Barrels, methods of manufacturing barrels and barrel segments and launching device comprising barrels

Abstract

The present invention relates to a method for producing barrel segments (1), wherein the method comprises the steps of i.) a capsule structure (10) is arranged enclosing a template core (20), ii.) powder is arranged in the cavity between the capsule structure (10) and the template core (20), wherein the template core (20) is fully or partially arranged with grooves for embossing groove patterns on the barrel segment (1) and wherein a foil (23) is arranged on the template core (20), (iii) the powder is pressed by means of high pressure and heat, also known as hot isostatic pressing, HIP, so that the powder, foil and capsule structure are joined together iv.) the template core (20) is removed to produce a barrel segment (1). The invention further relates to a barrel and a launching device.

Description

[0001] BARRELS, METHODS OF MANUFACTURING BARRELS AND BARREL SEGMENTS AND LAUNCHING DEVICE COMPRISING BARRELS

[0002] TECHNICAL AREA

[0003] The present invention relates to a method for producing barrel segments comprising arranging a capsule structure enclosing a template core provided with a foil, and wherein powder is arranged in the cavity between the capsule structure and the template core provided with foil, and the powder is pressed so that the powder and the capsule structure are joined together and the template core is removed for producing a barrel segment. Further, the invention relates to a method for manufacturing a barrel, a barrel and an ejection device.

[0004] THE BACKGROUND, PROBLEM AND PRIOR ART OF THE INVENTION

[0005] Barrel based weapons are fired by burning gunpowder, thereby creating a gas expansion where the gas expansion moves a projectile in a barrel. Barrels arranged with rifling are preferably arranged with a rifling having a pitch over the extent of the barrel, which causes the projectile to rotate during the ejection process. Rotation of the projectile is desirable in order to achieve a rotationally stabilized projectile, that is to say that the projectile rotates, after the projectile has left the barrel. As an alternative to a rotationally stabilized projectile, the projectile can be stabilized with, for example, fins, in which case it may be desirable that the projectile does not rotate when the projectile leaves the barrel, which is why the projectile in this case can be arranged with a sliding rim, which means that the projectile is not, or only to a certain extent, rotated during the ejection phase of the projectile when the projectile is fired in a grooved barrel. In this case, when the projectile leaves the barrel, the projectile is stabilized by fins arranged on the projectile. Alternatively, the projectile can be fired from a barrel without ribs / rifling, also known as a smoothbore, which means that no rotational force is transmitted to the projectile during the ejection process. Conventionally, barrels are manufactured by cutting a forged material. These manufacturing methods are costly and time-consuming and result in a barrel that is adapted to the manufacturing constraints and not to the functional requirements of the barrel.

[0006] Conventional barrel grooving involves several stages of machining including drilling, turning, honing and grooving with specially adapted equipment, which entails high costs but also limited possibilities to change the groove / rifling design.

[0007] An example of a manufacturing method for grooved / rifled barrels is given in patent EP 0 339 692 A2, which describes a method of manufacturing a barrel in which an inner template is made on which layers of powdered refractory materials are arranged.

[0008] The above prior art does not demonstrate that powder is arranged between the inner template and a capsule structure during manufacture.

[0009] Further problems that the present invention is intended to solve are set out in connection with the following detailed description of the various embodiments.

[0010] THE PURPOSE OF THE INVENTION AND ITS CHARACTERISTICS

[0011] The purpose of the present invention is to provide an improved way of manufacturing an improved barrel, with the possibility of adapting the length and the groove design according to the technical requirements of the barrel and not according to manufacturing limitations.

[0012] The invention relates to a method for producing barrel segments, wherein the method comprises the steps: i.) a capsule structure is arranged enclosing a template core, ii.) powder is arranged in the cavity between the capsule structure and the template core where the template core is fully or partially arranged with grooves for embossing groove patterns on the barrel segment and where a foil is arranged on the template core,

[0013] (iii) the powder is pressed by means of high pressure and heat, also known as hot isostatic pressing (HIP), so that the powder, foil and capsule structure are joined together

[0014] (iv) the template core is removed to produce a barrel segment.

[0015] According to further aspects of the method of making barrel segments according to the invention applies; that the barrel segments are heat treated and hardened after Hot Isostatic Pressing for the completion of a barrel segment. that the foil is made of tantalum.

[0016] The invention further comprises a method of manufacturing barrels characterized in that the method comprises the steps; i.) a barrel jacket is heated; ii.) a first barrel segment, comprising chambers, is arranged in the heated barrel jacket, iii.) barrel consisting of a barrel jacket arranged with barrel segments are cooled. According to further aspects of the method of making barrels according to the invention applies; that at least one second barrel segment is arranged after the first barrel segment in the barrel jacket before the barrel consisting of a barrel jacket arranged with barrel segments is cooled.

[0017] The invention further consists of a barrel.

[0018] The invention further consists of a launching device comprising a barrel.

[0019] BENEFITS AND EFFECTS OF THE INVENTION

[0020] By manufacturing barrels or barrel components using HIP with a foil-coated template core, an improved barrel can be manufactured where the length of the barrel can be adapted based on the needs that exist instead of based on manufacturing technical limitations that currently limit the length of the barrel. Furthermore, the barrel can be grooved in a simpler way and with greater freedom to choose the groove design compared to today's manufacturing methods for barrel grooving. Furthermore, better material performance can be achieved with regard to the inner surface of the barrel.

[0021] LIST OF FIGURES

[0022] The invention will be described in more detail below with reference to the accompanying figures:

[0023] Fig. 1 shows a schematic view of the manufacture of barrel segments, according to one embodiment of the invention.

[0024] Fig. 2a shows a capsule construction, according to one embodiment of the invention. Fig. 2b shows a cross-sectional view of a capsule structure, according to one embodiment of the invention.

[0025] Fig. 3 shows a barrel, according to one embodiment of the invention.

[0026] Fig. 4 shows a template core, according to one embodiment of the invention.

[0027] Fig. 5 shows the process steps of Hot Isostatic Pressing, HIP, in the manufacture of a barrel segment, according to one embodiment of the invention.

[0028] Fig. 6 shows the process steps in manufacturing a barrel from barrel segments, according to one embodiment of the invention.

[0029] DETAILED DESCRIPTION OF THE EXECUTION

[0030] The present invention discloses embodiments of manufacturing methods for barrels and / or components for barrels such as barrel segments.

[0031] A launching device, also known as a cannon, howitzer, or gun, such as an artillery piece, is designed to fire a projectile with a propellant. Preferably, a propellant, such as gunpowder, is initiated in a part of the gun, often a chamber specially adapted for this. Initiation is achieved by igniting the propellant, for example with a primer or igniter in an ammunition unit, which is initiated by impact. Other methods of igniting the propellant may be by laser or electrical energy igniting the propellant. The propellant burns with high velocity and high gas evolution, creating a gas pressure in the chamber that drives the projectile out of the barrel of the launcher. The propellant is adapted to generate, as far as possible, a constant pressure on the projectile throughout the barrel trajectory, as the projectile moves in the barrel, creating a high velocity of the projectile as the projectile leaves the barrel mouth.

[0032] Projectiles, such as various types of grenades, usually include some form of warhead and some form of fuze that initiates the warhead. Fuzes can be of different types, where fuzes are commonly used for projectiles that are intended to explode on contact with an object, time fuzes where the projectile is intended to explode at a certain predetermined time, and proximity fuzes where the projectile is intended to explode when an object comes within a certain distance of the projectile. Proximity fuzes are preferably used to combat aircraft and usually for medium caliber ammunition, such as 40 mm and 57 mm, while time fuzes and impact fuzes can be used to combat a large number of different objects. It is advantageous to combine different types of fuze functions in the same fuze, so that if a fuze with a zone tube function does not detect an object, the projectile will burst after a certain time, etc.

[0033] The warhead preferably includes some form of explosive and some form of shrapnel casing enclosing the explosive. Furthermore, various forms of guidance means, such as fins may be arranged in the fuze or in a separate sub-component.

[0034] In order to stabilize the projectiles after the projectiles have left the barrel, the projectiles are preferably arranged with rotation or with fins. In the case that the projectiles are arranged with rotation, the projectiles are said to be rotationally stabilized and in the case that the projectiles are arranged with fins, the projectiles are said to be fin- stabilized. Fin- stabilized projectiles should not have rotation or low rotation as they leave the barrel.

[0035] To achieve rotation of the projectiles, rifling is preferably arranged in the barrel to which the projectile mechanically couples during the ejection process. Grooving means that the barrel of a firearm, the barrel, is provided with spiral grooves. The opposite is smooth-bore barrel. When the grooves in the barrel engage with the projectile during firing, the projectile is rotated along its longitudinal axis. This rotation prevents minor irregularities or damage to the projectile from causing a drift in its trajectory. Rotation is also necessary for an oblong (torpedo- shaped) projectile to maintain its direction after leaving the barrel and not start tumbling around, this is referred to as the projectile being rotationally stabilized. In smoothbore weapons, only round (spherical) projectiles or fin-stabilized projectiles can be fired. An oblong projectile without fins will tumble as it leaves the muzzle.

[0036] Thus, rifling is the grooves arranged in the barrel of the gun, and the elevation between the grooves is called a boom. Typically, the rifling of small arms consists of four right-handed ribs, while guns, such as artillery pieces, have a greater number of ribs depending on the caliber of the launching device. In order for the rifling to engage the projectile, the projectile must either be slightly larger than the diameter between the booms, which is common for fine caliber weapons, or be fitted with a special flange, called an obturator or driving band, which has a slightly larger diameter than the booms, which is common in projectiles with a diameter greater than 20 mm. The rim may be made of plastic, composite material or a soft metal, such as copper or a copper alloy. The length of the barrel on which the groove turns a full revolution is called the pitch and is usually given in inches per revolution

[0037] Most barrels include rifling and by arranging projectiles with sliding driving bands, both spin-stabilized and fin-stabilized projectiles can be fired with rifled barrels. In principle, smoothbore barrels are only used for weapon systems intended to combat armored combat vehicles, as the rotation of the projectile means that the directional blast effect, RSV, works less well because the centrifugal force causes the jet to spread out.

[0038] As materials with high resistance to abrasion and thermal erosion gases often have a higher cost relative to other materials that are conveniently used in HIP, these materials can be optimally utilized in HIP Cladding to create a component with high performance but with as low a manufacturing cost as possible by using only a smaller amount of the more expensive material. The advantage of HIP Cladding is that there are no physical limitations on the thickness of the material applied, such as the surface treatment applied, compared to other surface treatment methods. This means that a thicker layer of the applied material can be achieved. With HIP Cladding it is also possible to combine metals with composites. With HIP Cladding, a bi-metallic component can be manufactured without welding or fastening techniques, resulting in a high strength component. Components made with HIP Cladding have an improved lifetime and performance compared to components made with the substrate alloy. Manufacturing of barrel components / barrel segments / fire tubes with HIP Cladding results in limited machining and / or surface treatment operations and a reduced number of process steps, thus shortening lead time compared to forged and coated components. HIP Cladding allows selected surfaces to be bonded to the surface by diffusion; the incorporation of a suitable resistant material in powder or solid form to a solid substrate to provide a surface with enhanced resistance to wear and / or corrosion via the manufacturing techniques of encapsulation (HIP Cladding) and HIP.

[0039] Hot Isostatic Pressing (HIP) is a manufacturing process to control the grain size and structure of the material. HIP also enables the packing of metal, polymer, ceramic and composite powders into solid form. Benefits include the removal of all internal voids in metal components created by additive manufacturing methods and the improvement of mechanical properties such as fatigue resistance / fatigue strength, toughness, plasticity and impact strength. Furthermore, HIP can produce a dense material from metal, composite, polymer or ceramic powders without melting and materials with partly different characteristics can be coordinated in the same component.

[0040] With HIP, a solid material with superior properties can be created from powder as powder / powder components have a fine, uniform grain size and isotropic structure. Furthermore, by utilizing HIP, dissimilar metals can be joined together without the need for temperature limiting binders. Through HIP, multiple diffusion bonds can be achieved in a single process cycle. HIP works for a wide range of metal alloys, as well as for example polymers and ceramic materials. Examples include alloys with nickel, cobalt, tungsten, titanium, molybdenum, aluminum, copper and iron, oxide and nitride ceramics, glass, intermetallic s and polymers. HIP allows for the joining and combining of materials that cannot otherwise be combined, i.e. composites.

[0041] In FIG. 1, a schematic sketch of the manufacture of a barrel segment 1 is shown in which a template core 20 is arranged in an outer tube 11, which is part of a capsule structure, so that a void, a cavity 30, is arranged between the capsule structure and the template core 20. The template core 20 is provided with a foil 23 which abuts on the outer surface of the template core and is arranged to follow the groove pattern of the template core. In cavity 30, powder may be arranged to produce a barrel segment 1 with HIP. The barrel segment 1 may be a complete barrel, but may also comprise components for a complete barrel, referred to as barrel segments. A complete barrel may thus be arranged by arranging several components, also referred to as barrel segments, to complete a complete barrel. Fig. 2a shows a view of a HIP container in the form of a capsule structure 10 for manufacturing a component for a barrel. The HIP container 10 is provided with connection means 12, 14, for evacuating air, vacuum pumping, before and / or during the execution of the manufacturing method as well as a front bottom plate 16 and an outer tube 11.

[0042] Fig. 2b shows a cross-sectional view of a HIP container in the form of a capsule structure 10 for manufacturing a component for a barrel. The HIP container 10 is provided with connection means 12, 14, for evacuation of air, vacuum pumping, before and / or during the execution of the manufacturing method as well as a front bottom plate 16 and a rear bottom plate 18 and an outer tube 11. The powder is freely arranged in the HIP container in the form of the capsule structure 10 between the capsule structure 10 and foil 23 arranged on the template core 20. By further processing in accordance with the HIP, the powder is fixed at the intended location for the production of a barrel segment 1. The material is applied in powder form and shaken into place inside a HIP container in the form of capsule structure 10, which is an enclosing component arranged to retain powder, wherein powder, in the form of applied material, is freely arranged in the capsule structure 10. By further processing in accordance with the HIP, the powder is fixed in the intended location for the production of a barrel segment 1. Manufacturing methods involving powders have advantages in confined manufacturing conditions where the material supplied has to reach into spaces of small dimensions. The capsule structure 10 is provided with connection means for evacuation of air and vacuum pumping, before and / or during the execution of the manufacturing method. Several different types of metal powders can be arranged in the capsule structure at different positions to improve the functionality of the barrel component. Preferably, the capsule structure 10 is made of any material that the skilled person realizes is suitable for the purpose. In one embodiment, the material of the capsule structure 10 is black plate, in another embodiment, the material is stainless steel which also contributes to an anti-corrosion function of the barrel segment 1. The sub-components of the capsule structure may also be additively manufactured. In Fig. 3, a barrel 60 is shown made of a number of barrel segments 1, 1' arranged in a barrel jacket 62. A complete barrel 60 includes further barrel segments so that the entire barrel jacket 62 is arranged with barrel segments. The first barrel segment 1 is arranged with chamber 2 and positioned where the barrel is arranged against the ejection device and where the projectile is arranged for ejection into the fire tube 60. After the first barrel segment 1, subsequent barrel segments 1', \ " are arranged up to the mouth of the barrel 4. Each barrel segment 1, 1', \ " is manufactured according to the above manufacturing method and arranged in a barrel jacket 62 by heating the barrel jacket 62 and thereby expanding it to a state such that the barrel segments 1, 1 ' , 1 " can be arranged in the barrel jacket 62. After the barrel segments 1, 1 ' , 1 " are arranged in the barrel jacket 62, the barrel jacket may cool so that the barrel jacket contracts and the barrel segments 1, 1', \ " are retained in the barrel jacket 62 so that a complete barrel 60 is provided. When some compressive stress is applied to the barrel segments 1, 1', 1 " of the cooled down barrel jacket 62, autofrettage is achieved on the inner surface of the barrel, resulting in improved resistance to crack propagation and / or cracking.

[0043] Fig. 4 shows a template core 20 for manufacturing the first barrel segment 1. The template core 20 is arranged with a first portion 21, for manufacturing chambers in the barrel segment 1, and a second portion 22 for manufacturing grooves in the barrel segment 1. The template core is preferably made of metal, but can also be made of other materials suitable for the further method of manufacturing barrel segments. A foil 23, also referred to as film, is arranged on the template core 20. The foil is arranged on the template core in such a way that the foil is stretched and without air pockets, which causes the foil to be alloyed in an advantageous way during hot isostatic pressing of barrels and / or barrel components. The foil is preferably made with a thickness of more than 100 nm and with a width that facilitates the arrangement of the foil on the template core, preferably the width is more than 200 mm. In a first embodiment, tantalum foil is used, but other materials can also be used. To facilitate adhesion of the tantalum foil to the template core, and where applicable when several turns of tantalum foil are wound on the template core, the template core / foil can be treated with an adhesive substance that facilitates adhesion of the tantalum foil to the template core when the foil is arranged / wound on the template core. Furthermore, the tantalum foil can be arranged against the template core in a vacuum chamber, which means that the tantalum foil can be arranged against the template core without air pockets occurring.

[0044] Fig. 5 shows the manufacturing method 100 for barrel segment 1 with HIP. Outer tube 11, rear base plate 18 and front base plate 16 are jointly arranged for the creation of a capsule structure 10 in the step of Designing a capsule structure 102. A capsule structure 10, also referred to as a HIP container, is a device in which powder is arranged to shape the powder into a HIPED body under high temperature and high pressure. Powder in the capsule structure 10 is arranged in the step Powder is arranged in the capsule structure 104 by arranging powder between the template core 20 and outer tube 11. The template core 20 can be centered in outer tube 11 by arranging the template core 20 to the rear base plate 18 and the front base plate 16.

[0045] After powder material is disposed in the capsule structure 10, the capsule structure 10 is evacuated, vibrated and sealed to evenly distribute the powder in the capsule structure 10 in the step of Evacuating, vibrating and sealing the capsule structure 106. Subsequently, hot isostatic pressing is performed in the step of HIP 108, that is, a gas is used to create an isostatic pressure on the capsule structure 10 by disposing the gas to a connecting device disposed on the capsule structure 60. Before the gas is arranged to the capsule structure, the capsule structure may be vacuum-pumped or otherwise evacuated of air or the filling gas / fluid arranged in the capsule structure 10 before evacuation, for example by flushing with a noble gas. Thereafter, the entire capsule structure 10 is heated for the creation of a precursor or HIPED body. The HIP temperature is preferably 20% below the melting temperature of the material, for martensitic stainless steels the HIP temperature is above the phase transformation to the austenitic state (which is in the order of 80% of the melting point of the material). In the HIP 108 step, the foil 23 arranged on the template core 20 will be joined to the powder arranged in the capsule structure. After hot isostatic pressing, the body can be subjected to Heat treatment / hardening 110, which means that the now joined body is heated. After heat treatment, the material is suitable for machining, for example cutting machining, so that excess material, for example material covering the opening for the outgoing passage for gas flow and possibly parts of the HIP container are machined away in the Machining / pickling step 112 where cutting machining such as turning or milling but also pickling or other chemical treatment such as treatment with acid can be performed. The template core 20 is preferably removed by a combination of mechanical processing, such as turning / drilling, and pickling in order to reveal the grooving performed in the fire tube segment. Where appropriate, a Surface treatment 114 is also carried out.

[0046] After the completion of barrel segment 1, several barrel segments 1 can be arranged to create a barrel.

[0047] Materials utilized as powders are preferably tool steels or martensitic stainless steels with high concentrations of chromium and nickel optionally with refractory material disposed in the surface of the muzzle brake to better resist erosion from gunpowder gases or powders specially adapted for application to the foil 23 disposed on the template core 20.

[0048] Fig. 6 shows manufacturing method 200 for manufacturing barrel 60 from a plurality of barrel segments 1, 1', \ " . Initially, the barrel jacket 62, in which the barrel segments are arranged, is heated in the step of Heating the barrel jacket 202. When the barrel jacket 62 is heated, the barrel jacket 62 expands, which means that barrel segments 1, 1 ' , 1 " can be arranged in the barrel jacket 62. In the step of Arranging barrel segments in the barrel jacket 204, one or more barrel segments 1, 1', \ " are arranged in the barrel jacket 62. In the step of Arranging barrel segment including chamber in the barrel jacket 206, barrel segment including chamber 1 is arranged in the barrel jacket to create a complete barrel 60. After the arrangement of the barrel segments, the barrel can be cooled, which is done in the step of Cooling the barrel jacket 208. When the barrel jacket with barrel segments is cooled down, a complete barrel 60 is completed which can be further arranged in an ejection device. In addition, parts of the barrel could be machined away in the Machining step 212 where cutting machining such as turning or milling but also pickling or other chemical treatment such as treatment with acid can be performed. Where appropriate, a Surface treatment 214 is also carried out. In an alternative embodiment of manufacturing method 200' for barrel 60, only one barrel segment 1 is utilized. Initially, barrel jacket 62, in which the barrel segment 1 is arranged, is heated in the step of heating the barrel jacket 202. When the barrel jacket 62 is heated, the barrel jacket 62 expands, which means that the barrel segment 1 can be arranged in the barrel jacket 62. In the step of arranging the barrel segment in the barrel jacket 204, no barrel segment is arranged in the barrel jacket 62 for the alternative embodiment of the manufacturing method 200' for barrels, instead, in the step of arranging the barrel segment including chambers in the barrel jacket 206, a barrel segment including chamber 1 is arranged in the barrel jacket to create a complete barrel 60. After the arrangement of barrel segments, the barrel can be cooled, which is done in the step of cooling the fire tube jacket 208. When the barrel jacket with barrel segments is cooled down, a complete barrel 60 is completed which can be further arranged in an ejection device.

[0049] ALTERNATIVE EMBODIMENTS

[0050] The invention is not limited to the particular embodiments shown, but can be varied in different ways within the scope of the claims.

[0051] It is recognized, for example, that the choice of materials, the choice of geometric shapes, the elements and details included in barrels or barrel components are adapted to the weapon system(s), platform and other design characteristics of the time. Preferably, the foil is made of tantalum, but other heat-resistant materials may also be used.

[0052] It also includes all forms of barrels and barrel components for fine, medium and large calibers.

Claims

PATENT CLAIMS1. Method for producing barrel segments (1), characterized in that the method comprises the steps:1.) a capsule structure (10) is arranged enclosing a template core (20), ii.) powder is arranged in the cavity between the capsule structure (10) and the template core (20), wherein the template core (20) is fully or partially arranged with grooves for embossing groove patterns on the barrel segment (1) and wherein a foil (23) is arranged on the template core (20),(iii) the powder is pressed by means of high pressure and heat, also known as hot isostatic pressing, HIP, so that the powder, foil and capsule structure are joined together iv.) the template core (20) is removed to produce a barrel segment (1).

2. Method according to claim 1, characterized in that the barrel segment (1) is heat treated and hardened after Hot Isostatic Pressing for the completion of a barrel segment (1).

3. Method according to any of the preceding claims, characterized in that the foil (23) is made of tantalum.

4. Method of manufacturing barrels characterized in that the method includes the steps; i.) a barrel jacket (62) is heated; ii.) a first barrel segment (1), wherein the barrel segment (1) is made according to any of claims 1 - 3, comprising a chamber, is arranged in the heated barrel jacket (62) iii.) the barrel (60) comprising a barrel jacket (62) arranged with barrel segments is cooled.

5. A method of manufacturing barrels according to claim 4 characterized in that the method further comprises the step of;at least one second barrel segment ( 1 ') is arranged after the first barrel segment (1) in the barrel jacket (62) before the barrel (60) comprising a barrel jacket (62) arranged with barrel segments is cooled.

6. Barrel (60) manufactured according to any of requirements 4 - 5.

7. Ejection device arranged with barrel according to requirement 6.

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