EP0283716A2 - Liner for a hollow charge - Google Patents

Abstract

The invention relates to an explosive charge with a projectile-forming metallic insert and optionally a body for detonation wave guidance. In order to produce the insert and the body cheaply, they should consist of a copper single crystal. Due to the anisotropy of the single crystals, the insert has a fold with pronounced stabilizing wings after it has been blown up, which, depending on the crystal axis orientation of the single crystal, [100] or [111], is four or three times.

Description

The invention relates to an explosive charge with a projectile-forming metallic insert which essentially has the shape of a spherical cap.

Such explosive charges are already known from DE-PS 33 17 352. They consist of a cylindrical container filled with explosives. A metallic insert is arranged on its front, which essentially has the shape of a spherical cap. An ignition device for igniting the explosive is arranged on its other side. The mechanism of action of such an explosive charge, in contrast to the cutting charge referred to as a so-called P-charge, consists in the fact that when the explosive is ignited, the insert is folded into a bullet several centimeters long, which has an armor-piercing effect due to its high flight speed and its mass. The difference to the cutting charge is that the latter produces a slender, elongated metallic jet which literally cuts open the target located at short distance due to the action of heat. The P-charge projectile, on the other hand, should fly over a greater distance than a normal projectile and the target due to its force punch through. The temperature of the flying body is irrelevant.

When folding the insert to produce a projectile, there is the problem that the projectile should not be rotationally symmetrical, but should, if possible, be given small stabilizing wings because of good flight characteristics. In the prior art cited above, this takes place in that the insert has regions of different thicknesses over its circular area, so that a non-rotationally symmetrical body can result when the insert is folded. The production of such inserts is not cheap because of their complicated flat design.

The object of the invention is to propose an explosive charge with a projectile-forming insert which has the same effect on the target, but is cheaper to produce than the prior art explosive charge. A good shape of the stabilizing wing should be ensured.

To achieve the object of the invention, it is proposed in a first alternative that the insert consists of a single crystal body. According to a second alternative to the solution of the problem, in the case of an explosive charge of the type mentioned at the outset, which additionally has a body for detonation wave guidance, it is proposed that this body consist of single crystal.

According to a preferred development of the invention, it is proposed that both the project-forming Insert and the body for the detonation wave guidance each consist of a single crystal.

Pure copper has preferably proven itself as the material for the metallic insert, but it is also possible to use copper alloys insofar as they are single-crystal capable. The use of tantalum and iron is also possible.

To produce the projectile body in a non-rotationally symmetrical configuration, it is proposed according to a development of the invention that the crystal axis orientation of the single crystal is [100]. In this case you get a 4-part bullet body, that is 4 stabilizing wings.

If, on the other hand, one wants to produce a projectile body with a 3-fold design, then according to a further proposal of the invention one has to choose a crystal axis orientation [111] of the single crystal.

Single crystals are bodies, preferably made of metal, which are grown using special processes and, in contrast to the polycrystalline bodies present in technology and in everyday life, consist only of a single, but possibly large, crystal. These are chemically high-purity bodies whose behavior largely corresponds to that of the theoretical behavior of the pure crystal of the element in question. These monocrystalline bodies are anisotropic, have no grain boundaries, as is the case with polycrystalline bodies, and their strength is significantly higher in certain crystal axes than is the case with polycrystalline material.

Single crystals can not only be made from pure elements, they can also be made from alloyed metals. They have a more or less pronounced anisotropy depending on the element or alloy, that is, their properties are different along the crystal axes [100], [110] and [111]. These properties are, for example, the modulus of elasticity, the strength or the deformation limit stress. In the case of copper, which has a very pronounced anisotropy as an example, the moduli of elasticity are approximately 6800, 12000 and 18000 kp / mm² when loaded in the direction of the aforementioned crystal axes.

The pronounced anisotropy of single crystals, in particular copper single crystals, is used in the invention in such a way that when the single crystal is loaded by the explosive, with a predetermined orientation of its crystal axes, for example [100], a different decay rate and intensity depending on its lattice structure has, so that a cylindrical single-crystalline body with a correspondingly strong deformation by pressure or tension subsequently has a pronounced asymmetry with respect to its axis of rotation, this asymmetry, however, being reproducibly dependent on the lattice structure. In testing technology, it was found that in the tensile test of single crystals with the crystal axis orientation [100], a round single crystal rod at the constriction takes on the shape similar to a four-leaf clover. With single crystal rods with the crystal axis orientation [111], a body corresponding to a three-leaf clover is obtained during the deformation. This deformation is also reproducible and only results from single crystals of orientation [111].

Using these findings, a single-crystalline insert in the form of a spherical cap is to be used according to the invention, in which the single crystal has a crystal axis orientation [100] or [111]. So you get when folding the insert projectile body with 4 or 3 stabilizing wings, whereby it must be ensured by the shape of the insert, for example in terms of its thickness, that the stabilizing wings do not start at the head of the projectile, but only in the rear part.

By using a body for detonation wave guidance, the aforementioned purpose can also be achieved or even reinforced. If a single crystal is used for such a body, while conventional material is used for the insert, the insert must be designed approximately as shown in the prior art mentioned at the beginning. Due to its decay, the body for the detonation wave guidance makes it possible to influence the subsequent folding of the insert. The said body must be spatially assigned to the insert so that the lines of its weak crystal structure interact with the regions of the insert, which also have a weak structure, for example low material thickness.

In the sense of the invention, however, the use of a single-crystalline body for detonation wave guidance is particularly advantageous if the insert is also single-crystal and made of the same metal. In this case, the crystal axis orientation of the insert and the Body be the same and a spatial assignment of both in the manner described above.

The invention will be explained in more detail below with reference to the drawing.

• Fig. 1 in schematisierter Darstellung eine Sprengladung im Schnitt;
• Fig. 2 eine gefaltete Einlage nach der Sprengung;
• Fig. 3 eine typische Faltung bei verschiedenen Kristallachsenorientierungen;
• Fig. 4 in schematischer Form ein Werkzeug zur Herstellung einer Einkristalleinlage.

Show it:

• Figure 1 is a schematic representation of an explosive charge in section.
• 2 shows a folded insert after the explosion.
• 3 shows a typical convolution with different crystal axis orientations;
• Fig. 4 in schematic form a tool for producing a single crystal insert.

In Fig. 1, an explosive charge in a schematic form is shown in section. One recognizes a container 1 which is filled with explosives 2. An insert made of copper single crystal 3 is provided on one side. An ignition device 4 is arranged on the other side of the container. Finally, a body 5 for detonation wave guidance is provided, which is advantageous in the sense of the invention, but does not have to be used forcibly. The insert 3 has, for example, a diameter of 5 cm and can be of constant material thickness over its entire surface, but in the sense of the invention a thickening inwards or outwards is also conceivable.

A projectile body, as it flies towards the target after the detonation, is shown in idealized form in FIG. 2. Depending on the diameter and thickness of the insert 3, this projectile body 6 can vary in the ratio of length to thickness.

3 shows how a round single-crystalline rod behaves when deformed, depending on its crystal axis orientation. In the case of the axial direction [100], a 4-fold body results similar to a 4-leaf clover. If, on the other hand, the single crystal has an orientation corresponding to [111], a 3-fold body results after the deformation, similar to a 3-leaf clover. Since the deformation of the insert 3 during the detonation does not represent an ideal deformation, the design of the stabilizing wings 7 in FIG. 2 will also differ to a greater or lesser extent from the shapes according to FIG. 3, but in principle with their 4-fold or 3-fold remain.

A possible production method for an insert 3 will be explained with reference to FIG. 4. A body 5 for a detonation wave guidance, which essentially represents a flat circular surface, can be grown in basically the same way as the insert 3. A single crystal seed 9 of the crystal axis orientation, which the later single crystal is to receive, is inserted into a tool base body 8. A crucible-like container 10, into which the vaccine ring 9 projects, sits on the base body 8. This container 10 has in its bottom surface a shape as the monocrystalline insert should receive. A spring-loaded stamp 11 is used to cover the container 10, which is designed such that when its outer ring surface 12 is seated on the container 10, its end surface 13 is at such a distance from the bottom surface of the container 10 that the single-crystal insert in the final state can just fill the existing space. An HF coil 14 is arranged with its windings around the container 10 in such a way that in the basic position - as shown - it can heat and melt the insert. A pure copper body made of polycrystalline material is used as the material to be melted, which already has a shape similar to that of the later insert. This body is now heated by an RF field of the coil 14 and melts. At the same time, the top part of the seedling 9 also melts and communicates its crystal orientation to the bottom part of the molten insert. Now the base body 8 and the container 10 are slowly lowered in the direction of the arrow 15 and now the upper part of the insert 3 is melted down. A crystal growth front with the crystal axis orientation of the seedling progresses in the insert from bottom to top. The base body 8 and the container 10 are slowly lowered and moved out of the RF coil. The melting material of the insert 3 now slowly solidifies into a single crystal. As soon as the single crystal has cooled sufficiently, the stamp 11 is removed from the container 10 and the finished single crystal 3 can be removed from the container 10 after separation from the seed 9. Further processing of the single crystal is no longer necessary.

Claims (7)

1. explosive charge with a projectile-forming metallic insert which essentially has the shape of a spherical cap,
characterized,
that the insert (3) consists of a single crystal body. 2. explosive charge with a projectile-forming metallic insert, which essentially has the shape of a spherical cap, and with a body for detonation wave guidance,
characterized,
that the body (5) for detonation wave guidance consists of single crystal. 3. explosive charge according to claims 1 and 2,
characterized,
that the projectile-forming insert (3) and the body (5) for the detonation wave guidance each consist of a single crystal. 4. explosive charge according to one of claims 1 to 3,
characterized,
that the single-crystalline body (3, 5) consists of pure copper or a copper alloy. 5. explosive charge according to one of claims 1 to 3,
characterized,
that the single-crystalline body (3, 5) has a church axis orientation [100]. 6. explosive charge according to one of claims 1 to 3,
characterized,
that the single-crystalline body (3, 5) has a crystal axis orientation [111]. 7. explosive charge according to claims 3 and 5 or 6,
characterized,
that the insert (3) and the body (5) for the detonation wave guidance have the same crystal axis orientation and are aligned with respect to their lattice structure in the sense of the same directions of action.

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