KR100355000B1 - Continuous casting equipment and method for manufacturing rectangular thin slab - Google Patents

Abstract

The invention relates to a process and a continuous casting facility for the production of thin slabs, preferably of steel with a predetermined congealing thickness of (for example) 50 mm. In the said process, an optimal casting surface and internal quality, with minimal and predetermined congealing thickness and plant capacity, and thus minimal complexity of rolling material, is achieved by the optimal combination of such elements as the following: rolling of cast metal in the area of the casting guide (segment 0), cambered ingot mould with a cross-sectional area which increases from inlet to outlet, hydraulically driven lifting platform, casting powder and supply thereof, immersion discharge with specific flow cross section. Qualitative adjustment of these process and system parameters results in satisfactory supply of casting slag and circulation in the meniscus by comparison with a standard 200 mm thick slab. The conditions from the basin top to the meniscus have a direct effect on the superficial and interior quality of the casting and the reliability of the casting process.

Description

Continuous casting equipment and method for manufacturing rectangular thin slab

For example, techniques are known for using a flat sediment inlet at DE 37 09 188 Al. Further, during the casting process, a hydraulically driven lifting platform that changes the amplitude, frequency and waveform of the vibration by selecting a sine wave (sinusoidal wave) deviation to select an optimal one is common. Rolling of castings, in which the thickness of the castings is reduced in order to maintain the internal quality of the castings best during the casting hardening, is especially known in DE 38 18 077 A1.

The present invention relates to continuous casting such as processes for sheet slab production.

The invention is explained in detail on the basis of the accompanying drawings.

1 shows casting conditions in an ingot mold.

FIG. 2 shows the technical consumption of a uniform surface quality and consistent casting according to the slab thickness in relation to the slab 200 mm thick x 1. 000 mm wide.

Article 3. 1 degree to 3. 3 degrees is the technical consumption for achieving a uniform surface quality and slab thickness, depending on the casting speed, for slabs 200 mm thick x 1 000 mm wide.

4 shows the hydraulic ratio of the metal in the ingot mold according to the slab thickness in relation to the slab having a thickness of 200 mm x 1. 000 mm.

5 is a continuous casting equipment.

From a technical point of view, the production of thin castings has to solve complex problems, and the overall variables that can affect the entire continuous casting plant are too large to be solved by the average expert, which is one of the many solutions available. Finding satisfactory results at the lowest possible cost is very difficult.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a thin casting having a predetermined thickness by forming an optimal condition for processing slag and reducing casting thickness not only in an ingot mold but also in a feeder when rolling a casting. It is to provide continuous casting equipment.

This object is solved through the features of claims 1 and 3. Dependent claims include preferred embodiments of the invention. The object of the present invention is solved irrespective of the type of ingot mold such as a vertical ingot mold, a vertically curved ingot mold or an arc ingot mold.

Attempts to be made within the scope of the present invention reveal that the quality of the casting surface depends on the treatment of the original slag. Responsibility for this lies on the surface of the meniscus, ie the slag height (h _slag ) and the height of the _{casting surface} (h _{casting surface} ) resulting from the sediment boiling at high temperatures in the ingot mold. 1 degree).

It is a standard for optimizing lubrication and avoiding grooves on the surface (cast powder residue which can be seen directly under the casting surface in the form of oxides).

It is found that h slag ≧ h casting surface must be satisfied.

The slag height (h slag) is greater than the thickness of the cross section of the ingot mold inlet and the casting surface height (h casting surface) depends on the amplitude of the vibrating ingot mold. Investigating the slag height (h slag) and its dependence on the thickness of the ingot-shaped inlet cross section, the following relation can be obtained.

This relationship also leads to unexpected next results from technical efforts.

That is, for a casting operation set at 2.736 t / min, comparing a conventional 200 mm slab with a 50 mm slab, and assigning a value of 1 for a 200 mm slab in relation (2), the value for the 50 mm slab is the second As expected in the figure it rises to 16.62. In other words, the relation (2) is inversely proportional to the decrease in the casting thickness, where one exponential curve follows.

On the contrary, as shown in FIG. 3 for the ingot molds of 75/100 and 125 mm, the relational expression is modified to increase the casting speed at the determined casting thickness. The increase in the straight line increases.

Turbulent phenomena generated through the injection of metals into the ingot mold have a significant effect on relation (1). This turbulence often penetrates to the surface of the sediment and can be induced by wave motion. This wave crest can rise above the slab surface and interfere with the lubrication of the surface. This turbulence depends on the workload, thickness and width of the ingot mold, particularly on the outlet pipe cross section. Now, let's define the hydraulic ratio as the ratio of workload to thickness as a measure of turbulence phenomena and suggest the following relationship.

The value of the hydraulic ratio associated with the 200 mm thick slab can be estimated in FIG. 4, for example. There, the larger ingot mold thickness makes the hydraulic ratio much more favorable. In addition, the following relation is important in relation to turbulence phenomena.

In addition, the electromagnet brake in the ingot mold can greatly reduce turbulence on the casting surface.

The following results are obtained from the relations which have been verified and presented above. That is, for example, reducing the thickness of the casting in the ingot mold from the slab thickness of 100 mm to the slab thickness of 50 mm causes a great problem to satisfy the relation (1). In other words, except for the difficulty of transferring metals, it is almost impossible to supply sufficient casting powder to the cross section of the ingot mold inlet in order to smooth the fairly large casting surface to be produced and further maintain the relation (4). . In contrast, the casting speed, for example 75 mm of casting thickness, in an ingot mold can be increased without much further consumption on the casting surface. This represents an amazing solution: In other words, in thin slab casting, it is meaningless to keep the casting thickness of the ingot mold until the end of hardening (down to the bottom), but rather, the casting thickness is reduced with the aid of the casting rolling means when transferred to the rolling apparatus. It is technically more important and simpler to achieve the purpose. Multiple rolling devices (segment 0) formed for this purpose, for example as tong segments, have proven to be desirable. 5 shows a continuous casting plant incorporating the overall features of the present invention.

Description

1. Foundry powder 18, optimum casting powder

2. Powder Tli, 19. 75 × 800-1,600 mm, casting

(Rounded) slab on the step limit surface

3. Casting surface or shell 20. 11 × 220 mm,

Casting Surface Height / Base Surface Flow Cross-Inlet

4. Slag, slag height 21. Hydraulic ingot mold drive

5, powder, powder height 22. FST / FTA ≤ 50

6. Inlet 23. 75 × 800-1600 mm, ingot

7. Slab condition on sediment mold outlet

8. Acid on slag 24. Connected or hydraulically

9. Vg ≡ casting speed cylinder or similar

10.Q slag ≡ spent slag 25. compartment,

11. Air formed as forceps, for example

12. Decision limit, 26. Hydraulic cylinder or

Hardened steel / flow steel or the like

13. Casting surface 27. 50 mm,

14. Vibration of slab thickness due to vibration of casting (rise height, frequency, shape) 28. With hydraulic control device

15. Copper plate compartment 1 ... n

16. Splitter 29. Vgmax × 6 m / min

17. Inlet, 30. 50 mm, of casting feeder

External slab thickness at 210 × 45 mm ends

Internal value 220 × 15 mm

★) F _ST = cross section on the outlet of the sediment inlet

F _TA = casting cross section of hardened slab

Claims (4)

Injecting casting into a rectangular ingot mold through a precipitate inlet; Vibrating the ingot sphere; Depending on the amplitude, waveform and frequency of the ingot cast motion, Supplying a casting powder that satisfies the condition of slag height (h slag) ≥ casting surface height (h casting surface); Direct ingot casting through several steps in a multiple rolling device (segment 0) to consistently form a forced convection in the fluid casting, corresponding to electromagnetic agitation, to reduce the continuous casting thickness. Reducing the casting cross section at the bottom, Reaching the final thickness of the casting at the end of the multiple rolling apparatus (segment 0); Curing the two stage regions (crystals / fluids) when the final thickness is reached at the exit of the multiple rolling apparatus; When F _ST is the cross section on the outlet of the sediment inlet, and FTA is the casting cross section of the hardened slab, Laminated slab manufacturing method comprising the step of satisfying the condition. The method of claim 1, wherein the frequency, amplitude, and waveform for ingot casting motion can be freely selected during the casting process. A sediment inlet, A vibrating rectangular ingot mold, in which the vibration can be freely selected in frequency, amplitude and waveform during the casting process, A casting powder feeder supplied according to the amplitude, waveform and frequency of the casting powder satisfying the conditions of slag height (h slag) ≥ casting surface (h casting surface), Multiple rolling devices for continuous casting thickness reduction, where the core remains fluid when the casting is brought to final thickness at the exit of the multiple rolling devices, Where F _ST is the cross section on the outlet of the sediment inlet and F _Td is the casting cross section of the hardened slab, Continuous casting equipment for the execution of the method for producing a thin slab according to claim 1 or 2, characterized in that it comprises a cross section of the precipitate inlet and a cross-section of the hardened slab formed to meet the conditions of. 4. The continuous casting machine according to claim 3, wherein the rollers in the multi-rolling apparatus are arranged to complete the rabble operation by reducing the thickness of the casting while the inside of the casting is fluid, and to avoid the occurrence of internal cracking.