EP2918962B1 - Method for producing a cartridge case - Google Patents

Description

The present invention relates to a method for producing a cartridge case.

In general, cartridge cases are made of a material with sufficient strength so that the cartridge case does not tear when igniting the charge and jammed in the chamber. Often cartridge cases are made of brass. Brass has the disadvantage that the cartridges are very heavy. Especially with the loading of vehicles or aircraft, this weight is disadvantageous.

Attempts have been made for a long time to produce cartridge casings of a lighter material, for example of aluminum. However, it has been shown at an early stage that aluminum cartridge cases do not easily withstand the stresses during firing. Therefore, for example, in CH 503 966 proposed to use a special alloy of aluminum, copper, magnesium and silicon. However, it is disadvantageous that a heat treatment must be carried out before the sleeve can be reduced at its open end by pulling in the diameter. That's why production takes a lot of time and is relatively expensive.

Apart from attempts to change the alloy constituents of an aluminum alloy in order to obtain a light yet sufficiently stable cartridge case, other development approaches are also to be pursued. For example, beats DE 1 007 215 to use a pulled out of aluminum sleeve in another, pushed over plastic sleeve. This is to break the aluminum in the Shot can be prevented by the elastic plastic.

A cartridge case made of aluminum is also made DE 75 823 known. There, the bottom of the cartridge case is provided with a jacket or insert of a stronger material such as steel or brass.

To achieve sufficient stability of a cartridge case with an aluminum jacket suggests DE 21 36 77 to make the bottom piece from a separate part and to connect form-fitting with the jacket made of aluminum. The two parts are positively connected with each other. DE 24 39 99 describes a cartridge case in which a cup-shaped bottom is made of nickel, in which subsequently a jacket of the cartridge case forming aluminum sleeve is used. By pressure and heat, the two parts are connected. In these methods, the two parts must be made separately and then joined together.

Out DE 23 69 70 is known a cartridge case, in which a plated sheet is used as the starting material for the production. In this case, a coating of aluminum or an aluminum alloy is applied to a thin steel sheet. During subsequent reshaping, care is taken to ensure that the aluminum coating is on the outside to protect the cartridge case from corrosion. The cartridge case thus has a full stainless steel sheath to protect the steel.

Out DE 700 255 C , Which represents the generic state of the art, it is known to use two different aluminum alloys for the production of a cartridge case.

At the FR 971 326 A known cartridge case, the jacket of the sleeve made of copper or brass and the bottom of the sleeve made of steel. Such cartridge cases are heavy.

Out CH 5 650 A is a cartridge case made of sheet steel with a plating known, which also brings a high weight with it.

US Pat. No. 3,659,528 proposes to use a multilayer composite material as a starting material, from which a cartridge case is made. The cartridge case, for example, consists of three superimposed layers, with two outer layers of an aluminum alloy and an intermediate layer of carbon steel. The preparation of the starting material is expensive and the weight because of the steel layer is still relatively high.

The production of a cartridge case of two different, metal-containing materials is known, but consuming. It has been shown that, for example, the superimposition of two blanks made of different materials and the subsequent forming in a press does not ensure a sufficient connection between the two materials. The known from the prior art method in which initially two cartridge sleeve parts are prepared and then joined together, are time consuming and expensive and therefore unsuitable for mass production.

Starting from the known prior art, it can therefore be regarded as an object of the invention to provide a cost-effective method for the production of lightweight cartridge cases, which have a sufficient strength.

This object is achieved by a method having the features of claim 1 and a method having the features of claim 7.

To produce the cartridge case, a first workpiece part made of a first material containing metal and a second workpiece part made of a metal-containing second material is provided in a first method according to claim 1. The two materials may each be an aluminum alloy in one embodiment. The hardness or strength of the second material is greater than that of the first material, which can be effected by different processing methods or alloying components. Each of the workpiece parts has a joining surface, wherein the two workpiece parts are connected flat at their joining surfaces. After two-dimensional joining of the two workpiece parts, a workpiece is produced, which is subsequently shaped in a press to form the cartridge case. Preferably, the forming of the workpiece is carried out by extrusion. This results in a cartridge case, the closed bottom portion of the second material of the second workpiece part and the shell portion consists essentially of the first material of the first workpiece part. An overlap area may exist between the bottom portion and the skirt portion by having both materials present.

Important in the joining of the two workpiece parts is the elimination of the metal oxide layer, which is present on the joining surfaces. If aluminum alloys are used for the two materials, the metal oxide layer is an aluminum oxide layer. Such an oxide layer prevents a sufficiently strong connection, which results in the subsequent forming to the fact that the cartridge case in the transition region between the two materials has weak points at which the cartridge case can break or break when igniting the charge.

In order to avoid this problem, it is provided in a method according to the invention to remove the metal oxide layers on the joining surfaces before or during the connection of the two workpiece parts with one another. As a result, a surface secure connection between the two materials or between the two workpiece parts is achieved, so that no weaknesses arise during forming of the workpiece. The cartridge case thus produced has in the bottom portion of a sufficiently high strength, which withstands the loads when igniting the charge. In addition, the weight of the cartridge case is reduced. By combining the two materials or workpiece parts to a workpiece before forming the forming press can work with high stroke rates and it is an efficient and inexpensive method for producing the cartridge case achieved.

• Beispielsweise kann die Metalloxidschicht durch Beizen, durch Wärmezufuhr oder Laserbehandlung entfernt und die beiden Werkstückteile anschließend durch Plattieren, insbesondere Walzplattieren miteinander verbunden werden. Dieses Verfahren eignet sich insbesondere für Gesamtdicken des Werkstücks von bis zu etwa 3 mm. In soweit können aus einem solchen Werkstück Patronenhülsen mit kleinem Kaliber hergestellt werden.

For removing the metal oxide layer in the first process according to the invention, there are various possibilities, depending on the bonding method used:

• For example, the metal oxide layer can be removed by pickling, by heat or laser treatment and the two workpiece parts are then connected to one another by plating, in particular roll-plating. This method is particularly suitable for total thickness of the workpiece of up to about 3 mm. As far as can be made of such a workpiece cartridge cases with a small caliber.

Alternatively, the metal oxide layer can be rendered harmless, as it were, by using a solder or bonding material as an intermediate in plating or roll cladding. As an intermediate layer, a material is used for plating or roll cladding which has a higher oxygen affinity than the metal of the first and second material. As a result, in spite of the existing metal oxide layer, a stable and solid surface connection between the two workpiece parts can be achieved. For example, a copper-based material is suitable as a material for the intermediate layer when the first and / or the second material contains aluminum.

It is also possible to connect the two workpiece parts by pulsed magnetic welding. In particular, the joining surface is formed on a workpiece such that it does not run parallel to the joining surface of the other workpiece part. Rather, the one joining surface, starting from all side edges, rises to a projecting point in a central region of the joining surface. For example, the relevant workpiece part in the region of the joining surface have a conical, a pyramidal, a frusto-conical or a truncated pyramidal shape. When juxtaposed, therefore, form around the protruding point a wedge-shaped gap. Due to the magnetic field during pulsed magnetic welding, the two joining surfaces are applied at high speed starting from this protruding point to each other, wherein the metal oxide present on the two joining surfaces is discharged from the gap in all directions and, so to speak, eject laterally. It creates a solid weld.

It is also possible to connect the two workpiece parts by friction welding. The two Joining surfaces are preferably designed as flat surfaces. Due to the relative rotation of the two joining surfaces against each other during friction welding, the metal oxide layer is removed and the metal oxide is discharged radially outward, so that here too a firm connection is created between the two workpiece parts.

It is also possible to connect the two workpiece parts by capacitor discharge welding. In particular, a projection or an elevation is present at the joining surface of a workpiece part. At the survey, the two joining surfaces abut each other. In addition to the survey, there is initially a gap between the two joining surfaces. By discharging the capacitor in the capacitor discharge welding a particularly high current density is achieved at the survey. The material liquefies and creates a kind of plasma cloud, which expands outwards in the gap and removes the metal oxide layers on the joint surfaces.

In a second inventive method according to claim 7, the workpiece, which consists of the first material and the second material, produced by casting in a mold. The casting mold has two mold sections separated from each other by a movable partition wall. The liquefied first or second material is filled into the respective associated mold section. The gradual or continuous slow withdrawal of the partition during solidification of the two materials, the two materials are connected flat. This process can be carried out in the absence of oxygen, so that no metal oxide layer can form in the joining region of the two materials and thus a firm connection between the two materials in the production of the workpiece by the casting arises.

In both methods of the invention, the first material is formed by an aluminum alloy containing no copper. As a result, the shell portion of the cartridge case can be deformed without heat treatment, for example, to collect the end portion in the region of the open end of the cartridge case. As a second material, for example, aluminum, brass or steel may be used or an alloy having at least one of these constituents.

Since a heat or annealing treatment of the cartridge case is avoided, embrittlement of the first material at the bottom portion - including at the edge of the cartridge case bottom - avoided because the überetektische silicon is not deposited at the grain boundaries. As a result, there is no risk that the cartridge case breaks when pulling out of the chamber after delivery of the shot.

Preferably, the thickness of the layer of the first material is greater than the thickness of the layer of the second material of the workpiece produced for forming. For example, the thickness of the layer of the first material 12 to 14 mm and the thickness of the layer of the second material 6 to 8 mm.

When forming the workpiece for producing the cartridge case, a cylindrical sleeve is first produced, for example by a one-stage or multi-stage extrusion process. Subsequently, the diameter of the end portion is reduced with the open end of the cylindrical sleeve, the sleeve is thus retracted in the end portion. This retraction takes place in particular without prior heat. After retraction, the cartridge case is replaced by a Cutting process cut to the desired length. Before or after drawing in, the bottom section is reshaped. In this case, for example, a ignition hole and / or an ejector groove can be produced.

In all of these connection methods, a stable connection between the two workpiece parts can be achieved very cost-effectively before forming. The forming itself can be done with high stroke rates.

• Figur 1 eine schematische Darstellung eines Ausführungsbeispiels zweier Werkstückteile in einer Seitenansicht,
• Figur 2 eine schematische Darstellung eines Ausführungsbeispiels eines Werkstücks in einer Seitenansicht,
• Figur 3 eine schematische Darstellung eines weiteren Ausführungsbeispiels eines Werkstücks in Seitenansicht,
• Figur 4 eine schematische eines Ausführungsbeispiels zur Verbindung zweier Werkstückteile durch Walzplattieren,
• Figur 5 eine schematische Darstellung einer abgewandelten Ausführungsform zur Verbindung der beiden Werkstückteile durch Walzplattieren,
• Figur 6 eine schematische Darstellung eines Ausführungsbeispiels zur Verbindung der beiden Werkstückteile durch Kondensatorentladungsschweißen,
• Figur 7 eine schematische Darstellung eines Ausführungsbeispiels zur Verbindung der beiden Werkstückteile durch Impulsmagnetschweißen,
• Figur 8 eine schematische Darstellung eines Ausführungsbeispiels zur Verbindung der beiden Werkstückteile durch Reibschweißen,
• Figur 9 eine schematische Darstellung zur Herstellung des Werkstücks aus zwei unterschiedlichen Werkstoffen durch Gießen und
• Figuren 10a bis 10h jeweils eine schematische Darstellung eines Stadiums für das Umformen des Werkstücks zur Patronenhülse.

Advantageous embodiments of the invention will become apparent from the dependent claims and the description. The description is limited to essential features of the invention. The drawing is to be used as a supplement. Hereinafter, embodiments of the invention will be explained in detail with reference to the drawing. Show it:

• FIG. 1 a schematic representation of an embodiment of two workpiece parts in a side view,
• FIG. 2 a schematic representation of an embodiment of a workpiece in a side view,
• FIG. 3 a schematic representation of another embodiment of a workpiece in side view,
• FIG. 4 a schematic of an embodiment for connecting two workpiece parts by roll cladding,
• FIG. 5 a schematic representation of a modified embodiment for connecting the two workpiece parts by roll cladding,
• FIG. 6 a schematic representation of an embodiment for connecting the two workpiece parts by capacitor discharge welding,
• FIG. 7 a schematic representation of an embodiment for connecting the two workpiece parts by pulse magnetic welding,
• FIG. 8 a schematic representation of an embodiment for connecting the two workpiece parts by friction welding,
• FIG. 9 a schematic representation of the production of the workpiece from two different materials by casting and
• FIGS. 10a to 10h each a schematic representation of a stage for the forming of the workpiece to the cartridge case.

The invention relates to a method for producing a cartridge case 20, as in FIG. 10h is shown schematically. The cartridge case 20 has a bottom portion 21 on which the cartridge case 20 is closed. At the bottom portion 21, a jacket portion 22 connects. In this shell portion 22, the cartridge case 20 is at least partially hollow cylindrical or conical and has a cavity 23 for receiving a propellant charge. At the bottom portion 21 opposite open end 24, the cartridge case 20 to the cavity 23 is open.

By means of the method according to the invention, a lightweight yet sufficiently stable cartridge shell 20 is to be produced. To achieve this, the cartridge case 20 is made of two different materials. Both materials contain or consist of metal. A first material W1 is formed from a copper-free aluminum alloy. A second material W2 has a greater hardness than the first material W1 and is also formed in the exemplary embodiment by a comparison with the aluminum alloy of the first material W1 harder aluminum alloy. Alternatively, the second material W2 could also be brass or steel or an alloy of one of these components.

From these two materials W1, W2, a workpiece 25 is produced. The workpiece 25 serves as a starting material for the forming. From the workpiece 25, the cartridge case 20 is produced by forming, as will be described later with reference to FIGS. 10a to 10h will be explained.

The workpiece 25 can be manufactured in various ways. In FIG. 9 is a first embodiment of a manufacturing method for producing the Workpiece 25 illustrated. A mold 30 having two mold sections 32, 33 separated from each other by a movable partition 31 is provided. The mold sections 32, 33 form a cavity in the mold 30, which corresponds to the shape of the workpiece 25 to be produced. In FIG. 9 this is illustrated only in a very schematic way.

Liquefied first material W1 and second material W2 liquefied in the respective other mold section 33 are filled into one mold section 32. During the solidification process, the partition wall 31 is gradually pulled out of the mold 30, so that the still flowable materials W1, W2 directly contact each other and establish a connection with each other. This process can take place in the absence of an oxygen atmosphere, so that no metal oxide layer and, in the exemplary embodiment, no aluminum oxide layer can form on the joining surface between the first material W1 and the second material W2.

It is additionally possible to apply a compressive force F to movable walls or wall sections of the casting mold 30, so that the flowable materials W1, W2 the volume additionally available during extraction of the partition wall 31 within the casting mold 30 without formation of voids in the produced workpiece 25 fill at the joint.

Thus, a workpiece 25 is made as shown in FIG FIG. 2 schematically illustrated in side view. The two materials W1, W2 abut each other directly at a joint. The workpiece 25 thus has a layered structure and consists of a first workpiece part 37 of the first workpiece material W1 and a second workpiece part 38 of the second material W2. The two workpiece parts 37, 38 may in particular have a circular peripheral shape. The workpiece 25 preferably has a cylindrical shape. The thickness D1 of the first workpiece part 37 may be different and in particular greater than the thickness D2 of the second workpiece part 38. The thickness D2 of the second workpiece part 38 substantially corresponds to the thickness of the bottom portion 21 of the cartridge shell 20 to be produced. The thickness D1 of the first workpiece part 37 is depending on the length of the shell portion 22 of the cartridge case 20 predetermined.

For the preparation of the workpiece 25, there are in addition to the basis of FIG. 9 described pouring also other possibilities. In this case, the two workpiece parts 37, 38 are provided in particular separately and joined together flat by a joining process. For connection, the first workpiece part 37 has a first joining surface 39 and the second workpiece part 38 has a second joining surface 40. By connecting the two workpiece parts 37, 38 on their fins surfaces 39, 40, the workpiece 25 is produced. In this case, the circular peripheral shape before the joining process can already be present or produced at the two workpiece parts 37, 38 or the circular peripheral shape for the workpiece 25 can alternatively by connecting a sheet-metal or band-shaped workpiece parts 37, 38 by a separation process, such as cutting or Punching, to be obtained.

When connecting the two workpiece parts 37, 38 there is the problem that forms on the joining surfaces 39, 40, a metal oxide layer 41 and, for example, an aluminum oxide layer, which prevents a stable connection of the two workpiece parts 37, 38 with each other or at least hindered. This may result in later forming of the workpiece 25 to the cartridge case 20 to weak points or connection defects between the two materials W1, W2 come. This in turn means that the cartridge case 20 tear or break during ignition of the propellant charge and can jam in the chamber.

For example, it is therefore proposed to remove or render harmless the metal oxide layer 41 before or during connection of the two workpiece parts 37, 38. Based on FIGS. 4 to 8 For this purpose, different joining methods are explained, wherein workpieces 25 according to FIG. 2 or 3 arise.

In an embodiment according to the FIGS. 4 and 5 For example, two band-shaped or sheet-shaped workpiece parts 37, 38 are connected to one another by plating and, for example, by roll-plating. In the first embodiment according to FIG. 4 For this purpose, the metal oxide layer is removed by pickling, by heat or using a laser prior to roll-plating. As a result, a good connection to the joining surfaces 39, 40 can subsequently be achieved during roll cladding. It arises after joining and leaving a workpiece 25 according to FIG. 2 ,

Alternatively, the metal oxide layer 41 may remain on the workpiece parts 37, 38 and an intermediate layer 42 between the two workpieces 37, 38 may be used for welding by roll cladding. The intermediate layer 42 is made of a material having a higher oxygen affinity than the metal of the first material W1 and the second material W2. In the embodiment, therefore, the intermediate layer must have a greater oxygen affinity than aluminum. For example, a copper-based material may be used as the intermediate layer. Because of the greater oxygen affinity of the liner 42 A firm connection between the two workpiece parts 37, 38 is created without the aluminum oxide layer or metal oxide layer 41 having to be removed beforehand. It arises after joining and leaving a workpiece 25 according to FIG. 3 ,

In FIG. 6 is highly schematic illustrates the possibility of connecting the two workpiece parts 37, 38 by capacitor discharge welding. In this case, a high voltage is applied to the two workpiece parts 37, 38, to which a capacitor has been previously charged. In the exemplary embodiment, a projection or an elevation 46 is provided on one of the two workpiece parts 37, 38 and, according to the example, on the first workpiece part 37. The elevation 46 may be designed with a similar cross-section, for example a circular cross-section. The elevation 46 is present on the first joining surface 39. Only on the survey 46 are the two workpiece parts 37, 38 initially against each other. In addition to the elevation 46 thus initially remains a gap between the two joining surfaces 39, 40 of the workpiece parts 37, 38. If then the capacitor voltage applied to the two workpiece parts 37, 38, flows through the survey 46, a current with high current density. The elevation 46 is thereby melted and it can develop a plasma cloud. The molten material is displaced from the elevation 46 through the gap to the outside. In this case, the metal oxide layers 41 at the joining surfaces 39, 40 are removed and the two workpiece parts 37, 38 are welded together firmly. The elevation 46 is preferably present in a middle section of the respective joining surfaces 39, 40. The result is a workpiece 25, as shown schematically in FIG FIG. 2 is illustrated.

Another possibility to connect the two workpiece parts 37, 38 is in FIG. 7 shown. In this method, the workpiece parts 37, 38 are connected to each other by pulse magnetic welding. By way of example, a profile which rises from the edge of the first joining surface 39 to a projecting point of the first joining surface 39 is present on one of the joining surfaces 39, 40 and, according to the example, on the first joining surface 39. The first joining surface 39 may therefore have the shape of the shell of a pyramid, a truncated pyramid, a cone or a truncated cone. In the embodiment, the first joining surface 39 has a conical surface shape, so that the first workpiece part 37 rests against the tip 47 of the cone on the second workpiece part 38. The height of the gap between the two joining surfaces 39, 40 thus increases starting from the tip 47 toward the edge of the two joining surfaces 39, 40.

Via a coil, a magnetic field M is generated, which acts at least on the first workpiece part 37 and there causes a force that presses the first workpiece part 37 on the second workpiece part 38 back. By suddenly generating the magnetic field M with a large field strength, the force acting on the workpiece part 37 force can cause a large forming speed, wherein the first joining surface 39, starting from the tip 47 gradually applies to the second joining surface 40 of the second workpiece part 38. In this application, which can be done at supersonic speed, the metal oxide layers 41 are blasted off at the two joining surfaces 39, 40 and removed to the outside through the wedge-shaped gap. In this method, a firm connection between the two materials W1, W2 of the two workpiece parts 37, 38 is achieved and there is a workpiece 25 as shown schematically in Figure 2.

FIG. 8 shows another way to connect the two workpiece parts 37, 38 by friction welding. The two joining surfaces 39, 40 are parallel to each other in this method and are aligned at right angles to a rotation axis D. In friction welding, for example, one of the two workpiece parts 37, 38 is driven to rotate about the axis of rotation D and at the same time the two joining surfaces 39, 40 of the two workpiece parts 37, 38 are pressed against each other. In this case, the two metal oxide layers 41 at the joining surfaces 39, 40 are abraded, as it were, and the metal oxide is pressed radially outward with respect to the axis of rotation D. Due to the frictional heat of the first material W1 and / or the second material W2 are liquefied and interconnected. Because of the different melting points of the metal oxide in the metal oxide layer 41 and of the metal in the materials W1 and W2, the metal oxide layer 41 is first removed before a welding together of the two materials W1, W2 takes place. Also in this method, a workpiece 25 is produced, as shown schematically in FIG FIG. 2 is shown.

In the FIGS. 10a to 10h various stages of the forming process starting from the workpiece 25 to the finished cartridge case 20 are illustrated. As a workpiece 25, both the in FIG. 2 shown schematically workpiece 25 are used, in which the two materials W1, W2 of the two workpiece parts 37, 38 abut directly against each other at the joint, or it can the workpiece 25 according to FIG. 3 be used, in which at the joint between the first material W1 and the second material W2, an intermediate layer 42 is present.

Starting from the workpiece 25 from the two workpiece parts 37, 38, according to the example, in a first step ( FIG. 10b ) made a cup 55 (so-called "cup"). This can be done, for example, by ironing or pulling or extruding.

Subsequently, in a second step, a cylindrical sleeve 56 is produced from the cup 55, for example by extrusion (US Pat. FIG. 10d ). This forming process of the cup 55 in the cylindrical sleeve 56 may also include one or more intermediate stages 57, which is exemplified in FIG. 10c is illustrated.

The cylindrical sleeve 56 has the bottom portion 21, which consists of the second material W2, to which the shell portion 22 made of the first material W1 connects. After producing the cylindrical sleeve 56, in a third step ( FIG. 10e ) an ignition hole 58 in the bottom portion 21 along the central longitudinal axis of the cylindrical sleeve 56 is introduced. In addition, the end portion 59 having the open end 24 of the cylindrical sleeve 56 is formed by drawing, so that the diameter of the cylindrical sleeve 56 in the region of the end portion 59 is smaller than in the part of the almond portion 22, which adjoins the bottom portion 21. In the embodiment, the end portion 59 has a conical portion 59a and a cylindrical portion 59b having the open end of the cylindrical sleeve 56.

The retraction of the cylindrical sleeve 56 in the end portion 59 is shown schematically in FIG FIG. 10f shown. When retracting the end portion 59 no heat input is necessary due to the copper-free aluminum alloy of the first material W1. The first material W1 can be reshaped without supplying heat first.

As in Figure 10g 1, depending on the type of cartridge case 20, an ejector groove 60 may be inserted into the bottom portion 21. The ejector groove 60 is annular and open radially outward. It is used in automatic weapons to eject the cartridge case 20 after the ignition of the propellant charge.

The in the FIGS. 10e to 10g Sub-steps shown can be performed in any order.

Finally, in the last step ( FIG. 10h ) an annular part in the region of the open end 24 is separated, so that the cartridge case 20, the desired length and a straight edge at the open end 24 receives. The separation can be carried out for example by means of a pulse magnetic separation process.

The invention relates to a method for producing a cartridge case 20 according to claim 1 or claim 7. The cartridge case 20 is to reduce its weight from a lightweight first material W1 in a shell portion 22 and a solid second material W2 in a bottom portion 21. Als first material W1 is a copper-free aluminum alloy used. The first material W1 is non-deformable without heat. As the second material W2 also an aluminum alloy can be used, which has a greater hardness compared to the aluminum alloy of the first material W1.

The two materials W1, W2 are connected together to produce a workpiece 25. For example, a casting method can be used for this purpose. Alternatively, it is also possible to connect a first workpiece part 37 made of the first material W1 and a second workpiece part 38 of the second material W2 in the region of their respective joining surface 39, 40 with each other. In order to achieve a firm connection, a is at the joining surfaces 39, 40 forming metal oxide layer 41 removed before or during the connection or made harmless by the use of an additional intermediate layer 42.

20

Patronenhülse

21

Bodenabschnitt

22

Mantelabschnitt

23

Hohlraum

24

offenes Ende

25

Werkstück

30

Gussform

31

Trennwand

32

Formabschnitt

33

Formabschnitt

37

erstes Werkstückteil

38

zweites Werkstückteil

39

erste Fügefläche

40

zweite Fügefläche

41

Metalloxidschicht

42

Zwischenlage

46

Erhebung

47

Spitze

55

Becher

56

zylindrische Hülse

57

Zwischenstufe

58

Zündloch

59

Endabschnitt

59a

konischer Teil

59b

zylindrischer Teil

60

Auswerferrille

D

Drehachse

F

Druckkraft

M

Magnetfeld

W1

erster Werkstoff

W2

zweiter Werkstoff

LIST OF REFERENCE NUMBERS

20

cartridge case

21

bottom section

22

shell section

23

cavity

24

open end

25

workpiece

30

mold

31

partition wall

32

mold section

33

mold section

37

first workpiece part

38

second workpiece part

39

first joining surface

40

second joint surface

41

metal

42

liner

46

survey

47

top

55

cups

56

cylindrical sleeve

57

intermediate stage

58

touchhole

59

end

59a

conical part

59b

cylindrical part

60

Auswerferrille

D

axis of rotation

F

thrust

M

magnetic field

W1

first material

W2

second material

Claims (10)

1. Method for producing a cartridge case (20) with the following steps:

   - provision of a first workpiece part (37) with a first joint surface (39), from a first material (W1) containing a metal, wherein the first material (W1) is formed by an aluminium alloy which is free from a copper content,

   - provision of a second workpiece part (38) with a second joint surface (40), from a second material (W2) containing a metal, wherein the hardness of the second material (W2) is greater than that of the first material (W1),

   - superficial connection of the two workpiece parts (37, 38) with their joint surfaces (39, 40) abutting each other, wherein before or during the connection of the two workpiece parts (37, 38), a metal oxide layer (41) present on the respective joint surfaces (39, 40) is removed or the metal oxide layers (41) are connected to an intermediate layer (42),

   - forming of the workpiece (25) produced from the two connected workpiece parts (37, 38) into a cartridge case (20), wherein on forming the workpiece (25), firstly a cylindrical sleeve (56) is produced with a casing portion (22) of the first material (W1) and a base portion (21) of the second material (W2), wherein the open end portion (59) of the sleeve (56) is then reduced in diameter, and wherein the forming of the open end portion (59) to reduce its diameter takes place without prior heat supply.
2. Method according to claim 1, characterised in that the metal oxide layer (41) is removed before connection, and the two workpiece parts (37, 38) are then connected together by plating.
3. Method according to claim 1 or 2, characterised in that the two workpiece parts (37, 38) are connected together by plating, and the intermediate layer (42) consists of a material which has a higher oxygen affinity than the metal of the first and second workpieces (W1, W2).
4. Method according to claim 1, characterised in that one of the joint surfaces (39) rises towards its surface centre (47), and the two workpiece parts (37, 38) are connected together by pulse-magnet welding.
5. Method according to claim 1, characterised in that the two workpiece parts (37, 38) are connected together by friction welding, wherein the metal oxide layers (41) are removed by the relative twist of the two joint surfaces (39, 40) relative to each other.
6. Method according to claim 1, characterised in that one of the joint surfaces (39, 40) has a protrusion (46), and the two workpiece parts (37, 38) are connected together by capacitor discharge welding.
7. Method for producing a cartridge case (20) with the following steps:

   - provision of a casting mould (30) with two mould portions (32, 33) which are separated from each other by a movable partition wall (31),

   - introduction of a liquefied first material (W1) containing metal into the one mould portion (32), wherein the first material (W1) is formed by an aluminium alloy which is free from a copper content,

   - introduction of a liquefied second material (W2) containing metal into the other mould portion (33), wherein the hardness of the second material (W2) is greater than that of the first material (W1) when the two materials (W1, W2) are fully set and cooled,

   - extraction of the partition wall (31) while the two materials (W1, W2) are setting and thereby connecting together superficially, so as to produce a workpiece (25) from two mutually connected workpiece parts (37, 38),

   - removal of the workpiece (25) from the casting mould (30),

   - forming of the workpiece (25) produced from the two connected workpiece parts (37, 38) into a cartridge case (20), wherein on forming the workpiece (25), firstly a cylindrical sleeve (56) is produced with a casing portion (22) of the first material (W1) and a base portion (21) of the second material (W2), wherein the open end portion (59) of the sleeve (56) is then reduced in diameter, and wherein the forming of the open end portion (59) to reduce its diameter takes place without prior heat supply.
8. Method according to any of the preceding claims, characterised in that the second material (W2) contains aluminium or nickel or brass.
9. Method according to any of the preceding claims, characterised in that the second material (W2) comprises aluminium, brass or steel or consists of one of these materials.
10. Method according to any of the preceding claims, characterised in that the thickness (D1) of the first workpiece part (37) is greater than the thickness (D2) of the second workpiece part (38).

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