JPH084882B2 - Continuous casting method for heterogeneous small lot metal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention uses a large-scale and highly efficient continuous casting equipment suitable for producing mass-produced metal ingots, and uses a small lot of heterogeneous metal ingots. To a method of manufacturing.

[Prior Art] For example, alloy steels and special steels with small production lots are often manufactured using small-scale refining equipment and continuous casting equipment, but small-scale equipment has low productivity and efficiency. In addition, the manufacturing cost of small lot materials is increased.

Mass-produced metal slabs are manufactured in large-scale and highly efficient refining equipment and continuous casting equipment, so the manufacturing cost is low.
If a small lot of alloy steel with a small monthly production is manufactured in a 300 ton / charge converter for ordinary steel, a large amount of surplus product will be generated by the production of one charge.

JP-A-61-147593 discloses a continuous casting method in which a part of molten steel in a ladle is caused to flow into a dividing tank in which a tundish is divided by a partition wall, an alloy is added, and casting is performed in a mold. When this invention is carried out, one strand of a multi-strand continuous casting machine becomes a slab having a composition different from that of the ladle molten steel, so that an alloy steel slab of a lot smaller than the ladle molten steel is also produced with high efficiency. can do. However, even with this method, the production amount of the alloy steel slab does not fall below the casting amount of one strand.

[Problems to be Solved by the Invention] With the diversification of usage techniques of metal materials, various kinds of metal materials having different components have been required, but the demand lot of each product type is small. Therefore, there is a demand for a technique for manufacturing a large number of kinds of metal materials in small quantities with high efficiency and low cost.

The present invention aims to produce a small lot of metal slabs whose components are different from mass-produced metals at low cost using a large-scale facility with high efficiency for mass-produced metals without generating surplus products. There is.

As the equipment, existing equipment is used without requiring a large amount of additional equipment investment.

[Means and Actions for Solving Problems] In the present invention, a dividing tank corresponding to the capacity of a small lot of molten metal is provided in a tundish for continuous casting of metal, and a casting nozzle of the dividing tank is provided at the end of casting of the mother molten metal. Close the molten metal for small lots in the dividing tank, add alloy to this to make small lots of different components, and open the casting nozzle again to continuously cast small lots of different components. It is a continuous casting method for small-lot metal with different composition.

If a heating device for a small lot of molten metal, a stirring device, or both are arranged in the dividing tank, the small lot of molten metal with different components will be sufficiently homogeneous by adding the alloy component and heating and stirring. The proper casting temperature is secured. During this period, the casting of the mother molten metal on the strand is temporarily stopped, and the head is held in the mold. The small lot molten metal whose components and temperature have been adjusted is continuously cast by opening the nozzle of the dividing tank again to produce a small lot slab.

 The present invention will be specifically described below with reference to the drawings.

FIG. 1 is a diagram showing an example of a process flow of the present invention. (A) In FIG. 1, reference numeral 1 is a high-efficiency refining furnace for mass production, for example, a 300 ton / charge converter for steelmaking. The entire amount of the mother molten metal 2 is transferred to the ladle 3. (B) is a diagram showing ladle refining, and if necessary, the mother molten metal 2 is subjected to ladle refining treatment by, for example, the RH degassing device 4. (C) The figure shows the process of continuous casting and the work in the middle period. The mother molten metal 2 is caused to flow into the tundish 7 provided with the dividing tank 8 by the weir 5, for example.
The dividing tank 8 is provided with a stopper 6. By making the molten metal level 11 in the tundish higher than that of the weir 5, the molten metal fills the tundish beyond the weir 5 and is injected into the mold as a steady flow. 9-1 and 9-2 are continuous casting molds, and the mother molten metal 2 is injected into the molds 9-1 and 9-2 via the tundish at the stage of this casting as shown in the figure, and the mother molten metal 2 Mass production of components 10-1 and 10-2
Becomes (D) The figure shows the final stage of casting of the molten metal.
At the end of casting, the nozzle of the dividing tank 8 is closed by the stopper 6. The molten metal in the tundish other than the dividing tank 8 is continuously cast in the continuous casting mold 9-2 to complete the continuous casting, but the dividing molten metal is stored in the dividing tank 8 according to the height of the weir 5. It will be. (D) The figure shows a state in which the nozzle of the dividing tank 8 is closed early, the 10-2 slab is continuously cast, and the 10-1 slab is interrupted. Reference numeral 12 is an alloy component, which is added to the molten metal stored in the split tank and is a small lot molten metal 13 of a different component different from the mother molten metal. (E) The figure is a diagram showing continuous casting of a small lot of different component molten metal. The different component small lot molten metal 13 whose components have been adjusted is continuously cast by using the mass-produced slab 10-1 as a guide (dummy bar) by opening the nozzle of the dividing tank again to form the different component small lot slab 14.

FIG. 2 shows a heating device for a small lot of molten metal according to the method of the present invention.
FIG. 3 is a diagram showing an example of a dividing tank provided with a stirrer 16 for molten metal 15 and a small lot. In the figure, 17 is an immersion nozzle, 18 and 19 are alloy adding devices, and 20 is an alloy.

As a heating device for a small lot of molten metal, a plasma heating device, an arc heating device, or an electromagnetic induction heating device can be used. If the addition of alloying components increases, the temperature of the small lot melt will decrease, so heating is required, and ensuring the temperature of the melt along the components of the different component small lot melt is extremely important for quality operation. In the case where the different lot of small lot molten metal has a composition containing a large amount of alloy components, or in the case of high quality molten metal, it is desirable to arrange a heating device to adjust the temperature of the small lot molten metal.
A porous plug, an electromagnetic induction heating device, or the like can be used as the stirring device for the small lot molten metal. The stirrer promotes the melting of the alloy components and makes the components and temperature of the molten metal uniform. Therefore, in the case where the different lot of small lot molten metal has a composition containing a large amount of alloy components, or in the case of a high quality molten metal, it is desirable to dispose a stirring device to stir the small lot molten metal.

[Example] The present invention was carried out at the final stage of continuous casting of 4 charges of mother molten metal which was melted in a steelmaking converter of 300 tons / charge and refined in a ladle.

The capacity of the tundish is 70 tons, with a capacity of 30 inside.
A ton dividing tank was provided by the weir.

Table 1 shows the components of the mother melt and the small lot of different components.

The total amount of alloy components added was 1724 kg, and a small lot of the split layer melted with Ar bubbles was dissolved in 16 minutes while stirring, and the mother melt stored in the split tank was mixed with a small lot of the different components shown in Table 1. After making the melt, the nozzle of the dividing tank was opened and casting was performed for 28 minutes to cast 31 tons of small lots of different components and continuous casting was completed.

Incidentally, the slabs of the components of the mother molten metal shown in Table 1 could be manufactured by this four-charge continuous casting to produce 1170 tons.

[Effect of the Invention] According to the present invention, the difference in lot is smaller than that of the conventional one. It is possible to manufacture a small-lot metal with a high-efficiency mass-production facility without generating surplus products.

In the present invention, the production of small lots of different components does not hinder the production efficiency of the mass-produced mother molten metal.

In the present invention, since the temperature of the small lot of the different component lot and the refining can be sufficiently performed in the dividing tank, the quality of the small lot of different component cast pieces is excellent.

The present invention is advantageous in terms of manufacturing cost because it requires less dedicated capital investment for melting and casting a small lot of metal and mainly uses equipment for mass production and high efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing an example of a process flow of the present invention, and FIG. 2 is a diagram showing an example of a dividing tank of the present invention equipped with a heating device and a stirring device. 1: High-efficiency refining furnace for mass production, 2: Mother molten metal, 3: Ladle, 4: Ladle molten metal refining equipment, 5: Weir, 6: Stopper, 7: Tundish, 8:
Dividing tank, 9 (9-1, 9-2): Continuous casting mold, 10: Mass-produced slab, 11: Molten level in tundish in early to middle casting, 1: Molten pouring flow from ladle, 13: Different Component small lot molten metal, 14: different component small lot slab, 15: heating device, 16: stirring device, 17: dipping nozzle, 18 and 19: alloy addition device, 20: alloy.

Claims (1)

[Claims] 1. A tundish for continuous casting of metal is provided with a dividing tank corresponding to the capacity of a small lot of molten metal, and the casting nozzle of the dividing tank is closed at the end of the casting of the mother molten metal so that the dividing tank can be used for small lots. It is characterized by storing molten metal, adding alloy to this to make small lot molten metal of different components, and opening the casting nozzle again to continuously cast small lot molten metal of different components. Continuous casting method