CA1036791A - Method of manufacturing steel ingots or castings - Google Patents
Method of manufacturing steel ingots or castingsInfo
- Publication number
- CA1036791A CA1036791A CA214,653A CA214653A CA1036791A CA 1036791 A CA1036791 A CA 1036791A CA 214653 A CA214653 A CA 214653A CA 1036791 A CA1036791 A CA 1036791A
- Authority
- CA
- Canada
- Prior art keywords
- casting
- cover
- metal
- molten metal
- insulating member
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D7/00—Casting ingots, e.g. from ferrous metals
- B22D7/06—Ingot moulds or their manufacture
- B22D7/10—Hot tops therefor
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
- Furnace Housings, Linings, Walls, And Ceilings (AREA)
- Compositions Of Oxide Ceramics (AREA)
- Molds, Cores, And Manufacturing Methods Thereof (AREA)
- Laminated Bodies (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
According to the present invention, a method of manufacturing cast metal bodies, for example moulded iron metal or iron metal alloy castings or ingots, is characterized in that instead of an anti piping agent, a reusable insulating material, which prevents radiation and convection, is applied at a small distance from the level of the metal but not in direct contact with the metal. According to another embodiment of the invention, the reusable insulating material can be used on a ladle.
According to the present invention, a method of manufacturing cast metal bodies, for example moulded iron metal or iron metal alloy castings or ingots, is characterized in that instead of an anti piping agent, a reusable insulating material, which prevents radiation and convection, is applied at a small distance from the level of the metal but not in direct contact with the metal. According to another embodiment of the invention, the reusable insulating material can be used on a ladle.
Description
103679~
The present invention relates to an improved method of manufacturing cast metal bodies, for example moulded cast-ings or ingots, the castings or ingots being composed of iron metal or iron metal alloys. Conventionally the casting may be carried out either up-hill or down-hill with mould paint and/or casting flux placed in the casting mould or ingot mould, an anti-piping agent being applied in direct contact with the molten upper portion of the cast metal body immediately after or just prior to concluded casting.
It is generally known that castings or ingots are manufactured by means of either up-hill or down-hill casting and that a casting flux is applied to the bottom portion of the casting mould or ingot mould in up-hill casting, said casting flux preventing oxidation by means of preventing atmospheric oxygen from reaching the steel.
Furthermore, it is generally known to apply an anti-piping agent directly on top of and in contact with the molten metal in the casting mould immediately after concluded casting.
In the manufacture of killed steel ingots a hot top, for example of the Vallak ~ type, which is applied to the upper portion of the ingot mould, is almost always used in order to reduce piping.
Even if the use of a hot top, for example of the Vallak ~ type, can substantially and economically reduce pipe formation in ingots, the use of anti-piping agent in the manufacture of both ingots or castings does not only ~.
~03679~
entail an increased cost of several Swedish ~rowns per ton casting wei~ht, it also carries with it the disadvantage of the production of clouds or dust both at and around the castin~
pit and therewith pollu~ion of the working area~ not forgetting possible health hazards encountered by persolmel in the form of the spread of dust and other ~articles in the air. Due to labour safety legislation in efect in most industrial nations, the use of unhealth~ anti-?iping agents has been prohibited.
~lowever, at the same time as such legislation has resulted in a smaller risk for personnel, the cost of anti-pipin~ agents has increased as it is no longer possible to choose inexpensive material for the production of anti-piping agent~ said materials mostly being a health hazard~
The application of ceramic fibres adjacent to but not in contact with the molten material, which has a temperature of approx. 1600C, has never been considered previously~as the material would be expected to be destroyed by the molten metal.
However~ it was found that the fibre--board in auestion not only maintained its integrity after the manu*acture of the first ingot but it also maintained its integrity after the manufac-ture of further ingots. Later, aluminum foil was placed between the ceramic fibre plates, the idea being that the reflecting aluminum foil would radiate the heat back to the molten material. Quite unexpectedly and contrar~ to the theoretical expectations, the aluminum did not melt. After this, experi-mentation was broadened with one or several layers of ceramic fibre material, one or several alu~inu~ -Foils etc. 3 all of which led to the present invention.
- ~03679i The fact that the heat from the still molten metal did not destroy the ceramic fibre material lying a slight distance above said molten metal is, in itself, perhaps explainable, but the fact that the aluminum foil applied to the ceramic material (the ceramic material can have a melting point which is sub-stantially greater than 1600C but the aluminum foil has a melt-ing point about 660C) did not melt is surprising, This surpris-ing result can be attributed to a synergetic effect in a com-bination of a ceramic material, in this case fibre material, and an aluminum foil.
According to the invention there is provided in a method of manufacturing cast metal bodies, moulded iron metal or iron metal alloy castings or ingots, in which teeming is carried out as an up-hill or down-hill casting with at least one of mould paint and casting flux applied to the casting mould or ingot mould, the improvement wherein an insulating member effective to prevent radiation and convection is disposed at a predetermined point in time, adjacent to and spaced apart from the level of the molten metal so as to substan~ially prevent access of outside cooling air to said metal, said insulating member consisting of ceramic fibres, said insulating member being spaced from said molten metal such that the molten metal will not contact the ceramic fibres under normal casting conditions, and such that the ceramic fibres are not destroyed by the heat of the molten metal, and such that the insulating material can be used again during a subsequent or later castings.
In the method of the invention cast m~tal bodies, for example moulded iron metal or iron metal alloy castings or ingots, are manufactured in a method in which teeming is carried out in the form of an up-hill or down-hill casting with mould paint and/or casting flux placed inside the casting mould or ingot mould, the method being characterized in that instead of ? - 3 -103679i conventionally employed anti-piping agent there is employed an insulating member which prevents radiation and convection and which is applied at a suitable point in time, that is, in down-hill casting when the casting is completed and in up-hill casting at any time after the placement of the hot top in the ingot mould, at a small distance from the level of the metal, i.e.
the molten metal with molten slag substance possibly flowing thereupon (subsequently referred to only as molten metal or molten steel), but not in direct contact with the metal, thereby substantially preventing outside cooling air from entering, the insulating member being suitably in the form of plate, board matting or the like consisting of ceramic fibres, the insulating member, if desired, being provided on at least one side with an aluminum foil, the slight distance being chosen so that it is large enough that the molten metal will not reach up to the insulating member in normal casting conditions and large enough that the ceramic fibres not be destroyed by the heat of the molten metal, and so that the insulating member can be used again and applied during the subsequent or later castings.
The method according to the invention is further characterized in that the insulating material is applied arranged in a cover or hood, the lower side wall edge of which abuts the upper portion of the present casting mould or ingot mould. The ceramic fibre material can advantageously be arranged in such a manner in the cover/hood that the most heat resistant ceramic fibre material is placed nearest the surface of the molten metal.
A less heat resistant ceramic fibre material is placed thereafter, etc. In other words, the heat resistance of the ceramic fibre material decreases as the distance to the surface of the molten metal increases. In this manner the cost of the ceramic fibr~
material, which is placed in the cover/hood, can be reduced.
; - 4 -'1036791 The method according to the invention is further characterized in that metal plate made of for example aluminum, iron etc. is used as material for the cover or hood.
Ceramic fibres comprise for example A1203 and SiO2 fibres, Fiberfrax ~ , Kaowool ~ , ZrO2 or Cr203 fibres. High temperature resisting, but not ceramic fibres comprise for example mineral wool, which has a temperature resistance of only about 800C.
Further aspects of the invention are characterized in that an aluminum foil is arranged on at least one side of an insulating plate or that an aluminumfoil is arranged at least between two plates if there are more than one insulating plate, or that an aluminum foil is arranged on the insulating plate surface which is facing the molten metal, or that an aluminum foil is arranged on the insulating plate surface which is facing the ceiling of said cover or the bottom surface of said cover.
According to another aspect of the in~ention, an aluminum foil can be arranged on the insulating plate surface which is facing the molten metal as well as on the insulating plate surface which is facing the inner surface of the ceiling (roof) of the cover.
According to another embodiment of the invention the reusable insulating cover, as a whole or as sections which can be joined together, can be used on a ladle. During pouring from the ladle into one or a plurality of ingot moulds, reusable insulating covers are also used on the ingot mould or moulds.
The invention is illustrated in particular and preferred embodiments by reference to the accompanying drawings in which:
FIGURE 1 illustrates an ingot mould in conjunction with an insulating member disposed in accordance with one embodiment of the invention, and r: ~ ~ 5 _ ~036791 FIGURE 2 illustrates a ladle in conjunction with an insulating member disposed in accordance with another embodiment of the invention.
The method according to this other embodiment of the invention is characterized in that the insulating material is applied arranged inside a cover or hood 3, the lower side wall edge 7a of which abuts the upper portion of the ladle 8 used in casting/ from which, in a manner - 5a -known in itself, the liquid metal is poured into the casting mould or ingot mould.
The above-mentioned method is further characterized in that the lower side wall edge 7a of the cover or hood 3 is furthermore designed as an angular tab 7a + 7b, the angular tab part 7a of which rests on the upper portion of the casing 9a of the ladle 8, while angular tab part 7b extends outwardly in a downward direction along the casing 9a of the ladle.
In the enclosed drawings Fig. 1 shows a possible arrangement for carrying out the method according to the invention. Fibre-board or plates 1 are arranged inside a cover 3 made of sheet iron, aluminum plate or similar suitable material, an aluminum foil 2 if desired, and further the cover 3 with its contents being arranged on an ingot mould 5 provided with a hot top 4, said cover and its contents, that is the ceramic material 1 and possible aluminum foils 2 being arranged at a distance above the level of the metal immediately after or just prior to concluded pouring of an ingot 6 (the same applies to a casting mould in up-hill or down-hill casting).
Fig. 2 in the enclosed drawings shows still another possible arrangement for carrying out the method according to the invention9 said arrangement, as in Fig. 1, having the fibre plate or plates 1, the cover 3 and the aluminum foil 2.
The cover 3 along with its contents is now arranged on a ladle 8 which, as known, consists of a ladle casing 9a having dowel(s) 9b for a lifting hook, refractory lining 10, nozzle 12 or stopper rod (not shown) and contains liquid metal, for example steel 6. In this case the lower portion of the plate casing of the cover 3, said lower portion resting on the upper portion of the ladle casing 9a, is formed as an angular tab 7a ~ 7b, whereby angular tab part 7a rests on the upper portion of the ladle casing 9a and angular tab part 7b extends outwardly in a downward direction along the ladle casîng 9a.
Fig. 2 shows a l~dle without any stopper arrangement , but the cover ~ can be advantageously used for ladles whose opening/teeming hole 11 is adjusted via stopper rods and/or ~0 sliding gate nozzles. When stopper rods are arranged on ladles the plate casing of the cover 3 is designed in such a manner that the upper portion of the stopper rod having an upper manoeuvring arm or sliding arm is covered preventing air exchange between the steel and the environment. The cover can also be advantageously designed in such a manner that recesses, holes or slots are provided on the cover, in which a stopper rod or several stopper rods fit without resul~ing in that the function or effect of the ceramic fibres is reduced. The ceramic fibre material can further be attached in various ways to the plate casing of the cover, for example by means of reinforcement wire, nails and the like in the fibre material itself, increasing the mechanical strength of the ceramic fibre material, said wire, nails etc. being attached to said plate casing. Said reinforcement wires, nails etc. should be 2S positioned in such a manner that they are not subjected to direct heat radiation from the metal bath.
In other words~ the ceramic fibre material shall protect said reinforcement by means of the reinforcement being ~.036791 surrounded by said material. The ceramic fibre material can also, in a manner known per se~ be treated with a refractory bonding agent~ whereby the fibre material is endowed with a certain self-supporting property.
The invention is further illuminated with the help of the following examples 1-10.
Example 1 Loose ceramic wool (1) was placed inside a cover (3) consisting of O.S mm sheet iron, uppermost against the ceiling of the same, said wool consisting of ceramic fibre having a SiO2-content of approx. ~8-50~ and an Al203-content of approx.
50-52%. After this an approx. 2.5 mm thick plate/board (1) was placed inside the cover, said plate/board consisting of approx-imately the same composition as that of the loose wool (1).
Aluminum foil (2) was laid between these two layers. The contents of the cover was held in place by the lower edge of the cover, said edge being bent in towards the ceramic fibre board (not shown in the figure). The cover was placed on top of the ingot mould (5) in such a way that the ceramic fibre board (1) rested directly on the hot top ~4) after concluded pouring when the metal had reached level (6). After the metal had solidified, the cover (3) was removed along with its contents (1 and 2), wherewith it was observed that the shrinkage of the metal was better than in the ingots, wholse upper sides had been covered with conventiDnal anti-piping agent. The process was repeated several times with the sheet iron cover and the same ceramic material without the result deviating from the first test, that is, the insulating properties of the ceramic material remained unchanged~
~036'7~1 .
Example 2 The same as Example 1 but the aluminum foil (2) was deleted and the cover (3) with its contents was laid onto the ingot mould t5) resting on the upper edge of the hot top (4) S and the cover (3) with its contents of ceramic fibre material was applied prior to the commencement of the pouring. Six ingots were poured up-hill~ whereby five of thase were provided with said arrangement. The sixth ingot mould was not provided with said arrangement as it was desired to visually see how quickly the steel rose in the ingot mould and when the pouring was completed. When this had been observed, the upper portion of the ingot mould/hot top/ingot was covered with the cover (3) ! containing the ceramic fibre (1). The process was repeated several times and the result was better than in ingots cast under the same conditions using conventional anti-piping agent~
Example 3 The same as Examples 1 and 2 but with the difference that the composition of the ceramic fibre was approx. 56% SiO
approx. 40% Al203 and approx. 4~ Cr203. Even in this example the shrinking was better than in ingots whose upper surfaces were covered with conventional anti-piping agents.
Example 4 The same as Examples 1 and 2 but with the difference that the composition of the ceramic fibre was approx. 43-47%
Al203, 50-54~ SiO2, 0~6-1~8% Fe203 and 1.2-3.5~ TiO2. The same good results as those of Examples 1-3 were obtained.
Example 5 The same as Examples 1 and 2 but with the difference that the loose wool was replaced with a 10 cm thick mineral wool matting and that two 2.5 cm ceramic fibre plates were used. The mineral wool mattin~ was hardly affected by the heat than~s to the protective effect of the ceramic fibre plate.
Exam~le 6 The same as Example 2 but with the difference that in a very special steel alloy having relatively high Cr and Ni content, in which exothermal anti-piping agent was applied to the surface of the molten metal and after the exothermal anti-piping agent had transferred heat to said metal surface, aninsulating agent consisting of kieselguhr, which is very health-hazardous, was applied. Instead of using the health-hazardous kieselguhr material, the cover (3) with the ceramic fibre (1) was applied. The results obtained therewith were as ¦ 15 good as the results in the previous examples.
Example 7 The same as Examples 1 and 2, whereby a plate consisting of Al203 and SiO2 was replaced with a plate consisting of Al203.
The results obtained therewith were as good as the results of Examples 1-6.
Example 8 The same as Examples 1 and 2 but with the difference that the plate consisting of Al203 was replaced with a plate consisting of ZrO2 fibres. The results obtained therewith were as good as the results obtained in the previous examples.
Example 9 The same as Examples 1 and 2 but with the difference that the upper portion o~ the hot top (4) lay a bit below the upper edge of the ingot mould (5)~ whereby the ceramic fibre material rested directly on the edge of the ingot mould. Even in this case, in which the ceramic fibre material still did not rest upon or stand in direct contact with tl~e smelt, the same good results as those o~tained in Examples 1-7 cou}d be noted.
Example 10 ~ cover of similar construction as those mentioned in Example.s 1-9 was made to cover the top part of a ladle, whereby the heat losses from the surface of the steel bath were reduced lQ considerably through a throughout application of the reusable ceramic fibres.
Beyond that which was mentioned above, the method according to the invention yields purely practical and economic j advantages in the manufacture of ingots or castings made of steel and the following advantages, listed without any judge-ment passed concerning the mutual importance of the advantages, namely 1~ Anti-piping agents used to date, either in a powdered form or solid form, applied to the level of the metal immediately after or JUst prior to concluded casting or during pouring from a ladle~ are omitted entirely.
The present invention relates to an improved method of manufacturing cast metal bodies, for example moulded cast-ings or ingots, the castings or ingots being composed of iron metal or iron metal alloys. Conventionally the casting may be carried out either up-hill or down-hill with mould paint and/or casting flux placed in the casting mould or ingot mould, an anti-piping agent being applied in direct contact with the molten upper portion of the cast metal body immediately after or just prior to concluded casting.
It is generally known that castings or ingots are manufactured by means of either up-hill or down-hill casting and that a casting flux is applied to the bottom portion of the casting mould or ingot mould in up-hill casting, said casting flux preventing oxidation by means of preventing atmospheric oxygen from reaching the steel.
Furthermore, it is generally known to apply an anti-piping agent directly on top of and in contact with the molten metal in the casting mould immediately after concluded casting.
In the manufacture of killed steel ingots a hot top, for example of the Vallak ~ type, which is applied to the upper portion of the ingot mould, is almost always used in order to reduce piping.
Even if the use of a hot top, for example of the Vallak ~ type, can substantially and economically reduce pipe formation in ingots, the use of anti-piping agent in the manufacture of both ingots or castings does not only ~.
~03679~
entail an increased cost of several Swedish ~rowns per ton casting wei~ht, it also carries with it the disadvantage of the production of clouds or dust both at and around the castin~
pit and therewith pollu~ion of the working area~ not forgetting possible health hazards encountered by persolmel in the form of the spread of dust and other ~articles in the air. Due to labour safety legislation in efect in most industrial nations, the use of unhealth~ anti-?iping agents has been prohibited.
~lowever, at the same time as such legislation has resulted in a smaller risk for personnel, the cost of anti-pipin~ agents has increased as it is no longer possible to choose inexpensive material for the production of anti-piping agent~ said materials mostly being a health hazard~
The application of ceramic fibres adjacent to but not in contact with the molten material, which has a temperature of approx. 1600C, has never been considered previously~as the material would be expected to be destroyed by the molten metal.
However~ it was found that the fibre--board in auestion not only maintained its integrity after the manu*acture of the first ingot but it also maintained its integrity after the manufac-ture of further ingots. Later, aluminum foil was placed between the ceramic fibre plates, the idea being that the reflecting aluminum foil would radiate the heat back to the molten material. Quite unexpectedly and contrar~ to the theoretical expectations, the aluminum did not melt. After this, experi-mentation was broadened with one or several layers of ceramic fibre material, one or several alu~inu~ -Foils etc. 3 all of which led to the present invention.
- ~03679i The fact that the heat from the still molten metal did not destroy the ceramic fibre material lying a slight distance above said molten metal is, in itself, perhaps explainable, but the fact that the aluminum foil applied to the ceramic material (the ceramic material can have a melting point which is sub-stantially greater than 1600C but the aluminum foil has a melt-ing point about 660C) did not melt is surprising, This surpris-ing result can be attributed to a synergetic effect in a com-bination of a ceramic material, in this case fibre material, and an aluminum foil.
According to the invention there is provided in a method of manufacturing cast metal bodies, moulded iron metal or iron metal alloy castings or ingots, in which teeming is carried out as an up-hill or down-hill casting with at least one of mould paint and casting flux applied to the casting mould or ingot mould, the improvement wherein an insulating member effective to prevent radiation and convection is disposed at a predetermined point in time, adjacent to and spaced apart from the level of the molten metal so as to substan~ially prevent access of outside cooling air to said metal, said insulating member consisting of ceramic fibres, said insulating member being spaced from said molten metal such that the molten metal will not contact the ceramic fibres under normal casting conditions, and such that the ceramic fibres are not destroyed by the heat of the molten metal, and such that the insulating material can be used again during a subsequent or later castings.
In the method of the invention cast m~tal bodies, for example moulded iron metal or iron metal alloy castings or ingots, are manufactured in a method in which teeming is carried out in the form of an up-hill or down-hill casting with mould paint and/or casting flux placed inside the casting mould or ingot mould, the method being characterized in that instead of ? - 3 -103679i conventionally employed anti-piping agent there is employed an insulating member which prevents radiation and convection and which is applied at a suitable point in time, that is, in down-hill casting when the casting is completed and in up-hill casting at any time after the placement of the hot top in the ingot mould, at a small distance from the level of the metal, i.e.
the molten metal with molten slag substance possibly flowing thereupon (subsequently referred to only as molten metal or molten steel), but not in direct contact with the metal, thereby substantially preventing outside cooling air from entering, the insulating member being suitably in the form of plate, board matting or the like consisting of ceramic fibres, the insulating member, if desired, being provided on at least one side with an aluminum foil, the slight distance being chosen so that it is large enough that the molten metal will not reach up to the insulating member in normal casting conditions and large enough that the ceramic fibres not be destroyed by the heat of the molten metal, and so that the insulating member can be used again and applied during the subsequent or later castings.
The method according to the invention is further characterized in that the insulating material is applied arranged in a cover or hood, the lower side wall edge of which abuts the upper portion of the present casting mould or ingot mould. The ceramic fibre material can advantageously be arranged in such a manner in the cover/hood that the most heat resistant ceramic fibre material is placed nearest the surface of the molten metal.
A less heat resistant ceramic fibre material is placed thereafter, etc. In other words, the heat resistance of the ceramic fibre material decreases as the distance to the surface of the molten metal increases. In this manner the cost of the ceramic fibr~
material, which is placed in the cover/hood, can be reduced.
; - 4 -'1036791 The method according to the invention is further characterized in that metal plate made of for example aluminum, iron etc. is used as material for the cover or hood.
Ceramic fibres comprise for example A1203 and SiO2 fibres, Fiberfrax ~ , Kaowool ~ , ZrO2 or Cr203 fibres. High temperature resisting, but not ceramic fibres comprise for example mineral wool, which has a temperature resistance of only about 800C.
Further aspects of the invention are characterized in that an aluminum foil is arranged on at least one side of an insulating plate or that an aluminumfoil is arranged at least between two plates if there are more than one insulating plate, or that an aluminum foil is arranged on the insulating plate surface which is facing the molten metal, or that an aluminum foil is arranged on the insulating plate surface which is facing the ceiling of said cover or the bottom surface of said cover.
According to another aspect of the in~ention, an aluminum foil can be arranged on the insulating plate surface which is facing the molten metal as well as on the insulating plate surface which is facing the inner surface of the ceiling (roof) of the cover.
According to another embodiment of the invention the reusable insulating cover, as a whole or as sections which can be joined together, can be used on a ladle. During pouring from the ladle into one or a plurality of ingot moulds, reusable insulating covers are also used on the ingot mould or moulds.
The invention is illustrated in particular and preferred embodiments by reference to the accompanying drawings in which:
FIGURE 1 illustrates an ingot mould in conjunction with an insulating member disposed in accordance with one embodiment of the invention, and r: ~ ~ 5 _ ~036791 FIGURE 2 illustrates a ladle in conjunction with an insulating member disposed in accordance with another embodiment of the invention.
The method according to this other embodiment of the invention is characterized in that the insulating material is applied arranged inside a cover or hood 3, the lower side wall edge 7a of which abuts the upper portion of the ladle 8 used in casting/ from which, in a manner - 5a -known in itself, the liquid metal is poured into the casting mould or ingot mould.
The above-mentioned method is further characterized in that the lower side wall edge 7a of the cover or hood 3 is furthermore designed as an angular tab 7a + 7b, the angular tab part 7a of which rests on the upper portion of the casing 9a of the ladle 8, while angular tab part 7b extends outwardly in a downward direction along the casing 9a of the ladle.
In the enclosed drawings Fig. 1 shows a possible arrangement for carrying out the method according to the invention. Fibre-board or plates 1 are arranged inside a cover 3 made of sheet iron, aluminum plate or similar suitable material, an aluminum foil 2 if desired, and further the cover 3 with its contents being arranged on an ingot mould 5 provided with a hot top 4, said cover and its contents, that is the ceramic material 1 and possible aluminum foils 2 being arranged at a distance above the level of the metal immediately after or just prior to concluded pouring of an ingot 6 (the same applies to a casting mould in up-hill or down-hill casting).
Fig. 2 in the enclosed drawings shows still another possible arrangement for carrying out the method according to the invention9 said arrangement, as in Fig. 1, having the fibre plate or plates 1, the cover 3 and the aluminum foil 2.
The cover 3 along with its contents is now arranged on a ladle 8 which, as known, consists of a ladle casing 9a having dowel(s) 9b for a lifting hook, refractory lining 10, nozzle 12 or stopper rod (not shown) and contains liquid metal, for example steel 6. In this case the lower portion of the plate casing of the cover 3, said lower portion resting on the upper portion of the ladle casing 9a, is formed as an angular tab 7a ~ 7b, whereby angular tab part 7a rests on the upper portion of the ladle casing 9a and angular tab part 7b extends outwardly in a downward direction along the ladle casîng 9a.
Fig. 2 shows a l~dle without any stopper arrangement , but the cover ~ can be advantageously used for ladles whose opening/teeming hole 11 is adjusted via stopper rods and/or ~0 sliding gate nozzles. When stopper rods are arranged on ladles the plate casing of the cover 3 is designed in such a manner that the upper portion of the stopper rod having an upper manoeuvring arm or sliding arm is covered preventing air exchange between the steel and the environment. The cover can also be advantageously designed in such a manner that recesses, holes or slots are provided on the cover, in which a stopper rod or several stopper rods fit without resul~ing in that the function or effect of the ceramic fibres is reduced. The ceramic fibre material can further be attached in various ways to the plate casing of the cover, for example by means of reinforcement wire, nails and the like in the fibre material itself, increasing the mechanical strength of the ceramic fibre material, said wire, nails etc. being attached to said plate casing. Said reinforcement wires, nails etc. should be 2S positioned in such a manner that they are not subjected to direct heat radiation from the metal bath.
In other words~ the ceramic fibre material shall protect said reinforcement by means of the reinforcement being ~.036791 surrounded by said material. The ceramic fibre material can also, in a manner known per se~ be treated with a refractory bonding agent~ whereby the fibre material is endowed with a certain self-supporting property.
The invention is further illuminated with the help of the following examples 1-10.
Example 1 Loose ceramic wool (1) was placed inside a cover (3) consisting of O.S mm sheet iron, uppermost against the ceiling of the same, said wool consisting of ceramic fibre having a SiO2-content of approx. ~8-50~ and an Al203-content of approx.
50-52%. After this an approx. 2.5 mm thick plate/board (1) was placed inside the cover, said plate/board consisting of approx-imately the same composition as that of the loose wool (1).
Aluminum foil (2) was laid between these two layers. The contents of the cover was held in place by the lower edge of the cover, said edge being bent in towards the ceramic fibre board (not shown in the figure). The cover was placed on top of the ingot mould (5) in such a way that the ceramic fibre board (1) rested directly on the hot top ~4) after concluded pouring when the metal had reached level (6). After the metal had solidified, the cover (3) was removed along with its contents (1 and 2), wherewith it was observed that the shrinkage of the metal was better than in the ingots, wholse upper sides had been covered with conventiDnal anti-piping agent. The process was repeated several times with the sheet iron cover and the same ceramic material without the result deviating from the first test, that is, the insulating properties of the ceramic material remained unchanged~
~036'7~1 .
Example 2 The same as Example 1 but the aluminum foil (2) was deleted and the cover (3) with its contents was laid onto the ingot mould t5) resting on the upper edge of the hot top (4) S and the cover (3) with its contents of ceramic fibre material was applied prior to the commencement of the pouring. Six ingots were poured up-hill~ whereby five of thase were provided with said arrangement. The sixth ingot mould was not provided with said arrangement as it was desired to visually see how quickly the steel rose in the ingot mould and when the pouring was completed. When this had been observed, the upper portion of the ingot mould/hot top/ingot was covered with the cover (3) ! containing the ceramic fibre (1). The process was repeated several times and the result was better than in ingots cast under the same conditions using conventional anti-piping agent~
Example 3 The same as Examples 1 and 2 but with the difference that the composition of the ceramic fibre was approx. 56% SiO
approx. 40% Al203 and approx. 4~ Cr203. Even in this example the shrinking was better than in ingots whose upper surfaces were covered with conventional anti-piping agents.
Example 4 The same as Examples 1 and 2 but with the difference that the composition of the ceramic fibre was approx. 43-47%
Al203, 50-54~ SiO2, 0~6-1~8% Fe203 and 1.2-3.5~ TiO2. The same good results as those of Examples 1-3 were obtained.
Example 5 The same as Examples 1 and 2 but with the difference that the loose wool was replaced with a 10 cm thick mineral wool matting and that two 2.5 cm ceramic fibre plates were used. The mineral wool mattin~ was hardly affected by the heat than~s to the protective effect of the ceramic fibre plate.
Exam~le 6 The same as Example 2 but with the difference that in a very special steel alloy having relatively high Cr and Ni content, in which exothermal anti-piping agent was applied to the surface of the molten metal and after the exothermal anti-piping agent had transferred heat to said metal surface, aninsulating agent consisting of kieselguhr, which is very health-hazardous, was applied. Instead of using the health-hazardous kieselguhr material, the cover (3) with the ceramic fibre (1) was applied. The results obtained therewith were as ¦ 15 good as the results in the previous examples.
Example 7 The same as Examples 1 and 2, whereby a plate consisting of Al203 and SiO2 was replaced with a plate consisting of Al203.
The results obtained therewith were as good as the results of Examples 1-6.
Example 8 The same as Examples 1 and 2 but with the difference that the plate consisting of Al203 was replaced with a plate consisting of ZrO2 fibres. The results obtained therewith were as good as the results obtained in the previous examples.
Example 9 The same as Examples 1 and 2 but with the difference that the upper portion o~ the hot top (4) lay a bit below the upper edge of the ingot mould (5)~ whereby the ceramic fibre material rested directly on the edge of the ingot mould. Even in this case, in which the ceramic fibre material still did not rest upon or stand in direct contact with tl~e smelt, the same good results as those o~tained in Examples 1-7 cou}d be noted.
Example 10 ~ cover of similar construction as those mentioned in Example.s 1-9 was made to cover the top part of a ladle, whereby the heat losses from the surface of the steel bath were reduced lQ considerably through a throughout application of the reusable ceramic fibres.
Beyond that which was mentioned above, the method according to the invention yields purely practical and economic j advantages in the manufacture of ingots or castings made of steel and the following advantages, listed without any judge-ment passed concerning the mutual importance of the advantages, namely 1~ Anti-piping agents used to date, either in a powdered form or solid form, applied to the level of the metal immediately after or JUst prior to concluded casting or during pouring from a ladle~ are omitted entirely.
2. The cost of the anti-piping agent, which is a one-time cost for each ingot, casting and insulating powder for ladles, is omitted entirely and only the cost of the ceramic fibre material exists, said material being able to be used a plurality of times; the economic gain should amount to several Swedish Crowns per ton ingot or casting~
3. The use of a firm, reusable ceramic material results in 103679i .
the fact that no dust formation or spreading arises at or around the casting station.
the fact that no dust formation or spreading arises at or around the casting station.
4. The ceramic fibre material prevents heat escape by radiation as well as convection from the metal during pouring from a ladle.
5. The application of one or more aliminum foils prevents air circulation in the porous layer of the ceramic fibres, wheréby ~he insulation ability is amplified at the same time as the aluminum layer applied nearest to the molten material reflects heat.
6. The synergetic effect of the combination of ceramic fibres and aluminum foil entails an increased heat re-radiation and an increas~ heat preservation in the molten metal during pouring from ladles together with, therewith not unexplainable 7 a reduced radiation of heat to the environment surrounding the ladle.
7. The method~ by means of which the ceramic fibre material, possibly with aluminum foils, is arranged at a distance from the molten metal but in abutting contact with the top of the ladle, prevents exchange of air and therewith decreases oxidation of the surface of the molten metal.
8. No dust is formed due to the fact that dust-forming material is not used.
9. Ingots which are clean~ that is free from dusty material~
are obtained from the pouring from the ladle to the ingot mould in the warm state~ said ingots being able to be passed on to a hot-rolling mill directly after casting.
are obtained from the pouring from the ladle to the ingot mould in the warm state~ said ingots being able to be passed on to a hot-rolling mill directly after casting.
10. By means of, in carrying out the method according to the 103~7~1 invention, arranging the ceramic J firm, fibrous material and the aluminum foils~ when used, in a cover, said cover prevents the spilling and splashing of steel in up-hill pouring entaîling that entrapments in the ingot are not formed and that the insulating material is proteoted, that is the ceramic fibres and possibly the aluminum foils are protected from steel dr~ppings; this due to the fact that the cover containing the ceramic material is arranged on the ingot moulds before the commencement of the pouring. This is of special importance in the cast~g of ingGts wherein a great number of ingot moulds are as a rule placed on a bottom plate and cast up-hill, wherein the metal is poured from the ladle into the trumpet. It is possible that the pouring stream misses the trumpet and there-with splashes the steel up into the ingot moulds, said steel freezing to the walls of the ingot moulds and creating unrepairable wounds and flaws on the ingot resulting in bad ingot sur$aces and consequently a poorly rolled product.
Claims (15)
1. In a method of manufacturing cast metal bodies, moulded iron metal or iron metal alloy castings or ingots, in which teem-ing is carried out as an up-hill or down-hill casting with at least one of mould paint and casting flux applied to the casting mould or ingot mould, the improvement wherein an insulating member effective to prevent radiation and convection is, disposed at a predetermined point in time, adjacent to and spaced apart from the level of the molten metal so as to substantially prevent access of outside cooling air to said metal, said insulating member consisting of ceramic fibres, said insulating member being spaced from said molten metal such that the molten metal will not contact the ceramic fibres under normal casting conditions, and such that the ceramic fibres are not destroyed by the heat of the molten metal, and such that the insulating material can be used again during a subsequent or later castings.
2. A method according to claim 1, wherein the insulating member is arranged in a cover or hood, having a lower side wall edge abutting an upper portion of the casting mould or ingot mould.
3. A method according to claim 2, wherein said cover or hood is formed from a metal plate.
4. A method according to claim 2, wherein an insulating material less heat resistant than ceramic fibres is disposed between said insulating member and said cover or hood.
5. A method according to claim 4, wherein said insulating material comprises mineral wool.
6. A method according to claim 1, wherein said teeming comprises an up-hill casting and said insulating member is disposed adjacent said level of molten metal after placement of a hot top in the mould.
7. A method according to claim 1, wherein said teeming comprises a down-hill casting and said insulating member is disposed at the conclusion of the casting operation.
8. A method according to claim 1, wherein said member is a board or matting of ceramic fibres.
9. A method according to claim 1, wherein said member is a board and an aluminum foil is arranged on at least one side of said board.
10. A method according to claim 1, wherein said member comprises a plurality of boards and an aluminum foil is disposed at least between two adjacent boards.
11. A method according to claim 9 or 10, wherein aluminum foil is disposed on the insulating member surface facing the molten metal.
12. A method according to claim 2, wherein said member comprises a board and an aluminum foil is arranged on the board surface which is facing the ceiling of the cover or hood.
13. A method according to claim 2 or 3, wherein said member comprises a board and a first aluminum foil is arranged on the board surface facing the molten metal and a second aluminum foil is arranged on the board surface facing the ceiling of the roof of the cover or hood.
14. A method according to claim 1, characterized in that the insulating member is arranged in a cover or hood having a lower side wall edge abutting an upper portion of a ladle from which the molten metal is poured into the casting mould or ingot mould.
15. A method according to claim 2 or 14, wherein the lower Aide wall edge of the cover or hood comprises an angular tab having a first part resting on an upper portion of the casing of the ladle, and a second part extending outwardly in a down-ward direction along the casing of the ladle.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE7316703A SE381832B (en) | 1973-12-11 | 1973-12-11 | WAY TO PROTECT THE SURFACE OF THE METAL IN THE MANUFACTURE OF CAST METAL BODIES, EX. DESIGNED CAST OR GOOD |
| SE7406768A SE442485B (en) | 1974-05-21 | 1974-05-21 | APPLICABLE LOCK FOR HEAT INSULATION OF A METAL CASTLE |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1036791A true CA1036791A (en) | 1978-08-22 |
Family
ID=26656429
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA214,653A Expired CA1036791A (en) | 1973-12-11 | 1974-11-26 | Method of manufacturing steel ingots or castings |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS5092230A (en) |
| CA (1) | CA1036791A (en) |
| DE (1) | DE2456241C2 (en) |
| ES (1) | ES432751A1 (en) |
| FR (1) | FR2253586B1 (en) |
| GB (1) | GB1496348A (en) |
| IT (1) | IT1023954B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3634892A1 (en) * | 1986-10-14 | 1988-04-28 | Didier Werke Ag | FIRE RESISTANT LINING, ESPECIALLY FOR LID OF INTERMEDIATE CONTAINERS |
| WO2011049698A2 (en) * | 2009-10-19 | 2011-04-28 | Micropyretics Heaters International, Inc. | Clean green energy electric protectors for materials |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE577693C (en) * | 1931-12-10 | 1933-06-02 | Eduard Herzog Dr Ing | Process and mold for improving unkilled steel |
| JPS4418824Y1 (en) * | 1965-10-11 | 1969-08-14 | ||
| JPS5310911Y2 (en) * | 1971-08-05 | 1978-03-24 | ||
| IT950259B (en) * | 1972-03-16 | 1973-06-20 | Montedison Spa | PROCEDURE FOR THE RECOVERY OF CATALYTIC SYSTEMS CONSTITUTED BY COM PLEXES OF TRANSITION METALS WITH ORGANIC BINDERS |
-
1974
- 1974-11-26 CA CA214,653A patent/CA1036791A/en not_active Expired
- 1974-11-28 DE DE19742456241 patent/DE2456241C2/en not_active Expired
- 1974-12-05 FR FR7439822A patent/FR2253586B1/fr not_active Expired
- 1974-12-10 ES ES432751A patent/ES432751A1/en not_active Expired
- 1974-12-10 JP JP14196474A patent/JPS5092230A/ja active Pending
- 1974-12-10 GB GB5339374A patent/GB1496348A/en not_active Expired
- 1974-12-10 IT IT1308774A patent/IT1023954B/en active
Also Published As
| Publication number | Publication date |
|---|---|
| FR2253586B1 (en) | 1981-01-23 |
| DE2456241A1 (en) | 1975-06-12 |
| JPS5092230A (en) | 1975-07-23 |
| GB1496348A (en) | 1977-12-30 |
| AU7579674A (en) | 1976-05-27 |
| FR2253586A1 (en) | 1975-07-04 |
| ES432751A1 (en) | 1976-12-01 |
| DE2456241C2 (en) | 1986-04-17 |
| IT1023954B (en) | 1978-05-30 |
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