RU2113309C1 - Method of manufacture of small arms cartridge cases - Google Patents

Abstract

FIELD: plastic metal working. SUBSTANCE: cartridge case is produced from a rod by cutting-off a measured piece from it. A stepped cup-shaped semifinished product is made with a primer holder formed by combination of reverse and direct extrusion. Then drawing is accomplished with ironing of the wall in the expanded part of the step. After that the flange is formed. Then a complex of finishing operations is carried out. Provision is made for different variants of fulfillment of the above operations. EFFECT: facilitated procedure. 15 cl, 11 dwg

Description

 The invention relates to the processing of metals by pressure and can be used in the manufacture of cartridges for small arms cartridges and similar products.

 There are various methods for producing such liners from sheet or bulk blanks.

 A known method of producing sleeves from sheet material, which includes cutting a cup, rolling it into a cap, then a multi-operation hood with thinning the walls with intermediate anneals, trimming the edges, forming a capsule socket and flange, punching ignition holes and crimping the barrel [1]. The considered process for producing sleeves has a long technological cycle and low metal utilization.

 Known methods for producing sleeves from rod material by cutting a workpiece, back extruding the cup and then directly extruding the sleeve wall with preliminary and intermediate heat treatments, drawing-calibration with thinning the wall to obtain the thickness of the specified dimensions, trimming the edge and then using the above analogue technology [2]. The disadvantage of this method is also a long technological cycle and, in addition, for direct extrusion, an ideal glass is required as a workpiece, both in difference and along the edge kosin.

 In the future, this method was improved due to the fact that, after backward extrusion, combined extrusion of the walls of the hollow billet was also used in the form of a cup, which reduced the accuracy requirements for this billet [3]. At the same time, it became possible to exclude a separate operation of trimming the edge by combining it with a hood-calibration. However, the technological cycle is still long due to the need for bottom stamping and capsule socket formation.

 There is also a method of producing sleeves from a pipe, characterized in that the cut-off measured workpiece of the corresponding mass is crimped to obtain a stepped glass-shaped semi-finished product, after which a capsular socket is formed and a flange is formed, and then a hood is drawn with thinning the wall in the part of the glassy semi-finished product having a larger diameter [4 ]. At the same time, the energy intensity of the process and the technological cycle are reduced, but a number of disadvantages arise. 1. When a pipe is cut in a stamp, burrs appear both inside the pipe and outside, for the removal of which an additional operation is necessary; 2. Transportation costs increase, since for the delivery of pipes of the same weight from a metallurgical to a machine-building enterprise, more transport is required than for bar stock; 3. An increase in rejects at the stage of delivery due to easy creasing of the pipes, insufficient accuracy in delimitation and kosin.

 These shortcomings are eliminated in the proposed method, in which a cylindrical stepped glass-shaped semi-finished product with a capsule socket decorated with a combination of direct and reverse extrusion is produced from a measured blank cut off from the rod, then an hood is drawn with thinning the wall in the expanded part of its stage. Then form a flange. Subsequently, a complex of finishing operations is performed (end trimming, muzzle crimping, etc.), which allows to obtain the final product.

 In this case, in one operation by reverse extrusion of the preform, the wall of a stepped glass-shaped semi-finished product is obtained, and by direct extrusion with simultaneous additional tangential compression of the preform, its bottom part is formed and the capsule nest is formed. Stepwise semi-finished product is obtained by reverse extrusion of the bottom of the semi-finished product with the formation of the capsule socket, and direct extrusion with simultaneous tangential extension of the workpiece gives the wall of this semi-finished product. Moreover, with such methods of squeezing the workpiece, the outflow of metal toward the formation of the bottom and the capsule socket is limited to a predetermined size along the bottom thickness.

 The formation of sleeve flanges, in addition to the universally used turning by a cutter, can be performed by the following methods. A flange with a groove is formed by processing with a rolling roller. A flange protruding above the diameter of the liner is formed by upsetting the bottom of the elongated semi-finished product. Having a smaller diameter, the step of the cup-shaped semi-finished product is squeezed out onto the diameter of the sleeve groove, and after drawing, the flange with the groove is planted in a detachable matrix. A flange with a groove is planted in a split matrix on a diameter either equal to or greater than the largest diameter of the sleeve.

 When the flange is formed by plastic deformation, the size of the capsule socket for the operation of extruding a stepped glass-shaped semi-finished product is preliminary, and in the process of forming the flange, they are calibrated to obtain the final values.

 Extrusion of a stepped glass-like semi-finished product is performed with an inner diameter greater than the outer diameter of the sleeve, and the hood with thinning of the wall is carried out with a simultaneous edge cutting.

 In addition to the traditional hood, the thinning of the wall of a step semi-finished product is carried out by a rotational hood. Or the thinning of the wall of a stepped semi-finished product is carried out by a multi-junction hood, for example through several exhaust dies.

 The workpiece before extrusion is calibrated by sediment. Its draft is carried out in a stamping tool designed for cutting the bar.

 At least before one of the shaping operations, thermochemical processing of the workpiece is performed.

The essence of the proposed method is illustrated by drawings, where:
in FIG. 1 shows a sketch of a workpiece;
in FIG. 2 - stepped glass-shaped semi-finished product with decorated capsule nest after cold extrusion;
figure 3 - semi-finished product after drawing with thinning the wall;
figure 4 - finished part after the operations of trimming the edges, punching the pilot hole, the groove of the flange and crimp dulza;
figure 5 - diagram of the flow of metal for one type of complex (a combination of reverse and forward flow with tangential compression of the workpiece) extrusion: a) - before the deformation of the workpiece, b) - after the deformation;
Fig.6 is a diagram of the flow of metal for another type of complex (a combination of reverse and forward flow with the tangential stretching of the workpiece) extrusion: a) before the deformation of the workpiece, b) after the deformation;
in FIG. 7 is a diagram of the metal flow during disembarkation of a flange with a subflange groove in a split matrix: a) in the initial position before disembarkation, b) in the final position after deformation;
on Fig is a diagram of the groove of the flange with a cutter of the obtained semi-finished product: a) in the initial position, b) in the final position;
in Fig.9 - the operation of obtaining a flange with a subflange groove with a rolling roller: a) in the initial position, b) in the final positions;
figure 10 - the operation of obtaining with a protruding over the sleeve of the sleeve flange with a flange groove disembarkation in a split matrix: a) in the original, b) in the final positions;
in FIG. 11 shows the landing of a flange protruding above the body without a subflange groove in the body itself, a) in the initial position, b) in the final position.

To implement the proposed method, a measured workpiece with a diameter of D ₀ and a height of H _{0 is} obtained by cutting from a bar (Fig. 1). Then it is deformed in a stamp for cold extrusion, the scheme of which is shown in Figs. 5 and 6. The blank 1 (Fig. 5, a) is placed in the cavity 2 of the matrix 3 on the shoulder 4, under the action of the press slider, the punch 5 begins to push the workpiece through the shoulder 4 until it touches the end face of the mandrel 6 of the step punch 7, the initial value of the tangential compression of the workpiece is realized. Then carry out a complex extrusion of the workpiece 1 to obtain a stepped glass-like semi-finished product (Fig. 5, b), which includes reverse extrusion of the wall of the semi-finished product 8 and direct extrusion with tangential compression of the bottom 9 of the sleeve with the formation of the capsule socket 10. In this case, the metal flows in the forward direction limited by the end face of the punch 7. This scheme contributes to the deformation of low-plastic materials without destruction. Removing the resulting semi-finished product is carried out either by pushing from the matrix 3 by the punch 7, or by a puller from the punch 5.

As a result of the operation, a stepped glass-shaped semi-finished product with a decorated capsule nest is shown, shown in FIG. 2, where D ₀ is the outer diameter of the semi-finished product, d ₁ is the inner diameter of the semi-finished product, D is the outer diameter of the bottom of the semi-finished product and sleeve, d _gn is the diameter of the capsule socket, h _gn is the depth of the capsule nest, h _d is the bottom thickness of the semifinished product, h _st is the height of the narrowed stage of the semifinished product, h _st1 is the height of the cylindrical part of this stage, H ₁ is the total height of the semifinished product, α is the angle of the transition bevel. All the given sizes of semi-finished products in transitions are equivalent, i.e. they either take into account technological clearances for placement in the tool or tool in the semi-finished product or allowances for calibration deformation to adjust the main size. They can vary depending on the dimensions of the cartridge case manufactured by the cartridge, on the metal used and the specified dimensional tolerances.

This semi-finished product can also be obtained by complex extrusion according to the scheme shown in FIG. 6. In this case, the workpiece 1 (Fig.6, a), having a lower value of D ₀ than in the previous case, is installed in the cavity of the matrix 3 on the lower punch 7, forming the wall of the semi-finished product 8, and carry out a complex extrusion, consisting of back extrusion the bottom part 9 of the future sleeve with the simultaneous formation of the capsule nest and direct extrusion while distributing the wall of the semi-finished product 8 (Fig.6, b). In this case, the reverse extrusion process is carried out with a restriction at the end of the punch 6. Removing the semi-finished product from the working area is carried out by a puller located on the punch 7. This extrusion method significantly reduces the deformation force and can be used for stamping highly plastic materials.

The stepped glass-shaped semi-finished product obtained in this way expands the subsequent possibilities of technological operations. For this, the wall of the expanded part of the stepped glass is first subjected to a hood with thinning so that it is of a variable profile of a given size. Analogs of a hood with thinning the wall can be a rotary hood, direct or combined extrusion, multi-junction hoods, etc. Extend the expanded part of a step semi-finished product so that D _{0 of the} step semi-finished product becomes equal to its value D. In this case, the resulting semi-finished product (Fig. 3) has an outer diameter D, the smallest inner diameter d _floor , the largest inner diameter d ₁ , l ₂ is the cylindrical part of the surface of the inner cavity, h _d is the bottom thickness, h _gn and d _gn are the depth and diameter of the floor, respectively awn capsule nests, H ₂ - the total height of the semi-finished product after drawing. The hood can be produced both through one or through several exhaust matrices. The number of exhaust operations or other operations to thin the wall of the semi-finished product is determined by the allowable degree of deformation and its height H ₂ .

 Depending on the used deformable metal and the degree of hardening, both during extrusion and when the wall is thinned by a hood (or other methods), thermochemical operations are introduced in front of them if necessary, including degreasing, annealing, etching, washing, etc.

The subsequent set of operations for obtaining the final product includes trimming the edge of the semi-finished product, punching the firing holes, minting the inscriptions on the bottom end of the semi-finished product, grooving the flange and crimping the barrel to obtain the finished product (figure 4). In the future, only non-mechanical operations such as passivation, phosphating, varnishing, etc. remain. FIG. 4, as an example, shows the sleeve for the cartridge of the Parabellum pistol, where H is the total height of the sleeve, h _d is the bottom thickness, h _gn and d _gn are the depth and diameter of the capsule socket, h _f is the flange thickness, h _pr , h _pr1 and D _CR - base heights and diameter of the groove, D ₁ and D - outer diameters of the liner, d and d _floor - the diameters of the main cavity of the liner, l ₁ and l ₂ - cylindrical sections respectively of the outer and inner surfaces of the muzzle of the liner, d _from - the diameter of the ignition holes.

 The expansion of technological capabilities after receiving the stepped semi-finished product and hood with thinning the wall consists in the fact that the flange and the groove of the sleeve (Fig. 8 and 9), the groove and the flange protruding above the sleeve (Fig. 10) and the flange without the groove (Fig. 11) can to receive both in the traditional way, for example, getting a flange with a groove with a cutter (Fig. 8), and in an unconventional way, for example, getting a flange and a groove with knurled rollers (Fig. 9), and in the latter case it is necessary to take into account the redistribution of metal into the wall of the sleeve.

The most acceptable way for automated technology is the stamping of the flange with the simultaneous formation of a groove (Fig.7 and 10). To carry out such an operation, it is necessary to obtain a stepped glass-like semi-finished product (Fig. 2) with a diameter D equal to the diameter D _{pr of the} groove of the sleeve (Fig. 4) and the increased length of the lower stage (i.e. h _hn , h _pr , h _pr1 and h _d ) by the value of δ, corresponding to the volume of the flange protruding above the groove (for example, δ = h _f (D ² -D $\genfrac{}{}{0ex}{}{\text{2}}{\text{etc}}$ ) / (D $\genfrac{}{}{0ex}{}{\text{2}}{\text{etc}}$ -d $\genfrac{}{}{0ex}{}{\text{2}}{\text{gn}}$ ) here D is the diameter of the flange and if it does not coincide with the diameter of the sleeve, it can be denoted as D _f , then extract to the diameter D of the sleeve and then drop the flange in the device shown in Fig.7.

 This device (Fig. 7) consists of a sleeve 1 with a conical cavity 2, in which there are two spring-loaded half-matrices 3, having protrusions 4 in the upper part corresponding to the profile of the groove of the sleeve, the conical part 5 of which is made so that in the working position (Fig. .7, b) they formed a working cavity closed without gaps. The progress of the half-matrices from above is limited by a bar 6 located at such a distance from the upper cut of the half-matrices in the working position so that it is possible for the protrusion 4 of the half-matrices to exit the groove of the sleeve after the end of the flange upsetting operation. The sleeve 1 rests on a plate 7, in which the mandrel 8 is centered. The deformation is carried out by a punch 10, in which a spring-loaded mandrel 11 with an elastic element 12 is located. The punch itself is located in the clamp 13.

 The device operates (Fig.7) as follows. When the press slider is in the upper position, and with it the punch 10, the mandrel 11 and the clamp 13, the half-matrix 3 are also in the upper position, abutting against the restriction bar 6. At this moment, the stepped glass-shaped semi-finished product is put on the mandrel 8. When during the press slide downward, the clamp 13 moves the half-matrix 3 down to the stop in the conical cavity 2 of the sleeve 1 until the gap between the half-matrixes 3 is completely selected. When the punch 10 approaches the end face of the semi-finished product, the mandrel 11 is placed in its capsule seat, abutting against the end face with some by the force created by the elastic element 12, and the protrusions 4 enter into conjugation with the conical part of the transition steps of the semi-finished product (Fig.7, a). Then the punch 10 deforms the bottom of the semi-finished product to the formation of the sleeve flange, while calibrating all sizes of the capsule socket and the groove (Fig. 7, b). If inscriptions are engraved on the end face of the punch 10 (for example, convex engraving), then the inscriptions are chased at the same time. During the reverse stroke of the press slide, the clamp 13 and the punch 10 are lifted, while under the action of the lower springs the half-matrices 3 are lifted together with the stamped semifinished product with simultaneous radial movement under the action of the expanding springs located in the slots 14 of the half-matrices 3. After the half-matrices 3 have reached level 6 and the protrusions 4 come out of the groove of the semi-finished product, the latter continues to rise, hovering on the mandrel 11. When leaving the working area of the tool, the semi-finished product from the mandrel 11 collides with a puller (not shown). The magnitude of the flange in such a device requires changing only the upper diameter of the half-matrix in the closed state (figure 10).

 When forming the flange without a groove (Fig. 11), the design of the device is greatly simplified, although the main elements remain.

 In all cases, it is possible to obtain sleeves both without anvil in the capsule and in the nest (boxer capsule) (Figs. 8 and 9), and with an anvil (under the central battle capsule) (Figs. 10 and 11).

 If the workpiece is cut off in a turning machine or, for example, with band saws, then there is no need to calibrate it. If it is cut off in a stamp, it is necessary to introduce calibration by draft. The workpiece is obtained of better quality when upsetting it in a tool designed for cutting bars.

An example of the production of cartridge cases according to the proposed method is a technology developed for a brass cartridge case for the Parabellum pistol cartridge. The main dimensions of the sleeve made of brass L68 are shown in accordance with the notation shown in figure 4, mm: H = 19.15; h _d = 4.05; _hn = 3; h _f = 1.27; h _ol = 3.5; h _pr1 = 2.47; D = 10; D ₁ = 9.6; D _ol = 8.8; _dn = 4.38; d = 8.9; d _floor = 8.6; d _from = 2.05; l ₁ = 6; l ₂ = 8.15.

From the volume of the part, taking into account the allowance for trimming the end and the groove of the flange, the dimensions of the workpiece shown in FIG. 1, mm: D ₀ = 10.5; H ₀ = 5.63, which is cut off from the bar followed by draft. The force of the segments is 13.7 kN, and the upsetting force is 12.84 kN. After thermochemical operations carry out complex extrusion according to the scheme shown in figure 5. The dimensions of the obtained stepped glass-like semi-finished product, indicated in figure 2, are equal, mm: D ₀ = 10.6; D = 10; d ₁ = 9.4; _dn = 4.38; _hn = 3.1; h _d = 4.15; h _st = 3.15 h _st1 = 2.85; H ₁ = 14.7; α = 45 ^o . The force of complex extrusion with tangential compression of the workpiece is calculated by the formula derived by the authors by the energy method and verified experimentally, equal to 58.9 kN.

To obtain a variable wall thickness of the sleeve, the next mechanical operation will be the hood with the thinning of the wall of the expanded part of the stepped glass-like semi-finished product. Depending on the state of the material, thermochemical operations may be included between these mechanical operations. The dimensions of the elongated semi-finished product, the designations of which are shown in FIG. 3, are equal, mm: D = 10; d ₁ = 9.3; d _floor = 8.6; _dn = 4.38; H ₂ = 19.8; l ₂ = 8.6; _hn = 3; h _d = 4.05. The draw force is 4.8 kN. The extraction coefficient in this case is equal to the upper part of the semifinished product m _S = 0.58, which is quite acceptable for brass L68 when drawing through two dies.

 Then, according to this technology, the following transitions are included, which are included in the complex of finishing operations: chasing inscriptions on the bottom end (force equal to 12.3 kN), piercing the pilot hole (force equal to 3.7 kN), grooving the flange and trimming the flange, crimping the barrel (force equal to 2.8 kN). After passivation and control operations, the finished product is obtained, which enters the assembly production.

 Compared with the existing version of the exhaust technology from a sheet blank, the proposed manufacturing process allows to reduce two mechanical operations and one thermochemical. Metal savings will be 15-20%.

If the complex extrusion is carried out according to the scheme shown in Fig.6, then the dimensions of the workpiece (Fig.1) will be equal, mm: D ₀ = 9.8; H ₀ = 6.46 mm. At the same time, the effort of complex extrusion with tangential stretching of the workpiece will be 41.2 kN, but die tooling will be somewhat more difficult due to the need to move both the punch and the die. In the future, all operations and sizes of semi-finished products are similar to the above technology.

In the event that the die-cast method for producing the groove and flange of the sleeve is implemented, then in the stepped glass-shaped semi-finished product (figure 2), due to a decrease in the diameter of the smaller step and an increase in its length by δ = 0.5 mm, the following dimensions will change, mm: D = 8.8; _dn = 4.48; _hn = 3.6; h _d = 4.65; h _article = 3.87; h _st1 = 2.97; H ₁ = 15.2. And in the semi-finished product in figure 3, only some dimensions will also change, mm: H ₂ = 20.3; _hn = 3.6; h _d = 4.65 mm and the upper surface of the future groove will appear, mm: h _ol = 3.57; h _pr1 = 2.97. In this case, the stamping force of the flange will be 27.4 kN. At the same time, metal savings of 7% are added to those received earlier.

 The proposed method can be used to obtain cartridges of various cartridges for combat small arms to such systems as a pistol, submachine gun, automatic machine, carbine, machine gun of an armored personnel carrier, tank and aircraft, anti-aircraft and some artillery mounts, hunting and sporting guns, construction, gas and signal pistols and etc. Depending on the purpose of the shooting system in this method, the sleeves can be made of cartridge steel (steel 11kp, 11yua or 18yua), as well as brass, aluminum alloys, bimetal steel - tompak, etc.

Claims (15)

 1. A method of producing shells for small arms, including cutting a measured billet, manufacturing a cylindrical stepped glass-shaped semi-finished product, forming a capsule socket, forming a flange in the bottom of the sleeve, thinning the wall in the glass-shaped semi-finished product, having a larger diameter, by drawing and a complex of finishing operations, characterized in that a rod is used as a billet, a cylindrical glass-shaped stepped semi-finished product with a decorated capsule nest is made by a combination direct and reverse extrusion, and the flange is formed after thinning the wall.  2. The method according to claim 1, characterized in that by extruding the preform, a wall of a stepped glass-shaped semi-finished product is obtained, and direct extrusion with simultaneous additional tangential compression of the preform forms its bottom and forms a capsule socket.  3. The method according to claim 1, characterized in that by back extrusion of the preform, the bottom part of the stepped cup-shaped semi-finished product is obtained and a capsule nest is formed, and direct extrusion with simultaneous additional tangential extension of the preform forms its wall.  4. The method according to claims 1 to 3, characterized in that when the workpiece is extruded, the metal flows towards the bottom and the capsule socket to form a restriction on a predetermined size along the bottom thickness.  5. The method according to PP1 to 4, characterized in that the flange is formed with a groove by processing with a rolling roller.  6. The method according to PP. 1 to 4, characterized in that the flange protruding above the diameter of the liner is formed by upsetting the bottom of the elongated semi-finished product.  7. The method according to PP. 1 - 4, characterized in that having a smaller diameter, the step of the glass-shaped semi-finished product is extruded onto the diameter of the sleeve groove, and after drawing, the flange with the groove is planted in a split matrix.  8. The method according to claims 1 to 4, 7, characterized in that the flange with the groove is planted to a diameter exceeding the largest diameter of the sleeve.  9. The method according to claims 1 to 8, characterized in that when extruding a stepped glass-shaped semi-finished product, the dimensions of the capsule socket are preliminary, and when forming the flange, they are calibrated to obtain the final values.  10. The method according to PP.1 to 9, characterized in that the extrusion of a glass-shaped semi-finished product is performed with an inner diameter greater than the outer diameter of the sleeve, and the hood with thinning of the wall is carried out with a simultaneous edge cutting.  11. The method according to claims 1 to 9, characterized in that the thinning of the wall of the stepped glass-shaped semi-finished product is carried out by a rotary hood.  12. The method according to claims 1 to 9, characterized in that the thinning of the wall of the stepped glass-shaped semi-finished product is carried out by a multi-junction hood.  13. The method according to PP.1 to 12, characterized in that the preform is extruded by calibrating before extrusion.  14. The method according to p. 13, characterized in that the draft of the workpiece is carried out in a stamping tool designed for cutting the bar.  15. The method according to PP. 1 to 14, characterized in that at least before one of the shaping operations produce thermochemical processing of the workpiece.

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