US3510562A - Equipment for electroslag remelting of metals - Google Patents

Description

May 5, 1970 M. e. FRAUENSTEIIN EQUIPMENT FOR ELECTROSLAG REMELTING 0F METALS Filed Sept. 17. 1968 4 Sheets-Sheet 1 INVENTOR MANFRED GERHARD FEAUENSTEIN AGENT y 1970 M. G. FRAUENSTEIN 3,510, 62

EQUIPMENT FOR ELECTROSLAG REMELTING OF METALS Filed Sept. 17, 1968 4 Sheets-Sheet 2 FIG.2 FIG. 3

o 57 o 5 s5 f 4 3 52 55 3 580 I i 75 o o I H" NIH 72 I I l 9 7| SI/ '0 1 I o i" 5s 75 l4 l2 I 0 7e 53 k o '54 b 3 MI W @HI I" INVENTOR MANFRED GERHARD FRAUENSTEIN M. G. FRAUENSTEIN 3,510,562

EQUIPMENT FOR ELECTROSLAG REMELTING OF METALS 4 Sheets-Sheet 5 May 5, 1970 Filed Sept. 17, 1968 y 1970 M. e. FRAUENSTEIN 3,510,562

EQUIPMENT FOR ELECTROSLAG REMELTING OF METALS 4 Sheets-Sheet 4 Filed Sept. 17, 1968 FIG. 7

INVENTOR MAN FRED GERHARD FRAUENSTEI N BY d United States Patent 3,510,562 EQUIPMENT FOR ELECTROSLAG REMELTING OF METALS Manfred Gerhard Frauenstein, Freital, Germany, assignor to VEB Qualitatsund Edelstahl-Kombinat, Hennigsdorf, Germany Filed Sept. 17, 1968, Ser. No. 760,187 Int. Cl. H05b 7/18, 3/60; C22d 7/00 U.S. Cl. 13-10 15 Claims ABSTRACT OF THE DISCLOSURE This invention relates to equipment for remelting metals according to the electro-slag remelting process. In this process, a self-consuming electrode is remelted into a block, in an ingot mold or a crystallizer, under a sla l lany types of equipment became known for remelting metals according to this process; these installations meet minimum requirements of the technological aspects of this process. They consist of an ingot mold which stands on the floor and of a guided arm, at whose end a steel electrode is clamped. The arm and consequently the electrode are lowered at the speed required by the melting process. In most cases the clamping jaws which hold the electrode are at the same time used for current transmission. For moveable ingot molds, the conductor to the base plate is designed in the form of a flexible cable.

In some of the more recent equipment, overall height is reduced in that two arms which can be lowered are attached to a guidance column system; one arm preforms the feed motion while the other arm rides over the first arm with its jaws open. The jaws of the first arm are opened in the lower terminal position, while those of the other arm take over the guidance and the feeding of the electrode. However, to insert a new electrode, the previous one must be lifted beyond the arm height or, if the ingot mold has been rolled out, it must be inserted from below.

Both types of feed require a complicated maneuver; in the first case, we have in addition the considerable lifting height of the hoisting equipment. Furthermore, the latter is required at certain specific times; in routine production operation this cannot always be guaranteed and this in turn leads to idle times.

Another disadvantage of these installations resides in the fact that electrode shapes which deviate from a specified cross sectionparticularly diamond-shaped electrodes and cast of rolled electrodes which are warped along their longitudinal axes-cannot be processed. The reasons are explained as follows: When we work with a diamond-shaped cross section, the jaw surfaces touch the electrode surfaces only to a small extent, and the transmission of electrical energy is thus unfavorably influenced. Similarly, electrode shapes which have become twisted or which deviate from a round cross section can- 'ice not be employed in connection with this type of electrode guidance.

Installations are also known which are equipped with several ingot molds. For instance, an installation is known which uses a three-phase current for simultaneously producing three blocks. These installations likewise are not more elficient in terms of time and, when it comes to a choice of the mechanical means required, they fall back upon the known solutions which were described above.

Further disadvantages result from the fact that the insertion of the electrodes is complicated because the same must be held in place either by means of screws, pressure jaws or clamping jaws. In the second case, it is necessary to lift the electrode with its lower end to a point above the upper pair of clamping jaws; thereafter it is lowered between the opened clamping jaws. This kind of electrode retaining arrangement requires very careful alignment of the electrode for the purpose of at least roughly lining up the respective axes of the ingot mold or crystallizer and of the electrode.

It is the object of the invention to provide an installation for the remelting of metals according to the electroslag remelting process, which enables us to remelt starting material of any desired geometrical shape in an unaligned rolled or cast state and to melt off the electrodes down to the clamped end.

Furthermore, it is the object of this invention to keep technologically caused idle times as small as possible.

In accordance with this invention, this can be achieved by an installation having the following main and optional features:

(a) Two or more crystallizers (ingot molds) are attached to a base plate each and the latter are arranged on a common turntable.

(b) Preferably, one side of each base plate is designed as a contact piece and, when the respective crystallizer is in the melting position, an electric contact can be closed by means of suitable connecting elements.

(c) At least one electrode stand is arranged on the turntable for holding an electrode.

(d) An electrode retaining device is provided which consists of two clamping elements each of which has one or more clamping jaws mounted on gimbals. When there is a total of more than three clamping jaws-that is, if we have two and more clamping jaws per clamping element-the clamping jaws of one or both clamping elements are preferably arranged on a rotatably positioned bar or crosspiece.

(e) The clamping elements are arranged on a clamping arm which can be adjusted in terms of height; the mass of this clamping arm and preferably half of the weight of the electrode can be balanced by means of a counterweight which, because of its potential energy, at the same time is the force that activates the clamping elements. To this end, the counterweight is attached at the end of an angle lever armwhose other end is connected with the clamping elements.

(f) Above the crystallizer, when it is in the melting position, there is a guidance device which can be swung away.

According to other important features, the installation is furthermore characterized in that the crystallizers and the electrode stand are preferably arranged on a common pitch circle on the turntable so that the clamping elements will be above the circle.

When there are two crystallizers on the turntable, there is one electrode stand, and the drive for the turntable is preferably designed so that it can be reversed. With an equipment which has two or more crystallizers on the turntable, there will be one electrode stand between two crystallizers.

In the center of the turntable there may be a central cooling-agent supply for cooling the crystallizers and the respective bottom plates. Under the turntable, a centered, trough-shaped drainage groove may also be disposed for the cooling agent.

The electrode stand may consist of guide members which are pivoted to a bottom that can be lowered by the weight of the electrodes so that the guide members come to rest against both sides of the electrodes. The guidance device which can be swung away may be designed in the form of a suction device.

To open the clamping elements at the end of the angle lever, there may be provided a roller over which runs a cable, one of whose ends is attached to the frame while the other is attached to a traction device.

Other objects and many of the attendant advantages of the invention will be readily appreciated as the same becomes better understood by reference to the following detailed description, when considered with the accompanying drawings, wherein- FIG. 1 is a perspective overall view of the equipment for remelting metals, according to the invention, with parts broken away:

FIG. 2 is a side view of an electrode holder for the equipment according to FIG. 1;

FIG. 3 is a somewhat schematic partial view relating to structural elements shown in FIG. 1, illustrating a system for lowering a clamping arm for the electrode;

FIG. 4 is a view similar to that of FIG. 3, illustrating another system for lowering the clamping arm;

FIG. 5 shows, on an enlarged scale, the afore-mentioned elements of FIG. 1 for clamping the electrode;

FIG. 6 is a side view of a crystallizer, together with a guidance column for the electrode; and

FIG. 7 is a top view of the details shown in FIG. 6.

As shown in FIG. 1, a frame 1 which is designed in the shape of a portal vertically guides a clamping arm 3 along rails 2. The arm 3 has a clamping device 4 for an electrode 71, as shown in FIGS. 2 to 4, 6 and 7, which is preferably placed in the middle of arm 3. Under the latter, a turntable 5 is so arranged that the center of the clamping device 4 is located substantially above an imaginary pitch circle of turntable 5 on which, as a matter of example, two crystallizers 6 and two electrode stands 7 are supported in alternating sequence. The turntable 5 has a preferably reversible drive. It will be understood that the invention is also intended to cover other arrangements, e.g. one in which two crystallizers are used in conjunction with only one stand.

As we can see in FIG. 2, the electrode stand 7 includes a frame 8 on whose upper portion there is an angle-lever pair, consisting of angle levers 9, 19. At the ends of the shorter shanks (not numbered) of the levers 9, 10, there are prismatic rollers 11, 12 positioned in a rotatable fashion. Connecting rods 13, 14 are attached in a hinged manner at the free ends of angle levers 9, At the end of rod 13, there is a centering funnel 15 (see FIG. 5) which, depending upon the cross section of the electrodes 71, is prismatically or circularly designed. Rod 14 is connected with the funnel 15 by means of a joint.

A toothed segment 16 is disposed of on the side of frame 8 of stand 7; this segment 16 is hingedly connected with the funnel 15 by means of a connecting rod 17. Segment 16 can be pivoted by means of a hand wheel 19 via a worm gear 18.

Referring once again to FIG. 1, we see that turntable 5 has a substantially central hollow guide pin 20 to which a cooling-agent supply line 21 is connected. A distribution piece 22 is installed on turntable 5; pipelines 23, 24 lead to the crystallizers 6 from this distribution piece 22. Shutolf valves 25 may be arranged in supply lines 23, 24. These supply lines run into the foot portions of the crystallizers 6, as shown in the right-hand bottom portion of the figure. From the head portions of the crystallizers, drainage lines 26, 27 run through the turntable 5 into a trough-shaped drainage groove 28 for the cooling agent, which is arranged centrally with respect to guide pin 20.

The crystallizers 6, visible in FIGS. 1, 6 and 7, consist of a base plate 29 which has a notch in the middle, of a bottom plate 30, and of walls 31, 32 between which the cooling agent flows. The bottom plate 30 consists preferably of copper and is provided with a side bar or cover plate 33 running in the radial direction of turntable 5; this side bar 33 extends beyond the edge of turntable 5.

As illustrated in FIGS. 1 and 6, we have a column 34 next to turntable 5, under frame 1. In this column there are positioned levers 35, 36 which, at one of their ends, hold respective clamping jaws 37, 38. At the other ends of levers 35, 36, one end of a clamping cylinder 39 and a piston rod thereof are respectively attached. Contact rails 40, 41 (see also FIG. 7) lead to the respective clamping jaws 37, 38.

As best shown in FIG. 7, guide arms 42, 43 are journaled on column 34; these arms can be swung apart by means of a toothed rack 44 and by toothed segments 45, 46. Guide arms 42, 43 are so designed that they enclose the opening of the crystallizer 6 which is in the melting position, that is to say when the crystallizer is beneath the clamping device 4 (the one to the left in FIG. 1). The cross section of the free ends of guide arms 42, 43 widen; at their end, there are cutouts which roughly correspond to the shape of the electrodes 71. To facilitate the guidance thereof, rollers 47 are attached to the front sides of arms 42, 43-, as shown in FIG. 7. These arms are preferably hollow and are connected with a fan 50 by means of conduits 48, 49.

FIG. 3 shows a system for lowering the electrode clamping arm 3. A cable 51 (see FIGS. 1, 3 and 4) is used for the parallel lifting and lowering of the arm 3; this cable is attached on both sides of arm 3 and is guided in frame 1 via rollers 52, 53 and 54. The cable 55 to which there is attached a counterweight 56 and which likewise engages clamping arm 3 via rollers 57, 58, maintains the balance. However cable 55 is not directly connected with the arm 3; instead it is connected to the long shank of an angle lever 57a. The other shank of the lever 57a is connected with the clamping device 4 by means of a pressure rod 58a.

To lift or to lower the clamping arm 3, one of the rollers 52, 53 or 54 has to be driven (to be described later in more detail, with reference to an appropriate traction device 78). Other details of the system shown in FIG. 3 will be described somewhat later.

FIG. 4 shows an alternative system to be used when the required power output is to be reduced or if the cable length is to be extended for better regulation. In this arrangement we have rollers 59, 59a and 60 on clamping arm 3 (the former substituting the roller 52 of FIG. 3); cable 51 is wound around these rollers and is attached to frame 1.

As we can see in the enlarged detail view of FIG. 5, the clamping device 4 includes jaws '61, 62, 63 and 64 which are grouped into two pairs. Each clamping jaw is attached to a respective universal joint of which 65, 66 and 68 are shown (not visible for the jaw 63); the pairs of universal joints are interconnected by respective bars 69, 70. Bar 69 is attached to pressure rod 58a, and clamping jaws 61, 62 can thus be moved back and forth in the plane of clamping arm 3. Bar 70 in turn is rotatably positioned in arm 3, as shown, and its axis of rotation is perpendicular to the plane of clamping arm 3.

To open the clamping device 4, a cable (shown in FIGS. 1, 3 and 4) runs over guide rollers 73, 74 and a roller 72 at the end of angle lever 57a; the end of the cable is attached to the frame 1. The free end of cable 75 is attached to a traction device 77 (see FIG. 1) which carries an appropriate winding drum 76 (also shown in FIGS. 3 and 4). A similar traction device 78 is shown in FIG. 1 for the afore-mentioned roller 54 mentioned when describing the systems of FIGS. 3 and 4. These traction devices are preferably in the form of reversible motors or the like drive means, as is conventional in hoisting equipment and the like.

Let us now explain how the equipment according to the invention works (mostly with reference to FIG. 1): An extraneous hoisting apparatus introduces the electrode 71, in a vertical position, into the electrode stand 7. The prismatic rollers 11, 12 are moved apart as a result of the lowering of electrode 71 and, consequently, centering funnel 15 is raised via angle levers 9, 10 and connecting rods 13, 14. When electrode 71 is placed into the funnel 15, the rollers are pressed against the surface of the electrode 71 because of its own weight. To correct the vertical position of the electrode, funnel 15 can be moved horizontally by means of hand wheel 19. By moving the toothed rack 44, we can swing guide arms 42, 43 apart, and then the clamping arm 3 can be lifted as a result of the movement of cable 51, upon actuation of the traction device or drive means 78.

To open the clamping device 4, traction force is transmitted to cable 75; this force overcomes the counterweight 56 which acts on cable 55 and swings angle lever 57a around its pivotal point. By rotating turntable 5, electrode stand 7 with electrode 71 is swung under the opened clamping device 4.

In case of an electrode which is warped along its longitudinal dimension the free end of the electrode is readjusted, if required, by moving the centering funnel 15 of stand 7 so that the opened clamping device 4 can be lowered without ditficulty exactly over the free end of the electrode. The clamping arm 3 is lowered by moving the cable 51 to such an extent that the required clamping end of electrode 71 is located within the clamping device 4.

By relieving the load on cable 75, the required force is transmitted to clamping jaws 61, 62 via angle lever 57a through counterweight 56 over cable 55 and pressure rod 58a.

It is particularly in connection with the use of rolling billets as electrodes that the rod end is deformed in most cases as a result of topping (that is, discarding the top of the ingot). In order nevertheless to be able to clamp the electrode at the upper end, clamping jaws 61, 62, 63, 64 are mounted, as was described, on gimbals by means of their respective universal joints. In addition, clamping jaws 63, 64 are connected on the rotatably positioned bar 70. Because of this arrangement crosssectional deviations and/ or longitudinal warp of the electrode materials have no influence on the Satisfactory placement of the jaw surfaces against the sides of the electrode.

By lifting clamping arm 3 in the manner described above, electrode 71 is lifted out of stand 7. The turntable 5 is swung further until the crystallizer 6, which has been prepared for melting, stands with its opening under the suspended electrode 71. Hereafter arm 3 is lowered and guide arms 42, 43 are swung against electrode 71 until rollers 47 come to rest against the sides of the electrode. In this way a simultaneous correction is made with respect to the centered position of electrode 71. By re-closing the clamping jaws 37, 38, which are activated by cylinder 39 via levers 35, 36, we can establish electrical contact to the bottom plate 30 of the crystallizer 6 via the side bar 33.

By opening the respective shutoff valve 25, we can 7 cool the bottom plate 30 and the crystallizer walls 31, 32.

The cooling agent flows from the head portion of crystallizer 6 via drainage line 26 into drainage groove or trough 28. Before the electrode 71 is ignited in crystallizer 6, fan 50 is turned on; through the hollow guide arms 42, 43, this fan exhausts gases and dust developing during the ignition and melting. During the melting process, the arm 3 is successively lowered to the required 6 extent until the arm is right above the guide arms 42, 43.

At that point, the gnide arms are swung to the side in the manner described, and the electrode 71 can then be melted off down to the previously clamped upper end. When the melting process has been completed, clamping arm 3 is raised somewhat, the clamping jaws 37, 38 are loosened, and crystallizer 6 is swung out of the melting position by rotating the turntable 5.

During the melting process, the afore-mentioned hoisting apparatus places a new electrode into the electrode stand or stands 7 on turntable 5. After the removal of the remelted block from the crystallizer 6, we clean any still adhering slag remnants out of the crystallizer, and we prepare it for the next remelting operation. By further swinging turntable 5, the electrode stand 7 having the new electrode 71 therein is swung under the clamping arm 3, and the cycle described before begins anew. The clamping device 4 has of course been opened before, and the arm 3 raised as required.

It will be understood by those skilled in the art that certain conventional elements, like means for rotating the turntable, and/or the customary structural and operational elements needed for the remelting process proper, have not been described since they are self-explanatory and do not affect the scope of the desired patent protection.

The equipment just described enables to remelt electrodes without any criitical requirements as to their tolerances in terms of cross section and/or longitudinal deviation. The idle times due to technological factors are reduced to a minimum because the full duration of a melting cycle is available in order to prepare the next one. The equipment according to the present invention enables us to become extensively independent of hoisting equipment, that is not directly connected with or tied down at the installation.

It should be understood, of course, that the foregoing disclosure relates only to preferred embodiments of the invention and that it is intended to cover all changes and modifications of the exemplary equipment described which do not constitute departures from the spirit and Scope of the invention as set forth in the appended claims.

What I claim is:

1. An equipment for remelting metals according to the electro-slag remelting process, comprising, in combination, a framework, a rotatable turntable mounted partly underneath said framework, at least two crystallizers mounted on said turntable in spaced-apart relationship, respective base plates on said turntable for supporting said crystallizers, at least one electrode stand mounted on said turntable for holding an electrode, a clamping arm vertically movable on a portion of said framework, electrode retaining means including at least two clamping elements, each of them having at least one clamping jaw secured to said clamping arm, means for balancing the mass of said clamping arm during its movement, an angle lever having one end attached to said balancing means while the other end is connected to said clamping elements, and stationary guidance means adjacent said turntable and mounted above one of said crystallizers when it is swung with said turntable into a melting position.

2. The equipment as defined in claim 1, wherein portions of said base plates are in the form of contact members for closing an electric circuit energizing said one crystallizer in the melting position.

3. The equipment as defined in claim 1, further comprising gimbal suspensions for said clamping jaws, and a crosspiece rotatably supported on said clamping arm for holding at least one of said clamping jaws, for movement in a plane different from that in which the other jaws move.

4. The equipment as defined in claim 1, wherein said crystallizers and said electrode stand are arranged on a common pitch circle of said turntable so that said clamping elements are substantially above said circle.

5. The equipment as defined in claim 1, further comprising reversible drive means for said turntable for selectively bringing one of said crystallizers and said electrode stand into the melting position.

6. The equipment as defined in claim 1, wherein said balancing means includes a counterweight attached to a cable which is operatively connected to said angle lever.

7. The equipment as defined in claim 1, further comprising coolant supply means for said crystallizers, at least partly centrally disposed with respect to said turntable.

8. The equipment as defined in claim 7, further comprising coolant drainage means at least partly centrally disposed with respect to said turntable.

9. The equipment as defined in claim 1, wherein said balancing means includes a cable operatively connected with said angle lever by way of a roller attached to its end.

10. The equipment as defined in claim 9, wherein said balancing means is provided with at least one traction means for selectively displacing said clamping arm and actuating said clamping elements.

11. The equipment as defined in claim 1, further comprising guide members constituting said electrode stand, pivoted to a bottom member into which the lower end of the electrode can be inserted, so that said bottom member is lowered by the weight of the electrode.

12. The equipment as defined in claim 11, further comprising roller means linked to said guide members and frictionally engageable by the electrode, so as to raise said bottom member which is substantially in the form of a funnel.

13. The equipment as defined in claim 1, wherein said guidance means includes a pair of guide arms, for gripping the electrode when inserted in said retaining means, and before being lowered into one of said crystallizers for starting the remelting process.

14. The equipment as defined in claim 13,, further comprising means for swinging apart said guide arms so as to release the electrode.

15. The equipment as defined in claim 13, wherein said guide arms are provided with suction means for removing hot air and gases from the area of the electrode during the remelting process.

References Cited UNITED STATES PATENTS 309,540 12/ 1884 Hainsworth 164266 3,202,751 8/ 1965 Wooding 13-31 3,190,949 6/1965 Gruber et a1. 133l 3,152,372 10/1964 Hopkins 16452 3,220,067 11/1965 Hopkins 164-52 H. B. GILSON, Primary Examiner US. Cl. X.R.

Images