CA2165143A1 - Method of applying to the interior faces of a metallurgical container a protective coating comprising at least two layers - Google Patents
Method of applying to the interior faces of a metallurgical container a protective coating comprising at least two layersInfo
- Publication number
- CA2165143A1 CA2165143A1 CA002165143A CA2165143A CA2165143A1 CA 2165143 A1 CA2165143 A1 CA 2165143A1 CA 002165143 A CA002165143 A CA 002165143A CA 2165143 A CA2165143 A CA 2165143A CA 2165143 A1 CA2165143 A1 CA 2165143A1
- Authority
- CA
- Canada
- Prior art keywords
- layer
- container
- mold
- liquid metal
- binder
- 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.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims abstract description 28
- 239000011253 protective coating Substances 0.000 title claims abstract description 8
- 239000010410 layer Substances 0.000 claims abstract description 71
- 239000011230 binding agent Substances 0.000 claims abstract description 24
- 239000000463 material Substances 0.000 claims abstract description 21
- 239000000843 powder Substances 0.000 claims abstract description 18
- 239000010954 inorganic particle Substances 0.000 claims abstract description 12
- 239000011241 protective layer Substances 0.000 claims abstract description 10
- 238000009998 heat setting Methods 0.000 claims abstract description 9
- 238000000465 moulding Methods 0.000 claims abstract description 7
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 30
- 229910001338 liquidmetal Inorganic materials 0.000 claims description 28
- 239000000292 calcium oxide Substances 0.000 claims description 15
- 235000012255 calcium oxide Nutrition 0.000 claims description 15
- 239000011248 coating agent Substances 0.000 claims description 15
- 238000000576 coating method Methods 0.000 claims description 15
- ZCCIPPOKBCJFDN-UHFFFAOYSA-N calcium nitrate Chemical compound [Ca+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ZCCIPPOKBCJFDN-UHFFFAOYSA-N 0.000 claims description 8
- 238000006243 chemical reaction Methods 0.000 claims description 7
- 239000002245 particle Substances 0.000 claims description 7
- 230000000694 effects Effects 0.000 claims description 6
- 239000000395 magnesium oxide Substances 0.000 claims description 6
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 6
- 230000004907 flux Effects 0.000 claims description 5
- 238000005507 spraying Methods 0.000 claims description 5
- 239000000126 substance Substances 0.000 claims description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 4
- 229910001632 barium fluoride Inorganic materials 0.000 claims description 4
- IWOUKMZUPDVPGQ-UHFFFAOYSA-N barium nitrate Chemical compound [Ba+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O IWOUKMZUPDVPGQ-UHFFFAOYSA-N 0.000 claims description 4
- 239000011575 calcium Substances 0.000 claims description 4
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims description 4
- 229910001634 calcium fluoride Inorganic materials 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 4
- 239000011777 magnesium Substances 0.000 claims description 4
- 229910001635 magnesium fluoride Inorganic materials 0.000 claims description 4
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 claims description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 3
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 239000000470 constituent Substances 0.000 claims description 3
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 2
- KKCBUQHMOMHUOY-UHFFFAOYSA-N Na2O Inorganic materials [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 claims description 2
- OYLGJCQECKOTOL-UHFFFAOYSA-L barium fluoride Chemical compound [F-].[F-].[Ba+2] OYLGJCQECKOTOL-UHFFFAOYSA-L 0.000 claims description 2
- 229910052791 calcium Inorganic materials 0.000 claims description 2
- 229910052681 coesite Inorganic materials 0.000 claims description 2
- 229910052906 cristobalite Inorganic materials 0.000 claims description 2
- 238000002425 crystallisation Methods 0.000 claims description 2
- 230000008025 crystallization Effects 0.000 claims description 2
- 229910052739 hydrogen Inorganic materials 0.000 claims description 2
- 229910052749 magnesium Inorganic materials 0.000 claims description 2
- 239000001095 magnesium carbonate Substances 0.000 claims description 2
- 229910000021 magnesium carbonate Inorganic materials 0.000 claims description 2
- ORUIBWPALBXDOA-UHFFFAOYSA-L magnesium fluoride Chemical compound [F-].[F-].[Mg+2] ORUIBWPALBXDOA-UHFFFAOYSA-L 0.000 claims description 2
- 238000002844 melting Methods 0.000 claims description 2
- 230000008018 melting Effects 0.000 claims description 2
- 239000000377 silicon dioxide Substances 0.000 claims description 2
- 235000012239 silicon dioxide Nutrition 0.000 claims description 2
- 229910052682 stishovite Inorganic materials 0.000 claims description 2
- 229910052905 tridymite Inorganic materials 0.000 claims description 2
- 229910002651 NO3 Inorganic materials 0.000 claims 1
- 229910052782 aluminium Inorganic materials 0.000 claims 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims 1
- 229910052593 corundum Inorganic materials 0.000 claims 1
- 238000000605 extraction Methods 0.000 claims 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims 1
- 239000011819 refractory material Substances 0.000 claims 1
- 229910001845 yogo sapphire Inorganic materials 0.000 claims 1
- 238000005266 casting Methods 0.000 description 8
- 239000007789 gas Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 238000004140 cleaning Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- BNGXYYYYKUGPPF-UHFFFAOYSA-M (3-methylphenyl)methyl-triphenylphosphanium;chloride Chemical compound [Cl-].CC1=CC=CC(C[P+](C=2C=CC=CC=2)(C=2C=CC=CC=2)C=2C=CC=CC=2)=C1 BNGXYYYYKUGPPF-UHFFFAOYSA-M 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000011449 brick Substances 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D1/00—Casings; Linings; Walls; Roofs
- F27D1/16—Making or repairing linings increasing the durability of linings or breaking away linings
- F27D1/1626—Making linings by compacting a refractory mass in the space defined by a backing mould or pattern and the furnace wall
-
- 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
- B22D41/02—Linings
- B22D41/023—Apparatus used for making or repairing linings
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D99/00—Subject matter not provided for in other groups of this subclass
- F27D99/0001—Heating elements or systems
- F27D99/0033—Heating elements or systems using burners
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Furnace Housings, Linings, Walls, And Ceilings (AREA)
Abstract
In a method for applying to the interior faces of a metallurgical container a protective coating comprising at least two layers, a first protective layer is wet sprayed onto the permanent lining of the container. The layer obtained in this way is heated to harden it. A
mold is introduced into the container, creating a molding space between the walls of the mold and the exterior surface of the first layer. A powder material is introduced into this molding space, made up of inorganic particles precoated with a heatsetting powder binder and/or mixed with a heatsetting powder binder, the material being dry or virtually dry. After hardening this layer, the mold is removed from the container to leave therein an exterior protective layer.
mold is introduced into the container, creating a molding space between the walls of the mold and the exterior surface of the first layer. A powder material is introduced into this molding space, made up of inorganic particles precoated with a heatsetting powder binder and/or mixed with a heatsetting powder binder, the material being dry or virtually dry. After hardening this layer, the mold is removed from the container to leave therein an exterior protective layer.
Description
- ~1651~
~THOD OF APPLYING TO THE INT~RIOR FACES OF A
MT~T~TTURGIC~T CONTAINER A PROTECTIVF~ COATING COMPRISING
AT LEAST TWO LAYERS
BACKGROUND OF THE INVENTION
Field of the invention The present invention concerns a method of applying to the interior faces of a metallurgical container for transferring liquid metal a consumable protective coating comprising at least two layers.
The invention also concerns the coating obtained by this method as well as the composition of this coating.
Description of the prior art French patents 2 646 367 and 2 657 549 describe various methods for applying to the interior faces of a metallurgical container such as a casting ladle a protective coating comprising at least two layers.
French patent 87757 describes a method for applying to the interior faces of a casting ladle a coating comprising two layers, this method comprising the following steps:
A. A core is placed inside the metallurgical container to be protected to create a molding space between the interior walls of said container and the exterior walls of the core.
B. A material made of up of heat-resistant inorganic particles is introduced into the molding space thus created, said particles being precoated with a hardenable binder and/or mixed with a binder, said material being dry or virtually dry.
C. After hardening of said material on the interior walls of the container, the core is extracted from the container, leaving in place a first or exterior protective layer.
D. A second or interior layer is sprayed onto the first or exterior protective layer by wet spraying a - ~1651~
material made up of inorganic particles able to withstand the temperature of the liquid metal.
E. The interior walls of the metallurgical container are heated until the protective coating thus deposited is perfectly dry.
In this method, the first layer is formed in the space between the mold and the interior wall of the container, whereas the second layer is sprayed.
The drawback of a method of this kind is that the second layer is sprayed in the form of an aqueous sludge.
This layer is therefore wet; it is therefore necessary to dry it carefully before pouring the liquid metal into the container, to avoid all risk of explosion resulting from the formation of hydrogen due to decomposition of the water by the high temperature.
Moreover, because the second layer is wet, it cannot contain any substances that are sensitive to water such as quick lime, which has the function of purifying oxides contained in the liquid metal.
The aim of the present invention is to overcome these drawbacks.
SUMMARY OF THE INVENTION
In accordance with the invention, the method of applying to the interior faces of a metallurgical container for transferring liquid metal a consumable protective coating comprising at least two layers includes the following steps:
a. a permanent coating of said container has sprayed onto it a first protective layer by wet spraying a material made up of inorganic particles resistant to the temperature of said liquid metal and a heatsetting binder, b. the layer thus obtained is heated to harden it, c. a preheated or heater mold is introduced into the interior of said metallurgical container to create a _ ~1651~3 molding space between exterior walls of said mold and the exterior surface of said first layer, d. a powder material is introduced into the mold space thus created, made up of inorganic particles resistant to the temperature at which the liquid metal is transferred, said particles being precoated with a hardenable powder binder and/or mixed with a hardenable powder binder, said material being dry or virtually dry, e. after hardening of said powder material on said exterior surface of said first layer due to the heating effect of said preheated or heater mold, said preheated or heater mold is extracted from said container to leave therein a second exterior protective layer.
Thus, in accordance with the invention, only the first layer is wet, whereas the second layer that will come into contact with the liquid metal is virtually dry, so that it can contain substances sensitive to water and having purifying properties, such as quick lime.
In an advantageous version of the method, before the preheated or heater mold is placed in position said powder material is applied to the hardened first layer in a bottom area of the container to form a second or bottom layer and the lateral parts of the second layer are formed after introducing the preheated or heater mold into the container.
In a preferred version of the method the second layer is formed of quick lime, a heatsetting binder and optionally a flux.
The quick lime can therefore exert its purifying properties in relation to oxides contained in the liquid metal.
The heatsetting binder contained in this layer ensures cohesion of the layer after hardening due to the effect of the heat exerted by the preheated or heater mold.
- 21~51~3 The presence of a flux facilitates the sintering of this layer due to the effect of the heating exerted by the liquid metal so that cohesion of the layer is maintained while the liquid metal remains in the container.
The first layer preferably contains magnesium oxide as its main constituent.
The particle sizes and the composition of the inorganic particles of the first layer are preferably chosen so that said layer is not sintered or is only slightly sintered at the temperature at which the liquid metal is transferred into the container.
Because of this, at the end of casting, the coating can be very easily detached from the wall of the container, which considerably facilitates cleaning of the latter.
In another preferred embodiment of the invention the second layer is mixed with 5% to 60% by weight of substances that can generate an exothermic reaction.
This exothermic reaction melts the quick lime and burns the carbon contained in the second layer.
Other features and advantages of the invention emerge from the following description given by way of non-limiting example with reference to the appended drawings.
BRIFF DFSCRIPTION OF THE DRAWINGS
Figure 1 is a diagrammatic view in cross-section of a metallurgical container and the mold used to implement the method of the invention, showing the step of spraying the first coating layer.
Figure 2 is a view analogous to figure 1 showing the stage of forming the second layer after introduction of the heater mold into the container.
Figure 3 is a view analogous to figure 2 showing a different embodiment of the second layer.
Figure 4 is a view in cross-section of the container complete with its two layers and a gas burner adapted to start the exothermic reaction in the second layer.
Figure 5 is a view analogous to figure 4 showing the gas burner in its in-service position inside the container.
DETAITl~n DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the embodiments shown in the appended figures 1 through 5 a continuous casting ladle 1 comprises a metal exterior jacket 2 and an interior coating 3 of refractory bricks or cement.
In the bottom of the container 1 is a casting orifice with a casting nozzle 4.
The method for applying to the interior faces of the casting ladle 1 a consumable protective coating comprising two layers comprises the following steps:
a. a permanent coating 3 of the container 1 has sprayed onto it a first protective layer 5 by wet spraying a material made up of inorganic particles resistant to the temperature of the liquid metal and a heatsetting binder (see figure 1), b. the layer 5 thus obtained is heated to harden it, c. a preheated or heater mold 7 is introduced into the interior of the metallurgical container to create a molding space 8 between exterior walls of the mold 7 and the exterior surface of the first layer 5 (see figure 2), d. a powder material 9 is introduced into the mold space thus created, made up of inorganic particles resistant to the temperature at which the liquid metal is transferred, said particles being precoated with a hardenable powder binder and/or mixed with a hardenable powder binder, said material being dry or virtually dry, e. after hardening of said powder material on the S~16~1~3 exterior surface of said first layer 5 due to the heating effect of the preheated or heater mold 7, the preheated or heater mold is extracted from the container to leave therein a second or exterior protective layer 6.
In the example shown in figures 1 and 2 the mold 7 is metal and is heated internally by means of gas burners 10.
In the version shown in figure 3, before fitting the preheated or heater mold 7, said powder material is applied to the hardened first layer 5 in the bottom part of the container to form a bottom or second layer 6a and the lateral parts of the second layer 6 are formed after introducing the pre-heated or heater mold 7 into the casting ladle 1.
The second layer 6 is preferably formed from quick lime, a heatsetting binder and a flux.
The quick lime has a purifying function in relation to oxides in the liquid metal in the ladle 1.
The binder provides the initial cohesion of the layer 6 after hardening, the flux facilitates sintering due to the effect of heat and maintains the cohesion of the layer 6 throughout the time that the liquid metal remains inside the ladle 1.
The first layer 5 preferably includes magnesium oxide as the major constituent. The proportion of the magnesium oxide is 75% by weight, for example.
The particle sizes and the composition of the inorganic particles of the first layer 5 are preferably chosen so that this layer is not sintered or is only slightly sintered at the temperature at which the liquid metal is transferred into the ladle 1.
Thus the layer 5 in contact with the permanent coating 2 does not adhere to the latter with the result that, at the end of casting, the coating is easily detachable from the wall of the ladle, which facilitates `- '21651~3 cleaning it.
Usually, the mold 7 is preheated or is a heater type mold that can produce a temperature between 400C
and 800C.
This hardens the layer 6 that comes into contact with the liquid metal.
The second layer 6 can be formed of quick lime precoated with a binder and/or mixed with an organic and/or inorganic binder.
When the mold 7 is introduced into the metallurgical container, the position and/or the dimensions of the mold in the container are adjusted to vary the thickness of the second layer 6.
In one embodiment of the method of the invention - 15 the layer 6 that comes into contact with the liquid metal and which contains quick lime is mixed with between 5% by weight and 6~ by weight of elements that can generate an exothermic reaction. These elements can be magnesium and/or calcium to which are added calcium nitrate and/or barium nitrate and/or aluminum nitrate and, for example, calcium fluoride and/or magnesium fluoride and/or barium fluoride.
After the mold 7 is removed, the exothermic reaction to melt the quick lime and to burn the carbon of the organic binder contained in the second layer 6 is instigated, for example using gas burners 10.
This variant of the method of the invention is shown in figures 4 and 5.
To give a non-limiting example, the composition for the coating coming into contact with the liquid metal to protect the interior of a liquid metal transfer container comprises the following substances in the proportions by weight indicated below:
Mg and/or Ca and/or Al 0 - 60%
SiO2 0 - 3.5 21~a l 43 Al23 0 - 4%
Quick lime 0 - 95%
MgO and/or chrome-magnesite 0 - 50%
Fe23 0 - 5%
Na2O 0 - 2.5%
Melting loss at 1 000C 0 - 5%
P 0 - 7%
H 0 - 0.5%
B2O3 0 - 3%
K2O 0 - 4%
H2O 0 - 3%
Total C 0 - 6%
Na 0 - 2.5%
K 0 - 1.80%
H2O of crystallization 0 - 3%
Ca(NO3)2 0 - 10%
(No3)2Ba 0 - 10%
MgF2 0-- 8%
CaF2 0 - 8%
BaF2 0 - 8%
~THOD OF APPLYING TO THE INT~RIOR FACES OF A
MT~T~TTURGIC~T CONTAINER A PROTECTIVF~ COATING COMPRISING
AT LEAST TWO LAYERS
BACKGROUND OF THE INVENTION
Field of the invention The present invention concerns a method of applying to the interior faces of a metallurgical container for transferring liquid metal a consumable protective coating comprising at least two layers.
The invention also concerns the coating obtained by this method as well as the composition of this coating.
Description of the prior art French patents 2 646 367 and 2 657 549 describe various methods for applying to the interior faces of a metallurgical container such as a casting ladle a protective coating comprising at least two layers.
French patent 87757 describes a method for applying to the interior faces of a casting ladle a coating comprising two layers, this method comprising the following steps:
A. A core is placed inside the metallurgical container to be protected to create a molding space between the interior walls of said container and the exterior walls of the core.
B. A material made of up of heat-resistant inorganic particles is introduced into the molding space thus created, said particles being precoated with a hardenable binder and/or mixed with a binder, said material being dry or virtually dry.
C. After hardening of said material on the interior walls of the container, the core is extracted from the container, leaving in place a first or exterior protective layer.
D. A second or interior layer is sprayed onto the first or exterior protective layer by wet spraying a - ~1651~
material made up of inorganic particles able to withstand the temperature of the liquid metal.
E. The interior walls of the metallurgical container are heated until the protective coating thus deposited is perfectly dry.
In this method, the first layer is formed in the space between the mold and the interior wall of the container, whereas the second layer is sprayed.
The drawback of a method of this kind is that the second layer is sprayed in the form of an aqueous sludge.
This layer is therefore wet; it is therefore necessary to dry it carefully before pouring the liquid metal into the container, to avoid all risk of explosion resulting from the formation of hydrogen due to decomposition of the water by the high temperature.
Moreover, because the second layer is wet, it cannot contain any substances that are sensitive to water such as quick lime, which has the function of purifying oxides contained in the liquid metal.
The aim of the present invention is to overcome these drawbacks.
SUMMARY OF THE INVENTION
In accordance with the invention, the method of applying to the interior faces of a metallurgical container for transferring liquid metal a consumable protective coating comprising at least two layers includes the following steps:
a. a permanent coating of said container has sprayed onto it a first protective layer by wet spraying a material made up of inorganic particles resistant to the temperature of said liquid metal and a heatsetting binder, b. the layer thus obtained is heated to harden it, c. a preheated or heater mold is introduced into the interior of said metallurgical container to create a _ ~1651~3 molding space between exterior walls of said mold and the exterior surface of said first layer, d. a powder material is introduced into the mold space thus created, made up of inorganic particles resistant to the temperature at which the liquid metal is transferred, said particles being precoated with a hardenable powder binder and/or mixed with a hardenable powder binder, said material being dry or virtually dry, e. after hardening of said powder material on said exterior surface of said first layer due to the heating effect of said preheated or heater mold, said preheated or heater mold is extracted from said container to leave therein a second exterior protective layer.
Thus, in accordance with the invention, only the first layer is wet, whereas the second layer that will come into contact with the liquid metal is virtually dry, so that it can contain substances sensitive to water and having purifying properties, such as quick lime.
In an advantageous version of the method, before the preheated or heater mold is placed in position said powder material is applied to the hardened first layer in a bottom area of the container to form a second or bottom layer and the lateral parts of the second layer are formed after introducing the preheated or heater mold into the container.
In a preferred version of the method the second layer is formed of quick lime, a heatsetting binder and optionally a flux.
The quick lime can therefore exert its purifying properties in relation to oxides contained in the liquid metal.
The heatsetting binder contained in this layer ensures cohesion of the layer after hardening due to the effect of the heat exerted by the preheated or heater mold.
- 21~51~3 The presence of a flux facilitates the sintering of this layer due to the effect of the heating exerted by the liquid metal so that cohesion of the layer is maintained while the liquid metal remains in the container.
The first layer preferably contains magnesium oxide as its main constituent.
The particle sizes and the composition of the inorganic particles of the first layer are preferably chosen so that said layer is not sintered or is only slightly sintered at the temperature at which the liquid metal is transferred into the container.
Because of this, at the end of casting, the coating can be very easily detached from the wall of the container, which considerably facilitates cleaning of the latter.
In another preferred embodiment of the invention the second layer is mixed with 5% to 60% by weight of substances that can generate an exothermic reaction.
This exothermic reaction melts the quick lime and burns the carbon contained in the second layer.
Other features and advantages of the invention emerge from the following description given by way of non-limiting example with reference to the appended drawings.
BRIFF DFSCRIPTION OF THE DRAWINGS
Figure 1 is a diagrammatic view in cross-section of a metallurgical container and the mold used to implement the method of the invention, showing the step of spraying the first coating layer.
Figure 2 is a view analogous to figure 1 showing the stage of forming the second layer after introduction of the heater mold into the container.
Figure 3 is a view analogous to figure 2 showing a different embodiment of the second layer.
Figure 4 is a view in cross-section of the container complete with its two layers and a gas burner adapted to start the exothermic reaction in the second layer.
Figure 5 is a view analogous to figure 4 showing the gas burner in its in-service position inside the container.
DETAITl~n DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the embodiments shown in the appended figures 1 through 5 a continuous casting ladle 1 comprises a metal exterior jacket 2 and an interior coating 3 of refractory bricks or cement.
In the bottom of the container 1 is a casting orifice with a casting nozzle 4.
The method for applying to the interior faces of the casting ladle 1 a consumable protective coating comprising two layers comprises the following steps:
a. a permanent coating 3 of the container 1 has sprayed onto it a first protective layer 5 by wet spraying a material made up of inorganic particles resistant to the temperature of the liquid metal and a heatsetting binder (see figure 1), b. the layer 5 thus obtained is heated to harden it, c. a preheated or heater mold 7 is introduced into the interior of the metallurgical container to create a molding space 8 between exterior walls of the mold 7 and the exterior surface of the first layer 5 (see figure 2), d. a powder material 9 is introduced into the mold space thus created, made up of inorganic particles resistant to the temperature at which the liquid metal is transferred, said particles being precoated with a hardenable powder binder and/or mixed with a hardenable powder binder, said material being dry or virtually dry, e. after hardening of said powder material on the S~16~1~3 exterior surface of said first layer 5 due to the heating effect of the preheated or heater mold 7, the preheated or heater mold is extracted from the container to leave therein a second or exterior protective layer 6.
In the example shown in figures 1 and 2 the mold 7 is metal and is heated internally by means of gas burners 10.
In the version shown in figure 3, before fitting the preheated or heater mold 7, said powder material is applied to the hardened first layer 5 in the bottom part of the container to form a bottom or second layer 6a and the lateral parts of the second layer 6 are formed after introducing the pre-heated or heater mold 7 into the casting ladle 1.
The second layer 6 is preferably formed from quick lime, a heatsetting binder and a flux.
The quick lime has a purifying function in relation to oxides in the liquid metal in the ladle 1.
The binder provides the initial cohesion of the layer 6 after hardening, the flux facilitates sintering due to the effect of heat and maintains the cohesion of the layer 6 throughout the time that the liquid metal remains inside the ladle 1.
The first layer 5 preferably includes magnesium oxide as the major constituent. The proportion of the magnesium oxide is 75% by weight, for example.
The particle sizes and the composition of the inorganic particles of the first layer 5 are preferably chosen so that this layer is not sintered or is only slightly sintered at the temperature at which the liquid metal is transferred into the ladle 1.
Thus the layer 5 in contact with the permanent coating 2 does not adhere to the latter with the result that, at the end of casting, the coating is easily detachable from the wall of the ladle, which facilitates `- '21651~3 cleaning it.
Usually, the mold 7 is preheated or is a heater type mold that can produce a temperature between 400C
and 800C.
This hardens the layer 6 that comes into contact with the liquid metal.
The second layer 6 can be formed of quick lime precoated with a binder and/or mixed with an organic and/or inorganic binder.
When the mold 7 is introduced into the metallurgical container, the position and/or the dimensions of the mold in the container are adjusted to vary the thickness of the second layer 6.
In one embodiment of the method of the invention - 15 the layer 6 that comes into contact with the liquid metal and which contains quick lime is mixed with between 5% by weight and 6~ by weight of elements that can generate an exothermic reaction. These elements can be magnesium and/or calcium to which are added calcium nitrate and/or barium nitrate and/or aluminum nitrate and, for example, calcium fluoride and/or magnesium fluoride and/or barium fluoride.
After the mold 7 is removed, the exothermic reaction to melt the quick lime and to burn the carbon of the organic binder contained in the second layer 6 is instigated, for example using gas burners 10.
This variant of the method of the invention is shown in figures 4 and 5.
To give a non-limiting example, the composition for the coating coming into contact with the liquid metal to protect the interior of a liquid metal transfer container comprises the following substances in the proportions by weight indicated below:
Mg and/or Ca and/or Al 0 - 60%
SiO2 0 - 3.5 21~a l 43 Al23 0 - 4%
Quick lime 0 - 95%
MgO and/or chrome-magnesite 0 - 50%
Fe23 0 - 5%
Na2O 0 - 2.5%
Melting loss at 1 000C 0 - 5%
P 0 - 7%
H 0 - 0.5%
B2O3 0 - 3%
K2O 0 - 4%
H2O 0 - 3%
Total C 0 - 6%
Na 0 - 2.5%
K 0 - 1.80%
H2O of crystallization 0 - 3%
Ca(NO3)2 0 - 10%
(No3)2Ba 0 - 10%
MgF2 0-- 8%
CaF2 0 - 8%
BaF2 0 - 8%
Claims (13)
1. Method of applying to the interior faces of a metallurgical container for transferring liquid metal a consumable protective coating comprising at least two layers, said method including the following steps:
a. a permanent coating of said container has sprayed onto it a first protective layer by wet spraying a material made up of inorganic particles resistant to the temperature of said liquid metal and a heatsetting binder, b. the layer thus obtained is heated to harden it, c. a preheated or heater mold is introduced into the interior of said metallurgical container to create a molding space between exterior walls of said mold and the exterior surface of said first layer, d. a powder material is introduced into the mold space thus created, made up of inorganic particles resistant to the temperature at which the liquid metal is transferred, said particles being precoated with a hardenable powder binder and/or mixed with a hardenable powder binder, said material being dry or virtually dry, e. after hardening of said powder material on said exterior surface of said first layer due to the heating effect of said preheated or heater mold, said preheated or heater mold is extracted from said container to leave therein a second exterior protective layer.
a. a permanent coating of said container has sprayed onto it a first protective layer by wet spraying a material made up of inorganic particles resistant to the temperature of said liquid metal and a heatsetting binder, b. the layer thus obtained is heated to harden it, c. a preheated or heater mold is introduced into the interior of said metallurgical container to create a molding space between exterior walls of said mold and the exterior surface of said first layer, d. a powder material is introduced into the mold space thus created, made up of inorganic particles resistant to the temperature at which the liquid metal is transferred, said particles being precoated with a hardenable powder binder and/or mixed with a hardenable powder binder, said material being dry or virtually dry, e. after hardening of said powder material on said exterior surface of said first layer due to the heating effect of said preheated or heater mold, said preheated or heater mold is extracted from said container to leave therein a second exterior protective layer.
2. Method according to claim 1 wherein before said preheated or heater mold is placed in position said powder material is applied to said hardened first layer in a bottom area of said container to form a second or bottom layer and the lateral parts of said second layer are formed after introducing said preheated or heater mold into said container.
3. Method according to claim 1 wherein said second layer is formed of quick lime, a heatsetting binder and optionally a flux.
4. Method according to claim 1 wherein said first layer contains magnesium oxide as its main constituent.
5. Method according to claim 1 wherein the particle sizes and the composition of said inorganic particles of said first layer are chosen so that said layer is not sintered or is only slightly sintered at the temperature at which said liquid metal is transferred into said container.
6. Method according to claim 1 wherein said mold is preheated or a heater mold is used to obtain a temperature between 400 °C and 800 °C.
7. Method according to claim 1 wherein said second layer is formed from quick lime precoated with a binder and/or mixed with an organic and/or inorganic binder.
8. Method according to claim 1 wherein, when said mold is introduced into said metallurgical container, the position and/or the dimensions of said mold in said container are adjusted to vary the thickness of said second layer.
9. Method according to claim 3 wherein said second layer is mixed with elements that can generate an exothermic reaction.
Method according to claim 9 wherein said elements are magnesium and/or calcium and/or aluminum to which are added calcium nitrate and/or barium nitrate, calcium fluoride and/or magnesium fluoride and/or barium fluoride and, after extraction of said mold (step e), the exothermic reaction is instigated to sinter the quick lime and to burn said carbon of said organic binder contained in said second layer.
11. Coating for protecting the interior of a liquid metal transfer container obtained by the method as claimed in any one of claims 1 through 9.
12. Coating according to claim 10 applied to the interior of a metallurgical container having a permanent refractory material lining.
13. Composition for making a coating coming into contact with liquid metal to protect the interior of a liquid metal transfer container according to claim 10, comprising the following substances in the proportions by weight indicated below:
Mg and/or Ca and/or Al 0 - 60%
SiO2 0 - 3.5%
Al2O3 0 - 4%
Quick lime 0 - 95%
MgO and/or chrome-magnesite 0 - 50%
Fe2O3 0 - 5%
Na2O 0 - 2.5%
Melting loss at 1 000 °C 0 - 5%
P 0 - 7%
H 0 - 0.5%
B2O3 0 - 3%
K2O 0 - 4%
H2O 0 - 3%
Total C 0 - 6%
Na 0 - 2.5%
K 0 - 1.80%
H2O of crystallization 0 - 3%
Ca(NO3)2 0 - 10%
(NO3)2Ba 0 - 10%
MgF2 0 - 8%
CaF2 0 - 8%
BaF2 0 - 8%
Mg and/or Ca and/or Al 0 - 60%
SiO2 0 - 3.5%
Al2O3 0 - 4%
Quick lime 0 - 95%
MgO and/or chrome-magnesite 0 - 50%
Fe2O3 0 - 5%
Na2O 0 - 2.5%
Melting loss at 1 000 °C 0 - 5%
P 0 - 7%
H 0 - 0.5%
B2O3 0 - 3%
K2O 0 - 4%
H2O 0 - 3%
Total C 0 - 6%
Na 0 - 2.5%
K 0 - 1.80%
H2O of crystallization 0 - 3%
Ca(NO3)2 0 - 10%
(NO3)2Ba 0 - 10%
MgF2 0 - 8%
CaF2 0 - 8%
BaF2 0 - 8%
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR9415230A FR2728185A1 (en) | 1994-12-19 | 1994-12-19 | METHOD FOR APPLYING TO THE INNER SIDES OF A METALLURGICAL CONTAINER A PROTECTIVE COATING COMPRISING AT LEAST TWO LAYERS |
| FR9415230 | 1994-12-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2165143A1 true CA2165143A1 (en) | 1996-06-20 |
Family
ID=9469909
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002165143A Abandoned CA2165143A1 (en) | 1994-12-19 | 1995-12-13 | Method of applying to the interior faces of a metallurgical container a protective coating comprising at least two layers |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0716894A1 (en) |
| CA (1) | CA2165143A1 (en) |
| FR (1) | FR2728185A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101858694B (en) * | 2010-06-22 | 2011-11-16 | 武汉科技大学 | Die used for molding prefabricated furnace liner of induction furnace |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1313447A (en) * | 1962-01-25 | 1962-12-28 | Foseco Trading Ag | Further training in the manufacture of refractory products |
| GB1454201A (en) * | 1974-05-09 | 1976-11-03 | Miki M | Method of lining a ladle |
| FR2316025A1 (en) * | 1975-07-02 | 1977-01-28 | Vayda Alexandre | Refractory monolithic lining for metallurgical vessels - by applying a thermite type mixt. contg. sinterable refractory materials |
| JPS6030718Y2 (en) * | 1981-07-07 | 1985-09-13 | 日本鋼管株式会社 | Fireproof lining curing device |
| FR2533492B1 (en) * | 1982-09-29 | 1986-06-13 | Gilson Jacques | METHOD AND INSTALLATION FOR MOLDING A REFRACTORY COATING OF A CONTAINER FOR LIQUID METAL |
| FR2646367B1 (en) | 1989-04-26 | 1994-04-01 | Daussan Cie | METHOD AND INSTALLATION FOR REALIZING A COATING ON THE INTERIOR WALLS OF A METALLURGICAL CONTAINER |
| FR2657549B1 (en) | 1990-01-26 | 1992-04-24 | Daussan & Co | PROCESS FOR APPLYING A PROTECTIVE COATING COMPRISING AT LEAST TWO LAYERS ON THE INNER FACES OF A METALLURGICAL CONTAINER AND PROTECTIVE COATING THUS OBTAINED. |
-
1994
- 1994-12-19 FR FR9415230A patent/FR2728185A1/en active Granted
-
1995
- 1995-12-06 EP EP95402750A patent/EP0716894A1/en not_active Withdrawn
- 1995-12-13 CA CA002165143A patent/CA2165143A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| FR2728185A1 (en) | 1996-06-21 |
| EP0716894A1 (en) | 1996-06-19 |
| FR2728185B1 (en) | 1997-02-28 |
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