JPS6120648A - Synchronous type horizontal and continuous casting device - Google Patents

Abstract

PURPOSE:To obtain a thin-walled billet consisting of a high-melting metal having an excellent surface characteristic by forming the spacing between the side faces of a casting mold facing each other in the casting direction to the size slightly smaller than the height of the side faces in the casting direction and decreasing gradually the spacing toward the casting direction thereby converging the same to the desired thickness of the billet. CONSTITUTION:The side faces facing each other in the casting direction of the casting mold 2 extending in the horizontal direction, the one side face intersecting orthogonally with the casting direction and the bottom surface in the casting direction are respectively constituted of an endless recurrent type support 1, a rear stationary block 3 and a bottom stationary block 4. The molten metal poured into the space area 7 constituted of the support 1 and the blocks 3, 4 facing each others made into an unsolidified billet 5 and is drawn in the direction B. The spacing between the side faces facing each othr in the casting direction of the mold 2 is made smaller than the height of the side faces in the casting direction and is gradually decreased in the casting direction so as to be converged to the thickness of the billet to be cast. The continuous casting of the thin-walled billet consisting of the high-melting metal having the good surface characteristic is thus made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a synchronous horizontal continuous casting device in which a mold is moved in synchronization with a slab that is pulled out in a horizontal direction.

[Prior art and its problems]

In conventional continuous casting, in order to prevent seizure between the slab and the mold, the mold must be vibrated in the case of vertical continuous casting, and the DJ piece must be vibrated in the case of horizontal continuous casting. Since the cast slab must be drawn out intermittently, fragile hot-water boundaries are formed on the surface layer of the cast slab, and as a result, the surface of the slab must be cleaned.

Therefore, a synchronous continuous casting method has been developed as a continuous casting method that does not, in principle, cause such difficulties, and is rapidly being put into practical use. This synchronous continuous casting method is
The slab is cast while moving the mold in synchronization with the slab being pulled out.

The synchronous continuous casting method includes (1) a method in which a slab is pulled downward from between the rolls while rotating a pair of horizontal twin rolls that together with the sump form the mold (hereinafter referred to as the twin roll method); ), (2) A method in which the slab is pulled out while moving the belt or block casters that make up the horizontal mold in the horizontal direction (hereinafter referred to as the horizontal method) +
(3) Belt or block casters forming vertical molds.

There is a method in which the slab is pulled out while moving in the vertical direction (hereinafter referred to as the vertical method).

The synchronous continuous casting method prevents mold seizure by moving the mold in synchronization with the slab.

It is intended to prevent the formation of weak parts in the initial solidified shell and to prevent the application of extra external forces such as frictional forces to the solidified shell. As a result, the synchronous continuous casting method is able to pull slabs from the mold at extremely high speeds without degrading the properties of the slab, and can produce thin-walled slabs close to the final product shape without reducing productivity. It has the unique feature of being able to cast slabs.

However, the reality is that the casting process itself using the above-mentioned synchronous continuous casting method is in operation with various problems and usage restrictions.

For example, in the twin roll method, it is impossible to pull out the piece in an unsolidified state due to the rigidity of the solidified shell, which limits productivity, and metals with a wide range of solid-liquid coexistence, such as AU
” When casting Mf-based alloys, there is a problem in that the slab breaks at the exit of the roll. Even in the case of general alloys, solidification progresses while being constantly subjected to the cleaning action of the solidification interface, and Due to the metallurgical instability at the point of complete solidification at the outlet, the concentration of solute components in the mother solution over time tends to increase.

So-called macro segregation occurs in the axial ID and longitudinal direction of the slab. In particular, macro-segregation in the longitudinal direction of the slab is determined by the solidification zone length (crater length), which is determined by the amount of molten metal in the sump between the twin rolls and the roll diameter, and by the cooling rate of the shell and the solute component. This is a fundamental problem unique to the twin-roll system because it is uniquely determined by the equilibrium distribution coefficient.

On the other hand, in the horizontal belt method and horizontal block method.

There are no inherent metallurgical problems as with the twin roll system.

However, even with these methods, there is no problem when dealing with M, Cu, and their alloys, which have low melting points, but when dealing with steel etc.
When dealing with high melting point metals and alloys that exceed 0°C, the belt, Glock, and insert nozzle may be deformed by the heat.

Since it becomes impossible to obtain a stable gap between the insert nozzle of the pouring part and the mold, casting abnormalities and deterioration of the surface properties of the slab result.

Therefore, in the horizontal belt method and horizontal block method, if belts, blocks, and insert nozzles that can withstand high heat are developed, it will be possible to cast high-melting point metals and alloys. Of these, regarding belts and blocks,
By selecting the material, devising the shape, and introducing preheating and forced cooling means, it is possible to maintain thermal deformation within an acceptable range. However, there are currently no prospects for insert nozzles. Therefore,
Although it is possible to cast thin-walled slabs using the synchronous continuous casting method, there are limits to the conventional horizontal method. Even if an insert nozzle is made, the thickness of the thin slab that can be cast is limited to 20 mm.

On the other hand, in the vertical belt method and vertical block method, by adopting open injection, such as not using an injection nozzle, the above-mentioned difficulties in the pouring section of the horizontal method are alleviated.
The restriction that it is not possible to cast thin slabs can also be alleviated to some extent.

However, in these vertical methods, it is difficult to maintain a constant level of hot water due to the presence of a meniscus at the hot water level. If short-period, long-amplitude level fluctuations occur on the surface of the molten metal that exceed the drawing speed, not only will the surface quality inevitably deteriorate, but the meniscus and solidification start point will deteriorate over the entire circumference of the slab. Since the levels are maintained at approximately the same level, slag and scum floating on the molten metal surface are likely to be captured by the initially solidified shell, and this also causes deterioration of the surface quality of the slab.

[Purpose of the invention]

In view of the above-mentioned current situation, this invention has been developed to enable casting of thin slabs of high-melting point metal without deteriorating the surface properties of the slabs, and to provide a synchronization system that does not cause any equipment or operational problems. The purpose is to provide a type horizontal continuous casting equipment.

[Summary of the invention]

This invention provides a synchronizer in which each of the opposite side surfaces in the casting direction of a horizontally extending mold is formed of an endless recursive support, and the upper surface of the mold and one side surface perpendicular to the casting direction are open. In the type horizontal continuous casting apparatus, the distance between opposing sides in the casting direction of the mold is smaller than the height of the sides in the casting direction, and is gradually reduced in the casting direction to converge to the thickness of the slab to be cast. It has certain characteristics.

[Structure of the invention]

Hereinafter, the synchronous horizontal continuous casting apparatus of the present invention will be explained in detail based on the drawings.

FIG. 1 is a perspective view showing one embodiment of the present invention. In FIG. 1, l is a caterpillar block constituting a side surface in the casting direction of the horizontally extending mold 2 of the continuous casting device;
3 is a rear fixed block forming one side of the mold 2 perpendicular to the casting direction.

Reference numeral 4 denotes a bottom fixing block that constitutes the lower surface of the mold 2 in the casting direction. The caterpillar blocks 1 are provided on both sides of the unsolidified slab 5, and one of them is omitted in the figure.

The caterpillar block 1 is electrically rotated in the direction of arrow A by a drive roll 6 and a brake roll 6', and is rotated in the direction of arrow B.
It moves in synchronization with the unsolidified slab 5 being pulled out in the direction.

In this invention, the width direction of the thin slab is set in the vertical direction of the caterpillar block 1 so that solidification of the thin slab cast in the mold 2 starts in contact with the d5 mold 2 in many parts, A thin slab is cast with the thickness direction of the thin slab being the direction between opposing surfaces of the caterpillar block 1. As a result, the free surface of the molten metal injected into the mold 2 can be made smaller, so that a slab can be cast while reducing the size of the portion where the surface quality is not good. In other words, the portion where the surface quality is not good can be limited to only the 10,000'' short side of the slab.

Therefore, in this invention, the distance between the opposing sides of the mold 2 in the casting direction is made smaller than the height of the sides in the casting direction. That is, the height of the molten metal injected into the mold 2 is made larger than the distance between the opposing surfaces of the caterpillar blocks 1 forming the side surfaces of the mold 2 in the lay-making direction.

The distance between the opposing surfaces of the caterpillar block l, which is made smaller than the height of the molten metal, becomes further narrower in the slab drawing direction (in the direction of arrow B), and at the final straightening completion position 10, After reaching a size corresponding to the thickness of the slab, it is maintained at that size thereafter.

A space area 7 constituted by the opposing surfaces of the two caterpillar blocks 1, the rear fixed block 3, and the bottom fixed block 4 forms the pouring part of the piece type 2. The distance between the opposing surfaces of the two caterpillar blocks 1 reaches its maximum at the pouring portion 7, and is large enough to impede insertion of a sufficiently thick pouring nozzle 8.

While the flow rate of the molten metal is controlled from the molten metal intermediate holding container 9,
The molten metal is injected into the pouring part 7 through the injection nozzle 8, and solidification progresses from the corner (solidification start line) 12 of the rear fixed block 3, resulting in an unsolidified slab. The solidification rate of the unsolidified slab 5 is set to be approximately 90 inches or less at the slab straightening completion position 10 so that the thickness can be properly straightened. The lower limit of the solidification rate of the unsolidified slab 5 is approximately 10 inches when considering the rigidity and casting efficiency of the unsolidified slab 5.

While the unsolidified slab 5 moves from the pouring section 7 to the slab straightening completion position 10, its thickness is reduced and straightened to the final slab thickness. There are no particular restrictions on how to reduce the thickness.
Pressing is force controllable and unrefined 1i! Considering the workability of the i1 button piece 5, progressive straightening is suitable, in which the thickness of the unsolidified slab 5 is linearly reduced from the pouring part 7 to the slab straightening completion position 10. ing.

The caterpillar block is preferably made of a material having a large heat content and a large heat diffusivity and a relatively high melting point, such as copper or a copper alloy.

After the caterpillar block 1 is separated from the unsolidified slab 5, it returns to form the mold 2 again, and the molten metal is received between the faces of the two caterpillar blocks 1, so it must be cooled before then. It is. The caterpillar block 1 is cooled so that the corner (solidification start line) 12 of the rear fixed block 3, where an initial solidified shell begins to form, reaches room temperature.

The caterpillar block 1 may be cooled by providing an external cooling means 13 in its return process, or by providing cooling means within each of the caterpillar blocks 1.

Regarding the bottom fixing block 4, it is necessary to prevent the shell from growing from the bottom of the unsolidified slab 5 as much as possible until the unsolidified vj piece 5 reaches the slab straightening completion position 10, so the bottom fixing block 4 is For 4a, a refractory with excellent heat insulation properties is used. After the slab straightening completion position 10, it is preferable to promote shell growth from the bottom surface of the unsolidified slab 5 to quickly form a healthy bottom shell.

The bottom fixing block 4b after the slab straightening completion position 10 is
It shall be equipped with cooling means either internally or externally.

The unsolidified slab 5 may be supported by the caterpillar block 1 until it is completely solidified.
Utilizing the rigidity of the unsolidified slab 5 itself, the support roll 14 may be used to carry out the process from the middle.

The fixed surface support 11 is designed to be able to locally control the pressing force in the height direction in order to press the back surface of the caterpillar block 1 and hold it in a predetermined trajectory with high precision. preferable.

In the above example, a casting apparatus is shown in which the side surface of the mold 2 in the casting direction is constituted by the caterpillar block 1, but the present invention is not limited thereto, as shown in FIG.

The side surface of the mold 15 in the casting direction may be constituted by a recursive metal belt 17 that is rotationally driven by a drive roll 16 and a brake roll 16'.

In addition, the present invention does not simply cast a slab, but also welds a cladding material 18 to the surface of the slab 5 at the same time as casting the slab 5 to form a clad slab 19, as shown in FIG. It can also be applied during manufacturing. In addition.

In Fig. 3, 20 is a coiler for continuously supplying the laminate 18, and 21 is a coiler for continuously supplying the laminate 18, and 21 is a coiler for continuously supplying the laminate 18. This is a rapid heating device that heats to the required temperature.

〔Example〕

Example 1 A casting apparatus shown in FIG. 1 was manufactured to continuously cast copper pieces of low C-AA killed steel. Rear fixed block 3 of casting equipment
The distance between and the slab straightening completion position 10 is 3000 ms.
, the distance between the tubular blocks 1 of the pouring section 7 is 20
It was set to 0 ms. + The thickness correction of the unsolidified slab 5 by the block 1 is carried out by moving the block 1 along an arcuate trajectory (with a radius of curvature of approximately 5.9 m) between the pouring part 7 and the slab straightening completion position lO.
The maximum strain applied to unsolidified slabs is 2 x 10-4~4
x 10'). The supporting distance of the unsolidified slab 5 by this block 1 (
The length of the temple block l in contact with the unsolidified slab 5 was 6 m. The dimensions of the final slab (same as the dimensions of the unsolidified slab upon completion of straightening) are 20 to 60 mm thick.

The width is 600 to 800 birds.

Table 1 shows the final slab dimensions, drawing speed, solidification rate of the unsolidified slab at the straightening completion position (solidification number = 18), and quality of the final slab.

As is clear from Table 1, the quality of the slabs was all good except for No. 4, which had poor surface and soldering properties, and N[ll, which had slightly poor segregation. In addition, casting stability was poor for Nll 3 and Nao 7, which had a fast drawing speed, and was slightly poor for h4, which had a slow drawing speed.

All were in good to excellent condition.

In addition, the controllability of the molten steel level when pouring molten steel is as follows: thickness 20mm 1 width 1
000, for a mold for casting a slab.

It is sufficiently stable up to about 3 tons/min per injection nozzle. However, if the injection speed is higher than that shown in Table 1', injection using multiple nozzles is appropriate.

Moreover, the drawing speed is 20. , 50m/
m ] n at 6 m/min with a fishing rod of 60 m/min.
If this value is exceeded, the crater length required for the slab to solidify completely will exceed 154 mm, and the length of the casting equipment will become longer.

Productivity 1 It is necessary to set the drawing speed within an appropriate range in consideration of quality and profitability.

Example 2 The casting apparatus used in Example 1 was changed to enlarge the width of the slab during casting. Initially 20m thick
, 1 A slab with a width of 1000+xa was pulled out at 20 m/min, and then the molten steel injection rate was increased to about 42 tons/ml at a rate of o, s toy/min to raise the molten steel level. The width of the second slab was expanded. As a result, after passing through a width transition slab spanning approximately 45'rn, a slab with a width of 1,600 mm and a continuous slab with a width of 1,600 mm are formed. A slab was obtained, and there were no problems with the slab.

Example 3 The casting apparatus of Example 1 (casting apparatus shown in Fig. 1) was improved,
A casting apparatus shown in Fig. 4 was manufactured. That is, the width of the bottom fixed block 4' is expanded so that the lower surface of the caterpillar Glock 1, whose side surface contacts the rear fixed block 3, slides on the upper surface of the bottom fixed block 4'. The rear part of the support 11 and the support roll 1 following it
4. The positions of the drive rolls 6 can be controlled independently.

Using this casting equipment, a method in which the thickness of the slab is changed by temporarily interrupting the drawing of the slab during casting, and a method in which the thickness of the slab is changed in stages without interrupting the drawing of the slab during casting. Casting was carried out using the following two methods while changing the thickness from 20mrA to 60mrA.

As a result, although there was a difference in the length of the thickness transition slab, slabs with good surface and internal quality were obtained in all cases.

Example 4 The apparatus shown in Fig. 3 was manufactured and used.

At the same time that a rimmed steel slab was cast, a rimmed steel slab was welded to the slab to produce a clad steel plate in which both the laminate and the base material were made of rimmed steel. When this clad steel plate was rolled, a rimmed steel plate with one surface that was sound was obtained with good workability.

〔Effect of the invention〕

As explained above, the synchronous horizontal continuous casting apparatus of the present invention is capable of eliminating the problems that occur in conventional synchronous continuous casting apparatus when casting thin slabs of high melting point metals such as steel and alloys. Moreover, slabs of excellent quality can be obtained without causing any operational problems.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a perspective view showing one embodiment of the casting device of the present invention, Fig. 2 is a perspective view showing another embodiment of the casting device of the invention, and Fig. 3 is a perspective view showing another embodiment of the casting device of the invention. FIG. 4 is a perspective view showing a clad slab manufacturing apparatus to which the above method is applied, and FIG. 4 is a perspective view showing a casting apparatus in which the caterpillar block of the casting apparatus shown in FIG. 1 is replaced with a solid bottom contact surface of the block. In the drawings: 1... Caterpillar Pro 2.15 Disease type. Tsuku, 3... Rear fixed prong 4...
Bottom S fixed prong 5 ・Unsolidified slab. 6.16... Drive roll, 6', 16'... Brake roll. 7...Pouring part, 8...Pouring nozzle. 9... Molten metal intermediate retainer, Co-... Slab straightening completed position 11... Fixed surface support, position, 12... Corner, ] 3... External cooling means. ]4...Support roll, 17-pa regressive metal belt.

Claims (1)

[Claims] 1. Each of the opposing side surfaces in the casting direction of a horizontally extending mold is formed of an endless recursive support, and the upper surface of the mold and one side surface perpendicular to the casting direction are In an open synchronous horizontal continuous casting apparatus, the distance between opposing sides in the casting direction of the mold is made smaller than the height of the sides in the casting direction, and gradually reduces in the casting direction to form a slab to be cast. Synchronous horizontal continuous casting equipment characterized by convergence in thickness. 2. Synchronous horizontal continuous casting according to claim 1, characterized in that the distance between the side surfaces in the casting direction converges at a position where the solidification rate of the slab in the mold does not exceed 90%. Device.