warhead

Abstract

The present invention relates to a method of producing a part for a warhead, the method comprising the steps of (i) placing an inner shell on a tool, (ii) placing a preformed projectile on the inner shell, (iii) placing powder to encapsulate the preformed projectile, (iv) pressing the powder so that the preformed projectile and the inner shell bond together, and (v) removing the tool from the part formed by the powder, preformed projectile and inner shell. The present invention further relates to a warhead and projectile.

Description

[Technical field]

[0001] The present invention relates to a method of producing a warhead such as a projectile, which comprises combining a powder, a preformed projectile, and an inner shell, preferably using Hot Isostatic Pressing (HIP), and also to a projectile produced by the method. [Background technology]

[0002] The placement of preformed fragments / splinters / projectiles within a warhead has been known for a long time. By selecting the type of preformed projectile to be utilized, a tailored effect can be achieved. Based on the type of target to be attacked, for example, one of the following can be determined: the number of preformed projectiles, the size of the preformed projectiles, the material of the preformed projectiles, and the shape of the preformed projectiles. When the warhead explodes, the preformed projectiles or preformed fragments are dispersed with a predetermined size and mass. It is also possible to influence the direction in which the preformed projectiles are dispersed.

[0003] Besides the arrangement of pre-formed projectiles, an alternative method known to those skilled in the art for forming projectiles of a given size and mass is a method for forming a controlled fragmentation structure of the warhead, which basically involves creating weakened points in the warhead, such as by machining grooves in the material of the warhead, so that fragmentation of the warhead is more likely to occur along these weakened points upon fragmentation / explosion.

[0004] The combination of a preformed projectile arrangement and a controlled fragmentation structure within the same warhead is also known.

[0005] Rubber fixtures are often utilized throughout part of the production process to place pre-formed projectiles. The production of rubber fixtures is itself a relatively costly and labor-intensive process. The flexibility of producing new products or adapting / modifying existing products is similarly limited, as new shapes and geometries require new rubber molding tools. This means long lead times and development efforts, and thus high costs. Thus, creating controlled fragmentation structures by milling grooves into warhead material is often difficult and time-consuming.

[0006] An example of a method for producing a warhead with a preformed projectile is described in US Patent Publication No. 3,815,504, which shows a method for producing a warhead / projectile and the produced warhead / projectile. The produced warhead / projectile is produced by two tubular bodies arranged coaxially with a distance corresponding to the diameter of the included chips / fragments / balls, the chips / fragments / balls being placed between the two tubular bodies. When placed on the outside with an anvil, the tubular body is formed around the chips / fragments / balls by pressure from the inside.

[0007] Another example of a method for producing a warhead with a preformed projectile is described in US Patent Publication No. 4,032,335, which shows a process for producing a composite material consisting of a metal powder with fragments / preformed projectiles arranged together against a metal structure. By subjecting the composite to an isostatic compressing force, the metal powder becomes embedded in the surrounding metal.

[0008] The common features of the above prior arts are that the materials have pores and have low impact toughness and elongation upon bursting, which may cause problems in terms of strength and airtightness.The above prior arts also have production problems such as the number of steps in the process and / or machining method, and material consumption. Summary of the Invention

[0009] It is an object of the present invention to provide a simpler, faster and more cost effective method of producing pre-shaped projectiles and / or warheads having controlled fragmentation structures.

[0010] The present invention relates to a method of producing a part for a warhead, the method comprising the steps of (i) placing an inner shell on a tool, (ii) placing a preformed projectile on the inner shell, (iii) placing powder to encapsulate the preformed projectile, (iv) compressing the powder so that the preformed projectile and the inner shell bond together, and (v) removing the tool from the part formed by the powder, the preformed projectile and the inner shell.

[0011] A further aspect of the method for producing parts for a warhead is as follows.

[0012] The powder is compressed using high pressure and heat in a process known as Hot Isostatic Pressing (HIP).

[0013] The powder, preformed projectiles and inner shells are placed together in a suitable HIP vessel.

[0014] The inner shell is the case for the grenade body.

[0015] The inner shell is a spacer material.

[0016] The preformed projectiles are disposed in an encapsulating network.

[0017] The reticulation is configured to have a mesh and to retain the preformed projectile when the reticulation is disposed around the preformed projectile disposed on the inner shell.

[0018] The present invention further relates to a warhead produced by the above-described method.

[0019] The present invention further relates to a warhead that includes the projectile.

[0020] (Advantages and Effects of the Invention) By producing the warheads / projectiles using hot isostatic pressing (HIP), warheads can be produced with better performance than the prior art, with improved control over performance due to improvements in homogenous warheads without porosity, fewer process steps, and less machining required for each warhead thus produced, resulting in lower production costs and less material consumption.

[0021] The present invention will now be described in more detail with reference to the accompanying drawings. [Brief description of the drawings]

[0022] [Figure 1a] FIG. 1 is a perspective view of an inner shell for a warhead arranged in a tool according to the invention, in a first embodiment of the invention; [Figure 1b] FIG. 1 is a perspective view of an inner shell for a warhead and an inner shell arranged in a tool according to the present invention, in a second embodiment of the present invention; [Figure 2a] 1b is a perspective view of the inner shell of FIG. 1a with a preformed projectile disposed therein in a first embodiment of the present invention; [Figure 2b] FIG. 1b is a perspective view of the inner shell of FIG. 1b with the encapsulation network disposed therein and containing a preformed projectile in accordance with a second embodiment of the present invention; [Figure 3a] FIG. 1 is a perspective view of a warhead with powder placed thereon prior to HIP processing in accordance with a first embodiment of the present invention; [Figure 3b] FIG. 1 is a perspective view of a warhead with powder placed thereon prior to HIP processing in accordance with a second embodiment of the present invention; [Figure 4a] FIG. 1 shows a warhead produced according to the proposed method, going through all the process steps in a first embodiment of the invention. [Figure 4b]FIG. 2 shows a warhead produced according to the proposed method, going through all the steps of the process, in a second embodiment of the present invention. [Diagram 5] FIG. 1 illustrates steps in the hot isostatic pressing (HIP) process for producing a warhead in one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The present invention shows an embodiment of a method for producing parts for warheads such as projectiles and grenades by utilizing hot isostatic pressing. Hot isostatic pressing, also known as HIP, is a production process applied to eliminate or reduce the internal porosity of cast metal pieces or other materials. By HIP, metal, polymer, ceramic, and composite powders can be packed in solid form. The advantages include the elimination of all internal voids of the metal parts produced by the production method, and the improvement of mechanical properties such as fatigue resistance / strength, toughness, plasticity, and impact strength. Also, HIP allows the formation of a coherent material from metal, composite, polymer, or ceramic powders without melting.

[0024] By using HIP, solid materials can be formed from powders with excellent properties of fine, uniform grain size and isotropic structure for the powders / powder components. Also, by using HIP, dissimilar materials can be bonded without the need for temperature-limited binders. Using HIP, multiple diffusion bonds can be made in a single process cycle. Many metal alloys, as well as many composite materials, polymers, and ceramics can be processed by HIP. Materials that can be processed by HIP include alloys of nickel, cobalt, tungsten, titanium, molybdenum, aluminum, copper, and iron, oxide and nitride ceramics, glasses, intermetallic compounds, and premium plastics, among others.

[0025] FIG. 1a shows an inner shell for a warhead according to a first embodiment of the invention, the inner shell being formed as a spacer material, also known as a liner. The warhead is configured to attack a target and may consist of a projectile, such as a grenade, or may be configured as a part within a projectile, such as a grenade. The inner shell 1 is hollow so that an explosive can be placed therein. The inner shell 1 is also configured to receive a nose portion and an aft portion at its front end 2 and rear end 3. The nose portion and the aft portion may have various configurations depending on the desired characteristics of the warhead, which are not shown in the drawings as they are not part of the present invention. The inner shell 1 is preferably made of a material that a person skilled in the art considers suitable for the purpose, typically a metallic material, but may also be made of a plastic or composite material, many examples of which are already known in the art. The tool 10 is placed inside the inner shell 1, is preferably made of homogenous steel, and is configured to be utilizable at high pressures and / or high temperatures. If the inner shell 1 is a spacer material, the spacer material acts like a driving mirror for the projectile. The bottom plate 33 of the HIP vessel is also shown in the drawing.

[0026] Figure 1b shows an alternative embodiment in which the inner hull 1 is configured as a grenade body, preferably made from metal machined by conventional turning or additive manufacturing methods. Indications of where the projectile should be placed are displayed on the inner hull 1. The bottom plate 33 of the HIP vessel is also shown in the drawing.

[0027] FIG. 2a shows one step in the production of a warhead 4 according to the invention. A network 5 containing preformed projectiles 20 is arranged around the inner hull 1, preferably circumferentially enclosing the inner hull 1. The network 5 extends axially along a portion of the inner hull 1, but not at the front end 2 and rear end 3 in the preferred embodiment, in order to connect the front end 2 and rear end 3 to the nose and rear, respectively. The network 5 in the shown embodiment has a mesh 7 adapted to the shape of the preformed projectile 20. The size and shape of the mesh 7 vary slightly in the axial direction of the warhead 4 to correspond to the shape of the inner hull 1, which has a radius that varies slightly in the axial direction. The shape of the mesh 7, as well as its size, may vary within certain limits, the size and shape of the mesh 7 being adapted to the size and shape of the preformed projectile 20. The preformed projectiles 20 are also called fragments and / or pieces. In the configuration shown in FIG. 2a, the preformed projectiles are ball-shaped or spherical. The network 5 is designed to purposely retain the projectile such that the shape and size of the mesh 7 prevents the projectile from passing through the mesh 7. If the preformed projectile 20 is ball-shaped, the mesh 7 may be configured to be fully circular or partially circular, for example as shown in the embodiment of FIG. 2a, to ensure retention of the preformed projectile 20 when it is placed against the inner shell 1 and enclosed by the network 5. The material utilized in the production of the network 5 is preferably metal, but may also be plastic or ceramic, selected for its thermal properties or melting point, brittleness after heat treatment, ability to form alloys with other metals, etc. The network may be made from a plate, which is punched or otherwise machined to have the appropriate configuration. The network may be bent or pressed into a shape suitable for placement to enclose the inner shell 1 and the preformed projectile 20.

[0028] One possible production method for the network 5 is to form holes of the desired size in a plate, which are produced by punching, etching, laser cutting, or other production methods deemed appropriate by the skilled person. The depicted network is particularly suitable for holding preformed projectiles with a cross section slightly larger than the size of the mesh 7. The placement of many preformed projectiles 20 in the warhead is achieved with the aid of the network 5, which may be a standard product or a product that can be produced by a relatively simple and cost-effective production method. The network 5 does not need to be removed, but rather may remain partly integrated with the warhead 4, greatly simplifying the production process. In an alternative embodiment, the network 5 also serves for a controlled fragmentation structure of the warhead 4 in a way that allows for a cost-effective production of the warhead. The bottom plate 33 of the HIP vessel is also shown in the figure.

[0029] FIG. 2b shows one of the steps of the production of a warhead 4 according to a second embodiment, an alternative embodiment of the invention, in which the inner shell 1 is configured as a grenade body. The mesh 5 extends axially along a portion of the inner shell 1, but not at the front end 2 and rear end 3 in the preferred embodiment, in order to connect them to the nose and rear, respectively. The mesh 5 in the shown embodiment has a mesh 7 adapted to the shape of the preformed projectile 20. The size and shape of the mesh 7 vary slightly in the axial direction of the warhead 4 in order to correspond to the shape of the inner shell 1, which has a radius that varies slightly in the axial direction. The shape of the mesh 7, as well as its size, may vary within certain limits, the size and shape of the mesh 7 being adapted to the size and shape of the preformed projectile 20. The preformed projectile 20 is also called fragments and / or pieces. In the configuration shown in FIG. 2b, the preformed projectile is ball-shaped or spherical. The network 5 is designed to purposely retain the projectile such that the shape and size of the mesh 7 prevents the projectile from passing through the mesh 7. If the preformed projectile 20 is ball-shaped, the mesh 7 may be configured to be fully circular or partially circular, for example as shown in the embodiment of FIG. 2b, to securely retain the preformed projectile 20 when it is placed against the inner shell 1 and enclosed by the network 5. The material utilized in the production of the network 5 is preferably metal, but may also be plastic or ceramic, selected for its thermal properties or melting point, brittleness after heat treatment, ability to form alloys with other metals, etc. The network may be made from a plate, which is punched or otherwise machined to have the appropriate configuration. The network may be bent or pressed into a shape suitable for placement to enclose the inner shell 1 and the preformed projectile 20. The bottom plate 33 of the HIP vessel is also shown in the figure.

[0030] FIG. 3a shows the warhead 4 in a production step according to a first embodiment of the invention. The material to be applied 8 is already placed on top of the inner shell 1, the network 5 and the preformed projectile 20 shown in FIG. 2a. FIG. 2a shows the inner shell 1 as a spacer material. The application method is preferably a specific type of additive manufacturing method, in which the material can be applied in the form of a powder inside the HIP vessel. The HIP vessel 30 is an enclosing part arranged to hold the inner shell 1 arranged on the tool 10. In the HIP vessel 30, the preformed projectile 20 enclosed by the network 5 is arranged. The powder as the material to be applied 8 is placed freely in the HIP vessel 30 which encloses the inner shell 1, the tool 10, the preformed projectile 20 and the network 5. By the continuous processing according to HIP, the powder is fixed in the desired place for the production of the warhead 4. The manufacturing method using powder is advantageous in demanding production conditions where the material to be supplied has to be placed in a space of small dimensions. The temperatures applicable according to HIP for the applied material 8 also influence the material in the underlying network 5. With appropriate material selection for both the material in the network 5 and the material in the applied material 8, the material in the network 5 will either remain brittle due to diffusion and / or partial melting or will form an alloy with the applied material 8. The HIP vessel 30 is arranged with connecting devices 31, 32 and a bottom plate 33 for air evacuation and vacuum drawing before and / or during the course of the production method.

[0031] In one embodiment, the material in the network 5 and the applied material or powder 8 are selected such that together with the applied material 8 and the network 5 they form a homogenous whole with no, controlled or limited material changes. A part of the resulting warhead 4 is constituted by the applied material 8 and the network 5.

[0032] In an alternative embodiment, the network 5 and the applied material 8 do not affect each other's physical properties, except that the layer of applied material 8 is thinner on top of the material that makes up the network 5.

[0033] In a further alternative embodiment, the materials of construction and the temperature over which the materials are applied are selected, depending on the material selection, to obtain the result that the applied material 8 and the network 5 together form a whole including a weakened area, the weakened area being where the network 5 was initially placed. The weakened area formed by the applied material 8 and the network 5 in the whole acts as a controlled fragmentation structure upon bursting of the warhead 4. In an alternative embodiment, the portion of the applied material 8 that is placed within the mesh 7 of the network 5 forms the projectile. In a preferred embodiment, this aspect is taken into account when selecting the applied material 8 so that the projectile formed by this method has an appropriate mass. Also, in a preferred embodiment, this aspect is taken into account when selecting the size and shape of the mesh so that the projectile formed by this method has an appropriate size and shape to interact with the preformed projectile 20 to achieve maximum effect.

[0034] FIG. 3b shows the warhead 4 in a production step according to a second embodiment, which is an alternative embodiment of the invention. The material to be applied 8 is already placed on top of the inner shell 1, the network 5 and the preformed projectile 20 shown in FIG. 2b. FIG. 3b shows the inner shell 1 as a grenade body. The application method is preferably a specific type of additive manufacturing method, in which the material can be applied in the form of a powder inside the HIP vessel. The HIP vessel 30 is an enclosing part arranged to hold the inner shell 1 arranged on the tool 10. In the HIP vessel 30, the preformed projectile 20 enclosed by the network 5 is arranged. The powder as the material to be applied 8 is placed freely in the HIP vessel 30, which encloses the inner shell 1, the tool 10, the preformed projectile 20 and the network 5. By the continuous processing according to HIP, the powder is fixed in the desired place for the production of the warhead 4. The manufacturing method using powder is advantageous in demanding production conditions, where the material to be supplied has to be placed in a space of small dimensions. The temperatures applicable according to HIP for the applied material 8 also influence the material in the underlying network 5. With appropriate material selection for both the material in the network 5 and the material in the applied material 8, the material in the network 5 will either remain brittle due to diffusion and / or partial melting or will form an alloy with the applied material 8. The HIP vessel 30 is arranged with connecting devices 31, 32 and a bottom plate 33 for air evacuation and vacuum drawing before and / or during the course of the production method.

[0035] In one embodiment, the material in the network 5 and the applied material or powder 8 are selected such that, together with the applied material 8 and the network 5, they form a homogenous whole with controlled material variations. The applied material 8 and the network 5 constitute a part of the resulting warhead 4.

[0036] In an alternative embodiment, the network 5 and the applied material 8 do not affect each other's physical properties, except that the layer of applied material 8 is thinner on top of the material that makes up the network 5.

[0037] In a further alternative embodiment, the materials of construction and the temperature over which the materials are applied are selected, depending on the selection of materials, to obtain the result that the applied material 8 and the network 5 together form a whole including a weakened area, the weakened area being where the network 5 was initially placed. The weakened area formed by the applied material 8 and the network 5 in the whole acts as a controlled fragmentation structure upon the bursting of the warhead 4. In an alternative embodiment, the portion of the applied material 8 that is placed within the mesh 7 of the network 5 forms the projectile. In a preferred embodiment, this aspect is taken into account when selecting the applied material 8 so that the projectile formed by this method has a suitable mass. Also, in a preferred embodiment, this aspect is taken into account when selecting the size and shape of the mesh so that the projectile formed by this method has a suitable size and shape to interact with the preformed projectile 20 to achieve maximum effect.

[0038] 4a shows the case for the warhead 4 produced according to the first embodiment, which is produced after the hot isostatic pressing production step has been performed, the tool 10 has been removed from the inner shell 1, and the HIP can is subjected to machining, such as cutting type machining. The warhead 4 is called a HIPPED body, and can be finished to form a complete warhead 4, which can be used as a part for producing projectiles such as grenades.

[0039] Fig. 4b shows the case for the warhead 4 produced according to the second embodiment, which is produced after the hot isostatic pressing production step has been performed, the tool 10 has been removed from the inner shell 1, and the HIP container has been subjected to machining, such as cutting type machining. The warhead 4 is called a HIPPED body and can be finished to form a complete warhead 4, which can be used as a part for producing projectiles such as grenades.

[0040] FIG. 5 shows a production method 100 for a warhead. A case for a warhead 4 is produced by a step 101 of providing a case, known as the active part or grenade body. The case is provided, for example, by cutting type machining, such as turning, alternatively by additive manufacturing, or by pressing or drawing. The case may be called the inner shell 1 and may be made of spacer material. After providing the case, a step 102 of placing a tool is performed, in which a tool 10 is placed so that the case encapsulates the tool. The geometry of the tool corresponds to the geometry of the interior of the inner shell / case and thus of the warhead. Preferably, the geometry is configured so that the tool can be removed after the execution of the production method 100. Then, in a step 103 of placing a preformed projectile, a preformed projectile is placed around the case. In a step 104 of placing a net 5, the preformed projectile 20 is held by the net 5. In one embodiment, the preformed projectile 20 and the reticulation 5 are placed together around the inner shell / case. Alternatively, the preformed projectile 20 is held by a reticulation integral with the warhead 4 throughout the production method 100. In a step of placing HIP vessel 105, the preformed projectile 20 and the inner shell 1 with the reticulation 5 are placed inside the HIP vessel 30. The HIP vessel 30 is positioned so that powder is placed therein and the powder is transformed under high heat and pressure to form a HIPPED body. After placing the preformed projectile 20, the reticulation 5 and the inner shell 1 together in the HIP vessel 30, in a step of placing powder in HIP vessel 106, powder is placed in the HIP vessel 30. After the powder material is placed in the HIP vessel 30, in a step of evacuating, vibrating and closing the HIP vessel 30, the HIP vessel 30 is evacuated, vibrated and closed. Thereafter, HIP 108 is performed, ie, gas is used to generate isostatic pressure within the HIP vessel 30 by being introduced into the connection devices 31 , 32 disposed within the HIP vessel 30 .Before introducing the gas into the HIP vessel, the HIP vessel may be evacuated, the gas in the HIP vessel may be evacuated, or the HIP vessel 30 may be filled with gas / liquid before evacuating. At the same time, the entire HIP vessel 30 is heated. In a machining HIP vessel step 109, the HIP vessel and any surplus material are machined. After machining the HIPPED body, the tool may be removed from the case in a tool removal step 110. After completing the machining and tool removal, a heat treatment step 111 of the body is performed, i.e., the assembled body is heated. After the heat treatment, the material is suitable for machining, such as cutting type machining. After tool removal, the HIPPED body may be hardened in a hardening step 112.

[0041] Alternative Embodiments The invention is not limited to the specific embodiments described, but can be varied in different ways within the scope of the claims.

[0042] For example, the number of preformed projectiles, material selection, geometrical selection, elements and components that make up the warhead may be tailored according to the weapon system, platform, and other design attributes of a particular implementation.

[0043] It also includes all forms of warheads, including projectiles, grenades, fragmentation grenades, guided missiles, missiles, and rockets. It also includes other forms of warheads, such as grenades and various types of land mines.

Claims

1. 1. A method of producing components for a warhead, comprising the steps of: (i) placing an inner shell onto the tool; (ii) placing a preformed projectile on said inner shell and then arranging a network to hold said preformed projectile; (iii) placing the inner shell, the preformed projectile, and the network in a Hot Isostatic Pressing (HIP) vessel and then placing powder in the HIP vessel to encapsulate the preformed projectile; (iv) compressing the powder so that the preformed projectile and the inner shell are bonded together; (v) removing the tool from the powder, the preformed projectile, and the part formed by the inner shell; Including, method.

2. The powder is pressed into the mold by a high pressure and heat process known as Hot Isostatic Pressing (HIP). The method of claim 1.

3. The inner shell is a case for a grenade body. The method according to claim 1 or 2.

4. The inner shell is a spacer material. The method according to claim 1 or 2.

5. the reticulated structure is configured to have a mesh and to retain the preformed projectile when the reticulated structure is disposed around the preformed projectile disposed on the inner shell; The method according to any one of claims 1 to 4.

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