WO2023097379A1

WO2023097379A1 - Ammunition cartridge and method for manufacturing an ammunition cartridge

Info

Publication number: WO2023097379A1
Application number: PCT/BR2022/050355
Authority: WO
Inventors: Andre Giacomini Dias CARMONA; André Viegas Wentz; Claudio Wietky JÚNIOR; Felipe Vannucchi De CAMARGO; Frederico Eggers; Gláucio De Almeida CARVALHO; Marcelo MORENO; Vinicius CABREIRA; Vinicius Oliveira; Rodrigo José BENATTI; Rodrigo Motta DARTORA
Original assignee: Companhia Brasileira De Cartuchos; Serviço Nacional De Aprendizagem Industrial - Departamento Regional Do Rio Grande Do Sul - Senai/Rs
Priority date: 2021-12-01
Filing date: 2022-09-06
Publication date: 2023-06-08
Also published as: BR102021024294B1; BR102021024294A2

Abstract

The invention relates to an ammunition cartridge (17) formed by a polymeric body (1) provided with a fastening ring (2) and a head (3) with a crown (4), both made of a metallic material, attached to the polymeric body (1) by a fastening device (15) and a press (6), such that when the cartridge is complete it can withstand mechanical stresses due to phenomena occurring at the moment of the shot. Another object of the invention is a method for manufacturing an ammunition cartridge based on metal alloy solubilising and ageing processes so as to achieve both the workability and mechanical resistance required for the head of the cartridge.

Description

AMMUNITION CASE AND AMMUNITION CASE MANUFACTURING PROCESS

TECHNICAL FIELD OF THE INVENTION

[01 ], The invention falls within the technical field of ammunition for firearms, the arms and metallurgical industry, as well as in the fields of materials engineering and chemical engineering.

[02], More specifically, the present invention refers to an ammunition case made of polymeric material and equipped with a metal head, designed to have reduced weight and thus facilitate its transport. In addition, a process for manufacturing said ammunition is also proposed.

STATE OF THE ART KNOWN

[03], Ammunition cases made of polymeric materials are commonly used in weapons of different calibers, automatically, semi-automatically or bolted. They are indicated, for example, for use in machine guns and rifles.

[04], The motivation for the invention is based on the fact that weight reduction in weapons brings greater comfort to the user in surrender situations, which involve keeping the arms in an extended position, pointing the weapon towards a potentially dangerous individual while the user waits for reinforcements to arrive. This comfort results in better security for the user, who should then be able to stay on guard for longer, especially necessary when the location is difficult to access for reinforcements.

[05], Another benefit of polymeric cases is the better logistical use, since certain means of delivering weapons have serious weight restrictions in transport, such as armored vans in rough and steep terrain, and military planes.

[06], With the emergence of polymeric materials in the twentieth century, weapons made of plastic materials began to appear, such as the consecrated semi-automatic pistols from the Austrian manufacturer Glock, which have a frame made of injected polyamide, reducing the weight of the unloaded weapon from 970g ( Beretta 9mm) to just 670g, a 30% weight reduction.

[07], However, even though improvements have been made to reduce the weight of firearms, the effort made to reduce the weight of ammunition for these weapons has not yet succeeded in producing a robust, reliable and financially viable solution. Even though the individual weight of these types of ammunition is only 10 to 25 g for weapons considered light, the weight accumulates quickly when considering the fact that an ammunition loader has about 15 ammunition in the case of a pistol, 30 in the case of rifles and 100 for .50BMG caliber safes, for example. Also, on the occasion of armed conflicts, it becomes necessary to transport tons of cartridges to supply the infantry, and each gram saved in the weight of an individual cartridge translates into the supply of additional supplies when considering the size of the shipments involved.

[08], The lack of innovations in the technical field of cartridges for ammunition is due to concerns about safety and reliability involved in the elaboration of an adequate ammunition, as well as the costs and productivity of manufacture.

[09], Not only must a case hold the propellant charge securely, preventing accidental ignition, but it must also be able to support the assembly of the other components that make up the ammunition.

[10], In addition, the mechanical strength of the cartridge in response to propellant ignition must also be considered. Although ammunition is a consumable, and cartridges are often not reused, they cannot deform or fragment after a shot, since it is necessary to eject the empty case after a shot, feeding other ammunition into the weapon's chamber. and restarting the firing cycle. Deformations or remaining fragments of the previous cartridge can cause the weapon to jam, making the user vulnerable until he is able to unjam the weapon.

[11]. Traditionally, the material used for the production of cartridges is brass, since it is able to remain intact after firing the ammunition, and is also resistant to corrosion, remaining functional even after being immersed or stored in the presence of humidity, essential for the most diverse conditions of use.

[12], The manufacture of these cartridges is carried out by automated conformation processes, resulting in high productivity. However, this type of process generates hardening of the brass used, requiring interspersed steps of molding and annealing thermal treatments.

[13], One of the proposed alternatives for replacing stamped brass for the production of cases is the use of the plastic injection process, aiming at lower weight and production cost, in addition to greater productivity. This process is known in the industry for being one of the most efficient for the production of components on a large scale, however it presents a series of limitations regarding the geometry of the possible parts. to be produced.

[14], In the injection molding process, parts with hollow parts inevitably need a mold part, called a core, to make the inner portion of the part cavity. After injection, this male needs to be removed from the part, and for that, an extraction angle must be used on the manufactured component, like a cone inside another, so that it can exit through the largest opening in the part.

[15], In the case of ammunition, the geometry of the case is such that the projectile is mounted at the front end of this cone, and at the rear end a portion called the head is formed, where a fuze (primer) is mounted inside it. ) to serve as an ignition mechanism for the gunpowder stored in the cartridge, through the impact of the needle triggered by the gun's trigger. The head is also where the user, or the weapon itself (in the case of automatic and semi-automatic weapons), manipulates the cartridge to insert and remove it from the weapon's chamber.

[16], Due to these geometric requirements, the simplest way to mold an injection case is to do it without the head, with the injection mold male entering through this opening, and later to mount a head on the injected body, due to the limitations of this manufacturing process.

[17], So that the ammunition can be manipulated by the weapon, it is necessary that a portion of the head of the cartridge is outside the barrel, so that the head rim can be accessed by the bolt of the weapon. As this portion of the ammunition head is not supported by the barrel, it must have mechanical strength to withstand the pressure of gas expansion alone. In this way, it becomes impracticable to make a case only of polymeric materials, being necessary that the polymeric ammunition have the head in material of greater resistance than that used in the body portion.

[18], To circumvent these limitations, in the state of the art there are dozens of patents that provide for forms of attachment between head and body, some use interference couplings, adhesives, others stamp fastening elements and there are those that make couplings of the “Snap” type. -fit”. The patents that mold the head as an insert in the injection process will not be cited, as this manufacturing method cannot be used in a case with a shoulder and neck, as the core that forms the inner part of the case cannot be extracted from the part.

[19], As will be seen below, the currently existing technologies present four problems involving the union between the body of the polymeric case and the metallic head. The first problem consists of the low mechanical resistance in the fixation between these two parts of the ammunition case, providing a material with flaws in the union of these parts.

[20], The second problem consists of the inefficient sealing of the combustion chamber after the union of the body of the case with the metallic head, allowing more easily that the pressure of the gases escape between the parts and leave for the breech of the armament. The low-efficiency seal also allows water to enter, which compromises product quality due to increased humidity.

[21 ], The third problem that exists in state-of-the-art ammunition, called "Crush Condition", occurs when the elastic return of the case is less than the elastic return of the gun barrel. The case ends up being trapped by the barrel of the weapon This name comes from the fact that the case has plastically increased in size with the expansion, and with the pressure relief it ends up crushed by the barrel when returning to the original dimension.

[22], The fourth problem refers to the use of adhesives for attaching the head to the body of the ammunition case which, as will be seen later in the description of state-of-the-art technologies, reduces the mechanical resistance of the product, demands an increase in steps in the manufacturing process and chemically damages the material.

[23], In order to better understand the aforementioned problems, which are solved by the present invention, the technologies currently existing in the state of the art will be described below.

[24], Document US2021041213A1 , for example, reveals Snap-Fit couplings. However, to make its execution feasible, the body of the case needs to be thick and, consequently, it is not possible to extract a tap from inside the piece if it is thin in the region close to the neck and shoulder, but thick below where the “teeth” of the coupling would be molded. Making the entire body thick as it currently exists loses the internal volume needed to house the propellant and increases raw material consumption.

[25], Document KR102255849 describes an ammunition comprising a projectile, a polymer body case and a metal head. Although the use of a fixation ring is revealed, this ring is placed internally to the body of the case (it is an internal ring), having as its only function the fixation of the metallic head in the polymeric case. As a result of the design of an inner ring, the ammunition described in this article presents a problem with the "Crush Condition", because at the time of firing, the polymeric material in the case flows, without elastic return, jamming the internal barrel of the weapon. used an adhesive for the coupling of the internal fixation ring in the case, which reduces the quality of the final product. The use of adhesives to fix the body and head in the ammunition case manufacturing process results in a mechanically unreliable product, and undesirable chemical interactions between the adhesive and the polymer that constitutes the case body are still common, leading to its damage. In this prior art document, for example, attaching the ring to the case using an adhesive implies additional steps for curing, making the process as a whole more complex.

[26], Document US4726296 describes an ammunition assembly process, performed by interference. In this context, the fixation of the head on the body is carried out by interference and does not apply another action on the internal part of the head that interfaces with the polymer. Solutions that join the head and body by interference deform the case during assembly, affecting its dimensional accuracy. In addition, the use of adhesives, foreseen in this type of assembly, requires additional steps in the manufacturing process, increases the need for time-consuming controls for a product made on a large scale and reduces the quality of the final product. As described for KR102255849, the use of adhesives for body and head attachment in the ammunition case manufacturing process results in a mechanically unreliable product. This process disclosed in US4726296 served as one of the inspirations for the present invention, because the process used damages the polymer and the interference forces the plastic out of its nominal dimension. For the dimensional variation to be negligible, the coupling teeth must be small and soon lose efficiency in the transmission of the traction effort between head and body.

Purpose and solution provided by the invention

[27], The invention is an ammunition case comprising a polymeric body open at the front for mounting the projectile and at the back for mounting a head insert in aluminum alloy, reinforced by a ring of external fixation also in aluminum, using a thermal treatment of solubilization and aging in the insert to make the manufacturing process feasible.

[28], Due to the limitations of the injection process, and necessary properties to ensure safe operation, a geometric form was developed to join head and body where the head is made using aluminum alloys and a heat treatment to enable its execution. . The assembly is made using a mechanical forming process and to make this forming possible without reducing the mechanical strength necessary in the unsupported region, a thermal treatment of the component during the manufacturing sequence is proposed.

[29], The invention ends up solving the sum of the 4 (four) problems mentioned, involving the union between the body of the polymeric case and the head in metallic material. The first problem is circumvented by ensuring a resistant form of fastening that can extract the case without failure in the union between the parts.

[30], The second is solved by means of an efficient seal provided by the constructiveness of the ammunition case and the particularities of its production process. This efficient seal makes it possible to isolate the combustion chamber to prevent gas pressure from escaping between the parts and exiting to the breech of the armament, in addition to sealing against water ingress.

[31 ], The third problem (“Crush Condition”) is circumvented by using, in the ammunition case, a material with a lower elastic modulus in relation to the armament barrel, and said material having yield stress and/or work hardening high, so that it can elastically return to a dimension smaller than the variation of the barrel.

[32], Finally, the fourth technical problem is solved by the present invention through the non-use of adhesive materials in the process, resulting in the reduction of steps. Removing the adhesive in this context was only possible due to the new constructiveness of the ammunition case, the result of development efforts, as well as the adaptation of the production process of said ammunition case.

[33], The conventional solution for problems one, two and three (and consequently for problem four), in the proposed body geometry, is to make a metal head joined by a snap-fit coupling, but for that, the thickness of the body must be large enough to create the hitch teeth, and this consumes material and adds to the overall weight of the component.

[34], As a way to solve these problems and reduce the thickness of the case body, a geometry was proposed where the rear portion of the case has a cylindrical part to interface with the head. This head has a conformable section, called crown, in the shape similar to an accordion and an external fixation ring to support the act of conformation with the negative shape of this accordion. This solution by itself is not viable, as it generates an additional problem, solved in an unprecedented way in the art of low weight ammunition.

[35], The solution to this additional problem is to obtain a material with adequate mechanical resistance to withstand the pressure of the shot, but also to provide elongation necessary to allow the mechanical conformation necessary to form the coupling between head and body.

[36], In general, materials with high yield stress achieve this characteristic by compromising the elongation at break. And the reverse is also true: very ductile metals that can be deformed without breaking have relatively low yield stress. In this way, the solution to the additional problem can be seen as the need to make the ammunition head with these two antagonistic characteristics in the same material.

[37], To solve this difficulty, the invention proposes the use of a unique characteristic of aluminum alloys, the thermal treatment of solubilization and artificial aging. Using solubilization heat treatment, a structural aluminum alloy can be altered so that it has the necessary ductility for the mechanical forming process. This treatment is initiated with a heating that will cause the dissolution of the alloying elements in the solid solution.

[38], After that, the solubilization process and rapid cooling occur, usually in water, which prevents the precipitation of the alloy elements, forming a saturated solution. At this moment, it is possible to shape the component without breaking it, as the material is ductile and it is the ideal moment to mount the head on the polymeric body. After this, as the solubilized state is unstable, other phases naturally precipitate in the material and it regains its mechanical resistance, a phenomenon called natural aging.

[39], If one tries to make the way of fixing proposed in this invention, by forming, but in a material other than aluminum with the proposed heat treatment, the result is that the material will break in the forming because it is too rigid or, if is ductile, it will not have the necessary elastic return to escape the displacement of the pipe, and avoid the phenomenon of Crush Condition explained previously.

BRIEF DESCRIPTION OF THE INVENTION

[40], In a first aspect, the present invention refers to an ammunition case comprising a polymeric body, a head insert provided with a head ring, a fuze pocket and at least one event hole, said ammunition case comprises the head insert provided with a crown in its upper portion, and comprises an external fixation ring fitted into a recessed lower portion of the polymeric body and joined with the head insert, said union of the external fixation ring with said metal insert is provided by means of the shaped crown mechanically inside the lower portion of the polymeric body.

[41], In a second aspect, the present invention refers to a process for manufacturing the ammunition case, said ammunition case being as described in the present invention, and said process comprising the following steps:

(A) manufacture of the polymeric body;

(B) fabrication of the external fixation ring and the head insert;

(C) assembly of the external fixation ring next to the polymeric body, in which the polymeric body is inserted in a positioning device and the external fixation ring is moved by a press to its final position;

(D) assembly of the head insert in the polymeric body comprising the external fixation ring assembled according to the step, in which the press moves the head insert to its final position; It is

(E) forming the crown of the head insert against the external fixation ring by means of a punch; and obtaining the ammo kit.

BRIEF DESCRIPTION OF THE DRAWINGS

[42]. In order for the invention to be fully understood and put into practice by any technician in this technological sector, it will be described in a clear, concise and sufficient manner, based on the attached drawings, which illustrate and support it:

Figure 1 represents an exploded perspective view of the ammunition case;

Figure 2 represents a front sectional view of the ammunition case;

Figure 3 represents a front sectional view detailing the head insert mounted on the body;

Figure 4 represents a front view in section detailing the head insert;

Figure 5 represents a perspective detailing the head insert;

Figure 6 represents a schematic diagram of an example of an ammunition case production process.

DETAILED DESCRIPTION OF THE INVENTION

[43], In a first aspect, the present invention refers to an ammunition case (17), as shown in figures 1 and 2, comprising a polymeric body (1), a head insert (3) equipped with a rim head (8), a fuse pocket (11) and at least one event hole, said ammunition case (17) comprising the head insert (3) provided with a crown (4) in its upper portion, and comprises an external fastening ring (2) fitted into a recessed lower portion (5) of the polymeric body (1) and joined to the head insert (3), said union of the fastening ring external fixation (2) with said metal insert (3) is provided by means of the crown (4) mechanically shaped inside the lower portion of the polymeric body (1).

[44], In a non-restrictive embodiment of the present invention, the crown (4) comprises a corrugated external surface (16) mounted inside the lower portion of the polymeric body (1) and the external fixation ring (2) comprises a surface internal corrugated (18) surrounding the recessed portion (5) of the polymeric body (1).

[45], In a non-restrictive embodiment of the present invention, the polymeric body (1) comprises a front end (1A) connected with a rear end (1B) by means of a cone portion (9), said rear end ( 1B) comprising the recessed lower portion (5) of the polymeric body (1).

[46], In a non-restrictive embodiment of the present invention, the head insert (3) comprises, above the at least one event hole, a curvilinear shape followed by a conical portion of the crown (4), whose outer surface is corrugated ( 16) is surrounded by the recessed lower portion (5) of the polymeric body (1). In a non-restrictive embodiment of the present invention, the head insert (3) is a precipitation-hardenable metallic alloy, the external fixation ring (2) is a metallic material selected from the group comprising alloys of brass, steel or aluminum, preferably low alloy steels 2200, 2700, 4605, 316L, 420, 430L, 17-4, 17-4PH, 17-7, F15, Fe-3 % Si, Fe-50% Ni and Fe-50% Co. In addition to specific metal compositions may include common trade names, for example, C-0000 Copper and Copper Alloys; copper alloys; CNZP-1816 Copper and copper alloys; CT-1000 Copper and Copper Alloys; CZ-1000 copper and copper alloys; CZ-2000 copper and copper alloys; CZ-3000 Copper and Copper Alloys; CZP-1002 copper and copper alloys; CZP-2002 Copper and copper alloys; CZP-3002 Copper and Copper Alloys; F-0000 Iron and Carbon Steel; F-0000-K; F-0005 Iron and carbon steel; FC-0200 Iron-Copper and Copper Steel; FC-0205 Iron-Copper and Copper Steel; FC-0208 Iron-Copper and Copper Steel; FC-0505 Iron-Copper and Copper Steel; FC-0508 Iron-Copper and Copper Steel; FC- 0808 Iron-Copper and Copper Steel; FC-1000 Iron-Copper and Copper Steel; FD-0200 Diffusion Alloy Steel; FD-0205 Diffusion Alloyed Steel; FD-0208 Diffusion Alloy Steel; FD-0400 Diffusion Alloyed Steel; FD-0405 Diffusion Alloyed Steel; FD-0408 Diffusion Alloyed Steel; FF-0000 Soft Magnetic Alloys; FL-4005 Prealloyed Steel; FL-4205 Prealloyed Steel; FL-4400 Pre-alloyed Steel; FL-4405 Prealloyed Steel; FL-4605 Prealloyed Steel; FL-4805 Prealloyed Steel; FL-48105 Pre-alloyed Steel; FL-4905 Prealloyed Steel; FL-5208 Prealloyed Steel; FL-5305 Prealloyed Steel; FLC-4608 Sinter Hardened Steel; FLC-4805 sintered steel; FLC-48108 Sinter Hardened Steel; FLC-4908 Steel hardened by sintering; FLC2-4808 Sinter Hardened Steel; FLDN2-4908 Diffusion Alloy Steel; FLDN4C2-4905 Diffusion-alloyed steel; FLN-4205 Steel; FLN- 48108 Sinter hardened steel; FLN2-4400; FLN2-4405 Steel; FLN2-4408 Sinter Hardened Steel; FLN2C-4005; FLN4-4400; FLN4-4405 low alloy hybrid steel; FLN4-4408 Sinter Hardened Steel; FLN4C-4005; FLN6-4405; FLN6-4408 Sinter Hardened Steel; FLNC-4405; FLNC-4408 Sinter Hardened Steel; FN-0200 Iron-Nickel and Nickel Steel; FN-0205 Iron-Nickel and Nickel Steel; FN-0208 Iron-Nickel and Nickel Steel; FN-0405 Iron-Nickel and Nickel Steel; FN-0408 Iron-Nickel and Nickel Steel; FN-5000 Soft Magnetic Alloys; FS-0300 Soft Magnetic Alloys; Iron and steel infiltrated with copper FX-1000; Iron and steel infiltrated with copper FX-1005; FX-1008 Iron and Steel Infiltrated with Copper; Iron and steel infiltrated with copper FX-2000; FX-2005 Iron and Steel Infiltrated with Copper; FX-2008 Iron and Steel Infiltrated with Copper; FY-4500 Soft Magnetic Alloys; FY-8000 Soft Magnetic Alloys; P / F- 1020 Carbon Steel PF; P / F-1040 Carbon Steel PF; P / F-1060 Carbon Steel PF; P / F- 10C40 Copper Steel PF; P / F-10050 Copper Steel PF; P / F-10060 Copper Steel PF; P / F-1140 Carbon Steel PF; P / F-1160 Carbon Steel PF; P / F-11 C40 Steel Copper PF; P / F-11050 Steel Copper PF; P / F-11060 Steel Copper PF; P / F-4220 Low Alloy P / F-42XX Steel PF; P / F-4240 Low Alloy P / F-42XX Steel PF; P / F-4260 Low Alloy P / F-42XX Steel PF; P / F-4620 Low Alloy P / F-46XX Steel PF; P / F-4640 Low Alloy P / F-46XX Steel PF; P / F-4660 Low Alloy P / F-46XX Steel PF; P / F-4680 Low Alloy P / F-46XX Steel PF; SS-303L Stainless Steel — Series 300 Alloy; SS-303N1 Stainless Steel — Alloy Series 300; SS-303N2 Stainless Steel — Series 300 Alloy; SS-304H Stainless Steel — Series 300 Alloy; SS-304L Stainless Steel — Series 300 Alloy; SS-304N1 Stainless Steel — Series 300 Alloy; SS-304N2 Stainless Steel — Series 300 Alloy; SS-316H Stainless Steel — Series 300 Alloy; SS-316L Stainless Steel — Series 300 Alloy; SS-316N1 Stainless Steel — Series 300 Alloy; SS-316N2 Stainless Steel — Series 300 Alloy; SS-409L Stainless Steel — 400 Series Alloy; SS-409LE Stainless Steel — 400 Series Alloy; SS-410 stainless steel - 400 series alloy; SS-410L Stainless Steel - Alloy Series 400; SS-430L Stainless Steel — 400 Series Alloy; SS-430N2 stainless steel - 400 series alloy; SS-434L Stainless Steel — 400 Series Alloy; SS-434LCb Stainless Steel - 400 Series Alloy; and SS-434N2 stainless steel - 400 series alloy. Titanium alloys that may be used in this invention include any known alloy or modified alloy, including titanium grades 5-38 and more specifically titanium grades 5, 9, 18, 19, 20 , 21, 23, 24, 25, 28, 29, 35, 36 or 38. Grades 5, 23, 24, 25, 29, 35 or 36 annealed or aged; Grade 9, 18, 28 or 38 cold worked and stress relieved or annealed; Grade 9, 18, 23, 28 or 29 transformed beta condition; and Grades 19, 20 or 21 solution-treated or solution-treated and aged. Grade 5, also known as TÍ6AI4V, TÍ-6AI-4V or Ti 6-4, is the most commonly used alloy. It has a chemical composition of 6% aluminum, 4% vanadium, 0.25% (maximum) iron, 0.2% (maximum) oxygen and the remainder titanium. One embodiment includes a composition with 3-12% aluminum, 2-8% vanadium, 0.1-0.75% iron, 0.1-0.5% oxygen, and the remainder titanium. More specifically, about 6% aluminum, about 4% vanadium, about 0.25% iron, about 0.2% oxygen, and the rest titanium. For example, a Ti composition may include 10 to 35% Cr, 0.05 to 15% Al, 0.05 to 2% Ti, 0.05 to 2% Y2O5, with the balance being Fe, Ni or Co, or an alloy consisting of 20 ± 1.0% Cr, 4.5 ± 0.5% Al, 0.5 ± 0.1% Y2O5 or ThO2, with the balance being Fe. Examples of metals for use in the present invention include, but are not limited to: stainless steel, including martensitic and austenitic stainless steel, steel alloys, tungsten alloys, soft magnetic alloys such as iron, ferrosilicon, electrical steel, ferrous nickel (50Ni -50F3), low thermal expansion alloys or combinations thereof. In one embodiment, the powdered metal is a mixture of stainless steel, brass and tungsten alloy. The stainless steel used in the present invention can be any series 1 carbon steels, series 2 nickel steels, series 3 nickel-chromium steels, series 4 molybdenum steels, series chromium steels, series 6 chrome-vanadium steels, series 7 tungsten steels, 8 series nickel-chromium-molybdenum steels or 9 series silicon-manganese steels, e.g. 102, 174, 201, 202, 300, 302, 303, 304, 308, 309, 316, 316L, 316TÍ, 321, 405, 408 , 409, 410, 416, 420, 430, 439, 440, 446 or 601 -665 stainless steel. In another embodiment, the material used may be; SAE: 409, 410, 430, 440A, 440B, 440C, 440F, 410, 416, 420, 420F, 430F, 431 , 630 (17 -4 stainless steel), 301 , 301 LN, 304, 304L, 304L, 304L No, 304H, 305, 310, 3105, 316, 316LN, 316L, 316L, 316L, 316TÍ, 316LN, 317L, 321 , 321H, 2304, 2205, J405, 904L, 254SMO, 620Ni, 718Ni, 920 or super chrome.

[47], In a non-restrictive embodiment of the present invention, the polymeric body (1) is a polymeric material selected from the group comprising polyurethane prepolymer, cellulose, fluoropolymer, ethylene interpolymer alloy elastomer, ethylene vinyl acetate, nylon , polyetherimide, polyester elastomer, polyester sulfone, polyphenylamide, polypropylene, polyvinylidene fluoride or thermosetting polyurea elastomer, acrylics, homopolymers, acetates, copolymers, acrylonitrile-butadiene-styrene, thermoplastic fluoropolymers, inomers, polyamides, polyamide-imides, polyacrylates , polyacrylates, polyacrylates, polyacrylates, polycarbonates, polybutylene, terephthalates, polyether imides, polyether sulfones, thermoplastic polyimides, thermoplastic polyurethanes, polyphenylene sulfides, polyethylene, polypropylene, polysulfones, polyvinylchlorides, styrene acrylonitriles, polystyrenes, polyphenylene, ether mixtures, styrene maleic anhydrides, polycarbonates, allyls, aminos, cyanates, epoxies, phenolics, unsaturated polyesters, bismaleimides, polyurethanes, silicones, vinylesters, urethane hybrids, polyphenylsulfones, copolymers of polyphenylsulfones with polyethersulfones or polysulfones, copolymers of polyphenylsulfones with siloxanes, blends of polyphenylsulfones with polyphenylsulfones with polyethersulfones or polysulfones, polyphenyl copolymers sulfones with siloxanes , mixtures of polyphenylsulfones of polyphenylsulfones with copolymers of polyphenylsulfones and copolymers of polyphenylsulfones with siloxanes, mixtures of polyphenylsulfones and copolymides of polyphenylsulfones, polysiloxanes, or mixtures of polyetherimides and copolymers of poly(etherimide-siloxane), preferably the group of polysulfones.

[48], In a non-restrictive embodiment of the present invention, the metal alloy hardenable by precipitation is chosen from aluminum alloys.

[49], In a non-restrictive embodiment of the present invention, the at least one event hole is an event hole (12).

[50], In one embodiment of the present invention, the ammunition case (17) is free of any adhesive materials for fixing the components together, such as the polymeric body (1), the external fixation ring (2) or the head insert (3). The elimination of adhesive materials is mainly due to the constructiveness of the ammunition case (17) with its referred components, as well as to the case manufacturing process (17), as described herein. When developing the ammunition case (17) and its respective manufacturing process, the inventors discovered that the use of any adhesive material for bonding said components is unnecessary, favoring the achievement of an ammunition case (17) that is more mechanically robust. State-of-the-art technologies, for example, make use of adhesive materials to bond their components, impairing the quality of the final product, such as mechanical resistance during ammunition firing.

[51 ], The polymeric body (1 ) has the function of housing the projectile at the end of the smallest diameter formed by the front end (1 A). In this region, the clearances between the barrel and the ammunition case (17) are greater to facilitate loading into the weapon, and therefore, at the time of firing, the ammunition case material (17) needs to be compliant and deform radially without breaking, leaning on the pipe weaponry. This deformation also has the function of sealing the combustion chamber, so that the gases do not return backwards through the gaps between the polymeric body (1) and the armament barrel.

[52], For this reason it is possible to build the ammunition case (17) using polymeric material in the frontal section of the ammunition, that is, in the polymeric body (1) as a whole, however, the same cannot be said for the region of the head, said head region comprising the head insert (3) and the external fixation ring (2).

[53], At this other extreme, part of the ammunition, which comprises the ammunition case (17), is outside the barrel of the weapon and does not have the radial support of the armament to withstand the pressures of the explosive, and, for this reason, a metallic component is required. The function of the head insert (3) is precisely to provide this mechanical resistance, as metallic materials can reach yield stresses above 500 MPa, a value necessary to withstand the internal pressures of military ammunition, for example.

[54], Aided by figures 3 to 5, the geometry of the head insert (3) allows the assembly of a fuze in the fuze pocket (11 ) and allows it to be loaded and extracted from the barrel in the conventional way by the head ring (8 ). The head insert (3) has a central hole called the event hole (12), as mentioned above, through which the fuze flame communicates with the interior of the ammunition. The inside of the head insert (3), above the event hole (12), has a curvilinear shape like the lid of a pressure vessel to homogeneously dissipate the efforts of gas expansion. Above the inner bottom of the head, a conical portion, now called crown (4) in the present invention, presents the corrugated external surface (16) to form a union with its metallic counterpart of the external fixation ring (2), restricting the movement of the recessed lower portion (5) of the polymeric body (1) when formed. This corrugated outer surface (16) of the crown (4) is seen in the images with four peaks and three valleys between these peaks, but it may have a greater or lesser amount of peaks, if the efforts to extract the ammunition case (17) allow this number to be reduced. Inevitably a minimum of one peak is required for coupling to occur.

[55], The difference between the invention and the state of the art begins with the fact that the head insert (3) does not follow the conventional dimensions of ammunition, as it comprises the crown (4) with the corrugated external surface (16 ), where the coupling between the crown (4) and the polymeric body (1) occurs. This crown (4) is dimensioned in such a way that during the conformation is flexible, using the solubilization treatment, so that it is able to fasten the polymeric body (1) against the corrugated internal surface (18) of the fixation ring (2), thus forming the ammunition case.

[56], Finally, the external fixation ring (2) has the function of maintaining the dimensional of the ammunition case (17) when the crown (4) is formed, because without the external fixation ring (2) the side of the polymer body (1) would be crushed, from the inside out, by the crown (4) of the head insert (3). Another function of the external fixation ring (2) is to transfer the longitudinal efforts of the polymeric body (1) to the head insert (3), through the straight sections (13) and (14) that interface between the polymeric body (1) and the head insert (3). At the moment of shooting, the external fixation ring (2) helps in the elastic recoil of the assembled assembly, when the propellant pressure ceases, preventing the ammunition case (17) from being trapped inside the weapon's chamber.

[57], In a second aspect, the present invention relates to a process for manufacturing an ammunition case (17), said ammunition case (17) being as described in the present invention, and said process comprising the following steps , referring to figure 6:

(A) manufacture of the polymeric body (1);

(B) manufacture of the external fixation ring (2) and the head insert (3);

(C) assembly of the external fixation ring (2) next to the polymeric body (1), in which the polymeric body (1) is inserted in a positioning device (15) and the external fixation ring (2) is moved by a press (6) to its final position;

(D) assembly of the head insert (3) in the polymeric body (1) comprising the external fixation ring (2) assembled according to step (C), in which the press (6) moves the head insert (3) to its final position; It is

(E) conformation of the crown (4) of the head insert (3) against the external fixation ring (2) by means of a punch (7); and obtaining the ammunition kit (17).

[58], In a non-restrictive embodiment of the present invention, in step (A) - not illustrated in the flowchart of figure 6 - the polymeric body (1) is manufactured by manufacturing methods selected from injection molding, machining, extrusion, blowing , rotational molding, thermosetting resin potting or additive manufacturing, preferably injection molding. More specifically, although injection molding is the preferred method for manufacturing the polymeric body (1), it can alternatively be manufactured by machining a semi-finished product such as a bar or tube, for example. [59], In a non-restrictive embodiment of the present invention, in step (B) - not illustrated in the flowchart of figure 6 - the external fixation ring (2) and the head insert (3) comprising the crown (4) are manufactured by manufacturing methods selected from mechanical forming, machining, additive manufacturing, sintering, casting or metal injection.

[60], Still regarding step (B), the external fixation ring (2) and the head insert (3) can alternatively be manufactured using any of the methods available to produce components in aluminum alloys of the 2xxx families, 6xxx, 7xxx and 8xxx such as machine forming, machining, additive manufacturing, sintering or even casting methods such as diecast aluminum injection.

[61], Still regarding step (B), and in a non-restrictive embodiment of the present invention, the external fixation ring (2) and the head insert (3) are manufactured by machining, more specifically, turning. Although turning is preferred, the external clamping ring (2) and the metallic insert can alternatively be manufactured by additive manufacturing or sintering.

[62], In a non-restrictive embodiment of the present invention, the ammunition case manufacturing process (17) additionally comprises a step (C1), subsequent to step (B), and parallel or prior to step (C), said step (C1) comprising sending the head insert (3) to a solubilization heat treatment process (not illustrated in the flowchart), said solubilization process taking place in an oven at temperatures selected from the range between 480°C to 600°C , and in a period varying from 2 to 22 hours. The temperature and time are dependent on the type of metallic material comprising the head insert (3). Furthermore, during the heating process there may be more than one temperature step during this cycle to allow the controlled melting of the different elements in the material comprising the head insert (3). After this stage, the components are rapidly cooled, which may be in water at room temperature, and are ready for assembly and shaping.

[63], Still regarding step (C1), the solution heat treatment process is traditionally used in the aeronautical industry to enable the conformation of high-strength aluminum components. In this way, it is possible to make the fuselage of an aircraft with molded plates and, with subsequent aging, return its rigidity and resistance to withstand the mechanical efforts of the application.

[64], Still regarding step (C1), when the solubilization thermal treatment is used in a structural aluminum alloy, the material is temporarily softened giving the necessary ductility for the mechanical conformation of the head insert (3) in the later step (D). This treatment is done with a heating that will cause the alloying elements to dissolve in the solid solution. After that, the solubilization process and rapid cooling occur, usually in water, which prevents the precipitation of the alloying elements, forming a saturated solution. At that moment, it is possible to shape the head insert (3) without breaking it in step (C), since said head insert (3) is ductile. This is the ideal moment to mount the head on the polymeric body (1), and using the punch (7), apply, internally, the deformation in the region of the crown (4) necessary to adjust the polymeric body (1) between the metallic components (2) and (3).

[65], Still regarding step (C1), the solubilization thermal treatment can alternatively be carried out using induction heating techniques, where the necessary temperatures are the same, but the times can be reduced due to the greater heating ramp provided by this method.

[66], Still regarding step (C1), the application of the solubilization heat treatment is performed on the entire head insert (3) of the ammunition case, but the objective with this treatment is to soften the crown region (4 ) so that it can be deformed beyond the breaking strength of aluminum, which is low when it is in its aged condition. This is important, as forming must achieve large deformations to generate a robust assembly. Another gain from using this treatment is the reduction of the springback of the aluminum during forming, since the greater this springback after applying the punch displacement (7), the greater the tendency to loosen the connection between the parts when this displacement recedes and occurs. the effect also called Spring Back. It must be remembered that the elastic return of a material is proportional to its yield stress and inversely proportional to its elastic modulus. Thus, it is important that the conformation occurs when the material has its yield stress reduced to minimize the elastic return. In summary, the solubilization thermal treatment allows two gains in the assembly of the ammunition case (17): it enables large deformations when crimping the components, and it reduces the elastic return of the crown (4) when it is formed.

[67], Above it was described how the elastic return of the crown (4) is harmful to the ammunition case (17) during assembly, but it is important to understand, that at the time of firing the ammunition comprising said ammunition case (17), it becomes beneficial. This occurs because it is this return to the original form that prevents the ammunition from get stuck in the pipe, that is, it avoids the phenomenon of Crush Condition.

[68], Step (D) is performed similarly to step (C), and is also illustrated in the flowchart of figure (6). With the polymeric body (1) and the fixation ring (2) already assembled, the head insert (3) is positioned and inserted into the polymeric body (1). At this moment, the pieces are positioned with minimal interference, just enough so that they do not disassemble under the action of their own weight.

[69], After this, as the solubilized state is unstable, naturally other phases precipitate in the material and it regains its mechanical resistance. This phenomenon is called natural aging. The instability of the solubilized state can be maintained for long periods only if the component is cooled, and if the component is heated, the aging process is accelerated. The use of this heating after forming is called artificial aging.

[70], Regarding step (E), the punch (7) is used to conform the crown (4) against the fixation ring (2), which results in the fixation of the polymeric body (1) between the crown ( 4) and the fixing ring (2). This step is visualized in the flowchart of figure 6. To carry out the conformation in the crown (4) the punch (7) enters through the mouth of the ammunition case (17) where the projectile is mounted. This punch (7) has the internal shape of the crown (4) in its deformed configuration and, thus, when used, imprints a deformation on this cylindrical section of the crown (4). This cylindrical section yields under the action of the punch (7) and its end deforms the polymeric body (1), pressing it against the external fixation ring (2), and creating a contact pressure that seals the combustion chamber. The punch (7) can be pressed by a hydraulic press, applying a pressure selected from the range between 1 and 10 tons force.

[71]. In a non-restrictive embodiment of the present invention, the ammunition case manufacturing process (17) additionally comprises a step (F), said step (F) being subsequent to step (E), and said step (F) comprising the submission of the ammunition case (17) of step (E) for an artificial aging method, said artificial aging being carried out at temperatures between 150°C and 250°C and for a period varying between 2h to 24h.

[72], Still regarding step (F), in a large-scale industrial process of a product such as ammunition, for example, it is not possible to wait for natural aging to occur for the material to recover its resistance, as this process can take months. In these cases a second treatment, i.e. artificial aging, is necessary to make the ammunition ready for sale. [73], Still regarding step (F), it is important to ensure that the artificial aging occurs at a temperature lower than the thermal deflection temperature of the polymer used in the polymeric body (1 ), as measured using the ASTM D648 standard. When the polymeric body is produced with polysulfone resin or some mixture containing sulfonated polymer, the maximum temperature at which artificial aging takes place, following ASTM D648, is up to 197°C.

EXAMPLES

[74], The following examples are intended only to describe, for purposes of better understanding, preferred embodiments of the present invention, and should not, therefore, be understood as a restriction of scope.

[75], From the point of view of the ammunition case (17), it has the components described herein, consisting of the following constituent materials:

- the polymeric body consists of polyphenyl sulfone polymer (PPSU), being manufactured from raw material marketed under the Radel trademark;

- the external fixation ring (2) is made of aluminum metal 7075, being manufactured from raw material marketed under the Zicral trade mark; It is

- the head insert (3) is made of 7075 aluminum metal, being manufactured from raw material marketed under the Zicral trademark.

[76], For purposes of better understanding of the present invention, aluminum 7075 is an aluminum alloy comprising, by mass, 87.1 - 91.4% aluminum, 5 - 6% zinc, 2.1

- 2.9% magnesium and 1.2 - 2% silicon, titanium, chromium, iron, manganese and other constituent metals.

[77], From the point of view of the ammunition case manufacturing process (17), its particularities are defined below.

[78], In step (C1 ) the oven temperature is 480°C and the heating time is 30 minutes. From the point of view of quenching in water, this is carried out at room temperature. After cooling, the conformation performed by the punch (7) must occur within ten hours.

[79], In step (F), artificial aging is performed at a temperature of 197°C and for a period of two hours.

[80], It is important to note that the figures and description made do not have the ability to limit the ways of implementing the inventive concept proposed here, but rather to illustrate and make understandable the conceptual innovations revealed in this solution. Thus, the descriptions and images must be interpreted in an illustrative and non-limiting, and there may be other equivalent or analogous ways of implementing the inventive concept now disclosed and that do not deviate from the spectrum of protection outlined in the proposed solution.

Claims

1. AMMUNITION KIT comprising a polymeric body (1), a head insert (3) provided with a head ring (8), a fuze pocket (11) and at least one event hole (12), characterized by the head insert (3) comprises a crown (4) in its upper portion, and comprises an external fixation ring (2) fitted into a recessed lower portion (5) of the polymeric body (1) and joined with the head insert (3), and said union of the external fixation ring (2) with said metallic insert (3) is provided by means of the crown (4) mechanically shaped inside the lower portion of the polymeric body (1).

2. CASE, according to claim 1, characterized in that the crown (4) comprises a corrugated external surface (16) mounted inside the lower portion of the polymeric body (1) and the external fixation ring (2) comprises a surface internal corrugated (18) surrounding the recessed portion (5) of the polymeric body (1).

3. CASE according to any one of claims 1 to 2, characterized in that it comprises a front end (1A) connected to a rear end (1B) by means of a cone portion (9), said rear end (1 B) comprising the recessed lower portion (5) of the polymeric body (1).

4. CASE, according to any one of claims 1 to 3, characterized in that the head insert (3) comprises, above the at least one hole of the event, a curvilinear shape followed by a conical crown portion (4), whose Corrugated external surface (16) is surrounded by the recessed lower portion (5) of the polymeric body (1).

5. CASE according to any one of claims 1 to 4, characterized in that the head insert (3) is made of a metal alloy hardenable by precipitation.

6. CASE according to any one of claims 1 to 5, characterized in that the external fixation ring (2) and the head insert (3) are an aluminum alloy and the polymeric body (1) is PPSU.

7. CASE according to any one of claims 1 to 6, characterized in that at least one event hole is an event hole (12) and the ammunition case (17) is free of any adhesive materials for fixing the polymeric body (1 ), external fixation ring (2) or the head insert (3).

8. AMMUNITION CASE MANUFACTURING PROCESS, said ammunition case (17) being defined according to any one of claims 1 to 7, and said process being characterized by comprising the steps:

(A) manufacture of the polymeric body (1);

(B) manufacture of the external fixation ring (2) and the head insert (3);

9. PROCESS, according to claim 8, characterized in that it additionally comprises additional steps, said additional steps being:

- a step (C1), subsequent to step (B), and parallel or prior to step (C), said step (C1) comprising a heat treatment process for solubilizing the head insert (3); It is

- a step (F), said step (F) being subsequent to step (E), and said step (F) comprising a method of artificial aging of the ammunition case (17) obtained according to step (E).

10. PROCESS, according to claim 9, characterized in that the solubilization thermal treatment process is carried out between 490°C to 600°C, for a period between 2 and 22 hours.

11. PROCESS, according to claim 9, characterized in that the artificial aging method is carried out at temperatures between 150°C and 250°C, for a period between 2h and 24h.

12. Process according to any one of claims 8 to 11, characterized in that the polymeric body (1) of step A is manufactured by manufacturing methods selected from injection molding, machining, extrusion, blowing, rotational molding, thermosetting resin potting or additive manufacturing.

13. Process according to any one of claims 8 to 12, characterized in that the external fixation ring (2) and the head insert (3) comprising the crown (4) are manufactured by manufacturing methods selected from forming methods mechanical, machining, additive manufacturing, sintering, casting or metal injection.