DE1263042B - Process for the continuous aftertreatment and casting of material coming from a shaft furnace used for premelting - Google Patents

Description

Process for continuous post-treatment and potting from a shaft furnace used for premelting. There are processes for treating and potting from one serving for premelting the material Shaft furnace, e.g. B, material derived from a cupola furnace, especially iron, in which the metal melted in the shaft furnace is placed in a downstream electric furnace is post-treated, with the required alloy surcharges only in the electric furnace are added and there, too, a possible temperature increase before the final casting is carried out in a liquid metal bath.

For example, it is known to use such a method from in Cupolas to produce remelted cast iron steel. This way can too Ordinary cast iron will experience an increase in quality.

It is also already known that in a gutter from a cupola furnace Transferring outflowing metal into a drum-shaped, trough-heated induction furnace and from there by means of ladles to lead to the places where the final cast should be made. Such a horizontally lying drum furnace offers the possibility of entering the melt at one end of the drum and it at the other Remove the end again so that continuous operation can be carried out can. In such a channel induction furnace downstream of a cupola furnace can easily be melted down additional alloy surcharges, and it is also an increase in temperature as well as a mixing of the in this furnace from the cupola furnace from inflowing metal possible, Such a combination of cupola and drum-shaped, The channel-heated induction furnace is particularly suitable for the production of quality cast iron suitable.

The channel-heated induction furnace, whatever its design however, it has the disadvantage that it is difficult to deliver, and that much more difficult than a crucible induction furnace. In addition, due to the complicated melt channel routing, the service life of the lining of the channel-heated induction furnace in relation significantly shorter to the crucible induction furnace. This results in the channel induction furnace relatively high maintenance costs and longer business interruptions failure of the furnace, while a crucible induction furnace due to the simple, conveniently accessible crucible shape can be delivered in the shortest possible time and the Control of any pitted crucible surfaces as well as their repair proportionally is easily possible. This is also the reason that the NF crucible induction furnace the channel induction furnace more and more in all areas of smelting technology displaced more.

But if you wanted to use the well-known combination of a cupola furnace a downstream electric furnace, in which the transfer of the liquid metal takes place from the cupola furnace to the electric furnace by means of a pouring channel, the drum-shaped one trough-heated induction furnace simply by using an elongated drum furnace would replace trained crucible induction furnace, so would be for such a crucible furnace result in an extremely difficult and expensive construction.

But if you wanted instead of a drum-shaped crucible induction furnace a single normally built crucible induction furnace for a continuous working process connect with a cupola, this project fails because even during the tilting of the crucible furnace to the one flowing in from the cupola furnace via a pouring channel Metal in the crucible furnace alloy surcharges would have to be added and that during this time a temperature increase must be made.

There are also known electric furnaces, in particular electric arc furnaces, which are equipped with swiveling casting rings, thereby increasing the possibilities of the Potting from such z. B. to expand rotatable ovens.

The effort to create a completely continuous in a simple manner Operation in the above-mentioned casting of metals, in particular especially treated iron, cannot be met with this without further ado.

In such a process for the continuous post-treatment and casting of derived from a serving for premelting shaft furnace material, in particular cast iron, the-called disadvantages and difficulties according to the invention avoided by the molten in the shaft furnace metal using a per se known hinged or at least two induction crucible furnaces, in particular low-frequency furnaces, are fed alternately to a laterally displaceable pouring channel, in which the addition and melting down of alloy additives including post-treatment and, if necessary, temperature increase of the melt takes place, and the final casting is made alternately from that crucible induction furnace that does not have the shaft furnace communicates through the launder.

A device for carrying out the method according to the invention consists of a known shaft furnace, for. B. a cupola for Premelting of the material and at least two tiltable ones downstream of this Induction crucible furnaces, especially low frequency furnaces, and a swiveling or displaceable pouring chute for alternating filling of each crucible furnace the metal melted in the shaft furnace.

Since according to the invention are two crucible furnaces available for the connected to the low-melting the metal in the shaft furnace alloy treatment process, for example, half-time, the effluent from blast furnace metal run into one of the two crucible furnaces, and within this time the alloy supplements may be added in the respective crucible furnace, melted, and a corresponding temperature increase in the bath can be made.

In the second half of this working period, i. H. while the metal flowing out from the shaft furnace enters the second of the two crucible furnaces, the finished melt can now be poured from the first crucible furnace into pans for final use. The metal itself in the crucible furnace only needs to be kept warm during the casting time.

In view of the changing workload of the two induction crucible furnaces downstream of the shaft furnace, it is expedient in the method according to the invention to provide two tiltable induction crucible furnaces of the same type, both of which are designed for the same electrical furnace connection value. Switching the pivotable or displaceable pouring chute for the z. B. Cupola draining metal from one crucible furnace to the other can be done without difficulty during operation, since a cupola is always drained intermittently, every 8 to 10 minutes. In any case, there is enough time available for changing the casting channel, as well as for checking the metal contained in the crucible furnace that is ready for final casting.

The inventive arrangement of a shaft furnace with two LF induction crucible furnaces is compared to the known connection of a shaft furnace with a channel induction drum furnace also achieved a better quality end product, with the iin NF crucible furnace being stronger The pinch effect that appears is more homogeneous and more uniform in temperature Product guaranteed.

The use of crucible induction furnaces in combination with a Cupola furnace results in particular for NF crucible induction furnaces compared to channel induction furnaces yet another benefit. Since a cupola furnace is now generally only available during the day is operated, it can also be easy for him with regard to the mode of operation of the NF crucible furnace must be adapted, as this can be approached cold in the morning. On the other hand you have to a channel induction furnace, this should not suffer in its lining Keep warm with a remnant part of liquid metal in the melt channels, what is cumbersome and uneconomical for operation in the foundries.

Since an induction crucible furnace of the usual design is tilted around the pouring spout the induction crucible furnace can be used, especially in a mechanized operation exiting metal directly into the conveyed on a casting belt in front of the induction furnace Mold boxes are potted. There is no need to transport the liquid metal in a ladle thereby completely.

The following are the method of the invention and facilities for carrying out this method explained in more detail on the basis of exemplary embodiments.

F i g. 1 and 2 show an embodiment of the device according to the invention, in which two LF crucible induction furnaces are connected downstream of a cupola furnace, which can be brought into connection with the cupola furnace through a pivotable pouring chute; the F i g. 1 shows the cupola furnace in side view and one of the two NF crucible induction furnaces in longitudinal section, while FIGS . Fig. 2 is a plan view of the entire device; F i g. 3 is a front view of the FIG. 1 and 2, however, with a pouring channel that can be displaced to the left and right according to C tD3, instead of the pivoting pouring channel of FIG. 1 and 2; F i g. 4 is a plan view of the device shown in Fig. 3, F i g. 5 to 7 represent a device for carrying out the method according to the invention, in which the crucible induction furnaces are not only designed to be tiltable, but also to be lovable and lowerable.

In the embodiment according to FIGS. 1 and 2, the cooperating with the two NF-Tiegelinduktionsöfen 9, 10 cupola furnace 1 is mounted on a stage 2 and has at its front lower side of the metal trough 3. The incoming from the cupola into the metal trough 3 the metal is a valve disposed in said duct Drain hole 4 passed into the collecting space 5 of a pouring channel 7 , which can be pivoted about a bracket 6 arranged below this collecting space. The pouring channel 7 is inclined from the collecting space 5 to its other end and has at this end at 8 a drainage hole, through which in the case of the FIGS . 1 and 2 shown position of the pouring trough, the metal flowing out of this into the NF crucible induction furnace 9 is passed.

If the pouring channel 7 is pivoted in the direction indicated by an arrow in F i 2, the liquid metal leaving the pouring channel reaches the other LF crucible induction furnace 10.

Each of the two LF crucible induction furnaces 9, 10 has a furnace body 12 with a melting chamber 11 and can be tilted about an axis 13 arranged below the furnace nose 14. The furnace cover is denoted by 19 and has a pouring-in opening 20 for the out of the drain hole 8 of the trough 7 in the NF-crucible induction furnace 9 and 10 respectively inflowing metal on, the tilt axis 13 of each crucible furnace is mounted in arranged on the front of the oven support columns 21 . In the basic position the furnace rests with its rear part on a support 15. The furnace is tilted about the axis 13 hydraulically by means of two tilting cylinders arranged on both sides of the furnace. In FIG. 1 the lower part of one of these tilt cylinders can be seen at 16 . The furnace platform, which is led around the upper furnace part as a termination for the furnace trench 17 , is designated by 18 .

In the F i g. 3 and 4 show an embodiment of the device according to the invention, in which a laterally displaceable pouring chute is used instead of a pivoting pouring chute. Here, as in the other figures,. the same reference numerals as in FIGS . 1 and 2 elected. The laterally displaceable pouring channel for alternately filling one of the two NF crucible induction furnaces 9 and 10 with the metal melted in the cupola furnace 1 is denoted by 23 and is arranged below the metal drainage channel 22 of the cupola furnace. The pouring channel 23 can, as shown in FIG. 3 can be seen, have a slightly curved shape and is mounted on a support frame 24 between two end positions. A fixed support frame 24 in the shaft 25 serves to guide the gutter 23 at its lateral displacement in conjunction with two on the bottom of the groove 23 provided for guiding segments. 26 and 27

The pouring channel 23 has drainage openings 28 and 29 at its ends 30, 31, respectively. Position of the trough 23 shown in Figure 3 reaches that of the cupola of the metal trough 22 into the trough 23 metal flowing through the opening 28 in the crucible furnace 10. By moving the gutter 23 into its other end position can, mutatis mutandis, the crucible furnace 9 are fed.

As the F i g. 3 and 4, the pouring channel 23 is slightly longer than the respective distance from the drainage hole in the drainage channel 22 of the cupola to the pouring opening of the crucible furnace 9 or 10. Since the openings 28, 29 of the channel 23 are wider (about 20% ) are apart from each other than the aforementioned distance, no metal can flow out of the drain hole of the channel 22 of the cupola furnace due to the inclination of the channel 23 through the opening of the movable channel 23 which is closest to the drain hole of the cupola channel 22 in the respective end position of this channel .

In the representation according to FIG. 4, the crucible furnaces 9 and 10 are arranged at the same distance from the associated cupola furnace 1 , as in the case of the arrangement according to FIG. 2. When using a laterally displaceable pouring channel 23 according to FIGS. 3 and 4 - if this is necessary for reasons of spatial arrangement - the metal drainage channel 22 of the cupola furnace could be kept as short as in the case of the arrangement according to FIGS. 1 and 2, so that the crucible furnaces 9 and 10 could then be moved significantly closer to the cupola furnace 1 , whereby considerable space can be saved.

The F i g. 5 to 7 show an arrangement in which the crucible induction furnaces 9 and 10 arranged in front of the cupola furnace 1 , according to a further embodiment of the invention, are not only designed to be tiltable, but also to be raised and lowered. This can be accomplished, for example, in that each crucible furnace 9, 10 is mounted pivotably about an axis 33 below the furnace snout in sliding blocks 34 arranged on both sides of the furnace, which can be moved to a limited extent in vertical guides 35 , and that the furnace body 12 on that of the furnace snout averted side is guided displaceably by means of at least one further sliding block 38 in vertical guides 37 open at their upper ends, which extend up to such a height that the sliding block or blocks 38 are removed from the guides 37 during the vertical upward movement of the crucible furnace 9 or 10 are released when the sliding blocks 34 assigned to the pivot axis 33 reach the upper limit of their guides 35. The guides 35 and 37 are provided in vertical support columns 36 or support frames 39 mounted in the furnace pit.

A hydraulic device can be provided for raising and lowering the crucible furnaces and the tilting of the furnace following the lifting movement, the points of application of this device on the crucibles each being above the crucible center of gravity; this hydraulic device can, as is the case with the exemplary embodiment according to FIGS. 5 and 6 are provided, consist of a pair of telescopic cylinders 40. Each telescopic cylinder has two push pistons 41, 42, with - as shown in FIG. 6 it can be seen - the piston 41 with the larger cross section is used for lifting and the piston 42 with the smaller cross section for the subsequent tilting of the furnace about the axis 33 .

The after the F i g. 5 to 7 equipped with elevating and lowering crucible induction furnaces offers particular advantages in cases in which an existing cupola furnace system is to be made usable by the subsequent installation of two induction crucible furnaces for the implementation of the method according to the invention and there is a requirement that the final casting points (molding boxes ) to transport liquid metal to be passed on as before with an already existing transport system by means of pouring ladles with the pouring height unchanged in the pouring ladles to the final pouring points.

For a more detailed explanation, FIG. 6 and 7, in addition to the metal drainage channel 3 arranged on the cupola furnace, the drainage channel 44, which was originally kept longer, is also shown in dash-dotted lines. If one now thinks that, in the original mode of operation, the liquid metal running out of the cupola passes through the opening 32 of the channel 44 into the ladle 43 which is suspended from a crane position in front of the furnace for the removal of the metal, then, as F i G. 6 and 7 show the invention-C 9 according to the cupola furnace, which can be raised and lowered downstream of the cupola furnace 9, 10 in such a way that the crane system that is already available for transporting the metal and the casting ladles that are already in place can continue to be used without any changes .

If, with such an arrangement according to the invention, the metal flowing out of the cupola is transferred halfway into the crucible furnaces 9, 10 downstream of it, this metal transfer always takes place in the crucible furnace position according to FIG. 5, d. H. when the corresponding crucible furnace is in its lowest position, while the pouring of the metal from the crucible furnace ready for pouring (furnace 10 in FIG. 7) into the transport pan 43 with the crucible furnace up, as shown in FIG. 6 takes place.

In an arrangement according to FIGS. 5 to 7 with a hydraulic device for raising and lowering the crucible furnaces 9, 10 can be connected to the pressure lines of the hydraulic device associated with the individual crucible furnaces pressure gauges, which are calibrated so that they indicate the respective weight of the crucible contents. In this way, the contents of the crucible can be weighed in a very simple manner.

The invention is not limited to the exemplary embodiments described limited. Various deviations, especially structural deviations, are conceivable.

So it can be in larger foundries z. B. be useful to a relatively large cupola around, which has several pouring openings, in a circle to arrange a plurality of crucible induction furnaces, from which correspondingly arranged ones or pouring ladles or casting molds passed by the furnace are fed can.

It may also be appropriate to provide a locking between the Kippvorrichtuhgen the crucible and the pivotable or displaceable runner through which the tilting movement is of the respectively locked with the shaft furnace through the runner associated crucible furnace, The pivoting or displacing the Gießritine 7, 23 can be either be done by hand, or motor drive means known per se can be provided for this purpose.

The method according to the invention and those used to carry it out Facilities are primarily suitable for the production of tempered cast iron, however, the invention is by no means limited thereto. She's having an advantage too can be used analogously for the production of other types of iron and also for steel production.

The crucible induction furnaces used can in per se be provided in a known manner with the crucible surrounding iron packages. It can but also induction crucible furnaces without such iron packages come into question. For the Crucible furnaces are primarily fed with low frequency, in particular mains frequency Crucible induction furnaces in question, but without the application of the invention is limited to the aforementioned frequency range.

Finally, in an arrangement according to FIGS. 5 to 7, the guides 37 or sliding blocks 38 provided for guiding the furnace on the side facing away from the furnace nose are not absolutely necessary. However, it is advisable to provide this guide means anyway, in order to avoid that the furnace begins to oscillate during its upward and downward movement.

Claims (2)

Claims: 1. A method for the continuous post-treatment and casting of material originating from a shaft furnace used for premelting, in particular cast iron, d a - characterized in that the metal melted in the shaft furnace is made using a known pivotable or laterally displaceable casting belt ( 7, 23) alternately at least two crucible induction furnaces, in particular low-frequency furnaces (9, 10), in which the addition and melting of alloy additives including post-treatment and, if necessary, temperature increase of the melt takes place and that the final casting is made from the crucible induction furnace which is not connected to the shaft furnace (1) through the casting channel (7, 23) . 2. Device for carrying out the method according to claim 1, marked eichnet by a known shaft furnace (1), for. 13. a cupola furnace for pre-melting the material and at least two tiltable induction crucible furnaces connected downstream, in particular low-frequency furnaces (9, 10), and a swiveling or displaceable pouring channel (7, 23) for alternating filling of a crucible furnace with the metal melted in the shaft furnace. 3. Device according to claim 2 with a displaceable pouring channel for alternating filling of one of two crucible induction furnaces with the metal melted in the shaft furnace, characterized by guide and support means, by means of which the pouring channel (23) in one end position with its one end (30) over the one crucible induction furnace (10) and with a point in front of its other end (31) below the shaft furnace drainage channel (U) and in its other end position with its other end (31) over the second crucible induction furnace (9) and with one in front of one of them End (30) located point below the shaft furnace drainage channel can be determined so that the channel (23) runs in both end positions in the direction from the shaft furnace to the crucible furnace with a slope required for the drainage of the liquid metal. 4. Device according to claim 2 or 3, characterized by a device for raising and lowering the Tiegeffinduktionsöfen. 5. Device according to claim 4, characterized in that the device for raising and lowering the Tiegeliiiduktionsöfen is a hydraulic device and the points of application of this device on the crucibles are each above the crucible center of gravity, 6. Device according to claim 5, characterized in that each crucible furnace (9, 10) is mounted pivotably about an axis (33) below the furnace snout in cow stones (34) which can be moved to a limited extent in vertical guides (35) , and that the furnace body on the side facing away from the furnace snout is by means of at least one further sliding block (38) is guided displaceably in vertical guides (37) which are open at their upper ends and which extend up to such a height that the sliding block (s) (38) are released from these guides during the vertical upward movement of the furnace when the the pivot axis (33) associated sliding blocks (34) reach the upper limit of their guides (35) en. That the hy draulic device # gauges are connected to each crucible associated Druckleitungeri which are calibrated so as to indicate 7. A device according to claim 5 or 6, characterized in that the specific weight of the crucible contents. 8. Device according to one of claims 2 to 7, characterized by a lock between the tilting devices of the crucible furnaces and the pivotable or displaceable pouring channel, through which the IGpp movement of the crucible furnace connected to the shaft furnace through the pouring channel is blocked. Documents considered: German Patent No. 381774.