CN100365136C - Method and apparatus for conveying molten metal of improved metallurgical composition - Google Patents

Abstract

The present invention relates to a method and an apparatus for enhancing a metallurgical technology of molten metal, wherein the apparatus comprises a closed inner chamber (23) of a casting ladle, and the closed inner chamber (23) avoids the casting ladle being delivered to the middle technology (15) or a refining position from a manufacturing container, such as a furnace (13), or the heat loss in the process of treating and delivering the casting ladle to a receiving container, such as a funnel (17). The method comprises the steps that a heat-resistant body is led in the inner chamber (23) of the casting ladle, and has adjustable specific weight, wherein the ratio of steel ballast to a refractory material is reduced, and the specific weight of the steel ballast is less than that of buoyancy required by molten metal in the casting ladle and molten metal at a slag interface for supporting the heat-resistant body and is preferably higher than the specific weight required by the buoyancy in a slag layer for completely supporting the heat-resistant body. The method comprises: closing the casting ladle (22), for example, the casting ladle is closed by a cover (90) and the heat-resistant body is kept in the casting ladle until the molten metal is basically discharged from the casting ladle. The method preferably comprises the step of intermediate refining, for example, a balancing component is added in the casting ladle before the casting ladle is closed. In order to achieve the optimal specific weight, the ratio of the steel ballast to the refractory material can be adjusted according to other temperature-resistant and corrosion-resistant variations of the heat-resistant body, for example, high temperature-resistant aluminum oxide different from the material of heat-resistant body is used as a higher temperature-resistant refractory material, high-temperature cement and a permeating inhibitor contaning carbon or silicic acid are added in the refractory material and the.

Description

Method and apparatus for conveying molten metal of improved metallurgical composition

technical field

The present invention relates to a method and apparatus for enhancing the metallurgical process of molten metal composition during conveying and transferring molten metal.

Background technique

In traditional metal alloy manufacturing, the intended material composition for making metal is introduced into blast furnaces such as basic oxygen furnaces and electric arc furnaces, where subsequent liquefaction and mixing processes to form metal casting melts take place. A layer of slag containing impurities and catalyst sits on top of the molten metal, which then flows into the ladle for feeding to the next processing location or another fabrication facility, such as strip or plate rolling equipment. In a manufacturing facility molten metal flows from a ladle into a vessel such as a hopper. The processing location may be provided with a heat source so that the casting liquid remains a liquid mixture when it reaches the processing location, but at the same time considerable heat is lost from the open top ladle as described above.

In avoiding the problem of energy loss, it has been found effective to transfer the molten metal from the furnace to the processing equipment and to close the ladle during processing. In addition, another recent innovation improves the metallurgical composition of the casting liquid by improving the metallurgical process of the slag layer or molten metal. At the same time, heat is maintained in the ladle or heat loss in the ladle is improved. Unfortunately, while sealing the ladle can bring about metallurgical, improvements during the transfer of molten metal from the blast furnace to the processing location or production facility, including extended periods of heating and heat-hard-to-reach process conditions, it cannot Enable existing casting control technology to be successfully used in existing vessels.

For example, previously known techniques for controlling molten casting within a ladle, such as placing refractory plugs and lowering nozzles with robotic arms in a stationary furnace, cannot be employed in a closed ladle. And the known refractory body described in KoFFron's US Patent No. 4,601,415 cannot be used in a sealed ladle when the molten metal in the ladle is located at a critical level above the discharge nozzle to swirl. In addition, the unique specific gravity design of the previous refractory bodies made them supported by buoyancy in the melt, and they would wear out quickly after long-term exposure to the casting ladle, so that they could not reach the long-term contact with the molten metal and slag layer interface. Predetermined role.

Contents of the invention

The present invention overcomes the above-mentioned disadvantages. It provides a method and equipment for continuously processing molten metal, and after improving the process, it increases the content of metal casting solution discharged from the casting ladle with improved quality. In summary, improved metallurgical treatment of metal castings combined with improved feeding, including capping and sealing of metal casting ladles, especially at the end of refining, e.g. by adding balancing components in the ladle to achieve a target balance composition. This method includes the introduction of a heat-resistant body with a special structure to maintain a better balanced composition of the metal casting liquid, and to maintain the heat-resistant body in the casting ladle until the molten metal is cast. The refractory body is formed from a homogeneous mixture of steel ballast, refractory material, and a penetration inhibitor material that, compared with the refractory material, inhibits the infiltration of molten metal and slag in the ladle to the refractory body have a better effect. And the specific gravity of the refractory body is smaller than the specific gravity required for the buoyancy of the molten metal in the ladle to support the refractory body, and larger than the specific gravity required for the buoyancy of the slag layer in the ladle to support the refractory body. The specific gravity of the heat-resistant body is in the range of 2.7-4.5, so that the penetration inhibitor material improves the ability of the heat-resistant body to resist the penetration of molten metal and slag in the ladle. Extended refractory body retention time requires a specially constructed vortex arrester consisting of a refractory body at least partially inside the casting ladle and fitted to its shape, with an adjusted specific gravity having a steel pressure of The ratio of hold to refractory material is less than the ratio of specific gravity required for buoyant support of the molten metal in the ladle to the molten metal in the slag interface. In order to better rectify the interface, the ratio is preferably higher than the ratio of the specific gravity required to fully support the refractory body in the slag layer. More preferably, the refractory body also includes a penetration inhibitor to prevent the refractory body from being damaged in the molten metal.

Therefore, the present invention provides a heat-resistant body that can be exposed to molten metal, slag or waste heat for a long time without being easily damaged. The refractory body of the present invention provides a relatively strong structure that maintains the integrity of the refractory body and reduces the amount of stress during casting as compared to previous uncovered ladles and previously known slag control or production enhancement techniques. swirl. In addition, the capped ladle has an improved conveying mechanism and an improved metallurgical fabrication system which allows greater precision in alloy fabrication, improved fabrication techniques, use of large quantities of high quality metal, and is more energy efficient than known fabrication systems higher.

Brief description of the drawings

Figure 1 is a partial schematic diagram of metal manufacturing process equipment, including a sectional view of the transfer casting ladle used by the system;

Figure 2 is an enlarged sectional view of the bottom of the ladle, including a nozzle valve controlling the outflow of molten metal;

Fig. 3 is an enlarged sectional view along line 3-3 in Fig. 2 .

Detailed ways

Referring to FIG. 1 , a metal fabrication system 10 includes a fabrication facility 12 , a transfer machine 14 and a processing facility 16 . Manufacturing equipment 12 may include a basic oxygen furnace, an electric arc furnace, or other alloy melting equipment. Raw materials for metal making are fed into a furnace, heated to melt and mixed to make a metal with a predetermined desired composition. Although the quality and specific composition of the metal in the furnace 13 is consistent with the raw material, impurities in the composition cause the processing equipment 16 to use a metal composition different from the intended metal composition. Processing equipment 16 may be finished mass production equipment, such as strip rolling equipment, which includes a hopper that receives conveyed molten metal, in the form of strips, plates, or other shapes, that hardens the molten metal for subsequent reprocessing. Heating, forming, stamping and other processing steps. However, differences in complexity, size, and functionality between fabrication facility 12 and processing facility 16 necessitate the use of transfer machinery 14 to unload and transfer molten metal from fabrication facility 12 to intermediate process location 15 or processing facility 16, or intermediate process Between location 15 and processing equipment 16 .

The present invention is also applicable to system 10 where an intermediate process location 15 , such as a secondary refining facility, may be located between manufacturing facility 12 and processing facility 16 . Usually, the melting furnace produces molten steel with chemical composition and temperature within the specified range, and then the molten steel flows into the ladle and is conveyed in turn to the casting refining furnace, stirring place, degassing place-each can be described as an intermediate process position- - Used to adjust the chemical composition of metals. Chemical composition and temperature are adjusted more precisely and within a narrower range to meet customer order requirements for product grades. Therefore, it is desirable that the heat (casting liquid) produced from the furnace each time have substantially the same chemical composition range. All the different grades are then chemically adjusted in refining furnaces. For example, adding materials such as Ca, Mn, Al, MgO, Si, and calcium carbide, blowing argon gas through molten steel, and reheating with electrodes or other heating methods to improve compliance with specifications. The intermediate process preferably takes place before the introduction of the refractory body, since the refractory body cannot be confined above the discharge nozzle by external means.

Generally speaking, the transfer mechanism 14 includes a displacer 18 for transferring a load of molten metal. In the preferred embodiment, the displacer 18 includes a ladle 22 supported by a crane 20 or other transport device, and the crane 20 for lifting the lid 90 of the ladle 22. Typically, the crane 20 transfers the ladle to the fabrication facility 12 , opening the top 26 of the ladle 22 to receive the casting liquid discharged from the nozzle or other opening of the furnace 13 of the fabrication facility 12 . Likewise, the ladle includes a discharge nozzle 28 which causes the melt to flow into a hopper or other receiving vessel of the processing apparatus 16 . Preferably, the discharge nozzle 28 has a valve 30 which is responsive to a controller 32 .

The controller 32 includes a detection sensor located at the nozzle to detect when the flow through the nozzle is reduced, i.e. the flow is reduced by a swirl stopper or other piston to stop the flow of metal from the ladle, preferably when the slag is floating on the molten metal The top layer of molten metal mixture terminates the metal outflow before. However, the movement from the molten metal layer to the slag layer occurs almost simultaneously when the vortex arrester is in operation because the vortex arrester rejects the metal-slag mixture by removing the vortex. Movement occurs so rapidly that it is almost inseparable. Although maximum output is not observed when the throttle valve stops responding, it is common to see slag flow stop when workers or automated detectors detect slag. Throttling effects and migration of molten metal to slag can be detected by workers or automated detectors. Additionally, the controller 32 may be controlled manually or automatically in response to throttling or detection of slag composition.

As shown in Figure 2, the response to terminate flow can be accomplished by hydromechanical means after throttling is detected. For example, the piston 42 of the hydraulic cylinder 40 is coupled with the transmission means 44 and the hydraulic cylinder 40 is engaged with the sliding housing 46 . The slide housing 46 includes a concave groove which supports a slide plate 48 of refractory material. Sliding disc 48 slides adjacent chassis 50 , also made of refractory material, and supported between brick-shaped metal fittings 52 . The metal brick 52 comprises four side supports supporting the chassis and an attachment mechanism with bolts 54 for adjusting the position of the chassis 50 relative to the nozzle insert when the brick metal is mounted on the ladle, The chassis opening 56 is thus aligned with the opening 58 in the nozzle insert 60 . The chassis support 62 is mounted or welded to the ladle shell and engages a sliding pan mechanism 64 which is bolted to the chassis support 62 .

The opening 66 cooperates with the hydraulic cylinder 40 in a well-known manner, and the opening 66 of the sliding plate 48 is replaced by a sliding housing. In addition, the slider is supported within the clip 68 by clip arms 76 (FIG. 3) so that the chute nozzle 70 is supported in the chute nozzle housing. The chute nozzle 70 also includes an opening 74 which may be aligned with the opening 66 of the slide plate 48 , the opening 56 of the chassis 50 and the opening 58 in the nozzle insert 60 . The chute nozzle housing 72 slides and rotates into the detents and is secured to the slide housing 46 . Clamp arm 76 includes an over-center crank lever mechanism that acts in response to clamping handle 80 for maintaining chute nozzle 70 in line with nozzle insert 60 and opened by sliding of slide disc 48 relative to chassis 50 valve. The coil spring 82 is mounted at a location where it is least affected by the heat of the valve and serves to support the surface load of the slider 48 .

The open top 26 of the ladle is closed by a cover 90 which may be made of refractory material or clad with refractory material. Cover 90 is supported and positioned by crane 24 . A cover 90 may be placed or hung on the ladle so as to close the bore 23 of the ladle between the closed nozzle 28 and the open top 26 . Such lids for closing the inner chamber 23 of the ladle to retain heat are previously known. Moreover, since the heat in the casting ladle is preserved, metallurgical adjustments can be made to the molten steel in the casting ladle during transfer. In particular, additional alloying elements and catalysts may be added to the bore 23 before the lid 90 is placed on the open top 26 of the ladle 22, thereby effecting refining of the molten steel. In particular, since the slag layer continues to provide catalyst and remove impurities from the molten metal, the re-intervention of impurities is avoided, so that the composition of the molten metal in the inner chamber 23 can be maintained within the composition range of the designed alloys and compounds.

It is best not to make adjustments during transfer, but while the ladle is in an intermediate process position 15 or in a secondary melting furnace. The ladle does not leave the intermediate process station 15 or the secondary melting furnace until the chemical composition and temperature of the molten steel are within narrow target ranges. Preferably the refractory body is inserted into the casting ladle after all adjustments made in the intermediate process position 15 or in the secondary melting furnace have been completed. Regardless of whether the intermediate process takes place in the refining furnace, or during transportation to the production furnace, or in the production furnace, it is best to finish the intermediate process before the lid 90 is placed on the top of the casting ladle, and preferably before the refractory body intervenes. craft.

As a result of closing the open top 26 and nozzle 28 of the ladle, the bore 23 is difficult to further modify so that when it is necessary to discharge the molten metal, a vortex arrester is used to control the mixture of the molten metal layer and the slag layer. In addition, when the ladle is transferred by the mechanical mechanism 24 to the destination container 17 of the processing facility 16, the lid 90 cannot be opened until the molten metal pour has flowed out substantially or completely. In some plants, the lid is not opened until the ladle is almost empty. The uncapping operation can be carried out while one ladle is substantially empty, while the other substantially full ladle for further casting is not yet closed.

As a result, the introduction of the swirl arrester into the closed ladle represents a completely different period in which the refractory body comes into contact with the molten metal and the slag layer more than in known uses. Unlike previously known swirl arresters, the specific gravity and refractoriness of the refractory body are adjusted to the appropriate level during the casting step, which takes place after the ladle has been filled and after a long closed transfer. Casting preferably occurs after the intermediate process. Although the duration of the casting ranges from 35 to 180 minutes, the refractory body must provide good performance during the final time of the casting step, eg 10 minutes.

As an example, when the specific gravity of the refractory body is in the range of 4.8-5.2, which is the specific gravity range that usually keeps the slag layer and the molten metal layer in the furnace separated for 2-10 minutes, the refractory body is ineffective in the closed ladle environment, where 2-10 minutes refers to the time from stopping the molten metal in the furnace, forming a vortex at a critical height, to throttling or using other termination methods to terminate the discharge of molten steel from the nozzle. Consequently, several improvements have been made to vortex arresters in the ladle environment that contribute to their life. In particular, the weight percent of alumina (Al ₂ O ₃ ) in the remaining components was increased from 45% to 70%, its content was increased to the high temperature range, and the properties were also increased and maintained. In addition, the refractory body component is mixed with high-temperature cement, such as calcium-aluminum high-temperature cement, high-strength cement or low-moisture-content cement, such as 1% to 2% by weight.

In addition, the ratio of steel ballast to refractory material is reduced, so that the optimum value of specific gravity is about 3.7, and the suitable value range is roughly 2.7-4.5. In addition, it is preferable to add infiltration inhibitors made of granular carbonaceous materials into the refractory mixture to reduce damage, erosion, corrosion, damage and spalling caused by long-term contact between the refractory body and molten metal or slag and its immersion quantity. However, other inorganic compounds may also be added as barriers, preferably silicon, borosilicates and other glasses.

Generally more expensive refractory materials such as MgO can be used, but should be avoided in order to limit the cost. In any case the refractory body consists of a mixture of steel ballast and refractory material, and the specific gravity of the refractory body is adjusted according to previously known refractory swirl arresters. Adjustments can include changes due to the target chemical composition of the design, such as stainless steel wire, silicon carbide, magnesium refractory, chromium refractory, zircon refractory, zirconia refractory, flake alumina refractory, mallite refractory materials etc. The adjustment is also determined by the specified bulk density and the average life of the molten metal. The optimal life of the steel ballast is 300-400# per cubic foot, and the optimal weight percentage is between 30% and 80%, while the weight percentage of the above-mentioned refractory materials disclosed above is 30% to 80%. The binder of high-temperature cement should withstand the high temperature of at least 1000 , but preferably can withstand the high temperature of 2400 -3300  without substantial damage, and the optimal weight percentage is 2% to 12%.

The ratio of steel ballast to refractory material is reduced, and its specific gravity is less than that required for the buoyancy of molten metal at the interface between molten metal and slag in the ladle to support the refractory body, but preferably higher than that in the slag layer completely The ratio of the specific gravity required to support the buoyancy of a refractory body. As a result, the specific gravity and heat resistance (the ability to support and survive in a liquid metal environment) are adjusted so that the refractory body remains stable even after prolonged exposure to molten metal in the closed ladle environment that is passed from the furnace to the receiving vessel. The shape of the work can perform the work of the vortex stopper and throttling. Change the specific gravity of the heat-resistant body so that the heat-resistant body is not adsorbed to the discharge nozzle prematurely.

While one embodiment of the invention has been illustrated and described, it is not intended to illustrate and describe all possible forms of the invention. Moreover, the words and phrases in the specification are words of description which are not limiting, and it is understood that various changes may be made without departing from the spirit and scope of the invention.

Claims (8)

1. one kind is used at the lasting whirlpool detainer of handling molten metal of transport process, molten metal is transmitted by casting ladle (22), casting ladle (22) has opening, is located at the lid that can seal (90) on the described opening and is located at the interior discharge nozzle (28) of casting ladle (22), and described whirlpool detainer comprises:

Shape can be engaged in the interior thermostabile bodies of opening of described casting ladle;

Described thermostabile bodies is formed by at least a mixture in steel ballasting, refractory materials and carbonaceous particles material, silica and the silicate-based glasses; And

The proportion of described thermostabile bodies is in the scope of 2.7-4.5, and the described at least a ability that has improved the infiltration of described thermostabile bodies opposing interior molten metal of casting ladle (22) and slag in carbonaceous particles material, silica and the silicate-based glasses.

2. whirlpool detainer as claimed in claim 1, wherein, described refractory materials comprises at least a in refractory mortar and the aluminum oxide.

3. whirlpool detainer as claimed in claim 1 wherein, contains high-temperature adhesives in the described mixture.

4. a method of utilizing casting of metals bag (22) to improve casting of metals technology fills molten metal in the described casting of metals bag (22) and has discharge nozzle (28), and described method comprises:

Formation is by at least a thermostabile bodies that mixture constituted in steel ballasting, heat-stable material and carbonaceous particles material, silica and the silicate-based glasses, the proportion of described thermostabile bodies is in the scope of 2.7-4.5, and the described at least a ability that has improved the infiltration of described thermostabile bodies opposing interior molten metal of casting ladle (22) and slag in carbonaceous particles material, silica and the silicate-based glasses;

Described thermostabile bodies is inserted in the casting of metals bag;

With closed with covers casting of metals bag; With

Described thermostabile bodies is remained in the described casting ladle, discharge until molten metal.

5. method as claimed in claim 4 wherein, further is included in and carries out the middle process processing in the casting ladle.

6. method as claimed in claim 5, wherein, described middle process comprises the casting ladle refining.

7. method as claimed in claim 6, wherein, described refinement step is included in the capping step interior composition of balance casting ladle before.

8. method as claimed in claim 6, wherein, described refinement step comprises the degassing.

Images