CA1238475A - Method of manufacturing nozzles for continuous casting - Google Patents
Method of manufacturing nozzles for continuous castingInfo
- Publication number
- CA1238475A CA1238475A CA000456285A CA456285A CA1238475A CA 1238475 A CA1238475 A CA 1238475A CA 000456285 A CA000456285 A CA 000456285A CA 456285 A CA456285 A CA 456285A CA 1238475 A CA1238475 A CA 1238475A
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- CA
- Canada
- Prior art keywords
- mixture
- phenol resin
- nozzles
- continuous casting
- hot air
- Prior art date
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- Expired
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- Compositions Of Oxide Ceramics (AREA)
- Continuous Casting (AREA)
- Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
Abstract
METHOD OF MANUFACTURING NOZZLES
FOR CONTINUOUS CASTING
Abstract of the Disclosure A method of manufacturing long or immersion type nozzles to be used for the continuous casting is provided.
In the process of manufacture, kneaded refractory mix-ture containing flake graphite, and liquid phenol resin as a binder is dried by blowing hot air while the mixture is being loosened in particles to obtain dried mixture having uniformly distributed required amount of remaining liquid therein.
By this process, occurrence of troubles in the subsequent processes is prevented thus the products of highly stable quality and improved service life can be obtained.
FOR CONTINUOUS CASTING
Abstract of the Disclosure A method of manufacturing long or immersion type nozzles to be used for the continuous casting is provided.
In the process of manufacture, kneaded refractory mix-ture containing flake graphite, and liquid phenol resin as a binder is dried by blowing hot air while the mixture is being loosened in particles to obtain dried mixture having uniformly distributed required amount of remaining liquid therein.
By this process, occurrence of troubles in the subsequent processes is prevented thus the products of highly stable quality and improved service life can be obtained.
Description
to Background of the Invention This invention relates to a method of manufacturing long or immersion type nozzles to be used for continuous casting -hereinafter will be called as "casting nozzles" - having highly stable quality, and high thermal shock- and corrosion-resistance.
Casting nozzles are very important and effective members in the continuous casting, for improving the quality of cast metal products. In response to the recent increasing demand for high-quality steel material, continuous casting operations using casting nozzles have been remarkably increased. As the continuous casting process is locating at an early stage of the steel production line, any trouble occurring in this process may affect the subsequent processes remarkably. Accordingly, the casting nozzles for use in this process have always been required to have a long service life and a highly stable quell-try. For instance, they are imposed such severe requirements that the occurrence of troubles in the casting nozzles must ye less than once per one or two thousands pieces of nozzles.
Besides that, the use of the continuous casting is extend-Ed to the wide variety of steels, including the kinds of highly corrosive to the refractories. Also there is an increased use of multi-ladle casting which requires long time continuous operations. Therefore, there is an increased demand for the development of casting nozzles having highly stable quality and high reliability, as well as high thermal shock- and corrosion-resistance.
According to our investigation of various troubles occurred in actual operations which seem to have a relation-ye ship to the quality of casting nozzles, such troubles may be classified into two major types, i.e., l). Occurrence of cracking or breakage which seems to be often caused at the beginning of casting operations.
Casting nozzles are very important and effective members in the continuous casting, for improving the quality of cast metal products. In response to the recent increasing demand for high-quality steel material, continuous casting operations using casting nozzles have been remarkably increased. As the continuous casting process is locating at an early stage of the steel production line, any trouble occurring in this process may affect the subsequent processes remarkably. Accordingly, the casting nozzles for use in this process have always been required to have a long service life and a highly stable quell-try. For instance, they are imposed such severe requirements that the occurrence of troubles in the casting nozzles must ye less than once per one or two thousands pieces of nozzles.
Besides that, the use of the continuous casting is extend-Ed to the wide variety of steels, including the kinds of highly corrosive to the refractories. Also there is an increased use of multi-ladle casting which requires long time continuous operations. Therefore, there is an increased demand for the development of casting nozzles having highly stable quality and high reliability, as well as high thermal shock- and corrosion-resistance.
According to our investigation of various troubles occurred in actual operations which seem to have a relation-ye ship to the quality of casting nozzles, such troubles may be classified into two major types, i.e., l). Occurrence of cracking or breakage which seems to be often caused at the beginning of casting operations.
2). Occurrence of pitting or boring on the inner surface of the nozzles due to local erosion which may be caused at the inter-mediate stage of casting operations.
Detailed study of these defective nozzles and other products of the same lot revealed that in the microscopic tests, there is a tendency of lack of the uniform distribution of the refractory constituent in one body of the casting nozzle on one hand, while on the other hand in the physical and comma-eel test results/ such as porosity, specific gravity, bending strength and modulus of elasticity, considerably wide phlox lion was observed in the results of measurements. This may indicate that the cracking or abnormal erosion takes place at the weak portion caused by the lack of uniform quality in the body of the casting nozzles.
Generally, two counter plans are considered to avoid such troubles:
l). Improving physical and chemical properties such as antis palling or anti-corrosion characteristics of the refractories used for the casting nozzles.
2). Minimizing the fluctuation of the quality in one body of the casting nozzle.
I to Both coun~erplans are intending, after all, to minimize the occurrence of the weak point described above.
As for the counter plan 1), efforts are being made to raise the refractoriness, corrosion-resistivity and anti-spelling characteristics of the material by controlling its composition and treatments. However, for the counter plan I
there has been found no effective procedures to minimize the fluctuation of the quality, and this may be also fundamentally important procedure to promote counterpl~n 1).
Next, we have studied the cause of the fluctuation of the quality in connection with the manufacturing process of the casting nozzles.
In the production of casing nozzles, flake graphite is generally used as a refractory component for improving thermal shock resistance of the products, and coal tar, pitch, phenol resin or other organic substances are added as a binder to the refractory materials.
Phenol resin is used as a binder for manufacturing cast in nozzles as well as it is used for manufacturing other kinds of fire bricks, such as those for converters, torpedo cars, ladles, eta, because phenol resin has better mixing properties at room temperature in case of liquid form, and assurance of an improved working environment over the use of coal tar, and also it gives to refractory material a high strength after drying and after sistering.
For such refractories a liquid phenol resin of resow type is generally used singly or in combination with a powdery phenol resin of novolak type. Powdery phenol resin is used substantially for increasing the strength of the refractories.
The addition of liquid phenol resin has been a convention-at practice in the production of refractories containing flake graphite. In the case of casting nozzles, however, cracking occurs sometimes while molding, and also shows insufficient and non-uniform mold packing and this may result in insufficient strength of final products, so that it has been difficult to obtain products of stable quality after molding or subsequent sistering.
It was found by our study that such instability of the quality is caused by uneven distribution of the liquid remaining in the kneaded mixture. This liquid may come from, for instance, organic volatile matter in the phenol resin, particularly methylol in the resow type phenol resin, and free water, and lo the condensation water which is generated in a large quantity while drying the molded products.
If an excessive amount of liquid remains in the molded products, cracks may-occur in the body thereof while drying or sistering the same, and if the amount of remaining liquid is too small, compression of the mixture may become difficult at the stage of molding, and if the amount of liquid is local-lye uneven, it is difficult to obtain molded products of dense and uniform texture when the mixture is compressed by the rubber press machine.
The ordinary method of improving above disadvantage is to cure the kneaded mixture by placing the same in a room under constant temperature and humidity for a long time/ for instance several days. This method, however, still cannot eliminate I
the local difference in -the amount of liquid between the sun-face and inner portion. Further, the kneaded mixture contain-in a large amount of organic additives tends to solidify into lumps, so that it is necessary to stir the mixture several times while curing until the amount of liquid is reduced to the desired values, and this requires troublesome operations.
Accordingly, an object of the present invention is to provide a method of manufacturing nozzles for continuous casting in which such disadvantages as mentioned above are eliminated, and the casting nozzles having high antis palling and corrosion resisting characteristics, and is highly stable in quality are obtainable.
The present invention is directed particularly to the manufacture ofcastingnozzles containing flake graphite as a refractory component and also phenol resin as a binder.
Summary of the Invention The method of manufacturing nozzles for continuous cast-in according to the present invention comprises the steps of;
a) kneading refractory material containing flake graphite with the addition of liquid phenol resin as a binder;
b) drying said kneaded mixture by blowing hot air while loosening said mixture into particles;
c) molding said dried mixture to the nozzle shape;
d) sistering by heating said molded refractory material to form nozzle body.
Thus a-t the step b) of the method, dried mixture having 7~3 uniformly distributed required amount of remaining liquid can be obtained and the products of highly stable in quality can be provided by the process of subsequent stops In one type of said refractory material, the liquid phenol resin of resow type is used independently as a binder, and in another type of the refractory material, the liquid phenol resin of resow type is used in combination with powdery phenol resin of novolak type, and in a preferred embodiment of this invention, about 5-20 percent by weight of liquid phenol resin of resow type is added in the step a) independently or in combination with the powdery phenol resin of novolak type.
retailed Description of the Invention Flake graphite and other suitable refractory materials are mixed together in the dry state, then 5-20 percent by weight of liquid phenol resin is added to the mixture and kneaded by the kneading machine.
In said refractory materials, for instance, alumina, æirconia, silica, metallic silicon powder, aluminum powder, boron nitride, silicon nitride, magnesia, spinet, and other refractory materials generally used for making ordinary casting nozzles may be included.
A powdery phenol resin may be added as required besides the liquid phenol resin. the addition of the latter contra-bytes to increase the strength of casting nozzles and also to improve their thermal shock resistance and corrosion no-distance.
Addition of less than 5 percent by weight of liquid phenol resin cannot ensure sufficient wetting of the material powder in the kneading, and the use of more -than 20 percent may cause formation of lumps or clods of the material during kneading and the acquisition of uniform mixture may become difficult and cause lowering of the thermal shock resistance and corrosion resistance.
The kneading machines suitable for thy purpose of this invention are, for instance, of the stirring type which may not break flaky particles of graphite. Breakage of the flaky particles of graphite adversely affects the product quality, and particularly raise the modulus of elasticity unfavorably.
The kneaded mixture is then dried by blowing hot air of about 30-90C while loosening the mixture into particles.
Air-flow type drier or rotary drum may be used suitably for such purpose. Air-flow type drier includes, for instance, a box type vessel having small holes on the bottom thereof and the hot air is blown in-to the vessel from said holes. The kneaded mixture is fed by the feeder into the vessel from the inlet port thereof, then the mixture is dried uniformly by the hot air while the same is blown up and loosened into particles.
After the required amount of remaining liquid is attained, the mixture is taken out from the vessel through the outlet port.
In the rotary drum method, the kneaded mixture is fed into the drum, and the hot air of about 30~90C is blown into the drum, while the same is rotated then -the liquid in the mixture is uniformly removed, besides, the mixture is stirred
Detailed study of these defective nozzles and other products of the same lot revealed that in the microscopic tests, there is a tendency of lack of the uniform distribution of the refractory constituent in one body of the casting nozzle on one hand, while on the other hand in the physical and comma-eel test results/ such as porosity, specific gravity, bending strength and modulus of elasticity, considerably wide phlox lion was observed in the results of measurements. This may indicate that the cracking or abnormal erosion takes place at the weak portion caused by the lack of uniform quality in the body of the casting nozzles.
Generally, two counter plans are considered to avoid such troubles:
l). Improving physical and chemical properties such as antis palling or anti-corrosion characteristics of the refractories used for the casting nozzles.
2). Minimizing the fluctuation of the quality in one body of the casting nozzle.
I to Both coun~erplans are intending, after all, to minimize the occurrence of the weak point described above.
As for the counter plan 1), efforts are being made to raise the refractoriness, corrosion-resistivity and anti-spelling characteristics of the material by controlling its composition and treatments. However, for the counter plan I
there has been found no effective procedures to minimize the fluctuation of the quality, and this may be also fundamentally important procedure to promote counterpl~n 1).
Next, we have studied the cause of the fluctuation of the quality in connection with the manufacturing process of the casting nozzles.
In the production of casing nozzles, flake graphite is generally used as a refractory component for improving thermal shock resistance of the products, and coal tar, pitch, phenol resin or other organic substances are added as a binder to the refractory materials.
Phenol resin is used as a binder for manufacturing cast in nozzles as well as it is used for manufacturing other kinds of fire bricks, such as those for converters, torpedo cars, ladles, eta, because phenol resin has better mixing properties at room temperature in case of liquid form, and assurance of an improved working environment over the use of coal tar, and also it gives to refractory material a high strength after drying and after sistering.
For such refractories a liquid phenol resin of resow type is generally used singly or in combination with a powdery phenol resin of novolak type. Powdery phenol resin is used substantially for increasing the strength of the refractories.
The addition of liquid phenol resin has been a convention-at practice in the production of refractories containing flake graphite. In the case of casting nozzles, however, cracking occurs sometimes while molding, and also shows insufficient and non-uniform mold packing and this may result in insufficient strength of final products, so that it has been difficult to obtain products of stable quality after molding or subsequent sistering.
It was found by our study that such instability of the quality is caused by uneven distribution of the liquid remaining in the kneaded mixture. This liquid may come from, for instance, organic volatile matter in the phenol resin, particularly methylol in the resow type phenol resin, and free water, and lo the condensation water which is generated in a large quantity while drying the molded products.
If an excessive amount of liquid remains in the molded products, cracks may-occur in the body thereof while drying or sistering the same, and if the amount of remaining liquid is too small, compression of the mixture may become difficult at the stage of molding, and if the amount of liquid is local-lye uneven, it is difficult to obtain molded products of dense and uniform texture when the mixture is compressed by the rubber press machine.
The ordinary method of improving above disadvantage is to cure the kneaded mixture by placing the same in a room under constant temperature and humidity for a long time/ for instance several days. This method, however, still cannot eliminate I
the local difference in -the amount of liquid between the sun-face and inner portion. Further, the kneaded mixture contain-in a large amount of organic additives tends to solidify into lumps, so that it is necessary to stir the mixture several times while curing until the amount of liquid is reduced to the desired values, and this requires troublesome operations.
Accordingly, an object of the present invention is to provide a method of manufacturing nozzles for continuous casting in which such disadvantages as mentioned above are eliminated, and the casting nozzles having high antis palling and corrosion resisting characteristics, and is highly stable in quality are obtainable.
The present invention is directed particularly to the manufacture ofcastingnozzles containing flake graphite as a refractory component and also phenol resin as a binder.
Summary of the Invention The method of manufacturing nozzles for continuous cast-in according to the present invention comprises the steps of;
a) kneading refractory material containing flake graphite with the addition of liquid phenol resin as a binder;
b) drying said kneaded mixture by blowing hot air while loosening said mixture into particles;
c) molding said dried mixture to the nozzle shape;
d) sistering by heating said molded refractory material to form nozzle body.
Thus a-t the step b) of the method, dried mixture having 7~3 uniformly distributed required amount of remaining liquid can be obtained and the products of highly stable in quality can be provided by the process of subsequent stops In one type of said refractory material, the liquid phenol resin of resow type is used independently as a binder, and in another type of the refractory material, the liquid phenol resin of resow type is used in combination with powdery phenol resin of novolak type, and in a preferred embodiment of this invention, about 5-20 percent by weight of liquid phenol resin of resow type is added in the step a) independently or in combination with the powdery phenol resin of novolak type.
retailed Description of the Invention Flake graphite and other suitable refractory materials are mixed together in the dry state, then 5-20 percent by weight of liquid phenol resin is added to the mixture and kneaded by the kneading machine.
In said refractory materials, for instance, alumina, æirconia, silica, metallic silicon powder, aluminum powder, boron nitride, silicon nitride, magnesia, spinet, and other refractory materials generally used for making ordinary casting nozzles may be included.
A powdery phenol resin may be added as required besides the liquid phenol resin. the addition of the latter contra-bytes to increase the strength of casting nozzles and also to improve their thermal shock resistance and corrosion no-distance.
Addition of less than 5 percent by weight of liquid phenol resin cannot ensure sufficient wetting of the material powder in the kneading, and the use of more -than 20 percent may cause formation of lumps or clods of the material during kneading and the acquisition of uniform mixture may become difficult and cause lowering of the thermal shock resistance and corrosion resistance.
The kneading machines suitable for thy purpose of this invention are, for instance, of the stirring type which may not break flaky particles of graphite. Breakage of the flaky particles of graphite adversely affects the product quality, and particularly raise the modulus of elasticity unfavorably.
The kneaded mixture is then dried by blowing hot air of about 30-90C while loosening the mixture into particles.
Air-flow type drier or rotary drum may be used suitably for such purpose. Air-flow type drier includes, for instance, a box type vessel having small holes on the bottom thereof and the hot air is blown in-to the vessel from said holes. The kneaded mixture is fed by the feeder into the vessel from the inlet port thereof, then the mixture is dried uniformly by the hot air while the same is blown up and loosened into particles.
After the required amount of remaining liquid is attained, the mixture is taken out from the vessel through the outlet port.
In the rotary drum method, the kneaded mixture is fed into the drum, and the hot air of about 30~90C is blown into the drum, while the same is rotated then -the liquid in the mixture is uniformly removed, besides, the mixture is stirred
3 I
by this rotation and made into uniform composition and divided into minute particles, -thus -the occurrence of cracking or lamination in -the nozzle body can be prevented at the sub-sequent molding process and the nozzle body having uniform qua lily and required density can be obtained by the molding process and the products of uniform quality can be obtained by Sinatra in said nozzle body.
As mentioned above, in the drying process according to the present invention, the kneaded mixture is dried by blowing hot air while the mixture is being forcedly loosened, so that the distribution of the liquid in the mixture can be made uniform, and the desired amount of remaining liquid in the mixture can be attained within a short time.
Example 30 parts by weight of flake graphite, 50 parts by weight of sistered alumina, 10 parts by weight of fused silica and 10 parts by weight of reinforcing material and anti-oxidant such as fine powder of silicon carbide, alumina, silica and alumino-silicate were kneaded with the addition of 10 parts by weight of liquid phenol resin.
The kneaded material was divided into two parts, and the one was treated by the methodofthe present invention and the other one was treated by the conventional method.
PA) Method of the Present Invention A lump of 300kg of the kneaded mixture was fed by a belt feeder, into the vessel of an air-flow type drier in which a hot air of about 60C being blown at a rate of 60m3/min. from the openings of about l-3mm diameter provided on the bottom of the vessel.
The mixture taken out of the drier was then put into a rotary drum in which a hot elf of about 60C being blown at a rate of 60m3/min. The drum was rotated at lOrpm. The total treating time or the method was two hours.
(B) Conventional Method The kneaded mixture was cured in a thermohygrostatic vessel kept at 20-30C temperature and 40-70 percent humidity for seven days.
Mixtures treated by both methods were Jo adjusted that they would have about log of final volatile matter content -as measured with an infrared-heated moisture meter - and the rate of weight decrease at 180C in five minutes would reach 1.7 percent in the average. Mixtures were then formed by the use of a rubber press machine according to the ordinary method, and fired in a reducing atmosphere.
Physical and chemical test results of the products made by the both methods are shown in Table 1.
In the Table, modulus of quasi-elasticity E' is defined by the following equation, (Pro - PLY
E' = ---- I--------- (1) 48(~60 I
where P60 and P30 are 60 percent and 30 percent load respective-lye of maximum load value Ppm in the stress-s~rain curve obtained I
by a three-point precision bending strength test made on a square pillar specimen having a rectangular section; and ~60 and ~30 are strain values at the load Pro and P30 respect-lively, and I is the moment of inertia of area of the specimen, and L is the distance between the supporting points.
The reason of the use of the modulus of quasi-elasticity for the evaluation of material quality is that the fire brick materials containing considerable amount of flake graphite shows relatively large plastic deformation and that a large error would appear in the measurement of elasticity within a very narrow elastic range. Actually, it was seen that the evaluation based on the modulus of quasi elasticity including the range of plastic deformation, can explain the quality of the material more really.
Table 1 . . .. _. . .. _ .
Conventional Product of this product invention _ Standard Standard Average deviation Average deviation ___ .......... .. .____ 20 Bending strength 65 8 70 5 . _ . . ____ _ ___ . .__ .___ __ _ Modules of quasi-elasticity E' 280 80 270 50 (kg/mm2 ) . .... .. __ .__ ___ Thermal shock no- -6 -6 distance parameter 2,320 x 10 2,593 x 10 M/E' . _._ _ __ _ . .. __ _ ___ __ _ _ _ Thermal shock test (Repetition of ha - Cracks sometimes No crack occurs in at 1,400C and occur at 5 repute- at over 7 repute-water cooling prove- lions lions dunes) . .. _.. _ Hot-metal resistance test, speed of Eros 0.4 0.3 soon (mm/hr) _ ............. I . .... _ _ .... _ . .. 1 I
Table 1 shows that the physical properties of the products according to the present invention are substantially similar to those of the conventional products, but in the fluctuation of quality, the products according to the present invention showed smaller values than those of the conventional products, and in the thermal shock test and corrosion resistance test, it was found that the products according to the present invention showed better results than the conventional products.
In the performance tests, the casting nozzles made in accordance with the present invention showed no spelling trouble, which have occurred sometimes in the conventional nozzles due to the quick temperature rise of the nozzles at the beginning of the continuous casting.
The products of this invention also showed good corrosion no instance, because, the speed of erosion became nearly uniform over the whole inner surface of the casting nozzles due to uniform quality so that no abnormal local corrosion occurred, and the service life was eventually stabilized.
As described above, the casting nozzles made in accord-ante with the present invention have not only an elongated service lifeboat also have a stable service performance, so that they may contribute greatly to the stabilization of the continuous casting. Besides, the method ox the present in-mention has an advantage ox shortening the time of the drying process in comparison with the conventional method as stated above.
What is claimed is:
by this rotation and made into uniform composition and divided into minute particles, -thus -the occurrence of cracking or lamination in -the nozzle body can be prevented at the sub-sequent molding process and the nozzle body having uniform qua lily and required density can be obtained by the molding process and the products of uniform quality can be obtained by Sinatra in said nozzle body.
As mentioned above, in the drying process according to the present invention, the kneaded mixture is dried by blowing hot air while the mixture is being forcedly loosened, so that the distribution of the liquid in the mixture can be made uniform, and the desired amount of remaining liquid in the mixture can be attained within a short time.
Example 30 parts by weight of flake graphite, 50 parts by weight of sistered alumina, 10 parts by weight of fused silica and 10 parts by weight of reinforcing material and anti-oxidant such as fine powder of silicon carbide, alumina, silica and alumino-silicate were kneaded with the addition of 10 parts by weight of liquid phenol resin.
The kneaded material was divided into two parts, and the one was treated by the methodofthe present invention and the other one was treated by the conventional method.
PA) Method of the Present Invention A lump of 300kg of the kneaded mixture was fed by a belt feeder, into the vessel of an air-flow type drier in which a hot air of about 60C being blown at a rate of 60m3/min. from the openings of about l-3mm diameter provided on the bottom of the vessel.
The mixture taken out of the drier was then put into a rotary drum in which a hot elf of about 60C being blown at a rate of 60m3/min. The drum was rotated at lOrpm. The total treating time or the method was two hours.
(B) Conventional Method The kneaded mixture was cured in a thermohygrostatic vessel kept at 20-30C temperature and 40-70 percent humidity for seven days.
Mixtures treated by both methods were Jo adjusted that they would have about log of final volatile matter content -as measured with an infrared-heated moisture meter - and the rate of weight decrease at 180C in five minutes would reach 1.7 percent in the average. Mixtures were then formed by the use of a rubber press machine according to the ordinary method, and fired in a reducing atmosphere.
Physical and chemical test results of the products made by the both methods are shown in Table 1.
In the Table, modulus of quasi-elasticity E' is defined by the following equation, (Pro - PLY
E' = ---- I--------- (1) 48(~60 I
where P60 and P30 are 60 percent and 30 percent load respective-lye of maximum load value Ppm in the stress-s~rain curve obtained I
by a three-point precision bending strength test made on a square pillar specimen having a rectangular section; and ~60 and ~30 are strain values at the load Pro and P30 respect-lively, and I is the moment of inertia of area of the specimen, and L is the distance between the supporting points.
The reason of the use of the modulus of quasi-elasticity for the evaluation of material quality is that the fire brick materials containing considerable amount of flake graphite shows relatively large plastic deformation and that a large error would appear in the measurement of elasticity within a very narrow elastic range. Actually, it was seen that the evaluation based on the modulus of quasi elasticity including the range of plastic deformation, can explain the quality of the material more really.
Table 1 . . .. _. . .. _ .
Conventional Product of this product invention _ Standard Standard Average deviation Average deviation ___ .......... .. .____ 20 Bending strength 65 8 70 5 . _ . . ____ _ ___ . .__ .___ __ _ Modules of quasi-elasticity E' 280 80 270 50 (kg/mm2 ) . .... .. __ .__ ___ Thermal shock no- -6 -6 distance parameter 2,320 x 10 2,593 x 10 M/E' . _._ _ __ _ . .. __ _ ___ __ _ _ _ Thermal shock test (Repetition of ha - Cracks sometimes No crack occurs in at 1,400C and occur at 5 repute- at over 7 repute-water cooling prove- lions lions dunes) . .. _.. _ Hot-metal resistance test, speed of Eros 0.4 0.3 soon (mm/hr) _ ............. I . .... _ _ .... _ . .. 1 I
Table 1 shows that the physical properties of the products according to the present invention are substantially similar to those of the conventional products, but in the fluctuation of quality, the products according to the present invention showed smaller values than those of the conventional products, and in the thermal shock test and corrosion resistance test, it was found that the products according to the present invention showed better results than the conventional products.
In the performance tests, the casting nozzles made in accordance with the present invention showed no spelling trouble, which have occurred sometimes in the conventional nozzles due to the quick temperature rise of the nozzles at the beginning of the continuous casting.
The products of this invention also showed good corrosion no instance, because, the speed of erosion became nearly uniform over the whole inner surface of the casting nozzles due to uniform quality so that no abnormal local corrosion occurred, and the service life was eventually stabilized.
As described above, the casting nozzles made in accord-ante with the present invention have not only an elongated service lifeboat also have a stable service performance, so that they may contribute greatly to the stabilization of the continuous casting. Besides, the method ox the present in-mention has an advantage ox shortening the time of the drying process in comparison with the conventional method as stated above.
What is claimed is:
Claims (4)
- THE embodiments of the invention in which an exclusive property of privilege is claimed are defined as follows:
I. method of manufacturing nozzles for continuous casting comprising steps of a) kneading refractory material containing flake graphite with the addition of liquid phenol resin as a binder;
b) drying said kneaded mixture by blowing hot air while loosening said mixture into Particles c) molding said dried mixture to -the nozzle shape;
d) sintering by heating said molded refractory material to form nozzle body. - 2. The method of claim 1, wherein further adding powdery phenol resin as a binder in said step a).
- 3. The method of claim 1 or 2, wherein the amount of addition of said liquid phenol resin is about 5-20 percent by weight.
- 4. A method of manufacturing nozzles for continuous casting comprising the steps of:
a) dneading refractory material containing flake graphite with the addition of liquid phenol resin as a binder:
b) drying the kneaded mixture to obtain uniform remaining moisture distribution therein by blowing hot air while continuously stirring concurrently and loosening said mixture into particles, thereby to cause said hot air to pass through the loosened mixture;
c) molding the dried mixture to a nozzle shape; and d) sintering by heating the refractory material molded to form a nozzle body.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58104492A JPS59232963A (en) | 1983-06-11 | 1983-06-11 | Manufacture of continuous casting nozzle |
| JP58-104492 | 1983-06-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1238475A true CA1238475A (en) | 1988-06-28 |
Family
ID=14382029
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000456285A Expired CA1238475A (en) | 1983-06-11 | 1984-06-11 | Method of manufacturing nozzles for continuous casting |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS59232963A (en) |
| CA (1) | CA1238475A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100335254C (en) * | 2004-07-22 | 2007-09-05 | 潍坊华美精细技术陶瓷有限公司 | Manufacturing method of silicon carbide atomization nozzle in wet method stack gas desulfur device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5828227B2 (en) * | 1974-10-21 | 1983-06-14 | トウシバセラミツクス カブシキガイシヤ | Kokiyodotaikabutsunoseizohouhou |
| JPS5212211A (en) * | 1975-07-21 | 1977-01-29 | Dainippon Ink & Chemicals | Admixtures for refractories |
-
1983
- 1983-06-11 JP JP58104492A patent/JPS59232963A/en active Pending
-
1984
- 1984-06-11 CA CA000456285A patent/CA1238475A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59232963A (en) | 1984-12-27 |
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