JPS61195756A - Method and device for continuous casting - Google Patents

Abstract

PURPOSE:To cast an ingot of which the top surface part is slightly projected by pouring a molten metal into an endless grooved annular casting mold under rotation in a horizontal direction and tilting the mold in the direction where the molten metal in the mold solidifies thereby casting the ingot. CONSTITUTION:The endless grooved annular mold 1 opened in the upper part of a continuous casting device consisting in rotating horizontally the mold 1 by a rotational driving mechanism 6 and pouring the molten metal into the mold 1 having a small section is constituted tiltably by means of a supporting joint 18 and a lifting jack 18 provided to the bottom surface of a mold frame bed 17 on which the mold is placed. The mold 1 is tilted in the direction where the molten metal poured from the pouring point 20 solidifies by which the ingot is cast. The angle theta of inclination of the top end face 14 of the mold with respect to the horizontal face 13 is adequately maintained within the range of the equation 0.03Vc<=theta<=0.12Vc (where Vc denotes casting speed m/min).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method and apparatus for continuous casting of molten metal, mainly molten steel, and more particularly to a method and apparatus for continuous casting of molten metal using a horizontal rotary continuous casting apparatus for casting small cross-section billets. Regarding.

Conventional technology There is a horizontal rotary groove type method for continuously casting small cross-section billets. This horizontal rotation type continuous casting method has a cross section of 10 to f.
It is suitable for billet casting with a small cross section of about lo + w + + angle, and is characterized by low equipment costs and high productivity.1 For example,
Iron and 5teel Engineer,
May 1978, P. 72 and US Patent 34
78810.

In the conventional horizontal rotary continuous casting method, a ring-shaped mold with an open top and an endless groove is used, and molten metal is continuously injected into the mold groove, and the metal is poured while the mold is moved horizontally. Let solidify. Then, the formed solidified slab is pulled out by the rotational movement of the mold. Therefore, generally, the manufactured slab often has a shape in which the upper part of the slab is depressed due to solidification shrinkage.

When rolling products such as steel bars from such slabs, in order to apply sufficient rolling to the upper recessed part,
The required reduction amount had to be larger than in the case without a depression. Furthermore, even when rolling with sufficient rolling reduction, if the top of the slab is concave, defects may occur on the product surface due to collapse of the top edge during rolling or extremely deep depressions at the top. There were problems such as a decrease in yield when producing high-quality products.

Problems to be Solved by the Invention The above-mentioned problems with the conventional method are due to the fact that the upper surface of the slab is depressed. Therefore, in order to solve the above-mentioned problem, the present invention provides a casting method and an apparatus for casting the slab with a slightly convex upper surface, thereby reducing the amount of reduction required during rolling. , and to improve product quality and yield.

Means and Function for Solving the Problems The present invention provides a mold for a conventional horizontal rotary continuous casting device that is tiltable, and furthermore, uses such a casting device to adjust the inclination angle of the mold to correspond to the casting speed. The casting method is characterized by setting the mold and tilting the mold so that the position of the slab after pouring the molten metal is lowered. Hereinafter, the present invention will be explained with reference to the drawings.

Figure 1 shows a plan view of the horizontally rotating continuous casting device of the present invention in which the mold surface is slightly inclined. Note that the mold ring of this continuous casting device does not rotate in a completely horizontal plane, but is inclined from the horizontal plane. However, since the amount of inclination is slight, it is considered to be a type of conventional horizontal rotary continuous casting machine and is referred to by the same name.

In FIG. 1, numeral 1 denotes a ring-shaped mold which rotates in the horizontal direction. By tilting the tilting pot 5, the molten metal is injected into the mold groove 4 through the tundish 12, and is cooled while the ring-shaped mold l rotates in the direction shown by the arrow 3, and the slab after solidification is drawn out. After being pulled out and corrected in shape by the straightening device g17, it is cut by the cutting device 8 and transferred to the conveyance table 9.
It is carried out by.

FIG. 2 is an explanatory elevational view of the ring-shaped mold 1 and the mold frame bed 17 of the apparatus shown in FIG. 1. As shown in FIG. It is characterized by casting.

In this case, the inclination of the mold is in the direction in which solidification progresses as the mold rotates after the molten metal is poured from the tundish.
That is, the entire ring-shaped mold is tilted so that the direction of movement of the slab after injecting the molten metal is downward to a lower position. In Figure 2, the left side is tilted to a lower position.

When performing casting with the mold tilted in this way, the mold tilt angle (
It has been found that θ) has an appropriate range as shown in the following formula.

0.03Vc≦θ≦O, 12Vc where θ is the mold inclination angle, and in FIG. 2, it is the angle formed between the horizontal line 13 at the molten metal injection point 20 and the mold groove upper end surface 14 at the lowest part of the ring-shaped mold, Vc is the casting speed (that is, the peripheral speed of mold rotation) rs/win.

The amount of inclination in the above formula is small at 6 to 25 mm per meter when the casting speed is 12 shoes/win, but even static pressure due to such a small amount of inclination can reduce the amount of depression on the top surface of the slab. It has the effect of significantly reducing it and even making it more convex.

The effect of making the upper surface of the slab convex due to the inclination of the mold can be explained as follows. Since the bottom and side surfaces of the slab are directly cooled by the mold, solidification progresses quickly, but the top surface of the slab is left to cool, so solidification is delayed and a thin, weak solidified shell results. As the slab moves from the injection point, it descends due to the slope.

Static pressure is applied through the molten metal in the unsolidified part of the slab,
It has the effect of inflating the thin and weak shell on the top of the slab into a convex shape.

The range of the inclination angle in the above formula was determined by repeatedly casting molten steel.The optimal inclination angle greatly depends on the casting speed, and the opening formula takes this into account. If the inclination angle is smaller than the indicated inclination angle, no improvement in the upper shape of the slab can be expected. On the other hand, if the pressure exceeds the above range, the thin solidified shell at the top of the slab will break due to the static pressure, molten metal will flow out, and the shape of the top of the slab will deteriorate. Therefore, the inclination angle range suitable for improving the top shape of the slab is within the range of the above formula.

Next, a horizontal rotary continuous casting apparatus used to carry out the method of the present invention will be explained. As described above, the method of the present invention is a method in which the mold inclination angle is set in accordance with the casting speed, and the entire ring-shaped mold is tilted for casting.

Therefore, an apparatus for carrying out this method is required to be capable of tilting the ring-shaped mold arbitrarily so that the mold inclination angle, which is set in accordance with the casting speed, can be arbitrarily adjusted.

As a means for providing a ring-shaped mold so as to be tiltable, for example, the center of mold rotation of the apparatus shown in FIG. 1 is connected to the injection point of molten metal! The ring-shaped mold can be tilted arbitrarily by providing a tilting axis for the ring-shaped mold on or near i2 and by providing a device for moving the ring-shaped mold up and down on either side of this axis.

Furthermore, another example of the apparatus of the present invention will be specifically explained with reference to FIG. In FIG. 2, the ring-shaped mold 1 is installed on a mold frame bed 17, and at the bottom of this frame bed, a support joint 18 is provided on one side outside the center, and a lifting jack 19 is provided on the other side. , support joint) 18 as a fulcrum, and by raising and lowering the mold frame bed 17 with a lifting jack 19, the ring-shaped mold 1 can be tilted arbitrarily via the mold frame bed.

Example: The cross-sectional shape of the slab is equivalent to 40 mm square, and the ring mold diameter is 7.
Using the horizontal rotary continuous casting equipment shown in Figures 1 and 2 with a mold inclination angle of 0.7° and a mold tilted state, AQ-5i killed ordinary carbon steel was cast at a casting speed (mold rotation Figure 3(a) shows the vertical cross-sectional shape of a slab cast at +2+s/l1in.

In addition, as a comparative experiment, the results of the conventional method in which there was no mold inclination and the mold ring was cast in a horizontal condition were shown in Figure 3 (b). By using the casting equipment, the top shape of the slab is significantly improved.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, as described in detail, the depression on the top surface of the slab, which was a drawback when using a conventional horizontal rotary continuous casting device, can be reduced, and furthermore, the top surface of the slab can be slightly convex. It became possible to produce slabs with This facilitates rolling in the subsequent process, and also makes it possible to produce products with good surface quality at a high yield.

[Brief explanation of drawings]

FIG. 1 is a plan view of the device of the present invention, FIG. 2 is an elevational view of the device of the present invention, and FIG. 3(a) is an explanatory diagram of the cross-sectional shape of the slab of the present invention.
FIG. 3(b) is an illumination diagram of the cross-sectional shape of a conventional cast slab. l...Ring-shaped mold, 2...Mold tilt axis, 3...
Mold rotation direction, 4...Mold groove, 5...Tilt steel, 6...
... Mold rotation drive mechanism, 7... Slab drawing straightening device, 8
-・e slab cutting device, 9...transport table, 10...
- Pan head movement mechanism, 11... Cooling water piping, 12... Fist tray, 13@... Horizontal surface, 14... Mold groove upper end surface, 16... Vertical line, 17... Mold frame bed, 1B ... Support joint, 13... Lifting jack, 20... Molten metal injection point.

Claims (1)

[Claims] 1. Injecting molten metal into a continuous small-section device for molten metal, which has an endless grooved ring-shaped mold with an open top and which can rotate horizontally and freely tilt. A continuous casting method characterized in that casting is performed by tilting a mold in the direction in which the molten metal subsequently solidifies. 2. The method according to claim 1, wherein the mold inclination angle is maintained within the range of the following formula. 0.03Vc≦θ≦0.12Vc (where θ is the mold inclination angle, and Vc is the casting speed (m/min)
represents. ) 3. An endless grooved ring mold with a mechanism that can rotate horizontally and an open top, a mold frame bed on which the mold is placed, and a mold frame bed provided at the bottom to tilt the frame bed. Continuous casting equipment consisting of a support joint and a lifting jack.