JPS6268657A - Continuous casting method and device - Google Patents

Abstract

1. Method for continuous casting in a continuous-casting mould having a mould cap (22) whose inner wall, while forming an overhang (8), protrudes beyond the inner wall of the continuous-casting mould, in which method the inner wall of the continuous-casting mould is cooled and lubricated, a gas under pressure, such as air, nitrogen or inert gas being fed at the overhang (8) of the mould cap (22) together with lubricant into the shaped hollow space into the continuous-casting mould, and a dummy block being used during casting, characterized in that a vacuum is produced in the gap between dummy block and mould running surface (7), and in that the parting compound and/or lubricant and the gas, before entry into the shaped hollow space of the continuous-casting mould (1), is mixed in a volumetric ration of 1-4:1000 while forming a gas/oil mist, and this mixture, starting at the overhang of the mould cap (22), is blown out in the discharge direction parallel to and along the mould running surface (7), a laminar flow being maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides continuous casting for continuous casting in a continuous casting mold, the inner wall of which has an attachment member protruding from the inner wall of the continuous casting mold under the formation of an overhang. Cooling and lubricating the inner walls of the casting mold, using a gas under pressure, such as air, nitrogen or an inert gas, at the transition from the mold fitting into the cavity for continuous casting. It relates to a method of introduction into a mold and an apparatus for carrying out the method.

PRIOR ART A method and a device of the above type are described in German Patent Application No. 273 438 δ [Showa
'). Under favorable preconditions, this known method only produces a somewhat smooth ingot surface.

During casting, monitoring and control of gas pressure and lubricating oil flow rates, as well as continuous temperature measurement, are required in the casting process, for example.
It is necessary to adjust the parameter. This often creates operational difficulties, which in continuous casting processes are further exacerbated by fluctuations in metal liquid level and changes in metal static pressure.

Furthermore, it has been found that the method according to DE 27 34 388 A1 cannot satisfactorily cast lead-containing alloys with a lead content of up to 2.5%. However, this alloy is particularly important for the production of continuously cast products to be machined.

Problems to be Solved by the Invention The object of the present invention is to develop a continuous casting method and apparatus that can avoid the above-mentioned drawbacks and provide a smooth and clean ingot surface regardless of the respective casting conditions. be. The special surface quality is excellent by preventing sticking spots and reducing surface elution to such an extent that post-treatment is possible without turning the ingot.

Means for Solving the Problem According to the present invention, this problem is solved by applying the feature set forth in the characteristic part of claim 1, that is, applying a mold release agent and/or a lubricant and a gas to the cavity of a continuous casting mold. Before flowing into the mold, the mixture is mixed at a volume ratio of 1 to 4:1000, and this mixture is ejected starting from the overhang of the mold mounting member in the direction of withdrawal, parallel to and along the running surface of the mold. This is solved by By arranging the annular gap in the direction of the running surface of the mold and premixing the mold release agent and/or lubricant and gas, the casting chimney meter, in particular the control of the gas and lubricant quantities, can be used to control the metal liquid height. It turns out that it is not necessary even if you do. Experiments with gaseous lubricants such as acetylene, butadiene, pronoξone, and trichlorethylene have shown that under the conditions prevailing in the mold (pressure and temperature), satisfactory mold release action is due to decomposition of the gaseous lubricant. showed that it is impossible. If conventional lubricants are fed parallel to the mold axis without gas, combustion of the lubricant occurs during the start-up phase, followed by underfeeding. Therefore, it is not possible to obtain optimal lubricant conditions by lubricant supply alone.

In the method according to the invention, it has been found to be important that the mold running surface below the overhang is absolutely smooth and has no perforations, steps or grooves.

In particular during casting, a laminar flow must be maintained through the casting parallel to the running surface in order to prevent the incoming metal from coming into contact with the mold walls. This effect becomes noticeable by providing a minimum distance of 2 to 5 mW between the dummy and the mold running surface, and the cold water (water pump effect) jetting out during this gap, especially at the mold outlet end, It is strengthened by creating low pressure.

Next, the present invention will be explained in detail with reference to examples.

EXAMPLE FIG. 1 shows a cross section of a mold according to the invention. A mold with a mounting member consisting of a hot spatula 42 and a gas guide block 3 with gas channels 13 is recognized. The mold l contains perforations 4 for a mold release agent and/or lubricant and channels 5 for water cooling. An annular gap 6 is formed between the mold 1, the hot spatula P2 and the gas guide block 3, and this annular gap 6 extends parallel to and continuous with the running surface 7 at least in the vicinity of the outlet hole. . In this case, in order to enable an approximately laminar flow of the mixture of mold release agent and/or lubricant and gas,
It is important that there are no projections, perforations or grooves on the running surface and on the exit part of the annular passage.

In operation, gas is blown through the annular channel 6 into the hemeniscus-like cavity 9 in the space below the bulge 8 .

In this case, the gas entrains part of the liquid release agent or lubricant, for example oil, at the lubricant supply point (bore 4). A gas/oil emulsion is formed which flows out in a laminar flow below the overhang 8 in the drawing direction and parallel to the running surface of the mold and which flows between the mold 1 and the dummy... Gu-
It reaches into the gap between. The low pressure prevailing here, created by the water flow exiting the channel 5, allows for the formation of an annular gas/oil fog which completely shields the mold wall 7 from the liquid metal.

In a number of experiments, it has been found that the gas/oil mixture feed according to the invention does not need to be controlled by varying the pimp pressure or the feed rate even when the metal liquid level fluctuates. It is clear that if a gas/oil mist is applied in combination with a suction action along the running surface, a damping effect between the metal and the running surface is always maintained even when the metal static pressure changes. It is.

The method according to the invention applies particularly to a group of alloys that are susceptible to cracking. The following is an example of a strand P having a diameter of 25.4 crn (10 inches), where the ratio of mold release agent to gas was 3:1000.

A1Mg 5 Casting speed 70 mz/
minAICuMg 2 Casting speed 65m
m/min AlZnMgCu 1.5 Casting speed 65 mm/min AlCuMgPb Casting speed 65 m1/min These casting speeds could be kept constant immediately after starting. Other casting parameters are:
I couldn't adjust it. The obtained ingot surface exhibited high surface properties.

2 to 5 show other embodiments of the invention. Compared to FIG. 1, the mold mounting member 22 in FIG. 2 is constructed in one piece. The perforations for the gas passages 14 are present in the mold mounting part 22 and open into a wide front chamber 15 between the overhang 8 and the mold running surface 7. Here, the formation of a mixture with the mold release agent and/or lubricant flowing out from the perforations in the mold 1 takes place. Water 11 is ejected from the passage 5 to cool the strand 10.

FIG. 3 shows another embodiment of the device according to the invention. Here, the mold mounting member is horizontally divided into two parts 22a, 22
It is divided into b. The gas pipe ↓6 extends into the upper part 22a in the strand discharge direction and is interrupted only by the gas distribution chamber 22C. The mold 1 has a mold mounting member 22a.
.

It has a supporting wall 12 for reliably positioning b. Other parts, such as the lubricant borehole 4 and the gap 9, correspond to the construction according to FIG.

In FIG. 4, a gas guide block of another construction is provided in the form of an insert 17 between the mold l and the hot spatula 1-42. In FIG. 5, an insert 18 is arranged in a corresponding manner between the mold 1 and the hot head. In the case of FIG. 5, unlike in FIG. 4, the gas passage 19 is placed horizontally in the mold 1.
and into the vestibule 20 through the insert member 18;
From the front chamber 20 the gas passes into the annular gap 6.

Mixing with the lubricant supplied by the drilling hand takes place variably between 2 and 10 m 711 in front of the outlet hole of the annular gap opening. All other symbols correspond to those described in connection with the previous figures.

[Brief explanation of drawings]

The accompanying drawings show embodiments of the device according to the present invention; FIG. 1 is a sectional view of the device according to the first embodiment, FIG. 2 is a sectional view of the device according to the second embodiment, and FIG. 3 is a cross-sectional view of the device according to the third embodiment, FIG. 4 is a cross-sectional view of the device according to the fourth embodiment, and FIG. 5 is a cross-sectional view of the device according to the fifth embodiment. . l... Mold, 2... High temperature head, 3... Gas guide block, Φ... Perforation, 5... Passage, 6... Annular gap, 7... Mold running surface, 8...・Overhang part, 9...
Meniscus-shaped void, 10... Strand, 11...
Water, 12... Support wall, 13... Gas passage, 14...
・Gas passage, 15...Ante chamber, 16...Gas passage, 1
7... Insertion member, 18... Insertion member, 19... Gas passage, 20... Front chamber, 21... Annular gap opening, 22a
, b... Mold mounting member part, 22C... Gas distribution chamber.

Claims (1)

[Claims] 1. Cooling the inner wall of the continuous casting mold for continuous casting in a continuous casting mold having a mold mounting member whose inner wall protrudes from the inner wall of the continuous casting mold while forming an overhang. death,
continuous casting method in which a gas under pressure, such as air, nitrogen or an inert gas, is introduced into the continuous casting mold at the transition from the mold mounting member into the mold cavity, and is lubricated. , the mold release agent and/or lubricant and the gas are mixed in a volume ratio of 1 to 4:1000 before flowing into the cavity of the continuous casting mold, and this mixture is drawn out starting from the overhang of the mold mounting member. A continuous casting method characterized by ejecting water in a direction parallel to and along a running surface of a mold. 2. The method according to claim 1, wherein a low pressure is created in the gap between the dummy bar and the mold running surface. 3. The method according to claim 1 or 2, wherein a certain amount of mold release agent and/or lubricant and gas are used during casting and continuous casting. 4. In a continuous casting mold having a mold mounting member whose inner wall protrudes from the inner wall of the continuous casting mold while forming an overhang, cooling the inner wall of the continuous casting mold and applying a lubricant; In an apparatus for carrying out a continuous casting process, in which a gas under pressure, such as air, nitrogen or an inert gas, is introduced into the continuous casting mold at the transition from the mold fitting into the mold cavity. In the mounting member (22) present on the mold (1), a passage-like opening is arranged starting from the meniscus-shaped cavity (9) and extending parallel to and along the drawing direction of the strand. Continuous casting equipment. 5. In a continuous casting mold, the inner wall has a mold mounting member protruding from the inner wall of the continuous casting mold while forming an overhang,
Cool the inner wall of the continuous casting mold, apply lubricant,
In an apparatus carrying out a continuous casting process, in which a gas under pressure, such as air, nitrogen or an inert gas, is introduced into the continuous casting mold at the transition from the mold mounting member into the mold cavity, the mold mounting An annular gap (6) is arranged in the bulge of the part (22), the walls of which are aligned, at least in the area of the exit hole, primarily parallel to the drawing direction and along the mold running surface (7). A continuous casting device characterized by: 6. Device according to claim 5, characterized in that the opening of the annular gap (6) is guided 10 to 30 mm parallel to the mold axis up to the outlet hole. 7. The merging of the mold release agent and/or lubricant and gas,
7. The device according to claim 5, wherein the arrangement is carried out within 2 to 10 mm in front of the exit hole of the annular gap opening (21). 8. Device according to claim 7, characterized in that the mold running surface (7) behind the overhang (8) is smooth and closed on all sides. 9. 2 to 5 m between the mold running surface (7) and the starting block
9. The device according to claim 5, wherein there is a gap of m and the dummy bar has a raised edge surrounding the upper edge.