JPH03133543A - Continuous casting method - Google Patents

Abstract

PURPOSE:To produce a cast material without developing any surface defect, segregation, etc., at high efficiency, even in single metal, depleted alloy, alloy, in which the solidus is apart from the liquidus, etc., by forcedly cooling only the prescribed zone at tip part of outlet of a continuous casting mold. CONSTITUTION:At the time of continuously casting molten metal 2 always holding the surface to the constant level while directly drawing out through the cylindrical mold 4, the casting product 7 is continuously drawn out with pinch rolls 1 and the molten metal 2 is continuously shifted to the tip part at the outlet side according to drawing-out of the casting material 7. Then, the molten metal is started to continuously solidify to approaching to the forced cooling zone 11 in the mold 4 and is perfectly solidified in the forced cooling zone 11. The casting material 7 drawn out from the tip part of outlet side in the mold 4 is cooled with water cooling shower 6. Therefore, by making conducting heat quantity in the forced cooling zone 11 at the outlet side of cylindrical mold 4 large, growth of crystal at inner wall face of the mold 4 is restrained, and friction between the mold 4 and the casting material 7 developed at the time of drawing out, is reduced and the development of surface defect, such as surface flaw, crack, is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field The uninvented area relates to a continuous casting method for metals or alloys.

(b) Prior Art In continuous casting methods for metals or alloys, it is common to repeatedly oscillate Go-9top while drawing out the material. At this time, since crystal formation occurs from the inner wall surface of the mold which is being cooled during solidification, segregation is likely to occur depending on the alloy with a certain composition. Also, it is not a continuous withdrawal method.
, Go-9top was oxidized, so oxidation marks were generated, and in order to remove them, it was necessary to use a solvent on the surface layer, grind it, or the like.

Furthermore, if the cracks on the surface are deep, even after the ingot is subjected to post-processing plastic working, scratches remain on the product, so it is rejected as a defective product.

Furthermore, in the conventional method shown in FIG. 2, since almost the entire zone of the cylindrical mold 4 is externally cooled, the molten metal begins to solidify from the part of the molten metal that is in contact with the inner wall of the mold 4 toward the center. Since the final solidification part 9 occurs in the part, there are disadvantages such as segregation of impurities and internal defects occurring in the center of the cast material 7 (including cast products such as metal or alloy compacts and ingots) due to poor water circulation. there were.

As a method for solving the drawbacks of the Pj manufacturing method as described in (h), a casting method described in Japanese Patent Publication No. 62-57418 has been proposed, and the n-molding method using a nuclear shape is shown in FIG.

According to the method disclosed in Japanese Patent Publication No. 62-57418, the solidified interface of the metal or alloy is circumferentially determined using a heated mold, and the final solidified position is the surface, so the surface condition of the ingot etc. is relatively good. It is said that it is possible to produce homogeneous unidirectional ingots with few internal defects.

However, this method heats the mold so that the internal temperature near the exit is maintained above the solidification temperature of the molten metal, and solidifies near the mold exit. In other words, casting is performed while keeping the solidification interface near the mold exit. Therefore, continuous casting of an alloy whose solidus line and liquidus line are far apart in the phase diagram is extremely difficult.

As mentioned above, the conventional general continuous casting method has the disadvantage that it tends to cause deterioration of the surface condition of the metal or alloy (scratches, cracks, etc.), segregation, and casting defects (cavities, etc.). In the method disclosed in Japanese Patent No. 57418, it was difficult to continuously cast an alloy whose solidus line and liquidus line were far apart.

(C) Disclosure of the Invention The present invention is a technology developed to solve the above-mentioned drawbacks, and is a technology that has been developed to solve the above-mentioned drawbacks. To provide a continuous casting method characterized in that only the exit side of the mold is forcibly cooled when molten alloy is drawn directly from a molten alloy through a cylindrical mold for continuous casting.

The forced cooling area on the outlet side of the cylindrical mold in the present invention is 0 to 30 mm, preferably 10 to 30 mm from the outlet tip of the mold.
It is preferable to install a water-cooled cage/wall at the tip of the outlet side to keep the core ball inside the mold so that the temperature is below the melting point of the metal to be cast or below the solidus temperature of the alloy. A forced cooling device such as this is installed.

According to the present invention, molten metals or alloys, such as single metals, dilute alloys, and alloys whose solidus and liquidus lines are far apart, can be made into various shapes without surface defects or segregation, and even without any internal defects. Metal or alloy ingots can be manufactured with high efficiency.

As described above, the present invention is a continuous casting method in which only a predetermined area at the outlet end of a continuous casting mold is forcibly cooled, an example of which is shown in FIG.

In casting, the molten metal 2, which is held in a molten metal holding furnace (not shown) so that the level of the molten metal is always constant, is continuously drawn out through the cylindrical mold 4, and the casting material 7 is continuously cast using the pinch roll 1. The molten metal 2 moves continuously to the outlet side tip as the casting material 7 is drawn out, and as it approaches the forced cooling zone 11 of the Fj type 4, it begins to harden continuously, and the forced cooling continues. It solidifies completely in area 11.

The casting material 7 drawn out from the outlet end of the mold 4 is cooled by a water-cooled shower 6 .

At this time, in the case of an alloy whose solidus line and liquidus line are far apart, No. 03
A solid-liquid coexistence region shown by is generated. The area around the mold indicated by reference numeral 4 is insulated with a heat insulating material, but there is no particular need for heating or cooling.

In the present invention, the forced cooling zone 1 on the outlet side of the cylindrical mold 4
The amount of heat released at 1 is increased to suppress crystal growth on the inner wall surface of the mold 4, and the friction between the mold 4 and the cast material 7 that occurs during drawing out is reduced.

By doing this, when the 1-% cast material 7 moves within the mold 4, surface defects such as scratches and cracks on the surface that are likely to occur due to friction between the cast material 7 and the mold 4 can be completely prevented. It will be done.

In addition, by controlling the amount of heat released in the forced cooling zone 11 provided on the exit side of the mold 4 (by appropriately setting the cooling curve in the mold 4), the drawer PI manufacturing speed can be easily controlled. Since the amount of heat released is large, general continuous M
It is possible to obtain a casting speed equivalent to that of the casting method.

Furthermore, even when casting an alloy whose solidus line and liquidus line are far apart in the phase diagram, the temperature gradient within the mold 4 can be increased by heat dissipation in the forced cooling zone 11 on the outlet side of the cylindrical mold 4. Therefore, the range of the solid-liquid coexistence region 3 can be significantly narrowed, so that the formation of floating crystals is reduced, and a cast material 7 with homogeneous fine crystals can be obtained.

As the forced cooling method for the mold 4 in the present invention, it is preferable to use a mold with high heat transfer, such as a water-cooled pure copper mold.

Furthermore, the shape of the inner wall surface of the cylindrical mold according to the present invention can be made into various shapes, so that

Of course, it is possible to continuously cast H-shaped lumber 7 of various shapes, such as those of Hayashi 9.

Next, the present invention will be explained by way of an example.

(D) Examples Example 1 The method of the present invention, the schematic diagram of which is shown in FIG. Type 3 phosphor bronze (Cu-
Sn8%-2082%), cross-sectional shape 100mm
Continuous casting was carried out to obtain a cast material of X l Omm.

The conditions are that the molten metal temperature is 1150℃, and the forced cooling area on the outlet side of the cylindrical mold is 0 to 30 mm from the tip of the outlet of the mold.
, preferably 10 to 30+*m inside, and continuous casting (Go-Stop 10-, silate method) was carried out while keeping the temperature inside the mold in the cooling zone below the solidus temperature of the alloy h.

Comparative Example 1 The above-mentioned Japanese Patent Publication No. 62-57418 whose schematic diagram is shown in Fig. 3
By the method disclosed in the publication, a heated mold is used to maintain the internal temperature near the mold outlet below the solidus temperature of the alloy,
Continuous casting was performed under the same conditions as in Example 1 except for the following conditions.

Comparative Example 2 The conventional horizontal type shown in Figure 2? Continuous M manufacturing was carried out using the & casting method at a molten metal temperature of 1150° C. and other conditions similar to those of Example 1, with a withdrawal mode of 0.5 seconds and a stop of 1.5 seconds.

PI production rate in Example 1 and Comparative Example 1.2.

Table 1 shows the results of internal structure and surface state observation.

(The following is a blank space) As can be seen from the results shown in Table 1, the method of the present invention yielded a cast material with a homogeneous internal structure and a good surface condition even at a casting speed of 200 am/min.

On the other hand, in Comparative Example 1, the internal structure and surface condition were good, but the upper limit of the casting speed was 50 mm/min. The upper limit is 501 m/min.

Although the method of Comparative Example 2 had the same casting speed as the method of the present invention, the surface roughness of the obtained cast material was extremely poor and the internal structure was non-uniform. Furthermore, in Comparative Example 2, Go-
200 in the continuous method, not the Stop oscillation method.
When casting was performed at a casting speed of mm/min, the surface defects of the cast material were significantly worse than those of the O7 sylate method, and internal defects also occurred.

(e) Effects of the invention As described above, according to the method of the present invention, not only @-gold metal alloys or ordinary alloys, but also the solidus line in the phase diagram, which was difficult to cast continuously with the conventional method, can be Even with alloys whose liquidus lines are far apart, homogeneous cast materials with no surface defects, segregation, or casting defects can be continuously cast with high yield and high production efficiency, and the technical and economic effects are enormous.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the continuous casting method according to the present invention, Fig. 2 is an explanatory diagram of the conventional general continuous casting method, and Fig. 3 is an explanatory diagram of the continuous casting method according to the present invention. J
62-57418 is an explanatory diagram of continuous g oiliness according to the method disclosed in Publication No. 62-57418. Symbol explanation 1 - Pinch roll 2 - Molten metal 3 - Solid-liquid coexistence zone 4 - Mold 5 - Cooling jacket 6 - Water cooling shower 7 - M material preparation 8 - Mold heater 9 - Final solidification section 10 - Exit side tip of mold 11 - Force Cooling area patent applicant Dowa Mining Co., Ltd. Figure 2 Figure 3

Claims (1)

[Claims] 1. A continuous casting method characterized by forcibly cooling only the exit side of the mold during continuous casting by drawing directly from molten metal through a cylindrical mold.