WO2000041827A1

WO2000041827A1 - Method and device for producing ingot molds for pig casting installations

Info

Publication number: WO2000041827A1
Application number: PCT/EP2000/000027
Authority: WO
Inventors: Volker Hille; Gereon Fehlemann
Original assignee: Sms Schloemann-Siemag Aktiengesellschaft
Priority date: 1999-01-12
Filing date: 2000-01-05
Publication date: 2000-07-20
Also published as: EP1150789A1; EP1150789B1; DE50000264D1; AU1865600A; DE19900780A1

Abstract

The invention relates to a method for producing ingot molds (1) for pig casting installations used for producing pigs. According to the invention, mill bars (2) comprised of copper are used as starting material. Said mill bars are, in particular, comprised of a copper alloy which is suited for cold forming and which has a comparatively high degree of elongation. The mill bars are formed into the shape of ingot molds by means of a conversion process in which the mill bars are formed under tensile conditions or under a combination of tensile and compressive conditions. The invention also relates to an appropriate device for producing the ingot molds for pig casting installations.

Description

Method and device for producing molds for ingot casting plants

The invention relates to a method for producing molds for ingot casting plants, copper or a copper alloy being used as the starting material. The invention also relates to an apparatus for performing the method.

It is state of the art to cast molten pig iron or other metals or metal alloys in the form of bars / plates, which are called ingots, on special ingot casting machines. Such ingots typically weigh 6 kg. E.g. four ingots are poured into a mold, the liquid pig iron solidifies in the mold and both the ingot and the mold are cooled by spray water. The ingot casting molds or molds of known ingot casting machines are usually made of cast iron. They are subject to comparatively high wear and tear and must therefore be replaced again and again in accordance with wear.

Another disadvantage of cast iron ingot molds is that they have a comparatively low thermal conductivity of approximately 40 to 50 W / mK. As a result, the molds and ingots have to be cooled by spray water each time they are transported from the casting station to the discharge station. The spray water is usually applied from above and from below.

From the not yet published patent application DE 198 35 824.5 it is known to provide a casting machine which has a higher production output by improving the cooling conditions of the solidification body in the individual molds. Due to the better cooling, the melt solidifies faster, the circulating speed of the endless belt can be increased and thus the amount of melt cast per Time interval. The improvement in cooling conditions is achieved in that the ingot molds are made of a heat-resistant material whose thermal conductivity is greater than that of cast iron. Copper or a copper alloy is proposed as the mold material, which has a significantly higher thermal conductivity than cast iron.

However, a technical teaching on the economical production of the proposed casting molds made of copper is not included in the aforementioned document.

DE 42 33 522 A1 describes a method for producing a wide mold side wall for a thin slab caster, which does not correspond to the type mentioned at the beginning.

A method is claimed there for producing a broad side wall for a thin slab caster, which has an extension area starting from the top edge and tapering to the sides and downwards. The broad side wall, which is essentially made of copper and is 5 to 50 mm thick, is provided with an extension area by means of tensile forming / tensile pressure forming. It is noteworthy here that the bending angle of the mold wall achieved during the forming is only about 25 ° relative to its base plane. The material is subjected to a comparatively very low elongation.

DE 42 33 739 A1 discloses a non-generic device for the precise, rational manufacture of a wide side wall for the continuous mold of a thin slab caster with an extension area starting from the top edge, tapering to the sides and downwards. To shape it, a die plate is provided, which has a shaped surface for receiving a wide mold side wall, the working side of which is assigned a pressure surface formed from a plurality of individually adjustable partial surfaces. With this device, too, only relatively slight changes in shape of the mold broad side wall are carried out, in which the structure of the broad side wall consisting of copper is loaded only with comparatively low tensile stresses.

Starting from the preceding prior art, it is the object of the invention to provide a method and an apparatus for producing molds for ingot casting plants which, using circuit boards made of copper or copper alloys as the starting material, overcome the difficulties and technical limits in cold-forming them into ingot casting molds Overcomes tensile forming / tensile pressure forming and which enables crack-free and economical production of the ingot molds.

To achieve the object, it is proposed in a method of the type mentioned in the preamble of claim 1 with the invention that copper plates, in particular of a copper alloy suitable for cold working with a comparatively high elongation, are used and these are formed by a forming process by means of tensile forming / tensile forming Form of ingot molds are brought.

It is proposed that, depending on the degree of deformation, a multi-stage deformation with intermediate annealing is carried out.

By dividing the overall forming process into several stages with intermediate annealing to reduce internal structural stresses, according to the teaching of the invention, it is possible to bring a flat circuit board made of copper of considerable thickness, for example 55 to 80 mm, into the shape of ingot molds without cracks. By dissolving the structural stresses after each partial deformation, crack-free molds can be formed in the originally flat board. One embodiment provides that a strain-hardened circuit board made of a copper alloy is soft-annealed before it is used for the first forming step. With a Brinell hardness of approx. 50 HB, the copper plate achieves an elongation at break of at least 35% and it is possible to achieve comparatively large changes in shape without crack formation.

A further development of the method provides that one or more integrally connected, preferably four, molds are molded into a copper plate used as the starting material.

In a further development of the invention, it is provided that the forming process of the copper plate is carried out between a massive die and a likewise massive die under high pressure and with a uniformly slow penetration rate. The slow deformation of the material is advantageous because it gives the structure the opportunity to relieve stress by flowing the material and to prevent the generation of heat.

Furthermore, an embodiment of the method according to the invention provides that the raised shaped elements of the die and the concavely formed recesses of the die cooperating therewith form congruent shaped contours. As a result, an approximately constant thickness of the material area to be deformed is achieved.

Essential to the invention is also the measure that all the shape contours with radii merge into one another both in the form of the die and in the die. Edges and sharp corners must be completely avoided in order to give the material the opportunity to relieve tension caused by cold-flowing material. Sharp edges would prevent this and therefore initiate crack formation. Furthermore, it is provided that the blank is clamped all around at its edge regions during the forming process.

In a further embodiment of the method it is provided that the copper plate is deformed by means of a detonation force, for example triggered by explosives, onto a concavely shaped die, the thickness of the copper plate corresponding to the wall thickness of the mold.

A preferred alternative development of the invention is that the copper plate is deformed by means of hydroforming, triggered by high water pressure, onto a concavely shaped die, the thickness of the copper plate corresponding to the wall thickness of the mold.

A device for the production of molds for ingot casting plants for the production of ingots comprises a pressing tool consisting of a press ram and a die for the cold forming of a copper plate. The die has concavely shaped depressions which form the molds in cross section. The mold or press die which can be interacted with the die has oppositely shaped, raised shaped elements.

Further developing the device, it is provided that the pressing tool has shaping means for the simultaneous configuration during a pressing process of at least one, preferably four, mold troughs. It is expedient that the die and the pressure stamp have two guide elements which are jointly assigned to them and can slide into one another.

An alternative device for the production of molds for ingot casting plants for the production of ingots is characterized in that a hydraulic pressure chamber with a high-pressure water connection is arranged between a die formed at least with a concave die form and a reaction stamp tensioned against the die, and the board made of copper or made of a copper alloy with sealing edges, that is clamped between the reaction stamp and the die via a pressure-resistant seal.

Details, features and advantages of the invention result from the following explanation of an exemplary embodiment schematically illustrated in the drawings. Show it:

Figure 1a in plan view a board with molded molds;

Figure 1 b, the circuit board of Figure 1a in side view, cut;

Figure 2 in side view cut with a stamp and die with

Press tool equipped with hold-down devices and guide elements for the production of molds from a blank,

Figure 3 shows the principle of hydroforming a copper plate into molds.

The circuit board 2 made of copper or of a copper alloy shown in plan view in FIG. 1 a has four adjacent, similar mold shapes 1 in the manner of trough-shaped depressions. As the side view of FIG. 1 b shows, the depressions of the mold shapes have a width / depth ratio> 1, for example, at an upper width B and a depth T.

From Fig. 1 b it can also be seen that the shape of the molds 1 formed according to the pressing tool 9 (FIG. 2) has egg-cup-shaped depressions 6.

Correspondingly, the pressing tool 9 shown in FIG. 2 has a solid die 4 with recesses 6 which are also concave and egg-cup-shaped in cross section and form the mold 1, whereas the die or press die 3 which can be interacted with the die 4 is of the bene shaped elements 5. Between these, the blank 2 to be deformed is pressed into the mold shape with a thickness between 50 and 85 mm. Copper or a copper alloy, for example CuAg, CuCrZr or CuNiBe, is provided as the board material.

It is advantageously provided here that the pressing tool 9 has molding means, namely forming die 3, shaped element 5, recess 6 and shaped contours 7 for the simultaneous configuration in a pressing process of at least one, preferably four, mold troughs.

Obviously, extremely high pressing forces are required for the forming process with the help of the pressing tool 9, which, for example, can be in the order of a few thousand tons and must be applied with a correspondingly powerful, preferably hydraulic press 13 at a uniformly slow penetration speed.

Finally, FIG. 2 shows that the pressing tool 9 has guide elements 10, 11 which are assigned to the pressure stamp 3 and the die 4 together. Furthermore, hold-down devices 12 are provided on the edge regions 8 of the blank 2 in a manner known per se, for example in the case of conventional deep-drawing processes, which prevent inadmissible deformation of these edge regions 8 and hold the blank in position and in tension during the deformation. Pure copper, copper alloys or solidified copper alloys can be used as the circuit board.

Furthermore, it can be seen from FIG. 2 that both in the form of the punch 3 and in the die 4, all the shape contours 7 with radii continuously merge into one another.

FIG. 3 shows an alternative device for the production of molds for ingot casting plants for the production of ingots with which the copper piatine is hydroformed. This device points between a at least with a concave mold 1 formed die 4 and a reaction stamp 14 stretched against the die 4 on a hydraulic pressure chamber 15. This hydraulic pressure chamber 15 is connected to a connection for high water pressure. The board 2 to be deformed, made of copper or of a copper alloy, is clamped on the edge and on all sides between the reaction stamp 14 and the die 4, as is also indicated in FIG. 2. The raised edge of the reaction stamp 13 lies on the edge areas 8 of the copper plate in a seal-tight manner, so that the water pressure in the hydraulic pressure chamber can act on the copper plate without pressure drop and can mold it into the mold 1 in the die 4. In this device as well, as far as possible, all the shape contours 7 are provided with radii which continuously merge into one another.

Claims

claims

1. A process for the manufacture of molds (1) for ingot casting plants for the production of ingots, copper or a copper alloy being used as the starting material, characterized in that blanks (2) made of copper, in particular of a copper alloy suitable for cold forming, are used with a comparatively high elongation and these are brought into the shape of ingot molds by a forming process by means of tensile forming / tensile pressure forming.

2. The method according to claim 1, characterized in that depending on the degree of deformation, a multi-stage deformation is carried out with intermediate annealing.

3. The method according to claim 1, characterized in that a work-hardened plate (2) made of a copper alloy is soft-annealed before being used for the first forming step.

4. The method according to claim 1, 2 or 3, characterized in that one or more integrally connected, preferably four, molds (1) are molded into a copper plate (2) used as the starting material.

5. The method according to one or more of claims 1 to 4, characterized in that the reshaping process of the copper plate (2) between a respective massive punch (3) and also a solid die (4) carried out under high pressure and with a uniformly slow penetration speed becomes.

6. The method according to one or more of claims 1 to 5, characterized in that the raised shaped elements (5) of the molding die (3) and the concavely formed recesses (6) of the die (4) cooperating therewith form congruent shape contours (7) .

7. The method according to one or more of claims 1 to 6, characterized in that both in the form punch (3) and in the die (4) all shape contours (7) with radii continuously merge.

8. The method according to one or more of claims 1 to 7, characterized in that the board (2) is clamped all around at its edge regions (8) during the forming process.

9. The method according to one or more of claims 1 to 8, characterized in that instead of pure copper, copper alloys or solidified copper alloys are used.

10. The method according to any one of the preceding claims 1 to 4, and 8 or 9, characterized in that the copper plate (2) is deformed by means of a detonation force, for example triggered by explosives, onto a concavely shaped die (4), the thickness of the copper plate (2) corresponding to the wall thickness of the mold.

11. The method according to any one of the preceding claims 1 to 4, and 8 or 9, characterized in that the copper plate (2) by means of hydroforming, triggered for example by high water pressure, is deformed onto a concavely shaped die (4), the thickness the copper plate (2) corresponds to the wall thickness of the mold.

12. Apparatus for the production of molds for ingot casting plants for the production of ingots, characterized in that it has a press tool (9) for cold forming a copper plate (2) consisting of a press ram (3) and die (4), that the die (4) concave recesses (6) which form the molds (1) in cross-section, and the form or press ram (3) which can be interacted with the die (4) and has oppositely shaped, raised form elements (5).

13. The apparatus according to claim 12, characterized in that the pressing tool (9) has molding means (3, 5-7) for the simultaneous configuration in a pressing process at least one, preferably of four mold troughs (1).

14. Device according to one of claims 12 or 13, characterized in that the die (4) and the pressure stamp (3) have two mutually associated, mutually slidable guide elements (10, 11).

5. Apparatus for the production of molds for ingot casting plants for the production of ingots, characterized in that a hydraulic pressure chamber (15) is formed between a die (4) formed at least with a concave mold (1) and a reaction stamp (14) clamped against the die (4) ) with a high-pressure connection (16), for example for water, and the circuit board (2) made of copper or a copper alloy is tightly sealed (seal 17) between the reaction stamp (14) and die (4).

Reference list

1 mold

2 circuit boards

3 stamps

4 die

5 shaped element

6 deepening

7 shape contours

8 edge areas of the board

9 pressing tool

10 guide element

11 guide element

12 hold-down devices

13 press

14 reaction stamps

15 hydraulic pressure chamber

16 High pressure water connection

17 seal