RU2534471C1 - Optimised design of pipe billet driving part for radial reduction - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming and can be used in production of 5.45-30 mm calibre gun smooth and rifled barrels. In production of gun barrel billet for radial reduction at radial-squeezing machine from 45 or 40X-grade steel several models are made of barrel driving part with two large-and small-diameter steps and stem. Everyone of the latter are fitted in turns in small cavity and on driving centre side surface by steps with cavity with teeth. Press is actuated to act on said model to make said teeth penetrate in model steps so that dents are produced. Optimum model is selected from maximum sizes of said dents for making of driving part on barrel billet.

EFFECT: lower labour input, higher hardness of driving centre.

1 dwg

Description

The invention relates to the processing of metals by pressure and is suitable for manufacture with smooth and threaded guiding parts of the barrels of small arms.

A known method of optimizing the parameters of the lead part of the billet pipe for radial compression, including the manufacture and heat treatment of the original billet, their subsequent machining with the formation of billet pipes, with lead-in and deformable parts, as well as lead with different design parameters, followed by horizontal placement on the radial crimping machine (POMe) and clamping them in the retaining (lead-in parts) and lead centers with the introduction of the teeth of the latter into the lead parts and select their design and for maximum sizes of tooth prints (see patent RU No. 2156670 C1, 09.27.2000).

The lead part of the workpiece-pipe can be in the form of a large and small cylinders, a cylinder and a technological chamfer from its end in the axial hole of the workpiece-pipe, two external steps with a shank (see patent RU No. 2156670 C1, September 27, 2000; patent RU No. 2429102 C1, 09/20/2011) under the corresponding centers with internal radius teeth and teeth on the front end, penetrating into the end of this part to a depth of not more than 0.5 mm (see OST V3-6011-85 Billets of caliber 4.5-30 mm Typical technological process of cold radial compression, sheets 26 and 62), which does not guarantee ezhnost its rotation at a reduction Romeo and therefore received quality forgings barrel. Preferably, the lead centers with internal radius teeth penetrating into the intersection zone of the end and side surfaces of the lead part, but due to local loading the teeth break prematurely, which negatively (see patent RU No. 2156670 C1, 09.27.2000) affects the cost and quality of the resulting forgings of the trunk.

New designs are also required for the drive parts of pipe blanks, which ensure their rotation reliability during radial compression and the increased resistance of the drive centers. As indicated above, such optimization is performed on pipe billets worth up to 10 thousand rubles (for trunks of 12.7 and 14.5 mm caliber) with their placement in the centers of an expensive ROM which consumes several hundred kilowatts of electricity during operation, and therefore it is very costly in monetary, temporary and material terms, which is a significant drawback.

The objective of the invention is to significantly reduce these costs for optimizing the parameters of the lead part of the billet pipe for radial compression.

This task is achieved by the fact that in the method of manufacturing a billet pipe of a gun barrel for radial compression on a radial crimping machine (POM), including the manufacture and heat treatment of the original billet, its subsequent machining to produce a billet pipe with a lead-in deformable part and the lead part for the ROMy lead center, the new one is that several models of its lead part are made of steel 45 or 40X with two steps of larger and smaller diameters and a shank, each of them is placed one by one in the small cavity, and by steps in the cavity with teeth on the lateral surface of the lead center, press force is applied to the model, under the influence of which these teeth are embedded in its steps and leave their prints in them, by the maximum sizes of which the optimum model and the lead part of the workpiece pipe.

The implementation of models of their lead parts of different sizes instead of billets-pipes significantly reduces the cost of their manufacture and subsequent tests also thanks to the use of a hydraulic press instead of a POM, on which these models are alternately mounted vertically in the center of the lead, and the force is applied to the rear ends of the models, as a result of which the teeth The lead centers are embedded in their respective surfaces.

After extracting the models from the lead center, the optimal geometry of the lead part of the billet-pipe is selected from them according to the maximum sizes of the prints of its teeth on it. Therefore, the proposed method reduces the cost of choosing the optimal lead part of the billet-pipe, using its model weighing no more than 1 kg, and not the billet-pipe weighing about 20 kg (for barrels of 12.7 and 14.5 mm caliber), thereby minimizing costs on the manufacture and testing of such models.

Technical solutions with features distinguishing the claimed solution from the prototype are not known and do not follow explicitly from the equation of technology. This allows us to assume that the claimed solution is new, has significant differences, is industrially applicable and therefore meets the criteria of the invention.

The invention is illustrated in the drawing, where in FIG. 1, instead of a billet-pipe with its geometrical parameters, the lead part is shown, its model placed in the cavity of the front part of the lead center installed by the rear end on the press.

Implementation of the proposed method is as follows: they do not produce tube blanks, trunks, but several solid or hollow models 1 of their lead parts, in which they perform a large step 2 with a diameter d, a small step 3 with a diameter d ₁ and a length l ₁ turning into a shank 4 with a diameter d ₂ and length l ₂ , located in a small cavity 5 of the lead center 6, which also has a large cavity 7, formed, like the previous one, from its front end 8 when internal radius teeth 9 with a maximum diameter D _{0 of} their troughs of front end face and maximum diameter D of these teeth in the same place. These parameters are minimal on the surface of a small cavity 5 with a diameter of d ₂ .

These models, made with different d, d ₁ and l ₁ , are placed alternately in the lead center 6 with the placement of the shank 4 in the cavity 5, and steps 2 and 3 in the cavity 7 with teeth 9 on its side surface. In this case, the center 6 with its rear end 10 is placed on the table 11, for example, of a hydraulic press and its slider acts on the rear end 12 of model 1. Under the action of the force created by the press, each of the models interacts with its steps 1 and 2 with the teeth 9 of this center, which are introduced into zones of intersection of their end and lateral surfaces, creating their own prints in them with depth hi, length li, and width bi.

After that, these parameters of steps 1 and 2 are measured for them, analyzed, and the model with the highest hi _max , li _max and bi _max will be optimal, ensuring the transfer of maximum torque from the center of the lead to the workpiece tube, crimped by the ROM strikers. Due to the optimal parameters d, d ₂ and l _{1 of} steps 1 and 2, there is also a depth l _{0 of the} large cavity 7, which determines the length 1 of the shank 4 of the disk model 1, which ensures its basing in a small cavity 5 of length L ₀ , which is necessary when the workpiece is radially crimped -pipes on ROM for receiving a high-quality forged barrel. When this condition is satisfied L ₀ > 1.

с учетом поля допуска на него, выбирая $$D\le D_{3-{\Delta }_2}$$

для беспрепятственного внедрения зубьев 9 поводкового центра в торец большой ступеньки 2.The diameter D of the large cavity 7 is selected based on the size of the initial billet (rolled, forged, stamped, etc.) with a diameter $$D_{3-{\Lambda }_2}^{+{\Delta }_{\mathrm{one}}}$$

taking into account the tolerance field on it, choosing $$D\le D_{3-{\Delta }_2}$$

for the smooth introduction of the teeth of the 9 lead center in the end face of a large step 2.

Similarly, the parameters of the lead part are optimized for the billet pipe, in the end of which the teeth of the lead center are implemented on its front end (see patent RU No. 2429102 C1, 09/20/2011), also making its models and using the corresponding center, and at the end the lead part may be, for example, annular grooves, cavities, etc.

When using the optimal parameters of these model steps on the billet-pipe, the parameters of the tooth imprints of the drive center will be less than the above values, with a guarantee of the reliability of rotation of the billet-pipe with its radial compression and the quality of the resulting forged barrel. This is due to the fact that the strength characteristics of the barrel steel of this billet are higher than these parameters of the models of its lead part, made, for example, of steel 45 or 40X.

, длиной 980, из которой получают механической обработкой штатную заготовку-трубу с поводковой частью следующих размеров: d=57, d₁=38 и l₀=22 (размеры в мм) под поводковый центр с образованными дисковой угловой фрезой диаметром 80 с 30-ю внутренними радиусными зубьями с параметрами: диаметры по их впадинам и выступам равны соответственно D₀=65 и D=60 на его переднем торце.An example of such optimization: for a barrel of 12.7 caliber machine gun "Cord" use a blank forging with a diameter $${60}_{-\mathrm{1,0}}^{+\mathrm{1,2}}$$

, length 980, from which a standard billet pipe with a lead part of the following sizes is obtained by machining: d = 57, d ₁ = 38 and l ₀ = 22 (dimensions in mm) under the center of the lead with formed disk angle mill with a diameter of 80 s 30- inner radius teeth with the following parameters: the diameters along their hollows and protrusions are equal, respectively, to D ₀ = 65 and D = 60 at its front end.

At the pipe blank in the zone of intersection of the end and side surfaces with d = 57 of this part, the teeth of the center leave regular prints with a depth of h _w ≤1.5 at the end and a length of l _w ≤2.5 on the cylinder and, therefore, their maximum lateral area F _W = 30 · 1.5 · 2.5 = 112.5 mm ² .

When optimizing the design of the lead part of the billet pipe, several models of this part were made of 40X steel with a variable diameter d, d ₂ and l, with constant shank sizes d ₂ = 38 and l ₀ = 22 (see figure 1).

On the steps of these models, fingerprints of the lead center teeth were obtained using a hydraulic press and their analysis revealed the optimal model geometry with a two-stage lead part with the following dimensions: d = 58.8; d ₁ = 53.5; l ₁ = 3.4; with h _b = 2 and l _b = 2 of the largest step and h _m = 2, l _m = 2.1 on the small step with a total lateral area of them F _HΣ = 30 · (2 · 2 + 2 · 2,1) = 246 mm ² . These data allowed us to offer the optimal parameters of the shank of the billet-pipe: l≤12, d ₂ ≤48.

On a model with d = 58.8 workpiece-pipe with one step, as well as a standard workpiece-pipe, tooth prints were obtained with parameters h ₁ = 2.3 with I = 3.8 and their total lateral area F _1Σ = 30 2.3 · 2.8 = 193.2 mm ² .

The above indicates the preference of the lead part of the billet pipe with two steps and reduced shank parameters, because This design increases the area of contact between the model and the teeth of the center of the lead by 1.27 times and decreases the stress of crushing and bending in the teeth of this center, which are distributed over a longer length than the standard structure of the side of the center, which has only one step.

Using a two-stage lead part at the pipe billet also reduces its complexity and material consumption and increases the resistance of the center, moreover, the stability of its model for such tests is no more than 100 rubles, which is two orders of magnitude less than the cost of the pipe billet currently used to optimize the design its leash part.

Thus, the proposed method for optimizing the geometrical parameters of the lead parts of tube blanks for radial compression provides a significant cost reduction due to the use of models instead of their shortened lead parts and the replacement of the POM with a hydraulic press, which ensures the introduction of the teeth of the lead center in the optimized elements of these models.

Claims (1)

A method of manufacturing a billet-pipe to obtain a barrel of small-cannon armament by radial compression on a radial crimping machine (POM), including the manufacture and heat treatment of the original billet, its subsequent machining to obtain on the billet-pipe a lead-in deformable part and a lead part for a lead center POM , characterized in that they produce models of the lead part of the billet pipe of steel 45 or 40X with two steps of larger and smaller diameters and a shank, each model is They are alternately installed in the POM lead center, made with a small cavity and a large cavity, on the side surface of which the teeth are made, with a shank, in the small cavity, and steps, in the large cavity with teeth on the side surface, act by the press force on the model under which the teeth are embedded in the steps of the lead part and leave their prints in them, by the maximum sizes of which the optimal model is revealed, by the size of which they get the lead part on the workpiece-pipe.