EP4616137A1

EP4616137A1 - Muzzle brake and method for manufacturing muzzle brake

Info

Publication number: EP4616137A1
Application number: EP23892122.5A
Authority: EP
Inventors: Martin PERKOVIC; Fredrik THUVANDER; Hamzah HAMDAN
Original assignee: BAE Systems Bofors AB
Current assignee: BAE Systems Bofors AB
Priority date: 2022-11-11
Filing date: 2023-10-26
Publication date: 2025-09-17
Also published as: SE2200126A1; WO2024107091A8; WO2024107091A1

Abstract

The present invention concerns a method for producing a muzzle brake for a barrel, characterized in that the method includes the steps: i.) a muzzle brake (1) comprising at least one brake disc (3, 5) is assembled, ii.) a surface treatment area (4, 6) on the brake disc is surface treated with one of the following surface treatment methods; a.) sputtering, b.) melting, c.) HIP-cladding, d.) cold-deposition. The invention also concerns a muzzle brake, a firing barrel and a firing device.

Description

MUZZLE BRAKE AND METHOD FOR MANUFACTURING MUZZLE BRAKE

TECHNICAL FIELD

[0001 ] The present invention concerns a method for the manufacture of a muzzle brake, a muzzle brake, a firing barrel designed with a muzzle brake, and a firing device designed with a barrel fitted with a muzzle brake.

BACKGROUND OF THE INVENTION, PROBLEM AREA AND STATE OF THE ART

[0002] When different forms of barrel-based weapons are fired by burning gun powder, which creates a gas expansion and the expanding gas moves a projectile along a barrel, a force is created in the opposite direction of the projectile’s direction of motion, commonly known as recoil. Depending on the choice of weapon, gunpowder, projectile, etc., extensive recoil arises under certain conditions, which can be counterbalanced by means of arranging a muzzle brake on the firing barrel. The recoil force also affects the position of the barrel, which is why the barrel’s aim may need to be adjusted after a projectile has been discharged. If the recoil can be reduced, and thereby the movement of the barrel reduced, the performance of the weapon system can be improved.

[0003] Muzzle brakes are conventionally manufactured through mill-turning, or by shaping sheet metal components and attaching them, primarily by welding. These manufacturing methods are both costly and time-consuming and result in a muzzle brake that is designed based on production limitations and not based on the functional requirements of the muzzle brake. It can also be difficult to ensure the technical performance of welded-on components. In existing muzzle brake designs, combustion also cause extensive erosion to the muzzle brake. The lifetime of the muzzle brake is limited based on wear on mainly the brake discs that are arranged on the muzzle brake. [0004] An example of a manufacturing method for components for assembly on fire pipes is given in patent document US 9,102,010 B2, which shows a manufacturing method for silencers including components that are arranged on fire pipes for a launching device. The manufacturing method demonstrates an additive manufacturing method where metal is melted onto a structure with a laser.

[0005] The aforementioned prior art does not demonstrate muzzle brake surface treatment.

[0006] Additional problems which the present invention seeks to solve will become apparent in connection with the following detailed description of the various embodiments.

PURPOSE AND FEATURES OF THE INVENTION

[0007] The purpose of the present invention is to achieve a better, simpler, faster and more cost-efficient way of manufacturing an improved muzzle brake.

[0008] The invention relates to a method for producing an improved muzzle brake for a fire tube, characterized in that the method includes the following steps: i.) a muzzle brake comprising at least one brake disc is assembled, ii.) a surface treatment area on the brake disc is surface treated with one of the following surface treatment methods; a.) sputtering, b.) melting, c.) HIP- cladding, d.) cold-deposition.

[0009] In that the extension of the surface treatment area on the front of the brake disc consists of a ring with an inner radius R1 and an outer radius R2 where R2 is less than or equal to R1 + 40 mm.

[0010] In that the extent of the surface treatment area on the brake disc's cavity surface, B, where the cavity surface is the surface that is arranged on the surface of the brake disc in a cavity arrangement is up to 100% of the thickness T of the brake disc.

[0011 ] In that when the surface treatment method is HIP-cladding, the entire muzzle brake is manufactured with Hot Isostatic Pressing and the muzzle brake is heat treated and hardened after Hot Isostatic Pressing for the completion of a muzzle brake and where a first type of powder is provided for the muzzle brake except for the surface treatment area and a second type of powder is provided for the surface treatment area.

[0012] In that when the surface treatment method is HIP cladding, the entire muzzle brake is manufactured with HIP in a capsule construction comprising an inner tube, a rear capsule, a front capsule, where the inner tube, the rear capsule, the front capsule are jointly arranged in an outer capsule. that the inner tube is designed with threads. that the powder completely or partially consists of refractory metal.

[0013] The invention also comprises a muzzle brake produced by means of the method described above.

[0014] The invention also comprises a firing barrel including a muzzle brake.

[0015] The invention also comprises a firing device including a firing barrel including a muzzle brake.

THE ADVANTAGES AND EFFECTS OF THE INVENTION

[0016] By manufacturing a muzzle brake with surface coating on the brake discs, a muzzle brake can be achieved with better performance than using previously known technology. Improvements include a muzzle brake with improved resistance to abrasive particles and thermal gases generated when projectiles are fired from barrel guns. The introduction of surface treatment on the brake discs also means that muzzle brakes with greater degrees of freedom in terms of design can be achieved.

LIST OF FIGURES

[0017] The invention will be described below by reference to the figures that are included there:

Fig. 1 shows a muzzle brake according to one embodiment of the invention.

Fig. 2a shows a brake disc viewed from the front according to one embodiment of the invention.

Fig. 2b shows a brake disc projectile viewed from the side according to one embodiment of the invention.

Fig. 3 shows a cross-section of the capsule assembly according to one embodiment of the invention.

Fig. 4 shows the process steps for Hot Isostatic Pressing, HIP, when manufacturing a muzzle brake according to one embodiment of the invention.

DETAILED DESCRIPTION OF EMBODIMENT

[0018] The present invention shows an embodiment of a manufacturing method for firing barrels and/or firing barrel components, such as muzzle brakes, by means of surface coating on the brake discs.

[0019] An ejection device, also termed a cannon, a howitzer, or a piece, in the sense of an artillery piece, has the goal of making use of a propellant for the purpose of firing a projectile. Preferably, a propellant, such as gunpowder, is initiated in one part of the cannon, oftentimes a chamber specifically adapted to the purpose. Initiation takes place by way of igniting the barrel, for instance by means of an ignition cartridge or an igniter in a munitions device, which is initiated by means of striking. Other methods for igniting the propellant may include ignition of the propellant by means of laser energy or electric energy. The propellant bums at a high rate and results in large amounts of gas being produced, which creates a gas pressure in the chamber which propels the projectile out of the barrel of the firing device. The propellant has been adapted in order to generate a constant pressure on the projectile during the entire barrel procedure, to the greatest extent possible, as the projectile moves in the barrel, which results in the projectile leaving the mouth of the barrel with high speed.

[0020] Projectiles, such as various types of grenades, generally include some form of warhead and some form of barrel which initiates the warhead. Fuzes can be of different types where contact fuzes are common for projectiles that are meant to burst when in contact with an object, timed fuzes when the projectile is meant to burst at a certain predetermined time and proximity fuzes when the projectile is meant to burst when an object comes within a certain distance from the projectile. The use of proximity fuzes is preferred when confronting flying vessels, while timed fuzes can be used when confronting a large number of various different objects. It is advantageous to combine various types of fuze functions in one and the same fuze, for instance in order for the projectile to burst after a certain time if it fails to detect any object, and so on.

[0021 ] It is advantageous for the warhead to comprise some type of explosive substance, as well as some type of shattering casing which encloses the explosive substance. Various types of propellants, such as fins, can furthermore be arranged in either the barrel or in its own subcomponent.

[0022] In order to stabilize the projectiles once the projectiles have left the barrel, the projectiles are preferably designed with rotation or with fins. In cases where the projectiles are designed with rotation, the projectiles are said to be rotationally stabilized and in cases where the projectiles are arranged with fins, the projectiles are said to be fin-stabilized. Fin-stabilized projectiles should have no rotation, or low rotation, when leaving the barrel. [0023] To achieve rotation on the projectiles, the barrel is often designed with rifling, to which the projectile connects during the firing process. Rifling means that the barrel in a firearm, the barrel, is provided with spiral-shaped rifling. The opposite is a smooth-bore barrel. When the rifling engages the projectile during firing, it rotates along its longitudinal axis. Due to the rotation, minor irregularities or damage to the projectile will not cause a drift in the trajectory of the projectile. Rotation is also necessary for an elongated (torpedo-shaped) projectile to maintain its direction after leaving the barrel and not start tumbling around. This is referred to as the projectile being rotation-stabilized. In smooth-bore weapons, only round (spherical) projectiles or fin-stabilized projectiles can be fired. An elongated projectile without fins will tumble as it leaves the muzzle.

[0024] Thus, rifling consists of grooves that are integrated into the track of the barrel, and the elevation in between is referred to as barriers. The rifling of fine- caliber firearms usually consists of four grooves that are turned to the right, while cannons, such as artillery pieces, have more grooves depending on the caliber of the launching device. In order for the rifling to be able to engage the projectile, the projectile must either be slightly larger than the diameter between the barriers, which is common for fine-caliber weapons, or be equipped with a special flange, called a belt, which has a slightly larger diameter than the barriers, which is common in projectiles with a diameter greater than 20 mm. The belt can be made out of plastic, composite material or a soft metal, such as copper or copper alloy. The length of the barrel on which the groove rotates an entire revolution is called the pitch and is usually the number of inches per revolution.

[0025] Most barrels include rifling, and, by arranging projectiles with sliding belts, both rotation-stabilized and fin-stabilized projectiles can be launched with rifled barrels. Smooth-bore barrels are basically only used for weapon systems intended to armored combat vehicles, as the rotation of the projectile means that the directed explosive action, RSV, is less effective since the centrifugal force causes the beam to be spread out. [0026] During firing, as the projectile leaves the barrel, a force arises called recoil, which works in the opposite direction of the movement of the projectile. The recoil affects the firing barrel, and thereby the position of the firing device. The recoil can move the firing barrel, which can result in the barrel needing to be re-aimed after a projectile is discharged. Furthermore, the recoil forces can affect the firing device and cause damage to the firing device over time. By placing a muzzle brake on the firing barrel, part of the force that is generated from the gunpowder gases that follow the projectile can be used to counteract the recoil force. For example, by directing the gunpowder gases so that they affect the muzzle brake in the opposite direction of the recoil forces. This counteracts the recoil, and a certain level of balance between these forces can be achieved.

[0027] Surface treatment through modification of the surface, such as PVD, CVD, sputtering, plating, etc., refers to various methods to make products or materials and equipment meet certain desired criteria, some of which may be aesthetic or to counteract wear in various contexts. Surface treatment, or modification of the surface, of parts of a muzzle brake has the main purpose of counteracting mechanical damage from abrasive particles and thermal erosion gases that arise when gunpowder is burned in a launch device. Surface treatment, or modification of the surface, is preferably carried out in different ways depending on which material is desired to be surface treated and which criteria are placed on the finished result. Examples of materials in the surface treatment are refractory metals such as chromium, tantalum, niobium or alloys of metals and hard carbides, nitrides or oxides such as chromium carbide (Stellite) or titanium nitride.

[0028] A method for surface coating includes methods for coating surfaces with a thin layer of, for example, a metal, such a method can be called PVD, Physical Vapor Deposition, where a material is removed from a source to a substrate to be surface coated. PVD means that a selected metal, in the source, evaporates, condenses and solidifies on a surface, which can be called a substrate and consists of the component to be surface treated. PVD preferably takes place in a vacuum, which means that PVD is a complex process, but where it is possible to control the surface coating in detail.

[0029] Deposition and/or fusing is another surface treatment option where one metal can be melted onto another metal. Preferably, a muzzle brake is manufactured with instructions for arranging the melted material so that after manufacturing the muzzle brake, the metal can be melted in the instructions on the muzzle brake. The fused material is preferably a metal with good resistance to abrasive particles and thermal erosion gases.

[0030] Cold deposition, also referred to as cold spraying (CS), is a surface coating method where powder is accelerated to high speeds and in contact with the substrate, the particles undergo a plastic deformation and adhere to the surface of the substrate. By moving the nozzle from which the powder is accelerated, a surface can be coated. Metals, polymers, ceramics and composites can all be used as powders. Unlike other thermal techniques, the powder does not melt during the surface treatment process.

[0031 ] HIP Cladding, or in Swedish H IP-inklading, is a method for creating a diffusion bond of solid material to solid material or solid material to powder to create a bimetallic component with good material properties on selected surfaces through encapsulation and hot isostatic pressing. HIP Cladding is especially useful if the muzzle brake is manufactured with a manufacturing method including HIP, for example in accordance with the method described in patent application SE 2200063-2. In case where the muzzle brake is manufactured with HIP, materials with high resistance to abrasion and thermal erosion gases, which arise when projectiles are fired from a fire tube, can be used on the physical positions of the muzzle brake where the need exists, especially on the brake plates. Since materials with high resistance to abrasion and thermal erosion gases often have higher costs relative to other materials that are suitably used in HIP, these materials can be used optimally in HIP Cladding to create a component with high performance but with as low a manufacturing cost as possible. Advantages of HIP Cladding are that the physical limitations regarding the thickness of added material, such as the surface treatment that is added, are not limited compared to other surface treatment methods. This means that a thicker layer of the added material can be created. With HIP Cladding, it is also possible to combine metals with composites. With HIP Cladding, a bimetallic component can be manufactured without welding or fastening techniques, resulting in a high-strength component. Components manufactured with HIP Cladding have an improved lifetime and performance compared to components manufactured with the substrate alloy. Manufacturing a muzzle brake with HIP Cladding involves limited machining and/or surface treatment operations as well as a reduced number of process steps and thus shortens lead time compared to forged and coated components. HIP Cladding allows selected surfaces to be bonded to the surface by diffusion; coating of a suitable resistant material in powder form or solid form to a solid substrate to provide a surface with increased resistance to wear and/or corrosion via the production technique encapsulation (HIP Cladding) and HIP.

[0032] Hot isostatic pressing, HIP (Hot Isostatic Pressing), is a production process to control the grain size and structure of the material. HIP also allows metal powder, polymer powder, ceramic powder and composite powder to be pressed into a solid form. The advantages include the fact that all the empty spaces inside metal components that are created through additional manufacturing methods are removed and that mechanical properties such as fatigue resistance/fatigue strength, toughness, plasticity and impact resistance are improved. Furthermore, HIP can create a dense material from metal powder, composite powder, polymer powder or ceramic powder without melting, and materials with partially different characteristics can be combined in the same component. [0033] Using HIP, a solid material can be created from powder with superior properties because the powder/powder components have a fine, uniform grain size and an isotropic structure. Furthermore, with HIP, different metals can be joined together without needing a temperature-limiting adhesive. Using HIP, several diffusion bonds can be achieved in one process cycle. HIP works for a large number of metal alloys, such as polymers and ceramic material. For example, alloys with nickel, cobalt, tungsten, titanium, molybdenum, aluminum, copper and iron, oxide- and nitride ceramics, glass, intermetallic substances and polymers. HIP enables the bonding and combining of materials that otherwise cannot be combined, i.e. composites.

[0034] Fig. 1 shows a muzzle brake 1 where two brake plates 3, 5 are arranged. On the muzzle brake 1 shown, the first brake disc 3 is arranged with a surface treatment on a first surface treatment area 4 and where the second brake disc 5 is arranged with a surface treatment on a second surface treatment area 6. In an alternative embodiment, the first surface treatment area 4 is larger than the second surface treatment area 6 as a greater amount of flue gases from the gunpowder meets the first brake disc 3 with the first surface treatment area 4 than the second brake disc 4 with the second surface treatment area 6.

[0035] In an alternative embodiment, the first surface treatment area 4 is larger than the second surface treatment area 6 as a greater amount of flue gases from the gunpowder meets the first brake disc 3 with the first surface treatment area 4 than the second brake disc 4 with the second surface treatment area 6.

[0036] In Fig. 2a, the first brake disc 3 is shown in a plan view from the front where the front side 8 of the brake disc is shown with surface treatment area 4 with an extension A of up to 40 mm. The brake disc 4 is arranged with a cavity formation 7 through which the projectile can pass. Surface treatment area 4 is defined as a ring with inner radius R1 and outer radius R2. Thus, R2 is greater than R1 and preferably up to R1 + 40 mm. [0037] In Fig. 2b, the first brake disc 3 is shown in a side view where the extension of the surface treatment area 4 into the cavity surface 9 is shown, where the cavity surface 9 is arranged in cavity formation 7 of the brake disc 3, and is shown with an extension B which is preferably up to 100% of the thickness T of brake disc 3.

[0038] Figure 3 shows a capsule assembly 60, also called a HIP container, in the form of a sheet metal construction, including a cavity 62, where powder can be placed. The powder is arranged freely in the HIP container in the form of the capsule assembly 60. Through continued HIP treatment, the powder can be fixed in the intended position in order to create a muzzle brake 1 . The capsule assembly 60 in the embodiment displayed consists of an inner tube 20, a rear capsule 30 and a front capsule 40, consisting of front plate 42 and a rear plate 44, which are arranged together in the outer capsule 50. Preferably, the rear capsule 30, the front capsule 40 consisting of a front plate 42 and a rear plate 44, as well as the outer capsule 50, are welded on the inner tube 20 in order to complete the capsule structure 60. The application method is preferably some type of additional manufacturing method where the material can be applied in powder form and shaken when they are located inside an HIP container in the form of capsule assembly 60, which is a surrounding component designed to hold powder, where powder, as the material to be applied, is arranged freely in the capsule assembly 60. Through continued HIP treatment, the powder can be fixed in the intended position in order to create a muzzle brake 1. Manufacturing methods involving powder have advantages under cramped manufacturing conditions because the material supplied can reach into areas with small dimensions. Capsule assembly 60 is designed with a connecting device, not shown in the diagram, for evacuating air and vacuum pumping before and/or during the manufacturing process. Preferably, a first type of powder is provided in the capsule construction 60 for the muzzle brake in addition to the surface treatment area 4, 6 and a second type of powder is provided for the surface treatment area 4, 6 which is not shown in the figure. Capsule assembly 60 is preferably made of some material that experts recognize as suitable for the purpose, usually a metallic material, but it may also be a plastic or a composite, and a variety of materials are already known in the field. In one embodiment, the material in capsule assembly 60 is black sheet plate, and in another embodiment, the material is stainless steel, which also provides a rust-protection function for the muzzle brake 1. The subcomponents of the capsule assembly can be manufactured additionally.

[0039] Fig. 4 shows the manufacturing method 100 for muzzle brake 1 with HIP. The inner tube 20, the rear capsule 30, as well as the front capsule 40 are arranged in the outer capsule 50 to create a capsule assembly 60 in the Formation stage of a capsule assembly 102. A capsule assembly 60, also called a HIP container, is a device in which powder is arranged in a manner that allows it to be shaped into a HIPed body under high temperature and high pressure. Powder in the capsule structure 60 is arranged in the step Powder is arranged in the capsule structure 104 by arranging a first type of powder for the muzzle brake in addition to the surface treatment area 4, 6 and a second type of powder is arranged for the surface treatment area 4, 6. After the powder material has been placed in the capsule assembly 60, the capsule assembly 60 is evacuated, vibrated and sealed in order to evenly distribute the powder in the capsule assembly 60 during the Evacuation, Vibration and Sealing step for capsule assembly 106. HIP is then carried out in the HIP 108 stage, i.e. a gas is used to create isostatic pressure on the capsule assembly 60 via a connecting device on the capsule assembly 60 that supplies the gas. Before the gas is supplied to the capsule assembly, the capsule assembly is vacuum- pumped or otherwise evacuated of air or the filling gas/fluid placed in the capsule assembly 60 prior to evacuation, e.g. by rinsing the assembly with a noble gas. The entire capsule assembly 60 is simultaneously heated to create a preform or a HIPed body. The HIP temperature is preferably 20% below the melting temperature for the material; for martensitic steel, the HIP temperature during the phase conversion (which is in the order of magnitude of 80% of the material’s melting point). After the hot isostatic pressing is completed, the body can undergo heat treatment/hardening 110, which means that the now merged body is heated. After heat treatment, the material is suitable for machining, e.g. mill-turning, as well as threading the connection geometry for the muzzle brake and machining away excess material, e.g. material that covers the opening for the outgoing gas flows and any other parts of the HIP container, in the Machining step 112, during which pickling may also be performed. Where applicable, a surface treatment 114 is also performed.

[0040] After the muzzle brake 1 is finished, the muzzle brake can be attached to a firing barrel, e.g. using the threading in the muzzle brake. Other ways of attaching the muzzle brake to the barrel can be, but are not limited to, welding, shrink-wrapping or other attachment methods.

[0041 ] Afinished muzzle brake must achieve an impact strength exceeding 27 J at -40° C, yield strength should exceed 650 MPa.

[0042] Furthermore, a finished muzzle brake must withstand a pressure level of at least 60 MPa and a temperature of approx. 1500 K in short time intervals.

[0043] The material used for the powder is preferably factory steel or martensitic stainless steel with high concentrations of chromium and nickel, potentially with refractory material forming a layer on the muzzle brake in order to better withstand erosion from gun powder gases.

ALTERNATIVE EMBODIMENTS

[0044] The invention is not limited to the embodiments specifically shown, but can be varied in different ways within the framework of the claims.

[0045] For instance, it is clear that the choice of material, choice of geometric forms, the elements and details included in the muzzle brake, are adapted to the weapons system(s), platforms and other construction-related properties that are applicable at this time.

[0046] Furthermore, all types of firing barrels, including small caliber, medium caliber and large caliber barrels are included.

Claims

1. A method of manufacturing a muzzle brake (1 ) for a barrel, characterized by the method including the following steps: i.) a muzzle brake (1 ) comprising at least one brake disc (3, 5) is assembled, ii.) a surface treatment area (4, 6) on the brake disc is surface treated with one of the following surface treatment methods; a.) sputtering, b.) melting, c.) HIP cladding, d.) cold-deposition.

2. Method according to claim 1 characterized in that the extension of the surface treatment area (4, 6) on the front (8) of the brake disc (3, 5) consists of a ring with an inner radius R1 and an outer radius R2 where R2 is less than or equal to R1 + 40 mm.

3. Method according to any of the above claims characterized in that the extent of the surface treatment area (4, 6) on the brake disc's (3, 5) cavity surface (9), B, where the cavity surface (9) is the surface that is arranged on the surface of the brake disc (3, 5) in a cavity arrangement (7) is up to 100% of thickness T of the brake disk (3, 5).

4. Method according to any of the above claims, characterized in that, when the surface treatment method is HIP-cladding, the entire muzzle brake is manufactured with Hot Isostatic Pressing and the muzzle brake is heat treated and hardened after Hot Isostatic Pressing for the completion of a muzzle brake and where a first type of powder is provided for the muzzle brake except for the surface treatment area and a second type of powder is provided for the surface treatment area.

5. Method according to claim 4 characterized in that when the surface treatment method is HIP cladding, the entire muzzle brake is manufactured with HIP in a capsule construction (60) comprising an inner tube, a rear capsule (30), a front capsule (40), where the inner tube (20), the rear capsule (30), the front capsule (40) are jointly arranged in an outer capsule (50).

6. Method according to claim 5, characterized by the inner tube (20) being designed with threads.

7. Method according to any claims 4-6, characterized by the powder completely or partly consisting of refractory metal.

8. A muzzle brake produced by a method specified in any of the claims 1 -7.

9. Firing barrel designed with a muzzle brake according to claim 8.

10. Firing device designed with a firing barrel according to claim 9.