EP2918962A1 - Method for producing a cartridge case - Google Patents

Abstract

The invention relates to a method for producing a cartridge case (20). To reduce its weight, the cartridge case (20) consists of a lightweight first material (W1) in a shell portion (22) and of a solid second material (W2) in a bottom portion (21). As the first material, a copper-free aluminum alloy is used according to the example. The first material is non-deformable without heat input. As the second material may also be used an aluminum alloy, which has a greater hardness compared to the aluminum alloy of the first material. The two materials are joined together to form a workpiece by a casting process or a plating process.

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 intended to prevent tearing of the aluminum during the shot through 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 the subsequent reshaping, care is taken 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 It is known to use two different aluminum alloys for producing a cartridge case.

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.

For the production of the cartridge case, in a first method according to the invention a first workpiece part from a metal-containing first material and a second workpiece part made of a metal-containing second material. 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 in the subsequent forming leads 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 the charge ignites.

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 charges when igniting the charge. In addition, the weight of the cartridge case is reduced. By connecting 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.

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 may be formed by using a solder or bonding material as an intermediate layer be rendered harmless during plating or roll cladding, so to speak. 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, a wedge-shaped gap is formed around the protruding point. Due to the magnetic field in pulsed magnetic welding, the two paddles are applied at high speed starting from this projecting point to each other, wherein the metal oxide present on the two joining surfaces is discharged in all directions from the gap and eject so to speak 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 Kodensators Kodensatorentladungsschweißen 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 method according to the invention, the workpiece, which consists of the first material and the second material, is produced by casting in a casting 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 bonding region of the two materials and thus a firm connection between the two materials in the production of the workpiece by casting arises.

In both methods according to the invention, the first material may be formed by an aluminum alloy which in particular does not contain 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 becomes the open end of the cylindrical sleeve reduced, the sleeve is thus retracted in the end section. This retraction takes place in particular without prior heat. After retraction, the cartridge case is cut to length by a separation process 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 in the embodiment of 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 a first embodiment of a manufacturing method for producing the workpiece 25 is 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 D 1 of the first workpiece part 37 can be different and in particular greater than the thickness D 2 of the second workpiece part 38. The thickness D 2 of the second workpiece part 38 essentially corresponds to the thickness of the bottom section 21 of the cartridge shell 20 to be produced. The thickness D 1 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 can already be present or produced in the two workpiece parts 37, 38 before the joining process or the circular Umfrangsform for the workpiece 25 may 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 at 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. As a result, weak points or connecting defects between the two materials W1, W2 may occur during later forming of the workpiece 25 relative to the cartridge case 20. 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 o- 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 are 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 intermediate layer 42, a firm connection is created between the two workpiece parts 37, 38 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 survey 46 is melted thereby 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 for connecting 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 sudden generation of the magnetic field M with a large field strength, the force acting on the workpiece part 37 a force cause 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 a further possibility for connecting 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 drawing or extrusion.

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 open end 24 having end portion 59 of the cylindrical sleeve 56 is formed by retraction, 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 Mandelabschnitts 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 process for the preparation a cartridge case 20. 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. As a first material W1 example, a copper-free aluminum alloy is 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 metal oxide layer 41 forming on the joining surfaces 39, 40 is removed before or during the connection or rendered harmless by the use of an additional intermediate layer 42.

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 (13)

Method for producing a cartridge case (20), comprising the following steps: Providing a first workpiece part (37) made of a metal-containing first material (W1) with a first joining surface (39), - Providing a second workpiece part (38) made of a metal-containing second material (W2) with a second joining surface (40), wherein the hardness of the second material (W2) is greater than that of the first material (W1), - Surface connection of the two workpiece parts (37, 38) with their joining surfaces (39, 40) to each other, wherein before or during the joining of the two workpiece parts (37, 38) each on the joining surfaces (39, 40) existing metal oxide layer (41) removed or the metal oxide layers (41) are connected to an intermediate layer (42), - Forming the workpiece (25) produced from the two connected workpiece parts (37, 38) to form a cartridge case (20). Method according to claim 1,
characterized in that the metal oxide layer (41) is removed prior to bonding and the two workpiece parts (37, 38) are subsequently joined together by plating. Method according to claim 1 or 2,
characterized in that the two workpiece parts (37, 38) are joined together by plating and the intermediate layer (42) is made of a material having a higher oxygen affinity than the metal of the first and second materials (W1, W2). Method according to claim 1,
characterized in that one of the joining surfaces (39) rises towards its mid-surface (47) and the connection of the two workpiece parts (37, 38) takes place by pulsed magnetic welding. Method according to claim 1,
characterized in that the connection of the two workpiece parts (37, 38) takes place by friction welding, wherein the metal oxide layers (41) by the relative rotation of the two joining surfaces (39, 40) is removed from each other. Method according to claim 1,
characterized in that one of the joining surfaces (39, 40) has a projection (46) and the connection of the two workpiece parts (37, 38) takes place by capacitor discharge welding. Method for producing a cartridge case (20), comprising the following steps: Providing a mold (30) with two mold sections (32, 33) separated from each other by a movable partition wall (31), Filling a liquefied metal-containing first material (W1) into the one mold section (32), - filling a liquefied, metal-containing second material (W2) in the respective other mold section (33), wherein the hardness of the second material (W2) is greater than that of the first material (W1), if the two materials (W1, W2) completely solidified and cooled, - Pulling out the partition (31) while the two materials (W1, W2) solidify and thereby connect flat to each other, so that a workpiece (25) consists of two interconnected workpiece parts (37, 38), Removing the workpiece (25) from the mold (30), - Forming the workpiece (25) produced from the two connected workpiece parts (37, 38) to form a cartridge case (20). Method according to one of the preceding claims, characterized in that the first material (W1) and / or the second material (W2) contains aluminum or nickel or brass. Method according to one of the preceding claims, characterized in that the first material (W1) are formed by an aluminum alloy which is free of a copper content. Method according to one of the preceding claims, characterized in that the second material (W2) comprises aluminum, brass or steel or consists of one of these materials. Method according to one of the preceding claims, characterized in that the thickness (D1) of the first Werstückteils (37) is greater than the thickness (D2) of the second workpiece part (38). Method according to one of the preceding claims, characterized in that during the forming of the workpiece (25) first a cylindrical sleeve (56) is produced, the open end portion (59) is subsequently reduced in diameter. Method according to claim 12,
characterized in that the forming of the open end portion (59) to reduce its diameter without prior heat.

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