JPS5890357A - Method and device for continuous casting of thin sheet - Google Patents

Abstract

PURPOSE:To increase a drawing speed and to cast a thin sheet continuously and efficiently by charging molten steel onto a flat plate assuming an inclined endless track, reversing the casting direction and the flow direction of the charging flow and allowing the flow to hold the bottom end thereof by itself under the surface tension of the molten steel. CONSTITUTION:Molten steel 14 is charged onto a mold surface from a tundish 13 and is moved down on the surface of a casting belt 11 for a specified distance according to gravity. The surface of the belt 11 is moved upward by driving wheels 12 and the preceding end of the steel 14 is stopped in approximately the specified position on the surface of the belt 11. A solidified shell is developed as the same moves toward the left in figure from the preceding end of the steel 14 on the surface of the belt 11 until finally the shell passes under the surface of the steel 14 to form a thoroughly solidified thin sheet 15 which is passed through guiding rolls or left lower rolls 17, and is coiled with a coiler 16. As a result, a thin sheet of about 2-20mm. is produced and therefore hot rolling stages are mostly eliminated and this method is advantageous in terms of economization of energy and equipment.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method and an apparatus for directly casting thin steel sheets.
i do 40.

The conventional method for producing thin steel sheets is to produce a 200 to 250 mm thick slab from a steel ingot by blooming or continuous casting, and then heat it to obtain a thin steel sheet. It is true.

However, these methods require large-scale hot rolling equipment and energy to heat the slab, making the development of technology for directly casting thin sheets an important issue.

Conventionally, when continuously casting molten steel, a method has generally been used in which the molten steel is poured into a mold, solidified around the cross section, and then pulled out downward. However, with this method, it is difficult to cast slabs with a thickness of several tens of meters or less due to (1) the relationship between the nozzle number and the Oshi in the mold.

(2) Due to the mass between the slab and the mold, the drawing speed was set at 2 m.
/win level or more. There are problems such as difficulty in raising the temperature.

The present invention solves these problems and provides an efficient method and apparatus for casting thin plates. That is, the gist of the present invention is that in a method of pouring molten steel onto a flat plate on an inclined endless track, the casting direction and the direction of the injection flow are reversed, so that the lower end of the flow is opposite to the flow direction of the molten steel. A method for casting a thin plate that is self-supported by surface tension, a belt mechanism that is driven by a drive wheel to form an endless track, and has an inclined plane, and a molten metal flowing down on the inclined plane of the belt. The apparatus is a continuous casting apparatus for molten metal, which includes a feeding means, a device for extracting slabs above the slope, and a device for driving a belt upwardly on the slope via a drive wheel.

In the present invention, first, the molten steel solidifies on the endless track plane, and the drawing speed of the solidified shell cannot be synchronized with the moving speed of the mold. can be raised.

Furthermore, because of single-sided solidification, the lower surface of the slab is in contact with the mold surface during casting, but the upper surface is in contact with the molten steel or air, so there is no need for an upper surface of the mold, so no particular problem arises in nozzle arrangement.

Next, the present invention will be explained in detail using an embodiment of the apparatus shown in FIG.

In the figure, 11 is a casting belt or endless track, 12 is a mold drive wheel, 13 is a tandish 1.14 is unsolidified molten steel, 1
5 is a coagulating thin plate, 16 is a winding device, and 17 is a guide roll or a reduction roll.

The molten steel 14 is injected onto the mold surface from the tamp 13 and falls down the mold surface a certain distance according to gravity, but since the mold surface is moving upward, the tip of the molten steel is 01 above the mold surface.
1 stands still at a fixed position. In addition, the solidified shell develops as it progresses from the tip of the molten steel on the mold surface to the left in the figure, and eventually passes through the molten steel surface and becomes a completely solidified thin plate, after which it passes through the guide roll or reduction roll 17 and is rolled up. It is taken up by the device.

Approximately 2 to 20 thin plates can be manufactured using this method.

2(a) and 2(b) show the top and side views of the embodiment device of FIG. 1. FIG. The side surfaces correspond to those in FIG. 1, and in the figure, 23 is a mold side surface, 24 is a mold side drive wheel, 25 is a molten steel injection flow, 26 is a molten steel flow on the mold surface, and 27 is a solidified thin plate.

The side surfaces of the mold may be moved using vertical rolls 24 at the same speed as the bottom surface of the mold, using bells 24, or endless tracks with side walls may be used.

The injected molten steel tries to spread around the falling point, but because the mold surface is sloped, as shown in 28 in the figure,
Flows from the parabolic molten steel boundary to the right in the figure. As shown in the side view, the molten steel solidifies 2. The molten steel also flows over the solidified shell. However, since the amount of molten steel supplied is the same mass velocity as the slab being rolled up, the molten steel flow is not allowed to descend infinitely downward, and it remains almost stationary, forming a leading edge of 9 molten steel as shown at 29 in the figure. do. Solidification is at the leading edge of molten steel 2
9 to the left in the figure, and to the right of the boundary 28, a solidified shell and molten steel coexist, but to the left of 28, only a solidified shell exists. The 4G image of a countercurrent casting method such as the method of the present invention is
In this way, the upper surface of the final solidified shell is formed in such a way that it protrudes through the surface of the molten steel, and as a result, the surface quality of the solidified shell becomes smooth.

On the other hand, the example shown in Fig. 3 shows the case where the direction in which the molten copper flows and the direction in which the slab is pulled out are the same.
3 is a casting belt, 32 is a drive wheel, 33 is a solidified thin plate, 34 is an inflow flow, 35 is a solidification completion point, 36 is a tandisi 1.3
7 is a winding device, and 38 is a guide or reduction wheel.

In this case, the injected molten steel 34 flows to the right in the figure, and solidification also progresses toward the right.

In the figure, 35 represents the point at which solidification is completed. In this case, unlike the case of the present invention], the upper surface of the solidified thin plate is initially formed as a coating surface of molten steel. Therefore, unevenness is likely to occur on the upper surface of the solidified thin plate due to the influence of surface waves generated on the surface of the molten steel. It is possible to eliminate the unevenness by using a rolling down roll as shown in Fig. 38, but in the case of the present invention, it is necessary to have a large rolling down ratio.

In order to stably produce thin sheets with good properties using the method of the present invention, it is necessary to accurately control the entire process.

FIG. 4 shows one example of the control mechanism of the device of the present invention. Under steady state conditions, the mass rates of injection and withdrawal must be balanced. These include a tandisi injection control device 2 and a winding control device 3, a speed control device 5 for the guide or reduction roll, and a speed control device 4 for the mold belt drive wheel.
can be controlled to adjust the rotation speed.

In addition, the tip position of the molten steel must be within an appropriate range on the left side of the contact point B between the belt and the belt drive wheel in order to prevent leakage of molten steel to the outside of the machine and deformation of the solidified shell shape, but this must be controlled. To do this, an optical or heat-sensitive molten steel tip detection device is installed as shown in the figure.In order to ensure that the molten steel tip position does not deviate from the appropriate range, the injection speed, take-up speed, belt movement speed, and belt surface inclination must be adjusted. Adjust angle 0. A similar operation is also effective for K in order to adjust the solidified thickness.

FIG. 5 is a diagram schematically representing the concept of process control of the present invention.

By adjusting the winding speed of the slab, (guiding or rolling) roll speed, roll opening, belt speed, injection speed, device inclination angle, molten steel tip position, production speed, solidified shell thickness,
Product thickness can be adjusted to a predetermined value.

The 49 images of the present invention are as follows.

(1) Since a thin plate of about 2 to 20 m can be directly cast, the hot air process 1 can be almost omitted, which is advantageous in terms of energy saving and equipment saving.

(2) Solidification progresses on one plane from the beginning to the M-edge, and there is no processing strain until complete solidification, so no cracking occurs.

(3) Since rolling by rolls is performed after complete solidification, surface scratches caused by collapse of the solidified shell due to unsolidified rolling, as in the case of injection between rolls, do not occur.

(4) Since the direction of solute flow and the direction of slab movement are opposite, the top surface is smooth and unaffected by surface waves, even though it is single-sided casting.

(5) High-speed drawing is possible because there is no relative movement between the cooling belt or track and the slab during solidification, and no strain is applied to the slab during solidification.

Next, the production speed of thin plates by the method of the present invention will be described.

In FIG. 2, molten steel flows through cross section A' and exits the machine through cross section BB' after complete solidification. Therefore, the mass velocity through beam A' matches that of BB'. Also, in a steady state, the total mass velocity passing through CO2 in the figure must be zero.

Further, let L be the length of the region where the solidified shell is growing.

When the moving speed of the belt is v1, the mass velocity of the main or winding sheet is m1, the solidification coefficient is ρ, the thickness of the produced plate is d1, and b is the inside of the plate, the following relationship holds true.

Ugly wealth-ba v (2) (
If we eliminate Hashi from 1) and (2), we get m -p b kJ-7- and "(3) If we eliminate V from (1) and (2), we get rmwmlk bLd-' (4)
Equation (4) shows that the production speed is proportional to the machine length ty and inversely proportional to the plate thickness d.

As an example, we will roughly estimate the production speed in the following case.

b wing 20G steel t-1000゜dmaro L5 cs pl 7.8g shoulder km L5 css・mim-2 According to formula (4), p m = 7-8 X 2.5 X200X1000÷
0.5 gr/m=19 e 5 TO1'i/'
m 1 m - 1170 TON/) Ir ヰ28080 TON/Day -842400 TON/M In this way, the production speed of the current continuous casting machine (maximum 300,000 pieces ON/
This results in a much greater production rate than the previous month). This is natural considering that when casting a thin plate, the solidification rate is fast. By the way, the pulling speed in the above example is (
From formula 1), V −k2. iT -2-5X 100G = 0.5 a(win=
The drawing speed is 25,000 cm/win, 2,501 m1n, and 4.16 m/C, which is much higher than the current CC drawing speed, but the slab and mold are non-sliding, and the plate thickness is 5- Since it is relatively thin, there are no particular problems with the pull-out mechanism and wind-up mechanism in terms of equipment.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an apparatus according to an embodiment of the present invention, and FIG. 2 (i);
Figure 3 is a diagram showing an example of flowing and drawing molten steel in a direction different from that of the present invention;
FIG. 4 is a diagram showing an example of the control mechanism of the apparatus of the present invention, and FIG. 5 is a diagram schematically showing the concept of process control of the present invention. 1: Molten steel tip detection device 2: Injection control device 3: Rolling pile control device 4: Pel F speed control device 5: Guide or reduction roll speed control device 11: Casting belt or endless track 12: Mold drive wheel 13: Tandissi. 14: Unsolidified molten steel 15: Solidified thin plate 16: Winding]
Device 17: Guide or reduction roll 23: Casting lid surface 24: Mold side drive wheel 25: #
Steel column inflow 26: Molten steel flow on the casting lid surface 27: Solidified thin plate 31: Casting belt 32: Drive wheel 33: Solidified thin plate 34: Inflow flow 3
5: Point of completion of solidification 36: Tandyshi, 37: Winding device 38: Guide or rolling roll (Fig. 5, 0 moxibustion notes) Procedural amendment 1, Indication of incident Relationship with multiple patent application No. 1F2B62 held in 1932 Applicant Name (Name) (665) Door = 0 Kutei - Mashiki Company 4,
Attorney Tadashi Tsumugi, Secretary 1, amends the scope of claims as shown in the attached sheet. 2. In the 8th line of page 4, the phrase "There is a nozzle" is corrected to "There is an injection nozzle." 3. On page 5, line 13, ``Using an endless track'' is corrected to ``Using an endless track or a fixed-length side plate that is applied with ultrasonic vibration to reduce friction by 1''. 4. In line 5g, line 11, ``The example is'' is corrected to ``The example is.''&, 7th Ni 13 12” is corrected to r42”j. 6. The 73j line 14th line “3” is corrected to r-43J. 7. The 7314th line is “5” Correct the statement to "45". 8. In the 7th * 15th line, correct "4" to "44". 9. Page 8, line 1 K Correct "1" to "41". 10, @11 member In the first line, 1' gr/z ■'' is corrected by 1 to r gr/m1n J. 11, 1* Delete the text "1: Molten steel tip... speed control device" in lines 8 to 11 on page 12. 12. Insert the following sentence below the 13th member S line. "41: Molten steel tip detection device 42: Injection control device 43: Winding control device 44: Belt speed control device Please correct as in the manual. Scope of Claims l A thin plate in which molten steel is poured onto a flat plate forming an inclined endless track. A thin plate casting method characterized in that the casting direction and the flow direction of the injection flow are reversely pressurized so that the lower end of the flow is self-supported by the surface tension of the molten steel. 2. The continuous casting method of a thin plate according to claim 1, characterized in that the position is detected and the inclination angle or moving speed of the endless track flat plate or the injection speed of molten steel is adjusted so that the position is constant. Claim 1 states that before rolling up one exit side, the slab is subjected to pressure treatment in order to remove the concavities -b'f- on one surface or to make it to a predetermined thickness after the slab is completely solidified. 4. A belt mechanism driven by a driving wheel to form an endless track and having an inclined plane, a means for supplying molten metal downward onto the inclined belt plane, and a belt mechanism arranged on the upper side of the inclined plane.
A continuous casting device for molten metal, consisting of a device for extracting slabs and a device for driving a belt upward on a slope via a drive wheel.

Claims (1)

[Claims] 1. In a method of pouring molten copper onto a flat plate forming an inclined endless track and casting a thin plate, the casting direction and the direction of the injection flow are reversed KL, and the lower end of the flow is set to the surface tension of the molten steel. A thin plate casting method characterized by self-holding. 2. The method for continuous casting of a thin plate according to claim 1, characterized in that the position of the leading edge of the molten steel flow is detected, and the inclination angle or moving speed of the endless track plate is adjusted so that the position of the leading edge of the molten steel flow remains constant. 3. Before rolling*b on the exit side of the slab, the slab is rolled in order to remove surface irregularities or to obtain a predetermined thickness K after the slab is completely solidified. Continuous casting method for thin sheets. 4. A belt mechanism driven by a driving wheel to form an endless track and having an inclined plane, a means for supplying molten metal downward onto the inclined belt plane, and on the upper side of the inclined surface,
Continuous casting equipment for molten metal, consisting of a device for extracting slabs and a device for driving a belt upward on a slope via a drive wheel.