RU201301U1 - BULLET FOR SMALL ARMS WITH CARBIDE CORE - Google Patents

Abstract

The utility model relates to ammunition, in particular to bullets with a carbide core with increased density for automatic weapons and rifles, having a high penetration capacity, high accuracy of combat and reduced manufacturing costs. The objective of the proposed technical solution is to increase the lethality of the bullet. In the process of solving the problem, the technical result is achieved, which consists in increasing the accuracy of the battle when firing, reducing the rejection of the core in terms of geometry, weight and, as a result, reducing the cost of the bullet as a whole. The specified technical result is achieved by a bullet for small arms with a carbide core, containing a shell, a lead jacket, the bullet length is equal to (3.52-4.60) d, a carbide core having a head and tail parts, the core length is (2.21 ÷ 3 , 48) d, the displacement of the rear end of the core from the rear end of the shell is (0.1 ÷ 0.4) d, the head part of the core has a length equal to (0.58 ÷ 1.65) d, is made in the form of a cone, the base diameter is of the cone of the head part is equal to (0.72-0.86) d, the head part of the cone has a top in the form of a hemisphere with a diameter of not more than 0.9 mm, the tail part of the core has the shape of a truncated cone, the larger diameter of which is equal to the diameter of the base of the cone of the head part, the smaller diameter is equal to (0.68-0.86) d, where d is the caliber of the bullet, the tail section, at the end, has a chamfer equal to (0.15 ÷ 0.40) mm, the coaxiality of the cone of the head section and the truncated cone of the tail section is not more (0.02-0.03) mm, the nominal mass of the core is equal to (34 ÷ 62)% of the mass of the bullet, all surfaces of the core ices obtained by pressing, sintering and tumbling, while the tapered part of the tail section has a mechanical surface treatment within (0.1-99)%, the hard core alloy contains tungsten carbide by mass (88-98)%, the rest is cobalt, and has ultimate bending strength is not less than 1475 MPa, the deviation of the core mass from the nominal value (Mn) is within the tolerance range equal to (0.011 ÷ 0.0585) Mn, where Mn is the nominal mass of the core.

Description

The utility model relates to ammunition, in particular to bullets with a carbide core with increased density for automatic weapons and rifles, having a high penetration capacity, high accuracy of combat and reduced manufacturing costs.

Known bullet for small arms cartridges, including a shell, a lead jacket and a core, characterized in that the core is made in the form of a combination of at least two truncated cones of the head and tail parts, while the generatrix of the truncated cone of the head part is made at an angle of 20 , 0-65.0 ° with a smaller base diameter of 0.02-0.3 caliber, and the generatrices of the truncated cone of the tail section are made with an angle from 15 min to 1 °, while the core is mounted in a shell with fixing its position - in front in the zone the head part of the shell, and in the rear part by the stop of the truncated cone of the tail part of the core through the lead jacket against the inner surface of the shell. (Patent RU No. 2468332, application No. 2011105037 dated 11.02.2011, IPC F42B 12/04).

The disadvantage of the known technical solution is not manufacturability of the core. All surfaces of the core are machined (grinding). The tail cone is also obtained by grinding. The head of the cone has a platform with a diameter of 0.02-0.3 caliber. This design of the head part reduces the core penetration capacity. The core material is not defined, which does not allow to fully assess its tactical and technical characteristics.

Known bullet for small arms with a hard-alloy core containing a shell, a lead jacket and a hard-alloy core having a head and a tail, the length of the core is equal to (2.21 ÷ 3.48) d, the displacement of the rear end of the core from the rear end of the shell is (0.1 ÷ 0.4) d, the head part of the core is made of a conical shape, the diameter of the base of the cone of the head part is equal to (0.72-0.86) d, has a chamfer at the end of the tail part, the nominal mass of the core is equal to (34 ÷ 62)% of the mass of the bullet , characterized in that the head of the core has a length equal to (0.58 ÷ 1.65) d, where d is the caliber of the bullet, the tail of the core has the shape of a cylinder, the diameter of which is equal to the diameter of the base of the cone, the head of the cone has a hemispherical apex with a diameter of not more than 0.9 mm., all surfaces of the core are obtained by pressing, sintering and tumbling, the chamfer at the end of the tail part of the core is equal to (0.15 ÷ 0.40) mm., the hard alloy of the core contains tungsten carbide by weight (88-98 )%, the rest is cobal m and has a bending strength of at least 1475 MPa, the deviation of the core mass from the nominal value (Mn) is within the tolerance field equal to (0.011-0.0585) Mn, where Mn is the nominal mass of the core. (Patent for utility model RU No. 193315, application No. 2019113549 dated 05/06/2019 IPC F42B 12/04). This technical solution was adopted as a prototype.

The disadvantage of this technical solution is not manufacturability of the core, which increases the cost of manufacturing a bullet. Part of the cores after the sintering operation and subsequent tumbling does not pass the control according to the parameters of the mass or geometry of the tail part of the core. During high-temperature sintering of a hard alloy core, the surfaces of the core have deviations from cylindricity, deviations from roundness, increased roughness as a result of partial sintering of hard alloy particles, and other defects that move the core outside the tolerance range.

The objective of the proposed technical solution is to increase the lethality of the bullet.

In the process of solving the problem, the technical result is achieved, which consists in reducing the rejection of the core in terms of geometry, weight and, as a consequence, reducing the cost of the core and the bullet as a whole, increasing the accuracy of the battle when firing.

The specified technical result is achieved by a bullet for small arms with a carbide core, containing a shell, a lead jacket, the bullet length is equal to (3.52-4.60) d, a carbide core having a head and tail parts, the core length is (2.21 ÷ 3 , 48) d, the displacement of the rear end of the core from the rear end of the shell is (0.1 ÷ 0.4) d, the head part of the core has a length equal to (0.58 ÷ 1.65) d, is made in the form of a cone, the base diameter is of the cone of the head part is equal to (0.72-0.86) d, the head part of the cone has a top in the form of a hemisphere with a diameter of not more than 0.9 mm, the tail part of the core has the shape of a truncated cone, the larger diameter of which is equal to the diameter of the base of the cone of the head part, the smaller diameter is equal to (0.68-0.86) d, where d is the caliber of the bullet, the tail section, at the end, has a chamfer equal to (0.15 ÷ 0.40) mm, the alignment of the cone of the head section and the truncated cone of the tail section is not more (0.02-0.03) mm, the nominal mass of the core is (34 ÷ 62)% of the mass of the bullet, all surfaces of the core ka obtained by pressing, sintering and tumbling, while the tapered part of the tail section has a mechanical surface treatment within (0.1-99)%, the hard core alloy contains tungsten carbide by mass (88-98)%, the rest is cobalt, and has ultimate bending strength is not less than 1475 MPa, the deviation of the core mass from the nominal value (Mn) is within the tolerance range equal to (0.011 ÷ 0.0585) Mn, where Mn is the nominal mass of the core.

Changing the ratios of the design parameters of the bullet will significantly affect its tactical and technical characteristics.

Reducing the length of the bullet to less than 3.52 caliber leads to a decrease in the mass of the bullet and core and, consequently, to a decrease in penetrating action and a significant change in the ballistic characteristics of the cartridge. Increasing the length of the bullet over 4.60 caliber leads to an increase in the mass of the bullet and, therefore, the recoil momentum of the cartridge. This increases the pressure of the powder gases and the speed of the moving parts of the weapon, which leads to its more rapid wear. It becomes difficult to stabilize the bullet on the trajectory and the accuracy of fire deteriorates.

Reducing the length of the core to less than 2.21 caliber reduces its weight and reduces the breakdown effect due to a decrease in the specific pressure on the target. Increasing the length of the core over 3.48 caliber reduces the penetration effect due to the decrease in its stability.

Optimization of the geometric parameters of the head part of the core, making it in the form of a cone with a base diameter (0.72-0.86) d, and a length equal to (0.58 ÷ 1.65) d, where d is a bullet caliber, making a core from more heavy alloys with a high tungsten carbide content made it possible to increase the armor penetration of the core. The hard alloy of the core contains tungsten carbide by mass (88-98)%, the rest is cobalt and has a flexural strength of at least 1475 MPa. The increase in penetration is achieved by increasing the specific impact energy per unit area in the initial period of contact of the core with the armor barrier.

The core with the top of the conical part made in the form of a hemisphere, the diameter of which is not more than 0.9 mm, destroys the metal armor by a mixed mechanism of penetration (destruction). At the point of contact, there appear areas with strongly localized plastic deformation, called adiabatic shear planes (AAS), in the vicinity of which heat is concentrated. Rapid deformation of the metal leads to localized heating of the contact and catastrophic destruction of the armor in the form of melting. Making the apex of the tapered part of the core in the form of a hemisphere, the diameter of which is no more than 0.9 mm, we obtain stable results on the penetration of armor, since each time the same penetration mechanism is repeated with the formation of a PAS in the first stage of penetration of the armor and brittle destruction of the rear sides of the armor plate in the second stage of breaking through the plate. With the implementation of such a penetration mechanism, brittle destruction of the core does not occur, it retains its shape, the implementation of less energy-intensive, fragile destruction of the rear side of the armor plate, preserves its kinetic energy, and, consequently, the beyond-barrier damaging effect. Obtaining all surfaces of the core with a pressing tool at the stage of pressing and tumbling after sintering made it possible to significantly reduce the costs of manufacturing the core, and the execution of the tail part of the core in the form of a truncated cone, the larger diameter of which is equal to the diameter of the base of the cone of the head part, the smaller diameter is (0.68- 0.86) d, the presence of a chamfer at the end of the tail part of the core equal to (0.15 ÷ 0.40) mm, made it possible to increase the reliability of the technological process, exclude the core from falling out of the lead jacket during the assembly of the bullet and reduce the cost of manufacturing the bullet and the cartridge as a whole ...

The deviation of the core mass from the nominal value (Mn) within the tolerance range equal to (0.011-0.0585) Mn, where Mn is the nominal mass, allows you to obtain batches of cores with a minimum spread in the core mass and increase the accuracy of fire, by reducing the mass spread cores intended for one batch of cartridges.

Mechanical processing by grinding the cone of the tail part of the core within (0.1-99)% of the surface allows to reduce core rejection in terms of geometry and weight. Such defects are formed as a result of the high-temperature sintering of the cores. After sintering of the hard alloy core, the surfaces have deviations from cylindricality, deviations from roundness, increased roughness as a result of partial sintering of hard alloy particles and other defects that lead the core out of tolerance. Most of these defects are not eliminated by heading, but are eliminated by partial grinding of the cone of the tail part of the core within (0.1-99)% of the surface.

The ratios of the design parameters of the cartridge are determined depending on the caliber of the bullet d.

FIG. 1 shows a bullet consisting of a bimetallic shell 1, a lead jacket 2 and a hard-alloy core 3. The core 3 consists of a cone-shaped head 3.1 and a 3.2 tail. The top of the tapered head part 3.1 of the core is made in the form of a hemisphere 3.1.1. diameter D1 not more than 0.9 mm. The tail section 3.2 has the shape of a truncated cone, the larger diameter D = (0.72-0.86) d of which is equal to the diameter of the base of the cone of the head section, the smaller diameter equal to D2 = (0.68-0.86) d, has a chamfer 3.2. 1 along the end face of the tail part of the core 3. The length l _{0 of the} core 3 is equal to l ₀ = (2.21 ÷ 3.48) d, the length l _{1 of the} head part 3.1 of the core 3 is l ₁ = (0.58-l, 65) d , the displacement of the rear end of the core 3 from the rear end of the shell 1 is equal to l ₂ = (0.1 ÷ 0.4) d.

Carbide cores were made from tungsten-cobalt powders with a tungsten carbide content of 92% and 97% by weight and a cobalt content of 8% and 3%, respectively. Sintering was carried out in two stages: preliminary - with the aim of removing the plasticizer in a hydrogen atmosphere and final vacuum-compression in a VKPgr 50/90/50 furnace from Degussa. The density of the cores after sintering was equal to 14.8 g / cm ² and 15.2 g / cm ² for the core with a cobalt content of 8% and 3%, respectively. The assembly of bullets and cartridges was carried out at the FKP APZ "Vympel"

The analysis of the cores made according to the prototype and the proposed technical solution was carried out. So grinding the cylindrical part of the core surface within (0.1-99)% allows you to return more than 98% of the cores that have not passed the initial control for geometry and weight, thereby reducing the percentage of scrap and the cost of manufacturing the core and the bullet as a whole.

The results of comparative tests confirmed the high penetration capacity of the proposed core and the reduction in manufacturing costs in comparison with the prototype while maintaining a high accuracy of the battle.

Thus, the combination of all the ratios of design parameters indicated in the formula ensures the creation of a bullet that has high accuracy and penetration characteristics and is (10-20)% less than the cost of its manufacture.

Claims (1)

A bullet for small arms with a carbide core, containing a sheath, a lead jacket, the length of the bullet is (3.52-4.60) d, a carbide core having a head and tail, the length of the core is (2.21 ÷ 3.48) d , the displacement of the rear end of the core from the rear end of the shell is equal to (0.1 ÷ 0.4) d, the head part of the core has a length equal to (0.58 ÷ 1.65) d, is made in the form of a cone, the diameter of the base of the cone of the head part is (0.72-0.86) d, the head of the cone has an apex in the form of a hemisphere with a diameter of not more than 0.9 mm, the tail of the core has the shape of a truncated cone, the larger diameter of which is equal to the diameter of the base of the cone of the head, the smaller diameter is (0 , 68-0.86) d, where d is the caliber of the bullet, the tail section, at the end, has a chamfer equal to (0.15 ÷ 0.40) mm, the coaxiality of the cone of the head section and the truncated cone of the tail section is not more than (0, 02-0.03) mm, the nominal mass of the core is equal to (34 ÷ 62)% of the mass of the bullet, all surfaces of the core are obtained by pressing, sintering and tumbling oh, while the tapered part of the tail section has a machined surface within (0.1-99)%, the hard alloy of the core contains tungsten carbide by mass (88-98)%, the rest is cobalt, and has a bending strength of at least 1475 MPa, the deviation of the core mass from the nominal value (Mn) is within the tolerance range equal to (0.011 ÷ 0.0585) Mn, where Mn is the nominal mass of the core.

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