CA2754323A1 - Bottom pouring nozzle for arrangement in the bottom of a metallurgical vessel - Google Patents
Bottom pouring nozzle for arrangement in the bottom of a metallurgical vessel Download PDFInfo
- Publication number
- CA2754323A1 CA2754323A1 CA2754323A CA2754323A CA2754323A1 CA 2754323 A1 CA2754323 A1 CA 2754323A1 CA 2754323 A CA2754323 A CA 2754323A CA 2754323 A CA2754323 A CA 2754323A CA 2754323 A1 CA2754323 A1 CA 2754323A1
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- Prior art keywords
- pouring nozzle
- housing
- bottom pouring
- gastight
- opening
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
- B22D41/50—Pouring-nozzles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
- B22D41/50—Pouring-nozzles
- B22D41/58—Pouring-nozzles with gas injecting means
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
- Continuous Casting (AREA)
- Furnace Charging Or Discharging (AREA)
- Glass Melting And Manufacturing (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
Bottom pouring nozzle for arrangement in or at a bottom of a metallurgical vessel, having an upper end, particularly for fitting to a metallurgical vessel or to a sliding gate of a metallurgical vessel and a lower end, whereby a throughflow channel is arranged in between both having at least a lower pouring opening arranged at the lower end, whereby the radially outermost surface of the wall of the throughflow opening is surrounded by a gastight housing, and is characterized in that the housing encases the lower end of the at least one pouring opening in a gastight manner.
Description
BOTTOM POURING NOZZLE FOR ARRANGEMENT IN THE BOTTOM OF A
METALLURGICAL VESSEL
The invention concerns a bottom pouring nozzle for arrangement in or at a bottom of a metallurgical vessel, having an upper end, particularly for fitting in a metallurgical vessel or onto a sliding gate of a metallurgical vessel and having a lower end, whereby in between both ends a throughflow channel is arranged having at least a lower pouring opening at the lower end, whereby the radially outermost surface of the wall of the throughflow opening is surrounded by a gastight housing. Furthermore, the invention concerns a method of using a bottom pouring nozzle.
Especially with steel melts, the molten metal is poured from a metallurgical vessel into a mould. Such a metallurgical vessel can for instance be a casting ladle (also called ladle) or a so called distrubutor (also known as intermediate vessel or tundish). For example, the liquid metal is poured from the ladle into the tundish and from the tundish into the mould of a continuous casting installation. It runs through the bottom of the ladle or tundish through a so called bottom pouring nozzle (also called nozzle).
Disadvantageous is the adhering of material onto the wall of the bottom pouring nozzle accumulated during throughflow. This reduces the cross sectional area, so that flow ratios and steel quality is detrimentally influenced because of turbulences. This accumulated material can also break free and cause inclusion related defects in the steel.
To prevent the adhering of material onto the wall, mostly an inert gas such as Argon is supplied in the throughflow opening. Too much gas can also negatively affect the steel quality, for instance the formation of pinholes in steel, which lead to surface defects during the rolling of steel.
A material for a bottom pouring nozzle is for instance described in WO
2004/035249 Al. A
bottom pouring nozzle in a metallurgical vessel is disclosed in KR 2003-0017154 A or in US
2003/0116893 Al. The use of inert gas is relied upon in the latter document, with the aim to reduce the adhering of material nozzle (so called Clogging) to the inner wall of the bottom pouring nozzle, similar to what is described in JP 2187239. A mechanism using a regulated gas supply is known in detail from WO 01/56725 Al. Nitrogen is supplied according to Japanese publication JP 8290250. JP 3193250 discloses a method for monitoring the adhering, particularly the sticking of material by means of a plurality of temperature sensors arranged after another alongside the bottom pouring nozzle. The supply of inert gas inside a bottom pouring nozzle is further known from JP 2002210545, JP 61206559, JP
and JP 7290422.
From some of these publications it is also known, in addition to the supply of inert gas, to prevent air aspiration by using housings around a part of the bottom pouring nozzle. In this case, for instance in JP 8290250, an inert gas excess pressure is partially obtained. JP
11170033 discloses a housing around the slide valve of a bottom pouring nozzle to prevent air aspiration. According to the forementioned publications, the throughflow of the metal melt through the bottom pouring nozzle is regulated by sliding valves. These valves slide perpendicular to the throughflow direction of the metal and can shut off the bottom pouring nozzle. Another possibility for regulating the throughflow is the so called stopper plug (also called stopper rod), for example as is known from JP 2002143994.
The arrangement of an additional housing around the valve of a bottom pouring nozzle is described in Korean publication KR 1020030054769 A. The gas that is present in the housing is being evacuated by means of a vacuum pump. JP 4270042 describes a similar housing. Herein, as well as in other previously mentioned publications, a non oxidizing atmosphere is obtained. The housing has an opening, through which inert gas can be supplied. A further arrangement, in which gas is evacuated from the housing partially surrounding the bottom pouring nozzle, is known from JP 61003652.
Further bottom pouring nozzles are for instance known from DE 10 2004 057381.
Herein, it is attempted to prevent clogging by means of a regulated inert gas supply or by means of a nearly complete sealing of the entire bottom pouring nozzle wall surface and the related prevention of air aspiration through the wall of the bottom pouring nozzle.
It is the object of the present invention to further improve upon the known techniques, to minimize the adhering of depositions in the nozzle of a bottom pouring nozzle in a simple and i effective manner, without influencing the quality of the metal melt, particularly the solidified metal.
The object is solved as described in the independent claims. Preferred embodiments are given in the subclaims.
Surprisingly, it was shown that good results could be obtained with a bottom pouring nozzle for arrangement in a bottom of a metallurgical vessel, having an upper end, particularly for fitting on a metallurgical vessel or onto a sliding gate of a metallurgical vessel and having a lower end, whereby in between both ends a throughflow channel is arranged having at least a lower pouring opening at the lower end, whereby the radially outermost surface of the (refractory) wall of the throughflow opening is surrounded by a gastight housing, by not only having the circumference of the bottom pouring nozzle, thus the radially outermost wall of the throughflow channel being surrounded by a gastight housing, but by having the housing also encasing the lower end of the bottom pouring nozzle having at least one pouring opening in a gastight manner. Gastight obviously does not mean totally leak free, but essentially stopping the ingress of gasses, mainly atmospheric oxygen and nitrogen.
It will clearly be understood for a skilled person that the bottom pouring nozzle, the sliding valve (or a stopper rod enclosure) and a further upper nozzle, which is surrounded by a casing and which is arranged in the bottom of the metallurgical vessel above the sliding valve are connected together gastightly thus establishing a system of a completely sealed nozzle.
A method of using a bottom pouring nozzle is an object of the invention, for example with the use of a bottom pouring nozzle according to the invention, characterized in that, the bottom pouring nozzle is fitted to a slide valve or a stopper rod closure of a metallurgical vessel and whereby prior to opening if the slide valve or the stopper rod enclosure a vacuum is obtained or an inert gas flushing with consequent inert gas excess or an overpressure is obtained after which the slide valve or stopper rod enclosure are opened.
Argon can be used as an inert gas. Oxygen can at least partially be removed out of the bottom pouring nozzle in this manner, through which an oxygen deficiency or a lower oxygen i partial pressure is obtained. The overpressure or particularly the vacuum (underpressure) exists in the complete volume inside the gastight housing.
The definition of "in the bottom pouring nozzle" thus means the space inside the housing or the outer wall thereof and including the internal volume and voids of the total pouring channel.
Said under- or overpressure also exists in the throughflow channel prior to the inflow of the steel melt. During flow of the steel melt in the bottom pouring nozzle, particularly in the throughflow channel, after the opening of the slide valve or the stopper rod closure, the housing melts when it comes into contact with the molten steel in the region of the at least one outflow opening, so that the steel melt can flow into the lower placed container. The bottom pouring nozzle can either be operated under vacuum or with inert gas after opening A type of bottom pouring nozzle is the so called immersion nozzle, known in the art as SEN/SES (Submerged Entry Nozzle/Submerged Entry Shroud). It is dipped with its lower end in the steel melt in the lower metallurgical vessel, whereby the housing melts when in contact with liquid steel, thus enabling a free throughflow.
It is advantageous that the housing comprises several gastight connected housing parts, particularly arranged on top of each other. Particularly, the housing is made of a metal, such as steel, so that it has sufficient strength but still melts when contacting the steel melt. The metal of the housing is selected such that it can be melted by metal in the receiving vessel.
It can be advantageous, that the housing comprises a lower housing part made of steel, which surrounds the lower end of the at least one throughflow opening in a gastight manner and that a gastight housing part is arranged thereupon as an integrated component of the wall, so that the throughflow opening is closed by a kind of cap, due to which the periphery (the wall) of the bottom pouring nozzle has a gastight layer, particularly surface, that can be considered as a housing part according to the invention.
It can be advantageous, that the housing comprises a lower housing part made of steel, which is inserted in the lower end with the at least one throughflow opening in a gastight manner and that a gastight housing part is arranged thereupon as an integrated component of the wall, so that the throughflow opening is closed by a plug, due to which the periphery of the bottom pouring nozzle has a gastight layer, particularly surface, that, including the plug, can be considered as a housing part according to the invention.
It can be advantageous to apply a layer of ablative material, such as a paper cover known to one skilled in the art to prevent the adherence of slag or dross which is typically present floating on the surface of the section of metal housing to be immersed, thus speeding the melting of said housing.
It is efficient to arrange a getter material, particularly of at least one metal from the group of Silicon, Calcium, Titanium, Aluminium, Magnesium or Zirconium inside the housing. This allows the free oxygen present in the housing to form a compound therewith.
The refractory material of the wall could have a low porosity of 2 to 13 %, preferably lower than 10 %. Such material, for example carbon impregnated alumina graphite material, could have sufficient sealing capacity in the meaning of the invention. Standard refractory materials have a porosity of more than 16 %.
It is also advantageous, to have a heating arranged in the wall of the throughflow channel, in order to preheat the bottom pouring nozzle prior to use and to prevent or reduce thermal shocks.
It is preferred that a layer of ablative material, such as a paper is arranged around the outer surface of the bottom pouring nozzle. Furthermore it could be advantageous that the outer circumference of the wall, below the gastight housing, is surrounded by an insulating cement seal at its upper end, whereby the cement seal preferably comprises a heat resistant castable cement, preferably at least one of alumina, aluminosilicate, magnesia. Further it is prefered that the outer circumference of the wall, below the gastight housing, is surrounded by an insulating material, especially ceramic paper or fiber cloth made of ceramic fibers at its lower end. The insulating material can be arranged immediately below the insulating cement seal.
It is also preferred that below the gastight housing, especially between the gastight housing and the wall gas channels are arranged in longitudinal direction of the nozzle.
An inventive sliding valve for use with a bottom pouring nozzle and especially for use with an above defined bottom pouring nozzle, comprising a gastight outer housing, characterized in that the gastight housing comprises at least one gas inlet and at least one gas outlet. The at least one gas inlet can be used for pumping inert gas like Argon into the housing and the at least one gas outlet can be used for establishing a vacuum within the housing.
An advantageous method is, after opening of the slide valve or the stopper rod closure to either have a. an inert gas overpressure is obtained, in case an underpressure was present prior to opening or b. an underpressure is obtained, in case an overpressure was present prior to opening.
It is especially advantageous, that the underpressure amounts to 1 up to 101 3mbar, particularly 150 to 1013mbar and the overpressure amounts to 1013 up to 1500mbar or more, that means, above atmospheric pressure.
First a vacuum (underpressure) can be obtained especially with a bottom pouring nozzle for use with a casting ladle and later on, after opening, an inert gas overpressure. For a bottom pouring nozzle for use in a tundish, it is advantageous to obtain an inert gas overpressure first, and a vacuum after opening.
The invention is explained in the drawings by way of example. The drawings are showing as follows Fig. 1 a bottom pouring nozzle for a tundish Fig. 2 a further bottom pouring nozzle for a tundish Fig. 3 a third kind of a bottom pouring nozzle for a tundish Fig. 4 a bottom pouring nozzle for a casting ladle Fig. 5 a further bottom pouring nozzle for a casting ladle Fig. 6 the arrangement of a bottom pouring nozzle to a tundish and Fig. 7 the arrangement of a bottom pouring nozzle to a casting ladle.
The bottom pouring nozzle according to Fig. 1 has a throughflow channel 1 with several outflow openings 2 in the side. The wall 3 of the throughflow channel 1 is essentially made of a mixture of aluminium oxide and graphite. A fitting collar 4 is arranged at its upper end for arrangement to a slide valve which is the main body of the sealed system. The outer circumference of the wall 3 is surrounded by an insulating cement seal 5 at its upper end, under which an insulating material 6, for example ceramic paper or fiber cloth made of ceramic fibers is arranged. A gastight housing 7 is arranged onto the cement seal 5 and the insulating material 6. This encases the entire bottom pouring nozzle all the way up to the fitting collar 4 and only has an opening 8 for the supply of inert gas (Argon). The inert gas may be introduced in a slit between gastight housing 7 and the insulating material 6 for purging purposes. A so called slag band 9 made of zirconium graphite 9 is fitted above the outflow openings 2. The outflow openings 2 are closed by the housing 7.
Fig. 2 shows a similar Bottom pouring nozzle. It has a cap 10 which is made, for example, of steel, at its lower end, which closes the outflow openings 2. At least above the cap 10 at least the surface of the wall 3 is gastight, thus establishing a gastight housing part. A layer of an ablative material 10' is arranged at the outer surface of the cap 10, for example made of paper. The ablative material could also cover the total outer surface of the bottom pouring nozzle.
Fig. 3 shows an arrangement similar to Fig. 1, whereby an annular slit 27 is arranged within the wall 3 and which is connected with opening 8. Herewith it is possible to introduce Argon into the wall 3 ant to establish an overpressure.
The bottom pouring nozzle for a casting ladle (Fig. 4) principally constructed in a similar manner, but it has a straight throughflow opening 1' and an outflow opening 2' arranged in the centre of the lower end. A similar arrangement is shown in Fig. 5, whereby the outflow opening 2' is closed by a plug 28 and whereby at least the outer surface of the wall 3 is made gastight. Plug 28 can melt or burn or dissolve by influence of the metal melt which is arranged in the metallurgical vessel, thus releasing outflow opening 2'. For example plug 28 can be made of steel or of stainless steel or of copper.
The arrangement of a bottom pouring nozzle as a lower nozzle 11 of a tundish 12 is shown in Fig. 6. The tundish 12 has a lining 13 composed of a plurality of layers to protect the tundish wall 14. In the bottom of the tundish 12, an upper nozzle 15 is arranged, in which electrode materials 16 are embedded and whereby the outer side 29 of the upper nozzle 15 is formed gastight. At its upper end, the upper nozzle 15 is surrounded by a well block 17 for protection. At the lower end of the upper nozzle 15, underneath the bottom of the tundish 12, a slide valve 18 is fitted, surrounded by a gastight slidegate housing 19, which at its upper end is connected in a gastight manner with the outer side 29 of the upper nozzle 15 and which at its lower side is connected in a gastight manner with the gastight housing 7. An inlet 20 for inert gas and a connection 21 for a vacuum pump is provided in the slidegate housing 19.
Fig. 7 shows the arrangement of a bottom pouring nozzle to a casting ladle 22 as well as the tundish 12 arrangement underneath. The inside of the tundish contains apart from the outlet 23 also so called baffles 24, that mechanically calm the steel melt, in order to prevent too heavy turbulences. The bottom pouring nozzle from Figure 4 is arranged to the casting ladle opening (sliding valve) 25. The inlet for inert gas as well as the connection for a vacuum pump are not shown in Fig. 7 for simplicity.
One skilled in the art will understand that the general mechanical arrangements of the described components of the invention employed to transfer molten metal from the ladle to tundish and then from the tundish to mould are very similar and share common shapes and functions. The casting ladle 22 itself comprises a multi layered lining 26 on its inside.
Prior to casting, the slide valve 25 is closed, a vacuum is obtained in the throughflow channel 1', FIG 4, of a casting ladle, in order to remove oxygen. A vacuum is obtained in this manner, in throughflow channel 1', in the wall of the bottom pouring nozzle, in between the inner wall surrounding the throughflow channel 1' and the outer housing and an underpressure (vacuum) is obtained in the slide valve 25 as well. During inflow of the steel melt in the throughflow channel 1' the gastight housing 7 melts in the region of the throughflow opening 2' when it comes into contact with the molten steel, so that the steel melt can flow into the lower arranged vessel (tundish 12). The underpressure is regulated for example in a range of 700 to 800 mbar, the subsequent overpressure was set to a maximum of 1500 mbar.
A bottom pouring nozzle is also arranged at the outlet of the tundish 12.
Herein an overpressure is obtained using an argon pressure of maximum 1500 mbar. The gastight housing 7 melts in the region of the outflow opening 2 during inflow of the steel melt in the throughflow channel 1, so that the steel melt can flow into the lower arranged vessel. The gas is being pumped out of the bottom pouring nozzle, so that a vacuum is obtained.
METALLURGICAL VESSEL
The invention concerns a bottom pouring nozzle for arrangement in or at a bottom of a metallurgical vessel, having an upper end, particularly for fitting in a metallurgical vessel or onto a sliding gate of a metallurgical vessel and having a lower end, whereby in between both ends a throughflow channel is arranged having at least a lower pouring opening at the lower end, whereby the radially outermost surface of the wall of the throughflow opening is surrounded by a gastight housing. Furthermore, the invention concerns a method of using a bottom pouring nozzle.
Especially with steel melts, the molten metal is poured from a metallurgical vessel into a mould. Such a metallurgical vessel can for instance be a casting ladle (also called ladle) or a so called distrubutor (also known as intermediate vessel or tundish). For example, the liquid metal is poured from the ladle into the tundish and from the tundish into the mould of a continuous casting installation. It runs through the bottom of the ladle or tundish through a so called bottom pouring nozzle (also called nozzle).
Disadvantageous is the adhering of material onto the wall of the bottom pouring nozzle accumulated during throughflow. This reduces the cross sectional area, so that flow ratios and steel quality is detrimentally influenced because of turbulences. This accumulated material can also break free and cause inclusion related defects in the steel.
To prevent the adhering of material onto the wall, mostly an inert gas such as Argon is supplied in the throughflow opening. Too much gas can also negatively affect the steel quality, for instance the formation of pinholes in steel, which lead to surface defects during the rolling of steel.
A material for a bottom pouring nozzle is for instance described in WO
2004/035249 Al. A
bottom pouring nozzle in a metallurgical vessel is disclosed in KR 2003-0017154 A or in US
2003/0116893 Al. The use of inert gas is relied upon in the latter document, with the aim to reduce the adhering of material nozzle (so called Clogging) to the inner wall of the bottom pouring nozzle, similar to what is described in JP 2187239. A mechanism using a regulated gas supply is known in detail from WO 01/56725 Al. Nitrogen is supplied according to Japanese publication JP 8290250. JP 3193250 discloses a method for monitoring the adhering, particularly the sticking of material by means of a plurality of temperature sensors arranged after another alongside the bottom pouring nozzle. The supply of inert gas inside a bottom pouring nozzle is further known from JP 2002210545, JP 61206559, JP
and JP 7290422.
From some of these publications it is also known, in addition to the supply of inert gas, to prevent air aspiration by using housings around a part of the bottom pouring nozzle. In this case, for instance in JP 8290250, an inert gas excess pressure is partially obtained. JP
11170033 discloses a housing around the slide valve of a bottom pouring nozzle to prevent air aspiration. According to the forementioned publications, the throughflow of the metal melt through the bottom pouring nozzle is regulated by sliding valves. These valves slide perpendicular to the throughflow direction of the metal and can shut off the bottom pouring nozzle. Another possibility for regulating the throughflow is the so called stopper plug (also called stopper rod), for example as is known from JP 2002143994.
The arrangement of an additional housing around the valve of a bottom pouring nozzle is described in Korean publication KR 1020030054769 A. The gas that is present in the housing is being evacuated by means of a vacuum pump. JP 4270042 describes a similar housing. Herein, as well as in other previously mentioned publications, a non oxidizing atmosphere is obtained. The housing has an opening, through which inert gas can be supplied. A further arrangement, in which gas is evacuated from the housing partially surrounding the bottom pouring nozzle, is known from JP 61003652.
Further bottom pouring nozzles are for instance known from DE 10 2004 057381.
Herein, it is attempted to prevent clogging by means of a regulated inert gas supply or by means of a nearly complete sealing of the entire bottom pouring nozzle wall surface and the related prevention of air aspiration through the wall of the bottom pouring nozzle.
It is the object of the present invention to further improve upon the known techniques, to minimize the adhering of depositions in the nozzle of a bottom pouring nozzle in a simple and i effective manner, without influencing the quality of the metal melt, particularly the solidified metal.
The object is solved as described in the independent claims. Preferred embodiments are given in the subclaims.
Surprisingly, it was shown that good results could be obtained with a bottom pouring nozzle for arrangement in a bottom of a metallurgical vessel, having an upper end, particularly for fitting on a metallurgical vessel or onto a sliding gate of a metallurgical vessel and having a lower end, whereby in between both ends a throughflow channel is arranged having at least a lower pouring opening at the lower end, whereby the radially outermost surface of the (refractory) wall of the throughflow opening is surrounded by a gastight housing, by not only having the circumference of the bottom pouring nozzle, thus the radially outermost wall of the throughflow channel being surrounded by a gastight housing, but by having the housing also encasing the lower end of the bottom pouring nozzle having at least one pouring opening in a gastight manner. Gastight obviously does not mean totally leak free, but essentially stopping the ingress of gasses, mainly atmospheric oxygen and nitrogen.
It will clearly be understood for a skilled person that the bottom pouring nozzle, the sliding valve (or a stopper rod enclosure) and a further upper nozzle, which is surrounded by a casing and which is arranged in the bottom of the metallurgical vessel above the sliding valve are connected together gastightly thus establishing a system of a completely sealed nozzle.
A method of using a bottom pouring nozzle is an object of the invention, for example with the use of a bottom pouring nozzle according to the invention, characterized in that, the bottom pouring nozzle is fitted to a slide valve or a stopper rod closure of a metallurgical vessel and whereby prior to opening if the slide valve or the stopper rod enclosure a vacuum is obtained or an inert gas flushing with consequent inert gas excess or an overpressure is obtained after which the slide valve or stopper rod enclosure are opened.
Argon can be used as an inert gas. Oxygen can at least partially be removed out of the bottom pouring nozzle in this manner, through which an oxygen deficiency or a lower oxygen i partial pressure is obtained. The overpressure or particularly the vacuum (underpressure) exists in the complete volume inside the gastight housing.
The definition of "in the bottom pouring nozzle" thus means the space inside the housing or the outer wall thereof and including the internal volume and voids of the total pouring channel.
Said under- or overpressure also exists in the throughflow channel prior to the inflow of the steel melt. During flow of the steel melt in the bottom pouring nozzle, particularly in the throughflow channel, after the opening of the slide valve or the stopper rod closure, the housing melts when it comes into contact with the molten steel in the region of the at least one outflow opening, so that the steel melt can flow into the lower placed container. The bottom pouring nozzle can either be operated under vacuum or with inert gas after opening A type of bottom pouring nozzle is the so called immersion nozzle, known in the art as SEN/SES (Submerged Entry Nozzle/Submerged Entry Shroud). It is dipped with its lower end in the steel melt in the lower metallurgical vessel, whereby the housing melts when in contact with liquid steel, thus enabling a free throughflow.
It is advantageous that the housing comprises several gastight connected housing parts, particularly arranged on top of each other. Particularly, the housing is made of a metal, such as steel, so that it has sufficient strength but still melts when contacting the steel melt. The metal of the housing is selected such that it can be melted by metal in the receiving vessel.
It can be advantageous, that the housing comprises a lower housing part made of steel, which surrounds the lower end of the at least one throughflow opening in a gastight manner and that a gastight housing part is arranged thereupon as an integrated component of the wall, so that the throughflow opening is closed by a kind of cap, due to which the periphery (the wall) of the bottom pouring nozzle has a gastight layer, particularly surface, that can be considered as a housing part according to the invention.
It can be advantageous, that the housing comprises a lower housing part made of steel, which is inserted in the lower end with the at least one throughflow opening in a gastight manner and that a gastight housing part is arranged thereupon as an integrated component of the wall, so that the throughflow opening is closed by a plug, due to which the periphery of the bottom pouring nozzle has a gastight layer, particularly surface, that, including the plug, can be considered as a housing part according to the invention.
It can be advantageous to apply a layer of ablative material, such as a paper cover known to one skilled in the art to prevent the adherence of slag or dross which is typically present floating on the surface of the section of metal housing to be immersed, thus speeding the melting of said housing.
It is efficient to arrange a getter material, particularly of at least one metal from the group of Silicon, Calcium, Titanium, Aluminium, Magnesium or Zirconium inside the housing. This allows the free oxygen present in the housing to form a compound therewith.
The refractory material of the wall could have a low porosity of 2 to 13 %, preferably lower than 10 %. Such material, for example carbon impregnated alumina graphite material, could have sufficient sealing capacity in the meaning of the invention. Standard refractory materials have a porosity of more than 16 %.
It is also advantageous, to have a heating arranged in the wall of the throughflow channel, in order to preheat the bottom pouring nozzle prior to use and to prevent or reduce thermal shocks.
It is preferred that a layer of ablative material, such as a paper is arranged around the outer surface of the bottom pouring nozzle. Furthermore it could be advantageous that the outer circumference of the wall, below the gastight housing, is surrounded by an insulating cement seal at its upper end, whereby the cement seal preferably comprises a heat resistant castable cement, preferably at least one of alumina, aluminosilicate, magnesia. Further it is prefered that the outer circumference of the wall, below the gastight housing, is surrounded by an insulating material, especially ceramic paper or fiber cloth made of ceramic fibers at its lower end. The insulating material can be arranged immediately below the insulating cement seal.
It is also preferred that below the gastight housing, especially between the gastight housing and the wall gas channels are arranged in longitudinal direction of the nozzle.
An inventive sliding valve for use with a bottom pouring nozzle and especially for use with an above defined bottom pouring nozzle, comprising a gastight outer housing, characterized in that the gastight housing comprises at least one gas inlet and at least one gas outlet. The at least one gas inlet can be used for pumping inert gas like Argon into the housing and the at least one gas outlet can be used for establishing a vacuum within the housing.
An advantageous method is, after opening of the slide valve or the stopper rod closure to either have a. an inert gas overpressure is obtained, in case an underpressure was present prior to opening or b. an underpressure is obtained, in case an overpressure was present prior to opening.
It is especially advantageous, that the underpressure amounts to 1 up to 101 3mbar, particularly 150 to 1013mbar and the overpressure amounts to 1013 up to 1500mbar or more, that means, above atmospheric pressure.
First a vacuum (underpressure) can be obtained especially with a bottom pouring nozzle for use with a casting ladle and later on, after opening, an inert gas overpressure. For a bottom pouring nozzle for use in a tundish, it is advantageous to obtain an inert gas overpressure first, and a vacuum after opening.
The invention is explained in the drawings by way of example. The drawings are showing as follows Fig. 1 a bottom pouring nozzle for a tundish Fig. 2 a further bottom pouring nozzle for a tundish Fig. 3 a third kind of a bottom pouring nozzle for a tundish Fig. 4 a bottom pouring nozzle for a casting ladle Fig. 5 a further bottom pouring nozzle for a casting ladle Fig. 6 the arrangement of a bottom pouring nozzle to a tundish and Fig. 7 the arrangement of a bottom pouring nozzle to a casting ladle.
The bottom pouring nozzle according to Fig. 1 has a throughflow channel 1 with several outflow openings 2 in the side. The wall 3 of the throughflow channel 1 is essentially made of a mixture of aluminium oxide and graphite. A fitting collar 4 is arranged at its upper end for arrangement to a slide valve which is the main body of the sealed system. The outer circumference of the wall 3 is surrounded by an insulating cement seal 5 at its upper end, under which an insulating material 6, for example ceramic paper or fiber cloth made of ceramic fibers is arranged. A gastight housing 7 is arranged onto the cement seal 5 and the insulating material 6. This encases the entire bottom pouring nozzle all the way up to the fitting collar 4 and only has an opening 8 for the supply of inert gas (Argon). The inert gas may be introduced in a slit between gastight housing 7 and the insulating material 6 for purging purposes. A so called slag band 9 made of zirconium graphite 9 is fitted above the outflow openings 2. The outflow openings 2 are closed by the housing 7.
Fig. 2 shows a similar Bottom pouring nozzle. It has a cap 10 which is made, for example, of steel, at its lower end, which closes the outflow openings 2. At least above the cap 10 at least the surface of the wall 3 is gastight, thus establishing a gastight housing part. A layer of an ablative material 10' is arranged at the outer surface of the cap 10, for example made of paper. The ablative material could also cover the total outer surface of the bottom pouring nozzle.
Fig. 3 shows an arrangement similar to Fig. 1, whereby an annular slit 27 is arranged within the wall 3 and which is connected with opening 8. Herewith it is possible to introduce Argon into the wall 3 ant to establish an overpressure.
The bottom pouring nozzle for a casting ladle (Fig. 4) principally constructed in a similar manner, but it has a straight throughflow opening 1' and an outflow opening 2' arranged in the centre of the lower end. A similar arrangement is shown in Fig. 5, whereby the outflow opening 2' is closed by a plug 28 and whereby at least the outer surface of the wall 3 is made gastight. Plug 28 can melt or burn or dissolve by influence of the metal melt which is arranged in the metallurgical vessel, thus releasing outflow opening 2'. For example plug 28 can be made of steel or of stainless steel or of copper.
The arrangement of a bottom pouring nozzle as a lower nozzle 11 of a tundish 12 is shown in Fig. 6. The tundish 12 has a lining 13 composed of a plurality of layers to protect the tundish wall 14. In the bottom of the tundish 12, an upper nozzle 15 is arranged, in which electrode materials 16 are embedded and whereby the outer side 29 of the upper nozzle 15 is formed gastight. At its upper end, the upper nozzle 15 is surrounded by a well block 17 for protection. At the lower end of the upper nozzle 15, underneath the bottom of the tundish 12, a slide valve 18 is fitted, surrounded by a gastight slidegate housing 19, which at its upper end is connected in a gastight manner with the outer side 29 of the upper nozzle 15 and which at its lower side is connected in a gastight manner with the gastight housing 7. An inlet 20 for inert gas and a connection 21 for a vacuum pump is provided in the slidegate housing 19.
Fig. 7 shows the arrangement of a bottom pouring nozzle to a casting ladle 22 as well as the tundish 12 arrangement underneath. The inside of the tundish contains apart from the outlet 23 also so called baffles 24, that mechanically calm the steel melt, in order to prevent too heavy turbulences. The bottom pouring nozzle from Figure 4 is arranged to the casting ladle opening (sliding valve) 25. The inlet for inert gas as well as the connection for a vacuum pump are not shown in Fig. 7 for simplicity.
One skilled in the art will understand that the general mechanical arrangements of the described components of the invention employed to transfer molten metal from the ladle to tundish and then from the tundish to mould are very similar and share common shapes and functions. The casting ladle 22 itself comprises a multi layered lining 26 on its inside.
Prior to casting, the slide valve 25 is closed, a vacuum is obtained in the throughflow channel 1', FIG 4, of a casting ladle, in order to remove oxygen. A vacuum is obtained in this manner, in throughflow channel 1', in the wall of the bottom pouring nozzle, in between the inner wall surrounding the throughflow channel 1' and the outer housing and an underpressure (vacuum) is obtained in the slide valve 25 as well. During inflow of the steel melt in the throughflow channel 1' the gastight housing 7 melts in the region of the throughflow opening 2' when it comes into contact with the molten steel, so that the steel melt can flow into the lower arranged vessel (tundish 12). The underpressure is regulated for example in a range of 700 to 800 mbar, the subsequent overpressure was set to a maximum of 1500 mbar.
A bottom pouring nozzle is also arranged at the outlet of the tundish 12.
Herein an overpressure is obtained using an argon pressure of maximum 1500 mbar. The gastight housing 7 melts in the region of the outflow opening 2 during inflow of the steel melt in the throughflow channel 1, so that the steel melt can flow into the lower arranged vessel. The gas is being pumped out of the bottom pouring nozzle, so that a vacuum is obtained.
Claims (16)
1. Bottom pouring nozzle for arrangement in or at a bottom of a metallurgical vessel, having a, particularly for fitting to a metallurgical vessel or to a sliding gate of a metallurgical vessel, upper end and a lower end, whereby a throughflow channel is arranged in between both having at least a lower pouring opening arranged at the lower end, whereby the radially outermost surface of the wall of the throughflow opening is surrounded by a gastight housing, characterized in that the housing encases the lower end of the at least one pouring opening in a gastight manner.
2. Bottom pouring nozzle according to claim 1, characterized in that the housing comprises several gastight connected housing parts, particularly arranged on top of each other.
3. Bottom pouring nozzle according to claim 1 or 2, characterized in that the housing is made of a metal, such as steel or other material capable of gas tightness and temperature resistance, such as copper, nickel, stainless steel.
4. Bottom pouring nozzle according to claim 2, characterized in that the housing comprises a lower housing part made of steel, which at least encases the lower end of the at least one throughflow opening in a gastight manner and which gastight housing part is arranged thereupon as an integrated component of the wall.
5. Bottom pouring nozzle according to claim 2, characterized in that that the housing comprises a lower housing part made of steel, which is inserted in the lower end of the at least one throughflow opening in a gastight manner and that a gastight housing part is arranged thereupon as an integrated component of the wall, so that the throughflow opening is closed by a plug, due to which the periphery of the bottom pouring nozzle has a gastight surface being part of the housing.
6. Bottom pouring nozzle according to one of claims 1 to 5, characterized in that a getter material, particularly of at least one metal from the group of Silicon, Calcium, Titanium, Aluminium, Magnesium or Zirconium is arranged inside the housing.
7. Bottom pouring nozzle according to one of claims 1 to 6, characterized in that heating means are arranged in the wall of the throughflow opening.
8. Bottom pouring nozzle according to one of claims 1 to 7, characterized in that a layer of ablative material, such as a paper is arranged around the outer surface of the bottom pouring nozzle.
9. Bottom pouring nozzle according to one of claims 1 to 8, characterized in that the outer circumference of the wall, below the gastight housing, is surrounded by an insulating cement seal at its upper end, whereby the cement seal preferably comprises a heat resistant castable cement, preferably at least one of alumina, aluminosilicate, magnesia.
10. Bottom pouring nozzle according to one of claims 1 to 9, characterized in that the outer circumference of the wall, below the gastight housing, is surrounded by an insulating material, especially ceramic paper or fiber cloth made of ceramic fibers at its lower end.
11. Bottom pouring nozzle according to claims 9 and 10, characterized in that the insulating material is arranged immediately below the insulating cement seal.
12. Bottom pouring nozzle according to one of the claims 1 to 11, characterized in that below the gastight housing, especially between the gastight housing and the wall gas channels are arranged in longitudinal direction of the nozzle.
13. Sliding valve for use with a bottom pouring nozzle, comprising a gastight housing, characterized in that the gastight housing comprises at least one gas inlet and at least one gas outlet.
14. Method of using a bottom pouring nozzle, characterized in that the bottom pouring nozzle is fitted to a slide valve or a stopper rod closure of a metallurgical vessel and that either a vacuum is obtained in the bottom pouring nozzle prior to opening the slide valve or the stopper rod closure or that flushing of an inert gas flushing consequently an inert gas excess or an inert gas overpressure is obtained after which the slide valve or the stopper rod closure are opened.
15. Method according to claim 14, characterized in that after opening of the slide valve or the stopper rod closure either a. an inert gas overpressure is obtained, in case an underpressure was present prior to opening b. an underpressure is obtained, in case an overpressure was present prior to opening.
16. Method according to claim 14 or 15, characterized in that the underpressure amounts to 1 up to 1013mbar and the overpressure amounts to above atmospheric pressure.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102010050936A DE102010050936A1 (en) | 2010-11-11 | 2010-11-11 | Floor spout nozzle for placement in the bottom of a metallurgical vessel |
| DE102010050936.1-24 | 2010-11-11 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2754323A1 true CA2754323A1 (en) | 2012-05-11 |
| CA2754323C CA2754323C (en) | 2014-12-16 |
Family
ID=44640677
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2754323A Expired - Fee Related CA2754323C (en) | 2010-11-11 | 2011-10-05 | Bottom pouring nozzle for arrangement in the bottom of a metallurgical vessel |
Country Status (15)
| Country | Link |
|---|---|
| US (1) | US20130233899A1 (en) |
| EP (1) | EP2637814A1 (en) |
| JP (1) | JP5572266B2 (en) |
| KR (1) | KR20130100160A (en) |
| CN (1) | CN103228382A (en) |
| AU (1) | AU2011328557B2 (en) |
| BE (1) | BE1019916A5 (en) |
| BR (1) | BR112013011578A2 (en) |
| CA (1) | CA2754323C (en) |
| DE (1) | DE102010050936A1 (en) |
| MX (1) | MX2013005164A (en) |
| RU (1) | RU2013121151A (en) |
| UA (1) | UA107409C2 (en) |
| WO (1) | WO2012062414A1 (en) |
| ZA (1) | ZA201303150B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE202015001370U1 (en) | 2014-03-12 | 2015-03-03 | Sheffield Hi-Tech Refractories Germany Gmbh | Plug in a distribution vessel |
| CN105965005A (en) * | 2016-07-07 | 2016-09-28 | 宜兴市耐火材料有限公司 | Extended nozzle brick |
| CN111036891A (en) * | 2019-11-29 | 2020-04-21 | 浙江科宇金属材料有限公司 | Pouring pipe for vertical casting |
| CN112974790B (en) * | 2021-02-03 | 2022-07-19 | 鞍山市和丰耐火材料有限公司 | Production process for preventing iron shell of tundish nozzle from falling off |
| WO2023047153A1 (en) * | 2021-09-24 | 2023-03-30 | Arcelormittal | Leak-proof upper tundish nozzle |
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-
2010
- 2010-11-11 DE DE102010050936A patent/DE102010050936A1/en not_active Withdrawn
-
2011
- 2011-05-05 BE BE2011/0274A patent/BE1019916A5/en active
- 2011-10-05 CA CA2754323A patent/CA2754323C/en not_active Expired - Fee Related
- 2011-10-25 KR KR1020137011376A patent/KR20130100160A/en not_active Application Discontinuation
- 2011-10-25 UA UAA201305830A patent/UA107409C2/en unknown
- 2011-10-25 WO PCT/EP2011/005373 patent/WO2012062414A1/en active Application Filing
- 2011-10-25 BR BR112013011578A patent/BR112013011578A2/en not_active IP Right Cessation
- 2011-10-25 CN CN2011800545900A patent/CN103228382A/en active Pending
- 2011-10-25 MX MX2013005164A patent/MX2013005164A/en not_active Application Discontinuation
- 2011-10-25 AU AU2011328557A patent/AU2011328557B2/en not_active Ceased
- 2011-10-25 EP EP11788766.1A patent/EP2637814A1/en not_active Withdrawn
- 2011-10-25 JP JP2013538090A patent/JP5572266B2/en not_active Expired - Fee Related
- 2011-10-25 US US13/883,606 patent/US20130233899A1/en not_active Abandoned
- 2011-10-25 RU RU2013121151/02A patent/RU2013121151A/en not_active Application Discontinuation
-
2013
- 2013-04-30 ZA ZA2013/03150A patent/ZA201303150B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| DE102010050936A1 (en) | 2012-05-16 |
| UA107409C2 (en) | 2014-12-25 |
| US20130233899A1 (en) | 2013-09-12 |
| MX2013005164A (en) | 2013-08-29 |
| CN103228382A (en) | 2013-07-31 |
| JP2013542856A (en) | 2013-11-28 |
| BE1019916A5 (en) | 2013-02-05 |
| WO2012062414A1 (en) | 2012-05-18 |
| EP2637814A1 (en) | 2013-09-18 |
| AU2011328557B2 (en) | 2015-02-05 |
| AU2011328557A1 (en) | 2013-05-02 |
| CA2754323C (en) | 2014-12-16 |
| RU2013121151A (en) | 2014-11-20 |
| ZA201303150B (en) | 2014-01-29 |
| BR112013011578A2 (en) | 2016-08-09 |
| JP5572266B2 (en) | 2014-08-13 |
| KR20130100160A (en) | 2013-09-09 |
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Legal Events
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| EEER | Examination request |
Effective date: 20130416 |
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| MKLA | Lapsed |
Effective date: 20161005 |