ZA200901211B

ZA200901211B - Arrangement for slag-free tapping of a steel melt

Info

Publication number: ZA200901211B
Application number: ZA2009/01211A
Authority: ZA
Inventors: Stilkerieg Berthold
Original assignee: Stilkerieg Berthold
Priority date: 2008-04-01
Filing date: 2009-02-20
Publication date: 2010-02-24
Also published as: DE102008016621A1

Description

DrG REF: 675814 | [IN

TITLE OF INVENTION

Arrangement for slag-free tapping of a steel melt

FIELD OF INVENTION : 5s The invention relates to an arrangement for slag-free tapping of a metal "melt, in particular a steel melt, from a metallurgical vessel such as a ladle with floor outlet, which is suitably open and to which one or more plate- : shaped inserts are allocated, which are arranged ahead of the floor outlet facing the flow reversal region.

BACKGROUND TO INVENTION

During discharging metallurgical vessels with floor outlets when the bath level height drops below an undesired height, an undesired taking along of the slag located on the metal melt takes place. During discharge of the metal or steel melt a steel swirling or whirling thus takes place, which, due _ 15 to the high rotational speed, sucks the slag in. The circumferential speed even increases during the dropping distance to the floor outlet so that drawing in of the slag impairs the melt quality. According ‘to the EP 1 172 447 Al these problems are to be countered therewith that one or more plate shaped inserts are placed at a given distance to the floor outlet.

According to the EP 1 172 447 Al these inserts have a rectangular form, consisting of refractory material and are designed plate-shaped such that a circumferentially suitably wide side or edge surface is created. It now has been found in tests that no effect occurs even then if these inserts are arranged sufficiently up to the flow reversal region. At the most the steel melt flows like water around these plate-shaped inserts and its side surfaces, so that it cannot result in an impairment of the negative whirling.

For this reason these arrangements could not be accepted. As before

— . disadvantageous swirling results and therewith the taking along of considerable slag quantities.

The invention therefore has object to create inserts by way of which the swirling is reliably influenced such that slag cannot be “sucked in” into the outlet in mentionable quantities.

SUMMARY OF INVENTION ’ :

According to the invention, an arrangement for slag-free tapping of a metal melt, in particular a steel melt, from a metallurgical vessel such as a ladle with floor outlet, which is suitably open and to which one or more plate- shaped inserts are allocated, which are arranged ahead of the floor outlet facing the flow reversal region, is characterized thereby that the inserts have a vertically arranged brake part and a horizontally arranged fixing part, whereby the brake part is provided with a wedge-shaped edge which, in use, is positioned pointing into the steel whirl or swirl. :

The wedge-shaped edge of the brake part or the overall brake part may be arranged counter to the rotational direction of the steel whirl or swirl.

The wedge-shaped edge and a horizontal edge of the brake part may both be joined together by way of an edge-shaped edge describing an arc.

The wedge-shaped edge may be arranged at a distance of 10-100 mm, preferably 30 mm, from the floor outlet reaching into the steel swirl.

The inserts allocated to a floor outlet may be designed to have different heights.

The fixing part and the brake part may be designed integrally, whereby the fixing part may have one or more tenons formed thereto and the ladle floor may be provided with a complementary slot.

The tenon(s) may be designed wedge-shaped.

The tenon may be designed cylindrically shaped, preferably as hollow cylinder.

The tenon(s) may have an outer ring at its free end, of which the outer diameter is smaller than the diameter of the slot.

The inserts may be designed L or T-shaped, that is the fixed part projects on the one side or both sides beyond the brake part.

By means of such an arrangement the swirling, which takes place, is not only influenced but is even torn down, so that a turbulent flow is produced, whereby the swirl as a whole becomes ineffective. The negative drawing in of the slag does almost not occur and therewith the melt quality can be maintained fully. It's also advantageous that, by way of these inserts, the possibility exists to allow the level, together with the top floating slag, to sink down to near the floor outlet because now the danger of taking along ‘of the slag is excluded. Therewith larger steel melt quantities can be withdrawn without problems in one move from the metallurgical vessel, that is in particular withdrawn from the distributor or a ladle. The economy of the corresponding arrangements increases clearly. Because the inserts consist of a vertical brake part and a horizontal fixing part a fixing at the ladle floor in the region of the floor outlet is possible without problem, the details thereof being described further down. The brake part reaching into the steel swirl or steel whirl takes care, by way of the wedge-shaped edge, that the whirl is torn up. Thus the liquid steel can not escape from the brake part or flow around the associated side surfaces. In this manner the liquid steel, that is the whirl, is effectively retarded such that a taking along of the slag in mentionable quantities cannot occur any longer.

According to a suitable embodiment it is provided that the wedge-shaped edge of the brake part or the overall brake part is arranged counter to the the rotational direction of the steel swirl or wirl. By way of this s = 2000/0121 arrangement the swirl is practically cut-up and advantageous turbulent flow results, which is desired to render the swirl correspondingly ineffective.

The rotational speed is reduced so strongly that, in particular in the region of the floor outlet, no taking along of the top floating slag can result.

According to a further suitable embodiment it is provided that the brake part has the wedge-shaped edge and a horizontal edge, which both are joined together by way of an edge describing an arc. Therewith the brake part forms a type of shark fin whereby the edge, describing the arc, also can be sharpened additionally. By way of this particular design the effect of the wedge-shaped edge at the front side is supported additionally and the stability of the overall constructional unit is ensured.

In order to ensure that the wedge-shaped edge also reaches into the steel swirl or steel wirl the invention provides that the wedge-shaped edge is - arranged at a spacing of 10 - 100 mm, preferably 30 mm from the floor outlet into the steel swirl. By way of this positioning it is ensured that the brake part in any case can exert its influence on the swirl so that the negative taking along of the slag cannot occur.

The height of the individual inserts is dependent on the height of the ladle or the distributor, whereby it is advantageous if the inserts allocated to a i floor outlet have different heights. The rotating swirl thus is influenced not only by the front vertical edge but also to a particular extent by the upper horizontal edge which overall supports the effect of stopping the taking along of the slag.

For simplification of the assembly of the inserts is provided that the fixing part and the brake part are formed integrally, whereby the fixing part has one or more spigots and the ladle floor is provided with a complementary slots. The inserts are inserted into the associated slots by way of their spigots and already then receive their working position whereby they or their residues then can be taken out of the steel bear together with this from the distributor or the ladle in order to be replaced by new inserts.

A suitable design of the spigot is when it is wedge-shaped whereby obviously it is to be understood that the slot in the ladie floor has a corresponding shape. Therewith the spigots can be introduced easily and then again be taken out together with the steel bears.

Another embodiment of the spigot is that in which it is designed cylindrically, preferably as hollow cylinder. This spigot designed as cylinder can be applied particularly easily into the associated slot in the distribution floor or the ladle floor so that an easy assembly is possible, in particular also then if work is done with a special mortar or another adhesive agent, in order to reliably prevent an unintentional removal of the spigots from the slots. If the spigot or the cylinder is introduced into an associated slot, then the special mortar previously filled therein, can be distributed easily, if the spigot has the shape of a hollow cylinder. Independent how much of this special mortar has been filled into the slot, it is always ensured that the hollow cylinder cuts in, displaces the excessive special mortar and therewith takes care of a secure positioning of the individual inserts. Thus a rotation of the individual inserts is simply and effectively prevented thereby that two or more spigots are allocated to the underside of the brake part as fixing part. :

Another fixing of the insert is achieved thereby that the spigot has an outer ring at the free end of which the outer diameter is smaller than the diameter of the slot. Thus the spigot can be introduced together with the associated constructional part into the slot, so that thereafter they are finally and effectively fixed by filling of special mortar into the slot or into the remaining gap.

If the placing of the inserts on the ladle or distribution floor is to be achieved, then this is possible if the inserts are L or T-shaped that is the fixing part is designed projecting horizontally over the brake part on one side or both sides. In particular in distributors with a small height the placing and positioning of the inserts is made easy and as a rule this is sufficient to secure an exact positioning of the insert.

The invention is characterized in particular thereby that an arrangement is created by way of which it is possible, when removing liquid steel from the distributor or also from a ladle, the taking along of the slag cover in the : liquid phase is reliably prevented. This is achieved thereby that on the . ladle floor or distributor floor especially shaped plate-shaped inserts are installed. When the liquid steel is moves down, in particular in the distributor, the negative influence of a whirl created thereby is prevented, so that this swirl is cut-up or is influenced in a particular manner so that the - laminar flow is converted purposefully into a turbulent flow so that in particular, due to the reduction of the circumferential speed, a taking along of the slag is not possible. Thereby it is further possible to withdraw the remaining steel to below 10 %, that is the ladle or the distributor is run practically empty, whereby the slag is held back reliably.

Joined thereto further substantially less or only very small steel bears result, which nevertheless take the residue of the plate-shaped inserts along, because these are connected in skilful manner on the ladle floor or the distributor floor or are only inserted there.

BRIEF DESCRIPTION OF DRAWINGS

The invention will now be described by way of example with reference to the accompanying schematic drawings.

In the drawings there is shown in:

Figure 1 a discharge vessel with down stream arranged distributor in accordance with the invention;

Figure 2 sections of a brake part of inserts shown in Figure 1;

Figure 3 a perspective view of a particular form of the inserts shown in

Figure 1,

Figure 4 a further form of inserts shown in Figure 1;

Figure 5 an L-shaped form of the inserts shown in Figure 1;

Figure 6 a T-shaped form of the inserts shown in Figure 1;

Figure 7 a brake part with hollow cylinder formed thereto shown in

Figure 1; and

Figure 8 a brake part with wedge-shaped fixing part formed thereto shown in Figure 1.

DETAILED DESCRIPTION OF DRAWINGS

Figure 1 shows a discharge vessel 1 with an outlet 3 and the filled liquid steel 2. In the region of the outlet 3 a plate-shaped insert 10" can be seen, which ensures that during outflow of the liquid steel 2 the slag layer 6 is not influenced, that is the whirl created here is influenced such that the slag layer 6 is not sucked in.

In the downstream arranged distributor 5 or this ladle-shaped formation has suitable inserts 10, 10’, 10”, which are arranged in the region of the floor outlets 8, 9, 8’ such that the liquid steel 7 cannot have any influence in the distributor 5 on the slag layer 6’. In the region of the floor outlet 8’ a steel whirl or steel swirl 12 is shown, whereby the allocated insert 10” is arranged such that it projects into the flow reversal region 11 and thus reliably influences the steel swirl 12. This influencing causes that the slag:

layer 6’ sinks down slowly with the withdrawal of the liquid steel 7, however such that the steel swirl or whirl 12 leaves the overall slag layer 6’ uninfluenced. It is thereby possible to withdraw the liquid steel 7 practically up to close to the floor outlets 8, 8’, 9, which is of great advantage because hitherto it was only possible to draw off up to about 2/3 “of the contents, in order to ensure that no slag is drawn along. Thereby a considerably reduced steel bear is created, that is the hardened steel, in which then the residues of the inserts 10, 10’, 10” are located, which can be removed easily together with the steel bear, because then they are not fixedly connected to the ladle floor 14. Details hereof are explained further down below.

By means of dotted lines the distribution channels 13, 13‘, 13” are indicated by way of which the liquid steel is supplied from the distributor 5 to further processing operations or operational positions.

Figure 2 shows firstly an insert 10 or the front part of the brake part 15. It _. can be seen that here a wedge-shaped edge 17 is formed, which, by way of skilful arrangement cuts into the steel whirl or swirl 12 and takes care that the laminar flow is converted into a turbulent flow , which "has a considerably reduced rotational speed or no such speed, so that the taking along of the slag layer 6, 6’ is reliably prevented. The second view in

Figure 2 explains that it is also possible to place an edge 17 of the front surface of the brake part 15 in front of the other edge so that again a wedge-shaped edge 17 is created, which can cut into a steel whirl or steel swirl 12,

Figure 3 shows a particular embodiment of an insert 10, whereby more clearly than in the other cases the. duality is presented. Here it is namely shown that the insert 10 consists of the brake part 15, that is of the perpendicular constructional part and a horizontally arranged fixing part 16, in which a slot 20 is provided, into which the fixing part 16, here in the form of a tenon 21 can be introduced. At its lower end or its free end 23 this tenon 21 has an outer ring 24, so that after the introduction of the tenon 21 into the slot 20, ready mortar, not shown here, can be introduced, fixing the tenon 21 in the ladle floor or a corresponding cut-out 14. Then the tenon 21 is introduced in the region of the lower edge 18 of the brake part 15 into it. This brake part 15 has an auxiliary slot 25 for this purpose. - Obviously also the possibility is given, as indicated in Figure 7, to provide the tenon 21 and the brake part 15 integrally and then to introduce the tenon 21 into a complementary slot 20 in the ladle floor 14. After completion of the filling of the liquid steel 7 from the distributor or the ladle 5 the vertical brake part 15 is included in the steel bear and there is fixed by the cooling steel so that this remaining brake part can be removed either together with the fixing part 16 or on its own.

Figure 3 shows furthermore that the inserts 10 do not of necessity have a rectangular form. Here it is shown that the wedge-shaped edge 17 and the lower edge 18 are joined by way of an arc-shaped edge 19 so that a type of shark fin results. In Figure 4 this shark fin is shown such that one can see that the rear edge 19 forms a sharp edge. The front edge 17, which is shaped wedge-shaped, is shaped according to Figure 4 slightly in the form of the plug 27 so as to secure a uniform development of the gap 26 between the plug 27 and the wedge-shaped edge 17.

Figure 4 furthermore shows an embodiment in which the vertically arranged brake part 15 is joined to a horizontally arranged fixing part 16, whereby the latter projects to a side beyond the brake part 15 so that a type of L- shaped design of the overall insert 10 results. Figure 5 shows this in individual representation whereby it can be seen that such an insert 10 has, by way of a wide horizontal fixing part 16, an advantageous stability reliability. The same also applies to the embodiment of Figure 6, where a fixing part 16 is shown projecting even to both sides over the brake part

According to the embodiment according to Figure 7 a corresponding vertical brake part 15 has a fixing part 16 formed thereto, here in the form of a hollow cylinder 22. The hollow cylinder 22 forms the above mentioned tenon 21, which can be introduced into a complementary shaped slot 20 in the ladle floor 14. The same also applies to the embodiment according to -

Figure 8, whereby here no hollow cylinder, but a wedge-shaped tenon 21 is . shown. Here also a complementary slot 20 must be present in the ladle floor or distributor floor 14 so that the lower edge 18 then rests on the ladle floor 14, whereas in the nature of things the tenon 21 is introduced as a whole into the complementary slot 20. :

Regarding Figure 1 it is to be added that here the discharge vessel 1 is joined to the ladle or the distributor 5 by way of a melting tube, so as to avoid the splashing of the liquid steel 2 into the liquid steel 7 of the downstream arranged distributor 5. It is shown that this melting tube 4 passes through the slag layer 6’.

The individual Figures “only explain partly that the inserts 10 shown preferably are arranged at an angle or tangentially to the floor outlet 8, 9, that is they stand not at right angles thereto but such that they project with the wedge-shaped edge 17 into the flow reversal region 11 or the steel whirl or swirl 12 and “cut these open”. The necessary reliability is given thereby that the laminar flow is interrupted. Only in the case of a uniform, that is laminar flow, the negative high flow speed is present, which leads to the sucking in of the slag layer 6 or 6’. Therewith the form of the wedge- shaped edge 17 is insofar important that it must secure that the swirl is broken up. It has been found that this is only ensured by way of a suitable “sharp” edge in each case.

All mentioned characteristics, which can be seen from the drawings, are considered to be essential to the invention individually or in combination.

Claims

Patent Claims N EL

1. Arrangement for slag-free tapping of a metal melt, in particular a steel melt (2), from a metallurgical vessel such as a ladle (2) with floor outlet (8, 9), which is suitably open and to which one or more plate-shaped inserts (10) are allocated, which are arranged ahead of the floor outlet (8, 9) facing the flow reversal region (11), characterized thereby that the inserts (10) have a vertically arranged brake part (15) and a horizontally arranged fixing part (16), whereby the brake part (15) is provided with a wedge-shaped edge (17) which, in use, is positioned pointing into the steel whirl or swirl (12).

2. Arrangement according to claim 1, characterized thereby that the wedge-shaped edge (17) of the brake part (15) or the overall brake part (15) is arranged counter to the rotational direction of the steel whirl or swirl (12).

3. Arrangement according to one of the preceding claims characterized thereby that the wedge-shaped edge (17) and a horizontal edge (18) of the brake part (15) are both joined together by way of an edge-shaped “edge (19) describing an arc.

4, Arrangement according to one of the preceding claims, characterized thereby that the wedge-shaped edge (17) is arranged at a distance of 10-100 mm, preferably 30 mm, from the floor outlet (8, 9) reaching into the steel swirl (12).

5. Arrangement according to one of the preceding claims, characterized thereby that the inserts (10) allocated to a floor outlet (8, 9) are designed to have different heights.

6. Arrangement according to one of the preceding claims, characterized thereby that the fixing part (16) and the brake part (15) are designed

13 i : integrally, whereby the fixing part (16) has one or more tenons (21) formed thereto and the ladle floor (15) is provided with a complementary slot (20).

7. Arrangement according to claim 6, characterized thereby that the tenon (21) is designed wedge-shaped.

8. Arrangement according to claim 6, characterized thereby that the tenon (21) is designed cylindrically shaped, preferably as holiow cylinder (22).

9. Arrangement according to claim 8, characterized thereby that the tenon (21) have an outer ring (24) at its free end, of which the outer diameter is smaller than the diameter of the slot (20).

10. Arrangement according to one of the preceding claims, characterized thereby that the inserts (10) are designed L or T-shaped, that is the © fixed part (16) projects on the one side or both sides beyond the brake : part (15).

11. Arrangement for slag-free tapping of a metal melt, in particular a steel melt, from a metallurgical vessel substantially as hereinbefore described with reference to and as illustrated in any one of the accompanying schematic drawings. - Date: 20 February 2009 DR R O P GERNTHOLTZ DR GERNTHOLTZ INC Patent Attorneys of Applicant(s) POBox 8 CAPE TOWN 8000 Union Road MILNERTON/CAPE 7441 : SOUTH AFRICA 30 Tel: (021) 551 2650 Telefax: (021) 551 2960 DrG Ref: 675814