device for casting a metal in the pasty phase11 ________________ 2. the delegation of power, dated__Brussels_____________________ le__27 November .1986 3. description in ______ French __________________ language of the invention in two copies; 4. .a _______________ drawing boards n, in two copies; 5. the receipt of the taxes paid to the Luxembourg Registration Office on .......... l.ar .... Mo.embm .... l.9afi ___________________________________________________________________________________________________________________________________ declare (s) assuming responsibility for this declaration, which inventor (s) is (are):

Mpns.ieur .... Raymond, ... D,.? .. HAE.YEB ^ ... „. R.ua ..„ iie.s .... Eorger.ons ..... 2 ........ 451A ~ Bascîae &, .....—

Belgium ................................................. .................................................. ................................... ......_______________________ claim · for the above request the priority of one (or more) application (s) of (6) ................................ ....................................... filed in (7) ... ............. /. / ____________________________! ............................

in the name of ...................... LL________________________________________________________________________________________________________________________________________________________________ (9) elect (elect) for him / her and, if appointed, for his / her representative, in Luxembourg_________________ lQâ ., ...... b..Quleyar.d ...... de ..... la .... Eoi.r.e ______________________________________________________ 1 _______________________________________________________ (10) requests the grant of a patent of invention for the object described and represented in the abovementioned appendices, - with postponement of this delivery to ____ ten hui t______mois. (11)

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............................ μ · [1 (ΠΑΑ * Μ <Π. Deposit Report

The above patent application has been filed with the Ministry of the Economy and the Middle Classes, Intellectual Property Service in Luxembourg, on:

1 eÆÎgftirl 986 J

ft # \ Pr. the Minister at 15.00 _ hours / «/ ^ | 1 ^ 0110111 ^ and "js Middle Classes, A 68007_ _ y _: 2.5412 - 4

DESCRIPTIVE MEMORY

filed in support of an INVENTION PATENT application in the Grand Duchy of LUXEMBOURG

on behalf of: METALLURGICAL RESEARCH CENTER

for: "Device for casting a metal in the pasty phase" -r. * f ~% C 2379/8612.

Device for casting a metal in the pasty phase.

The present invention relates to a device for casting a metal, in particular steel, in the pasty phase in a continuous casting ingot mold.

We know the advantages of casting steel in the pasty phase. This technique makes it possible to obtain fine and homogeneous structures which clearly reduce the segregations, and in particular the axial segregation in the cast products. It also increases the casting speed, thereby reducing the risk of breakthroughs.

In its patent LU-A-86,640, the present applicant has already proposed a device making it possible to create conditions which lead to the appearance of a pasty phase in the metal during its journey between the ladle or the tundish basket. on the one hand and the casting mold continues on the other.

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This known device comprises an inclined channel provided with a lining of refractory material and covered with a fin vault for cooling the metal which circulates therein.

In this device, the heat radiated by the molten metal heats the vault which, by conduction, in turn heats the fins; these are then cooled by a stream of air.

This cooling process requires a fairly long time and therefore a very long channel to ensure the appearance of the desired pasty phase.

The objective of. the present invention is to provide a device for operating cooling leading to said pasty phase in a significantly shorter time and therefore requiring only a channel of shorter length and therefore less bulk.

The device for casting a metal in the pasty phase in a continuous casting mold, which is the subject of the present invention, comprising a metal channel inclined to the horizontal and provided with a refractory lining, is essentially characterized in that, in at least one region of its bottom, the channel is made of a material having a high heat conductivity, in that said region of the bottom of the channel is subjected to intense cooling and in that the refractory lining of the bottom of the channel is interrupted in at least part of said region.

According to the invention, said region is advantageously located near the upstream end of said channel.

Also according to the invention, said region consists of a plate of a material having a high heat conductivity, in particular of copper, said plate being provided with water cooling means.

s * · - 3 - The interruption of the refractory lining in said region normally leaves the latter unprotected. It may nevertheless prove advantageous to deposit there a thin film of a refractory material in particular of ZrC ^, in order to lower the working temperature of the copper while reducing only very slightly the efficiency and the intensity of the cooling. .

According to a particular embodiment of the device of the invention, the part of said region in which the refractory lining is interrupted forms a zone preferably extending over the entire width of the bottom of the channel.

It would not, however, depart from the scope of the present invention to limit the transverse extent of this zone to a fraction of the width of the bottom of the channel, or to split this zone into a plurality of partial zones distributed along the width of the bottom of the channel. and separated by walkways of refractory material.

Finally, the device may include means for adjusting the inclination of the channel, making it possible to take into account factors such as the composition and the temperature of the metal to be cast in order to obtain the desired pasty phase.

The object of the invention will be better understood by referring to the description below of particular embodiments illustrated by the appended drawings, in which FIG. 1 shows a schematic view in elevation, in longitudinal section, of a channel according to the invention; and FIG. 2 presents various embodiments of the cooled region of said channel, each time using a plan view of this region and of a cross section through it, along the lines AA: BB and CC respectively.

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In these figures, only the elements necessary for the proper understanding of the subject of the invention have been shown. Thus, the elements already known, such as a channel covering vault or a metal protection enclosure between the outlet of the channel and the inlet to the ingot mold, have not been reported there. Finally, the same elements are designated by the same reference numerals in the different figures.

Figure 1 schematically illustrates the device of the invention, mounted between a ladle or a tundish 1 containing superheated metal and a continuous casting mold 2. This device comprises a channel, generally designated by the reference numeral 3, which consists of a metallic bottom 4 and side walls 5 also metallic. The metal used for this purpose is preferably steel. The bottom and the walls of the channel are lined with a refractory lining 6, 6 '.

In the bottom 4 of the channel is inserted a plate 7 of a material having a high heat conductivity, in particular copper, which is subjected to intense cooling. This cooling is preferably ensured by a water circulation circuit, symbolized by the arrows 8 for entering and leaving 9 for the water.

The refractory lining 6, 6 ′ is interrupted on a part of the upper surface of the plate 7, which is thus exposed directly to contact with the liquid metal. As shown in FIG. 2, this uncovered part of the plate 7 can be (a) an area extending over the entire width of the channel, (b) an area extending over only a fraction of this width, or (c) a plurality of partial zones distributed along the width of the channel and separated by walkways of refractory material.

The mode of operation of this device is easily understood by referring to FIG. 1.

* ..... .........

* "- 5 -

The superheated metal, in particular steel, coming from the ladle or the tundish 1 arrives in the upstream portion of the channel 3 where it flows over the refractory lining 6 'without undergoing significant cooling. It then arrives on the uncoated part of the copper plate 7, where it undergoes intense cooling for a limited time owing to the relatively small dimensions of the contact surface. The tests show that, on such a very localized contact surface, the steel instantly loses its overheating, which causes the appearance of solidified particles within the stream of liquid steel. This takes away the solidified particles, which therefore cannot be deposited on the plate 7. During its flow over the refractory lining 6, the steel continues to be cooled and becomes increasingly rich in solidified particles.

It thus acquires the pasty state sought upon entering the mold 2.

The device of the invention makes it possible to replace the conventional unidirectional flow of heat, that is to say the flow along the thickness of the copper plate, by a bi - or even three-way flow which is clearly more efficient.

When the entire upper surface of the cooled plate is brought into contact with a liquid metal, the heat can only flow according to the thickness of the plate. On the other hand, when only a part of this surface is exposed to liquid metal and the rest of the surface is protected, in particular by a refractory coating, the flow of heat in the plate takes place both according to the thickness and parallel to the plane of the surface. This results in an increase in the cross-section offered to the heat flow, and therefore an improvement in the cooling efficiency.

It goes without saying that the invention is not limited to the particular embodiment which has been described and illustrated above, but that it also encompasses the various variants and modifications coming within the scope of the claims which follow.

Claims (7)

1. Device for casting a metal in the pasty phase in a continuous casting mold, comprising a metal channel inclined to the horizontal and provided with a refractory lining, characterized in that, in at least one region of its bottom, the channel is made of a material having a high heat conductivity, in that said region of the bottom of the channel is subjected to "intense cooling, and in that the refractory lining of the bottom of the channel is interrupted in at least part of said region. 2. Device according to claim 1, characterized in that said region is located near the upstream end of said channel. 3. Device according to either of claims 1 and 2, characterized in that said region consists of a plate of a material having a high heat conductivity. 4. Device according to claim 3, characterized in that said region consists of a copper plate. 5. Device according to any one of claims 1 to 4, ca characterized in that the region in which the refractory lining is interrupted forms a zone extending over at least a fraction of the width of the channel, and preferably over this entire width. 6. Device according to either of claims (1 to 5, characterized in that it comprises means for adjusting the inclination of the channel. 7. Device according to any one of claims 1 to 6, ca acterized in that the region in which the refractory lining is interrupted is provided with a thin film of refractive material-tsirB. ) essins .......... y ^ · ...... pi & ni.ïife9! Λ _______ pages of which ....... a ....... paca de garde. ....... S ... description pages ... A ... reselling pages t.i $ ....... A ..... descriptive year Luxembro ·.-J, i; DEC."