JPH0740002A - Continuous casting method for small lot materials - Google Patents

Abstract

(57) [Abstract] [Object] The present invention relates to a continuous metal casting method, and more particularly to a continuous metal casting method for efficiently casting a small lot material. [Structure] Tundish 2 that splits water into multiple strands
In combination with a batch type continuous casting machine in which each strand can independently control the length of the cast piece, first the molten metal 5 in the ladle 1 is poured into one or a plurality of strands through the tundish, and then the cast piece 6 is formed. When the predetermined length is reached, the casting is finished and the slab is taken out, then the molten metal 5 for the next casting is poured from the ladle 1 into the tundish 2 and waits, during which the continuous casting machine The next casting preparation is performed, then the casting is restarted, and this step is sequentially repeated to perform casting. [Effect] It is possible to efficiently cast slabs of multiple sizes and small lots, and it is easy to handle many types of slabs.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous metal casting method, and more particularly to a continuous metal casting method for efficiently casting a small lot material.

[0002]

2. Description of the Related Art The production capacity of a continuous casting machine is shown by the following formula (1). The conventional continuous casting method is mainly developed for the purpose of improving the production capacity. There is almost no development related to continuous casting. In order to improve the production capacity, it is necessary to shorten the casting time and improve the casting lot.

[0003]

[Equation 1]

A means for shortening the casting time is to improve the casting speed, and in recent years, a slab having a slab thickness exceeding 200 mm has a thickness of 2 m / min. The continuous casting machine capable of high-speed casting has appeared. Further, in order to improve the casting lot (the number of continuous casting lots), the development of variable-width refractory materials has made it possible to incorporate casting lots exceeding 1000 tons / lot.

[0005]

However, the continuous casting method of different steel types, which is a continuous casting method of molten steel having different components, suppresses the mixing of molten steel components when changing the casting components, so that the tundish is exchanged or a separated iron plate or the like is used. Is required, and operability is poor.

Alternatively, since it is not possible to completely suppress the mixture of components at the seam, it is necessary to treat the components in the component mixing region by removing the components.
It is larger than the bottom cutting allowance, which causes a decrease in casting yield.

On the other hand, casting lots have been made smaller in recent years due to diversification of required specifications (components, functions, sizes) for steel materials, and as a result, continuous casting of different steel types tends to increase.

[0008] At present, for casting of a casting lot which is less than the refining lot, a method of treating by a normal ingot method or a method of producing the refining lot as much as possible is adopted. This ordinary ingot making method is naturally inferior in production capacity and labor productivity as a process as compared with the continuous casting method.

[0009] On the other hand, when a casting lot less than the refining lot is incorporated into the current continuous casting process, the portion not assigned to the order becomes a stock with a storage cost as a surplus material. Therefore, there is an increasing need to develop a process for efficiently performing continuous casting of small lot materials that are less than the refining lot.

As a casting method for a small lot material, for example, the inventions of Japanese Patent Application Laid-Open No. 2-70360 and Japanese Patent Application No. 4-241444, in which a mixed metal is inserted to perform continuous casting of different steel types, 1 in Japanese Patent Publication No. 2-38301
A different steel type continuous casting method in which a dummy bar is inserted between different steel types in a strand continuous casting machine, and Japanese Patent Publication No. 2-38302 describes a different steel type casting method in which a strand is changed by a multiple strand continuous casting machine as the steel type is changed. .

The present invention has been made in view of the above problems, and provides a continuous casting method for a small-lot material that solves the problems of small-lot production and facilitates the handling of a wide variety of products.

[0012]

SUMMARY OF THE INVENTION The present invention combines a tundish for hot water splitting into a multi-strand continuous casting machine and a multi-strand batch continuous casting machine in which each strand can independently control the slab length. , (A) ~
It is a continuous casting method for small lot materials, characterized in that the step (e) is sequentially repeated to perform casting.

(A) Molten metal in a ladle was poured through a tundish into one or more strands of a batch continuous casting machine, and (b) then the strands of each strand were of a predetermined length. At the time point, the first casting was completed and the slab was taken out, and (c) the molten metal in the amount required for the next casting was poured into the tundish from the ladle and waited (d) during this period. The casting machine prepares for the next casting including changing the size of the mold, (e) restarts the next casting, and when the slab of each strand reaches a predetermined length, the second casting is performed. finish.

In the continuous casting method for the small lot material, while the molten metal is poured from the ladle into the tundish and waiting, the alloy is added to the tundish in parallel with the next casting preparation to melt the molten metal. The component of is adjusted.

Further, in the above continuous casting method for small lot materials, while the molten metal is poured from the ladle into the tundish and is on standby, the molten steel temperature is adjusted by the molten steel heating device in parallel with the next casting preparation. is there.

[0016]

The present invention will be described in detail below together with its operation.

The present invention eliminates the surplus material that is incorporated when a casting lot less than the refining lot is incorporated into the conventional continuous casting process, efficiently produces a small lot material, and becomes a problem in the conventional method. This is a continuous casting method that reduces the production of surplus material and facilitates compatibility with a wide variety of products. It separates the required casting lot from the refining lot and meets the required specifications such as the composition and size of various cast pieces. A process of casting only the required amount,
It efficiently produces small lot materials and solves the problems of small lot production.

This process combines a tundish for distributing molten metal from a ladle and a multi-strand batch type continuous casting machine capable of freely completing casting within a range of a slab length limited by equipment capacity. Take composition.

The capacity of the tundish is the refining capacity (ladle)
Of about 40 to 60%. The function of the tundish is to receive the molten metal from the ladle and distribute it to each strand of the continuous casting machine, and as shown in JP-B-2-38302 and JP-A-2-299753.
The heating and agitating devices attached to the tundish maintain the injection temperature and make it uniform, and have a refining function for alloy addition. As the alloy to be added, for example, Si-Mn, Fe-
Si, Fe-Mn, Fe-Nb, Fe-Ti are considered.

The casting method of the continuous casting machine is a batch method in which the casting can be finished at any position within the operating range of the dummy block elevating device installed below the mold for holding the molten metal and the slab. Is.

An example of the procedure of the continuous casting method for small lot materials of the present invention will be described with reference to the process chart shown in FIG. The molten metal 5 (steel type A) in the ladle 1 is poured into the tundish 2 in a few times and cast.

The casting of the first cast is carried out by holding the molten metal 5 injected into the mold 3 at the start of casting with a dummy block 4 and lowering the dummy block 4 by an independent driving device for each strand. Be seen. Therefore, the dummy block 4 can be stopped at any position within the maximum casting stroke range. Furthermore, the casting speed can be controlled independently for each strand, and the casting size and casting length can also be changed for each strand.

Further, the casting length of each strand reaches a predetermined length in which the order lot weight (the length of a slab for a lot having a fixed cross section) is added to the cutting allowances of the top and bottom of the slab. At the stage, pouring into the mold 3 is completed by a pouring stop device such as a stopper and a sliding nozzle installed in the tundish 2.

The first casting (steel type A) is completed when the cast pieces 6 of all the strands have a predetermined length.

When the first casting is completed, the molten metal 5 (steel type A) required for the next casting is poured into the tundish 2 from the ladle 1, and the tundish is heated in the tundish 8 if necessary. The molten metal 5 is melted from the steel type A to the steel type B by adjusting the composition of the alloy addition 7 into the tundish and is on standby.

On the other hand, the continuous casting machine cools the slab 6 until the slab 6 is completely solidified, and after the solidification is completed, the slab 6 is immediately carried out of the continuous casting machine using a carry-out device 9 such as a crane. After the slab 6 has been carried out of the machine, the continuous casting machine performs casting preparation work such as changing the casting size and mold sealing work as necessary.

Casting of the second cast (steel type A or steel type B) when the casting preparation and the tundish preparation are completed
However, only strands with a radix suitable for the ordered lot are used for casting. Furthermore, by repeating the casting preparation and the tundish preparation described in the first cast, the third and subsequent castings can be performed.

That is, the present invention combines a tundish for splitting water into a multi-strand continuous casting machine and a multi-strand batch continuous casting machine in which each strand can independently control the slab length, and It is a continuous casting method for a small lot material, characterized in that the steps (e) to (e) are sequentially repeated to perform casting.

(A) Molten metal in a ladle was poured through a tundish into one or more strands of a batch continuous casting machine, (b) then the slab of each strand was of a predetermined length. At the time point, the first casting was completed and the slab was taken out, and (c) the molten metal in the amount required for the next casting was poured into the tundish from the ladle and waited (d) during this period. The casting machine prepares for the next casting including changing the size of the mold, (e) restarts the next casting, and when the slab of each strand reaches a predetermined length, the second casting is performed. finish.

In the continuous casting method for small lot materials, while the molten metal is poured into the tundish from the ladle and is on standby, an alloy is added to the tundish in parallel with the next casting preparation to melt the molten metal. The component of is adjusted.

In the above continuous casting method for small lot materials, the molten steel temperature is adjusted by the molten steel heating device in parallel with the next casting preparation while pouring molten metal from the ladle into the tundish and waiting. is there.

By the above process, a small lot of slabs having a required amount or a required length of various sizes and types can be efficiently manufactured.

[0033]

[Example] Tundish with plasma heating device and 3
A casting test was conducted under the casting conditions shown in Table 1 by the above-described casting method using a batch type continuous casting machine for strands.

Three pieces of three slabs were cast from the molten steel of 130 ton in the ladle at the first time and three strands were made at three strands, and the alloys of Si-Mn and Fe-Mn were added in the tundish, and then at the second time, two strands were formed into A slab of book was cast. As a result, 1
It was possible to cast a slab of 5 sizes and 2 components from the molten steel of the pot.

[0035]

[Table 1]

[0036]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, casting is performed by combining a tundish for splitting water into a multi-strand continuous casting machine and a batch type continuous casting machine in which each strand can independently control the slab length. By doing so, it is possible to efficiently cast slabs of multiple sizes and small lots from one pot of molten steel, which makes it easy to handle a wide variety of products, reduces the surplus material generation rate, and facilitates inventory management. Therefore, the storage cost can be reduced.

[Brief description of drawings]

FIG. 1 is a process chart showing an example of a procedure of a small lot material continuous casting method of the present invention.

[Explanation of symbols]

 1 Ladle 2 Tundish 3 Mold 4 Dummy block 5 Molten metal 6 Cast slab 7 Alloy addition 8 Melt heating 9 Discharge device

Claims (3)

[Claims] 1. A tundish for splitting water into a multi-strand continuous casting machine and a multi-strand batch continuous casting machine in which each strand can independently control the length of a slab are combined to obtain the following (a) to (e): ) The continuous casting method for small lot materials, characterized in that the steps (1) to (5) are sequentially repeated to perform casting. (A) The molten metal in the ladle is poured through a tundish into one strand or multiple strands of a batch continuous casting machine, and (b) when the slab of each strand reaches a predetermined length. After the first casting is finished, the slab is carried out, (c) then, the molten metal in an amount necessary for the next casting is poured into the tundish from the ladle and waits (d).
During this time, the continuous casting machine prepares for the next casting including the change of the mold size, (e) then restarts the next casting, and when the slab of each strand reaches a predetermined length, the second casting is performed. Finish casting. 2. A molten metal is poured into the tundish from a ladle and is standing by, and an alloy is added to the tundish in parallel with the next casting preparation to adjust the composition of the molten metal. The continuous casting method for a small lot material according to claim 1. 3. A molten steel temperature is adjusted by a molten steel heating device in parallel with the next casting preparation while pouring molten metal from the ladle into the tundish and waiting.
A method for continuously casting small lot materials as described.