JPS59116326A - Production installation for grain oriented silicon steel sheet - Google Patents

Abstract

PURPOSE:To provide an installation for cold rolling a hot rolled silicon steel sheet to a final thickness and subjecting the same to decarburization annealing, coating of an annealing separating agent and finish annealing which can reduce considerably energy cost by incorporating dry coating for said coating and retaining the temp. in the installation array between at least the decarburizing and coating. CONSTITUTION:A steel sheet 1 finished to a final thickness by cold rolling is annealed continuously in a decarburization annealing furnace 5 and is coated thereon with an annealing separating agent by a coater 7, whereafter it is finish-annealed in a finish annealing furnace 16. The installation array from the outlet of the furnace 5 to the device 7 or up to the inlet of the furnace 16 is held under a cover 8 so that the temp. thereof is retained and the inside is made airtight. A dry coater which sticks powder of the annealing separating agent on the surface of the steel sheet in a dry state, that is, without preparing the same into a water slurry, is used for the coater 7. The loss of energy owing to cooling after the decarburization annealing is thus averted, and the need for part of the heating energy for drying or baking after the coating of the annealing separating agent and the heating energy in the finish annealing is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a series of manufacturing equipment for manufacturing grain-oriented silicon steel sheets, and in particular to manufacturing equipment from decarburization annealing to application of an annealing separator and final annealing.

In general, grain-oriented silicon steel sheets are required to have excellent magnetic properties such as magnetization characteristics and iron loss characteristics, and in order to obtain grain-oriented silicon copper sheets with excellent magnetic properties, (110) It is essential to form a secondary recrystallization texture in which secondary recrystallization in the [001] orientation is sharply aligned, that is, a so-called Goss texture. Like this (110
) [001] In order to avoid the development of sharp secondary recrystallized grains, MnS, 1.4n as an inhibitor is generally used.
Fine precipitates such as S 8 are used, and if necessary, grain boundary segregation type elements I'i teal S 11 , △s, Bl, Pb,
Sn etc. are used together.

By the way, in manufacturing the above-mentioned grain-oriented silicon steel sheet, it is said that it is first necessary to heat the slab at a high temperature of 1250°C or higher to isolate and dissolve the inhibitor in order to uniformly and finely disperse the inhibitor. There is. Then, an appropriate amount of C is contained in order to form an appropriate texture, and a hot rolling process subsequent to the above slab heating, one cold rolling, or two or more cold rolling steps sandwiching intermediate annealing are performed. An appropriate texture is formed by rolling, and the hot-rolled sheet may be annealed if necessary. The silicon steel plate that has reached its final thickness through the cold rolling described above is subjected to decarburization annealing for the purpose of removing C that is harmful to the m properties and primary recrystallization, and then is annealed and separated using 1490 as the main component. After applying the agent and drying it, a long-term finishing annealing is performed to perform secondary recrystallization and to form an insulating glass film. After this, excess annealing separation agent is removed, tension coating is applied and the shape is corrected as necessary, and the product is made into a product.

Above) The production of grain-oriented silicon steel sheets requires extremely complex processes, especially those that involve heating.

In other words, the steps that involve heating include at least high-temperature slab heating before hot rolling, decarburization annealing after cold rolling, heating drying of the applied annealing separator, and final long finishing annealing. There are also processes such as annealing and intermediate annealing when cold rolling is performed two or more times. In addition to requiring multiple heating processes, conventional production equipment for grain-oriented silicon steel sheets has separate equipment for annealing and drying, and the steel sheets that have undergone one process are kept at room temperature. Normally, the steel sheet is cooled to a certain temperature before being subjected to the next process, so in each process such as annealing and drying, the steel plate is currently reheated from room temperature to the required temperature. Therefore, the amount of energy consumed in the production of conventional grain-oriented silicon steel sheets is extremely high.As a result, in recent years, as energy costs have been rising rapidly, the weight of energy costs in the production of grain-oriented silicon steel sheets has become significantly large. Reducing energy consumption has become an extremely important issue.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide manufacturing equipment that can significantly reduce energy costs in manufacturing grain-oriented silicon steel sheets compared to conventional methods.

The present inventors discovered that, as mentioned above, in conventional equipment, a steel plate that has undergone one process is once cooled to room temperature before being subjected to the next process, and then heated again from room temperature to the required temperature in the next process. Focusing on this, we investigated the cooling process in each process and found that the cooling process does not have a particularly large effect on the properties of grain-oriented silicon steel sheets during decarburization annealing and each subsequent process, and that the annealing process after decarburization annealing It was discovered that the application of the separating agent does not necessarily have to be carried out in a state cooled to room temperature, and that by applying the annealing separating agent in a dry state, the cooling process after decarburization annealing can be made unnecessary, and this invention has been achieved. I reached Nazu.

That is, the manufacturing equipment of the present invention performs decarburization annealing (X, and further applies an annealing separator) after cold rolling a hot rolled silicon steel sheet once or twice or more with intermediate annealing to achieve the final thickness. In a series of production equipment for grain-oriented steel sheets for finishing annealing after coating, the coating device for coating the annealing separator is configured with a dry coating device that directly applies the annealing separator powder in a dry state, Further, a series of equipment rows from the annealing furnace outlet to the coating device exit for performing decarburization annealing are kept warm, and the equipment rows are configured in an airtight manner. By this, the steel plate temperature is maintained at a high temperature at least until after the application of the annealing separator, thereby eliminating the need for heating for drying and baking after application, thereby saving energy.

Furthermore, the equipment row of the present invention uses a dry coating device as an annealing separator application device as described above, moisturizes all of the equipment row from the decarburization annealing furnace outlet to the finishing annealing furnace entrance, and All of the rows are constructed in an airtight manner so that the sensible heat imparted to the steel plate during decarburization annealing can be effectively used for finish annealing, thereby reducing energy consumption between the first and second annealing.

The equipment of this invention will be explained in more detail below.

FIG. 1 shows an example of production equipment for a series of grain-oriented silicon steel sheets according to the present invention, in which JNI? A steel plate 1 finished to a certain thickness is fed out from a payoff reel 2, made continuous by a welding machine 3, and then passed through a looper 4.
The IR coal is continuously charged into the annealing furnace 5. This decarburization annealing furnace 5 is constituted by a continuous furnace, and a looper 6 and a coating device 7 are arranged in that order on the exit side thereof. Here, between the outlet of the decarburization annealing furnace 5 and the inlet of the looper 6, and between the outlet of the looper 6 and the inlet of the coating device 7 are surrounded by heat-retaining/airtight covers 8A and 8B, respectively. The looper 6 and the applicator @7 themselves are also covered with heat-insulating and airtight covers 8c and 8D, respectively.

The coating device 7 is configured to apply the annealing separation agent powder to the surface of the m-plate in a dry state, that is, without turning it into a water slurry.

The mesh plate to which the annealing separator powder has been continuously applied by the coating device 7 passes through a shearer 〇 and is wound up by a tension reel 10 every predetermined length, and the wound coil 1
1 is supported and conveyed along with the reel 10 by a coil car 12, and is reversed by a coil reversing device 13 so that the coil 10 is upright and covered, and is further transferred to an inner cover mounting rack 14.
As a result, the inner cover 15 is placed over the coil 10 and reaches the inlet 16A of the finishing annealing furnace 16. Here, the equipment between the outlet of the coating device W7 and the entrance 16A of the finishing annealing furnace 16 is covered on the outside by a continuous and integrated moisture retaining wall 17, and is kept warm and airtight by this heat retaining wall 17. There is. The tension reel 10 is made of heat-resistant material such as heat-resistant steel or ceramic, and is of a cassette type that also serves as a deformation-preventing core to hold the center of the wound coil. The coil is then transported to the subsequent process along with the wound coil, and is also used as a payoff reel after final annealing.

The final annealing furnace 16 is loaded on the coil car 12 and carried out from the outlet 16B, and the inner cover 15 is removed at the disposal area 18 for the inner cover 1112, and the coil car 12 roughly applies tension coating and The tension reel 10 is transported to a subsequent process such as straightening, and in the subsequent process, the tension reel 10 functions as a payoff reel.

In the above equipment, all the equipment between the exit of the decarburization annealing furnace 5 and the entrance 16A of the finish annealing furnace 16 is kept warm, so the steel plate that has been decarburized and annealed is heated to a high temperature without being cooled. It reaches the finish annealing furnace 16 while being held.

As mentioned above, the purpose of decarburization annealing is to remove C from the steel, add subscale to the surface of the steel sheet, and form a primary recrystallized structure. It is well known that decarburization affects the magnetic properties of t'V! The process of later cooling the steel sheet to room temperature does not particularly affect the properties of the grain-oriented silicon steel sheet, so cooling after decarburization annealing can be omitted. Furthermore, in order to apply an annealing separator to the steel plate surface after decarburization annealing, a process of applying and drying using a water slurry has traditionally been adopted since the copper plate is cooled to room temperature. There is no need to cover the coating in the cooled state. Furthermore, finish annealing can be simply heated to the same temperature as decarburization annealing, and it does not particularly affect the properties of the grain-oriented silicon steel sheet, so this heating process is not essential and can be omitted.
Therefore, in the equipment shown in Figure 1, after decarburization annealing as described above, an annealing separator is applied to the steel plate while keeping it warm without cooling it, and the steel plate without cooling is subjected to finish annealing as it is. This avoids wasted energy loss due to cooling after decarburization annealing, eliminates the need for heating energy for drying and baking after application of an annealing separation agent, and part of the energy for Ml during final annealing, and thereby eliminates the need for conventional equipment. This made it possible to achieve significant energy savings.

Conventionally, the annealing separator was applied by applying a water slurry and then drying it.
I! When a water slurry is applied onto a high-temperature steel plate without post-cooling, the slurry boils on the steel plate, making it difficult to uniformly apply the annealing separator.

Therefore, in the equipment of the present invention, it was decided that the powdered annealed part chain side was directly attached to the surface of the m-plate in a dry state. In this way, the powdered annealing separator can be directly
By adhering it to the Pl plate surface, the annealing separator can be applied uniformly on the high-temperature T141 surface, and of course there is no need for drying after application, and since it is applied to the high-temperature disk surface, a separate process is required. It is also unnecessary to perform baking. In addition, as a specific means for directly attaching the powdered annealing separator to the surface of the WI plate, there is
Any known electrostatic powder coating means, such as the means described in Japanese Patent Application Laid-open No. 11 or 1983-106009, may be used, and the present invention does not particularly limit the specific means. .

When actually carrying out the process from decarburization annealing to finish annealing of silicon steel sheets using the equipment shown in Figure 1, the atmosphere from decarburization annealing to the start of finish annealing must be changed to argon gas, nitrogen gas, etc. Maintain under inert gas atmosphere. That is, when using the equipment shown in FIG. 1, as mentioned above, the steel plate after decarburization annealing is not cooled and one circular plate is maintained at a high temperature.
When a steel plate is exposed to the air as in the conventional method, one plate is oxidized due to reaction with the air, resulting in film defects and magnetic defects, but by performing the decarburization annealing to the start of finish annealing in an inert atmosphere. Oxidation can be prevented in six ways. In order to maintain the inert atmosphere in this manner, in the equipment shown in FIG. 1, each equipment from the outlet of the decarburization annealing furnace 5 to the inlet 16A of the finishing annealing furnace 16 is constructed in an airtight manner as described above.

Finishing gAtiI from the outlet of the decarburization annealing furnace 5! Furnace inlet 16A
It is desirable to set the degree of heat retention of the steel plate so that the temperature of the steel plate is always maintained at 100° C. or higher during this period. This is because if the temperature is lowered to a low temperature of less than 100° C. before final annealing, the energy saving effect compared to the conventional method will not be so great. In addition, in order to maintain the steel plate temperature above 100°C, it is desirable to shorten the time required from the end of decarburization annealing to the start of finish annealing as much as possible. It is desirable that the time up to the entrance of the final annealing furnace be within 24 hours.

Figure 2 shows an example of changes in steel plate temperature when the equipment of the present invention shown in Figure 1 is used to perform decarburization annealing to finish annealing, compared to when conventional equipment is used. .

From FIG. 2, it is clear that when the equipment of the present invention shown in FIG. 1 is used, significant energy savings can be achieved compared to the conventional method by subjecting the finishing annealing to the decarburization annealing completion temperature. be.

In the example shown in FIG. 1, the entire series of equipment rows from the outlet of the decarburization annealing furnace 5 to the entrance 16A of the finishing annealing furnace 16 are kept warm, and all of the equipment rows are configured to be airtight. Even if the equipment line between the outlet of the decarburization annealing furnace 5 and the outlet of the coating device 7 is kept warm, considerable energy savings can be achieved. In other words, even if only the temperature is maintained up to the exit of the coating device 7, the energy required for heating for drying and baking after coating is not needed, as conventional cooling is not performed immediately after decarburization annealing is completed. Energy savings can be achieved accordingly. Therefore, in the present application, the first invention is to maintain the temperature up to the outlet of the coating device 7, and the final annealing furnace entrance 16A is
The second invention is to continuously keep the temperature up to the temperature. Furthermore,
When maintaining heat up to the outlet of the coating device 7 as in the first invention, it goes without saying that the area from the outlet of the decarburization annealing furnace 5 to the outlet of the coating device 7 is constructed airtight, and a non-oxidizing atmosphere is maintained therebetween.

In the example shown in Fig. 1, a cassette-type tension reel 10 having a deformation-preventing core made of a heat-resistant material is used as a winding means after applying the powdered annealing separator, and the coil is transported to the subsequent process while being wound thereon. The reason for this decision is as follows.

In other words, in the case of the equipment of this invention, a high-temperature steel plate is wound up and the coil is conveyed while maintaining the high temperature, so if there is no core that serves as a sleeve at the center of the coil, there is a risk that the coil will be deformed. .

In addition, the tension reels commonly used in the past have a complicated A structure that changes the reel diameter in order to attach and detach the coil, and the reel needs to be cooled to wind at high temperatures, so the heat dissipation from the reel is difficult. Conventional tension reels are not suitable for the equipment of the present invention because of the risk that the coil temperature may drop due to an increase in the coil temperature. - Therefore, in the equipment of this invention, as mentioned above, the deformation of the high-temperature coil is prevented by not removing the reel from the coil immediately after winding, but by transporting the reel, which also serves as a deformation prevention core made of heat-resistant material, together with the coil. Moreover, by using the heat-resistant material r1, cooling of the reel is not necessary and heat radiation from the coil is prevented.

A specific example of manufacturing a oriented silicon n-plate using the equipment of the present invention shown in FIG. 1 will be described below.

Si 3.45%, CO, 070%, IAn 0, 0
85%, 3e0°, 025%, 3bO, 015%, and the remainder essentially ``e''.
The plate thickness is 0.30 by two times of cold rolling with intermediate annealing for 30 minutes.
Finished in mm. Then, for Sample A, the cold-rolled sheet was heated in wet hydrogen at 850°C for 3 hours using the equipment of the present invention.
After decarburizing annealing for 1 minute, immediately without cooling, a powder annealing separator containing M(IO as the main component) was applied by electrostatic coating and wound into a coil. Finish annealing was started when the steel plate temperature reached 50°C.Final annealing was performed at 900°C x 7 in an argon gas atmosphere.
After annealing for 0 hours, it was annealed in hydrogen gas at 1200°C for 10 hours.

On the other hand, regarding sample B of the cold-rolled sheet, using conventional equipment,
After decarburizing and annealing in wet hydrogen at 850°C for 3 minutes, the steel plate was cooled to room temperature, and a water slurry containing MIIO as the main component was applied as an annealing separator.
The annealing separator was dried by heating to 50° C. and wound into a coil. Furthermore, after 30 hours had passed after the completion of the above-mentioned decarburization annealing, the steel plate temperature returned to room temperature again, and the coil was annealed at 900°C for 70 hours in an argon gas atmosphere and at 1200°C for 0 hours in hydrogen gas. Finish annealing was performed. Table 1 shows the results of examining the magnetic properties of each of these samples A and B.

As is clear from Table 1, sample Δ, which was subjected to finish annealing in a short time without cooling after decarburization annealing using the equipment of the present invention, was decarburized and annealed using the conventional equipment, then cooled, coated with an annealing separator, and further heated. It was confirmed that the magnetic properties were comparable to Sample B, which was cooled to room temperature after drying and then subjected to final annealing, and exhibited excellent properties.

As is clear from the above explanation, according to the equipment of the first invention,
The energy required for drying and baking after applying the annealing dividing agent is unnecessary, and according to the equipment of the second invention, the energy required for drying and baking after applying the annealing dividing agent is unnecessary. However, part of the energy required to raise the temperature during final annealing is no longer required, and in both cases, the sensible heat of the chain plates provided by decarburization annealing is effectively used, resulting in significant energy savings compared to conventional methods. Therefore, a significant effect of reducing the manufacturing cost of the oriented silicon copper plate is achieved.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing an example of the equipment of the present invention, and Fig. 2 is a graph showing the relationship between the temperature of the n-plate and the elapsed time when steel plates are processed using the equipment shown in Fig. 1 and conventional equipment. It is. 1... Steel plate, 5... l152 charcoal annealing furnace, 7...
-Drying coating device, 16...finish annealing furnace. Applicant: Kawasaki Steel Co., Ltd. Agent Patent Attorney: Soiri Toyoda (and 1 other person)

Claims (2)

[Claims] (1) A silicon steel hot-rolled plate is cold-rolled once or twice or more with intermediate annealing to achieve the final thickness, then decarburized annealed, further coated with an annealing separator, and then finished annealed. In a series of production facilities for grain-oriented silicon m-plates, a coating device for applying an annealing separator is configured with a dry coating device that attaches powder of the annealing separator to the surface of the steel sheet in a dry state, and manufacturing a grain-oriented silicon steel sheet, characterized in that the equipment row from the exit of the decarburization annealing furnace for performing the decarburization annealing to at least the exit of the coating device is kept warm, and the equipment row is configured to be airtight. Facility. (2) After the silicon round plate is cold-rolled once or twice or more with intermediate annealing to achieve the final thickness, decarburization annealing is performed, and an annealing separator is further applied, followed by final annealing. In a series of production facilities for grain-oriented silicon steel sheets, a coating device for applying an annealing separator is configured with a dry coating device that attaches powder of the annealing separator to the steel sheet device in a dry state, and A oriented silicon material characterized in that a row of equipment between the outlet of a decarburization annealing furnace for performing decarburization annealing and the entrance of a final annealing furnace for performing finish annealing is kept warm and that the row of equipment is configured to be airtight. Steel sheet manufacturing equipment.