JPS6032541B2 - Continuous metal casting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for continuously casting metal and longitudinally cutting coins on the casting line.

Continuous casting of metals, for example continuous casting of steel, has recently made significant progress, but the casting capacity per strand has already reached its limit.

Casting capacity is expressed as a value proportional to the product of the casting speed and the cross-sectional area of the mirror piece, but the casting speed has already reached its limit due to the cooling capacity that controls the rate of shell formation and the occurrence of cracks in the coin piece due to thermal stress, and the cross-sectional area of the rust piece has already reached its limit. is limited by the cross-sectional dimensions of the finished product after rolling. In order to improve casting capacity, a method has been attempted in which slabs that have been continuously cast in integral multiple widths are reheated in the rolling process and cut using rolling rolls, but center segregation and center porosity are exposed in the cut parts. However, this is not desirable because it often remains as a defect in the final product. In this method, the coins are cooled and then reheated, resulting in a large loss of energy.

Furthermore, since the material is cut short enough to be charged into a heating furnace and heated and rolled, oxidation progresses from the cut surface along the center porosity during heating and rolling, causing product defects. Furthermore, the end portion after cutting was abnormally deformed during cutting and rolling, and this had to be cut off, resulting in a significant decrease in the length of the sheet. A method of cutting and rolling using rolling rolls on a casting line has also been considered, but the rolling speed is slow and the temperature of the rolls increases too much, which tends to cause thermal cracks in the rolls. The present invention aims to improve casting performance, prevent internal defects from being exposed on the cut surface, improve keystroke, and save energy.

When continuously casting metal, the present invention provides an overflow path in the mold along the direction of movement of the coin pieces, and forms grooves in the rust pieces.
The present invention is characterized in that the solidification completion time of the metal around the groove is shortened, center segregation and center porosity are removed elsewhere, and the groove is forged and cut without being reheated on the casting line.

In the present invention, for example, a slab conventionally cast with a width of 500 mm is cast with a width of 100 mm, 150 mm, or 200 mm.

Therefore, the casting capacity will be twice, three times, or four times that of the conventional method. In the present invention, the cooling rate at the position where the coin piece is to be cut is increased to obtain a sound casting structure. In order to make the cooling rate faster than other parts, it is possible to increase the amount of cooling water, the cooling water pressure, or the cooling water flow distance, but it is difficult to obtain a sufficient effect with these alone. The first aspect of the present invention
The feature is that, as shown in FIGS. 1 and 2, an overflow path is provided in the mold 1 along the direction of movement of the coin coin 2, and a groove 4 is formed in the coin coin 2, thereby solidifying the metal around the groove. Reduce completion time and
The purpose is to remove center segregation and center porosity 9 to other parts.

By doing this, the following three effects can be obtained. 1 Even if the groove is cut in a post-process, internal casting defects will not be exposed on the cut surface.

2 Thickness of the groove part Day 2 is the thickness day of the flat part, which is thinner and easier to cut the groove part.

3. There is little swelling or widening of the meat due to plastic deformation during cutting, and the shape after cutting is good.

The second feature of the present invention is that hot pressure forging is performed without reheating on the casting line.

Even if a slight casting defect occurs at the cutting position, it will be compressed by pressure forging and will not be exposed on the cut surface. The present invention will be explained in detail. FIG. 1 shows an example of a fully curved continuous casting equipment, in which a mold 1 has an overflow passage at the position where the coin coins are to be cut, and a groove is cast into the coin coins 2, as shown in FIG. The slab 2 is cooled by a secondary cooling zone 5, and then straightened by pinch rolls and a straightener 6 and drawn out. Subsequently, as shown in FIGS. 3 and 5, hammer blades 10 are simultaneously pushed into the grooves 4 of the slab from both sides facing each other by the high-grade forging machine 7, and as the mirror piece advances, it is longitudinally cut. For continuous steel casting,
Since the advancing speed of the coin is about 5 to 3 kn/sec, it is sufficient that the cycle of the hammer blade insertion is about 0.1 to 10, and the amplitude is about 10 to 100. In addition to a crank press as shown in FIG. 3, a hydraulic press using a hydraulic cylinder can be used for the reciprocating motion of the hammer blade. If there are two or more cutting positions, the pressing force can be reduced by shifting the pushing timing of adjacent hammer blades as shown in Figure 5, or by shifting the position of adjacent hammer blades in the mirror piece advancing direction. .

It is preferable to provide a side roll 11 for positioning the key piece 2, as shown in FIG. 4, immediately before the pressure forging machine 7. At the hammer blade position, or after that, as shown in Figure 5, the shift of the coin piece 2,
It is preferable to provide side rolls 11 to prevent the mirror from expanding wider than the planned value or from bending the mirror piece. It is desirable that the depth (day, 2 days) of the groove of the coin is 1'4 or more in order to make the cooling rate sufficiently faster than other parts. After being vertically cut by the pinch forging machine 7, the coins are cut by the horizontal cutting machine 8.
is cut to the desired length. The transverse cutter 8 is not particularly limited, and a conventionally used gas cutter or shear can be used. Note that the present invention can be applied not only to a fully curved continuous casting equipment but also to a vertical type or a vertically curved type. The method described above can improve casting ability, prevent internal defects from being exposed on cut surfaces, improve yield, and save energy for reheating.

[Brief explanation of the drawing]

Figures 1 to 5 are explanatory diagrams for implementing the present invention, in which Figure 1 is the installation position of a pressure forging machine in a fully curved continuous casting facility, and Figure 2 is A-A in Figure 1. 3 is a conceptual diagram of the pressure forging machine, and FIGS. 4 and 5 are sectional views taken along line BB and line CC in FIG. 3, respectively. 1... Mold, 2... Mirror piece, 3... Overflow, 4... Groove, 5... Cooling zone, 6... Straightening machine, 7... ...Pinch forging machine, 8...Transverse cutting machine,
9... Center porosity, 10... Hammer blade, 1
1... Side roll. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. When continuously casting metal, an overflow path is provided in the mold along the direction of progress of the slab to form a groove in the slab, and after the solidification of the vicinity of the groove is completed, the groove is clamp-forged on the casting line. A continuous metal casting method characterized by longitudinal casting.