RU2539548C2 - Method of barrel production - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming and may be used for production of rifled and smooth barrels. Pipe billet with lead-in part is produced as a temporary outer chamfer. Chamfer generatrix is arranged at the angle α<90° to lengthwise plane. Said chamfer has the base changing to auxiliary surface with peripheral diameter D₀. Auxiliary surface generatrix is inclined to lengthwise plane at the angle equal to that of temporary chamfer inclination. Pipe billet is subjected to first radial reduction to get intermediate barrel forged piece. After intermediate thermal and mechanical treatment, second reduction is made. Intermediate forged piece for second radial reduction is made with auxiliary surface generatrix inclined to lengthwise plane at the angle of zero degrees and peripheral diameter D₀′′ < D₀.

EFFECT: lower labour input, higher reliability of clamping.

3 dwg, 1 ex

Description

The invention relates to the field of metal forming and can be used in the manufacture of trunks with smooth and threaded guiding parts.

A known method of manufacturing a barrel (see patent RU No. 2429102 C2, 09/20/2011, B21K 21/06). It consists in the fact that from the initial and heat-treated billets, a billet-pipe is obtained by preliminary machining, having at its end under the retaining center a lead-in part in the form of external bevels and an auxiliary surface turning into a deformable part in the form of a lead-in cone and a cylinder, which is on the other the end of the lead part, which has a technological chamfer for the lead center from the end in the hole of the billet-pipe: compression of this billet-pipe on a radial crimping machine does not result in forgings ox subjected to final machining with the formation of the finished barrel.

The disadvantage of the analogue: the removed technological profit - the lead-in - is significant in weight and for trunks of 12.7 and 14.5 mm caliber is up to 0.4-0.6 kg; the utilization rate of the metal of the initial billet is low and does not exceed 50-60%, which negatively affects the production and economic indicators of barrel production (significant energy costs for manufacturing, large wear of the cutting tool - cutters and time for the formation of the billet pipe).

There is another method of manufacturing the barrel (see patent RU No. 2069594 C1, 11/27/1996, IPC ⁶ B21D 41/00). It consists in the manufacture and heat treatment of the initial billet, its preliminary machining to produce a pipe billet having an inlet in the form of an external technological bevel from one end under the retaining center, the base of which passes into the auxiliary surface, and that into the deformable part of the conical-cylindrical a form ending at the other end with a lead part in the form of a large and a small cylinder; the first compression of the billet pipe on a radial crimping machine gives an intermediate forging, which is subjected to heat and then machining the inner and outer surfaces to remove oxide films under the second radial compression, which receive the final forging of the barrel, subjected to further machining to form the finished barrel.

Its disadvantages: the lack of unification of the structural elements of the billet-pipe due to different technological chamfers of its ends (external and internal) and different tools used for their formation; reduced strength of the lead-in due to the presence of an external technological chamfer for radial compression and an internal one for machining a workpiece-pipe in the centers of turning equipment; low technology billet pipe due to the formation of these chamfers; limited contact area of the external technological chamfer with the working surface of the retaining center and its increased wear during operation; the difficulty of restoring this surface to it.

The objective of the invention is to improve production and economic indicators, namely reducing the number of tools used and the amount of machining of the billet pipe; unification of elements of its design; increasing the strength and reliability of its fastening during radial compression, as well as the resistance of retaining centers of the radial crimping machine and their adaptability.

.The technical result is achieved by the method of manufacturing the barrel, including the formation and heat treatment of the initial billet, its preliminary machining to obtain a billet-pipe having at one end under the retaining center of the radial crimping machine an inlet in the form of an external technological chamfer, passing at its base into an auxiliary surface , and that - into the part deformed by the strikers of this machine in the form of a lead-in cone turning into a cylinder, which at the other end is a lead part, which has billet-pipe holes technological chamfer for a center pivot. Next, the manufacture of it from the first radial compression of the intermediate forging of the barrel, its subsequent intermediate heat and mechanical treatment before the second radial compression to form the finished forging of the barrel and then its final machining. New in the proposed method is that under the first radial compression form a billet-pipe with a lead-in in the form of an external technological chamfer with a generatrix located at an angle α <90 ° to the longitudinal plane and passing into its base into an auxiliary surface with a diameter around the periphery D ₀ and with a generatrix inclined to the longitudinal plane at an angle equal to the angle of inclination of the generatrix of the outer chamfer and intermediate forging a second radial compression manufactured with an inclined surface forming an auxiliary longitudinal plane at an angle of 0 °, and a diameter at the periphery $${D^{″}}_o=D_o$$

.

 Using, for the first and second radial reductions, respectively, a pipe billet and an intermediate forgings with the same lead-in: an external technological chamfer with its own parameters (the first has more than the forgings for the second radial compression), the strength characteristics of not only this part, but and at each of the retaining centers used in these reductions, the wear of their working surfaces interacting with these chamfers during the first radial reduction decreases due to their larger values than the increase tsya resistance of these centers.

The slope of the auxiliary surface of the inlet part of the billet-pipe or intermediate forgings at an angle α = 30 °, 45 ° or 60 ° relative to its longitudinal plane simplifies the design of this part, provided that it is equal to the angle of inclination of the generatrix of the external technological chamfer.

In this case, the auxiliary surface is the continuation of this chamfer until the beginning of the deformable part of the billet-pipe or intermediate forging, or may be the beginning of the deformable part of the billet-pipe.

This increases the strength of this part and provides the maximum contact area of the working surface of the retaining center with this chamfer and auxiliary surface, which increases its resistance.

When the auxiliary surface has α = 0 °, it is the cylindrical and cross sections of the forgings in the zone of its location of minimum strength, which is used for the final compression of the intermediate forgings, providing the required parameters for the final forging of the barrel.

 The execution of the cylindrical deformable part of the billet pipe reduces the mass of the initial billet, the amount of metal removed from it and the volume of mechanical processing of the barrel as a whole.

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

The invention is illustrated in the drawing, where in FIG. 1-3 show the billet-pipe for the first radial compression, intermediate and final forgings with geometric parameters, where Dpc is the outer diameter of the retaining center of the radial crimping machine (POM).

This barrel manufacturing method is implemented as follows: at the metallurgical enterprise, the initial billet is manufactured and heat treated (round rolled or forged), and at the weapon manufacturing plant, for example, the rolled steel is cut into billets of the required length, which are then processed.

On the milling-centering machine, the ends of the workpiece are cut, and then chamfers are formed on their periphery, one of which is an external technological chamfer with parameters dп <2d _o , lп and α <90 ° of its future input part, turning into an auxiliary surface of length lв and α < 90 ° ending on the side surface of the workpiece.

 Then this workpiece is drilled based on chamfers and a through hole do is deployed; from one end it forms a technological chamfer of 45 ° under the thrust center of the lathe, and on the opposite side, a chamfer with dz and lz under the same center and POM drive center, used for crimping the billet pipe and intermediate forging.

Further turning of the billet-pipe consists in the formation of a deformable entry cone with an inclination angle β of its generatrix relative to the longitudinal plane of this billet and its cylinder with a diameter of D ₁ .

, lв<lв, $${D^{\prime }}_l<D_l$$

, а l_o>l_o. При этом на длине l поводковой части остается D₁. или его уменьшают под второе радиальное обжатие точением до диаметра бурта казенной части ствола, а на длине lкч обеспечивают диаметральные размеры $$2,5d_o<{D^{\prime }}_1<3d_o$$

.In FIG. 2 presents obtained by compression of the workpiece pipe with the parameters $${D^{\prime }}_o<D_o$$

, lv <lv, $${D^{\prime }}_l<D_l$$

, and l _o > l _o . In this case, D ₁ remains on the length l of the lead part. or it is reduced under the second radial compression by turning to the diameter of the shoulder of the breech of the breech, and on the length lкч provide diametrical dimensions $$2,5d_o<{D^{\prime }}_{\mathrm{one}}<3d_o$$

.

(с углом наклона образующей α=0° и длиной $$l{в}^{″}<l{в}^{\prime }$$

, которая далее переходит в заходный конус с углом наклона β и основанием $${D^{‴}}_o<D_o$$

) деформируемой части промежуточной поковки. Здесь же штриховыми линиями показаны подпорный центр и окончательная поковка ствола калибра d до хромирования длиной lс после подрезки торцов ее (см. фиг. 3).Then this preform is subjected to thermal and mechanical treatments, including the removal of oxide films from the first before the second radial compression; from the end of the lead-in, the auxiliary surface of the cylinder $${D^{″}}_o={d^{\prime }}_P<D_o$$

(with generatrix tilt angle α = 0 ° and length $$l{\mathrm{at}}^{″}<l{\mathrm{at}}^{\prime }$$

, which then goes into the entry cone with an angle of inclination β and the base $${D^{‴}}_o<D_o$$

) the deformable part of the intermediate forging. Here, dashed lines show the retaining center and the final forging of the barrel of caliber d before chrome-plating of length lс after trimming its ends (see Fig. 3).

, получая ствол длиной lс (см. фиг. 3).The second radial compression of the intermediate forgings results in the final forging of the barrel (see Fig. 3), in which the end of the lead part is cut no more than 0.5 mm to remove the imprints of the teeth of the lead center (the same end face trimming is carried out at the intermediate forging), then the technological one is cut off profit from the lead-in, consisting of its outer auxiliary surface and transition zone with portions of holes d _o and $${d^{\prime }}_o$$

getting a barrel with length lс (see Fig. 3).

Examples of the manufacture of a barrel of 14.5 mm caliber KPVT machine gun.

The initial billet - round rolled products with a diameter of 56 mm, is cut into billets with a length of at least 750 mm. Then the ends of the workpiece are milled to a size of l _o = 742 mm, chamfers are performed on their periphery, including an external technological one with a base diameter of dp = 33 mm and lp = 6 mm with an inclination angle of α = 45 °, turning into a formed auxiliary surface with angle α = 45 °, having a diameter D _o = 56 mm on the periphery and a length lв = 11.5 mm.

After that, from the end where this chamfer begins, the workpiece is drilled into the passage and then the resulting hole is turned into a diameter d _o = 17 mm, from the ends of which then internal technological chamfers 2 × 45 ° from the side of the technological chamfer and dz = 28 mm and lz = 5.5 mm from the opposite side, the latter being used twice under the POM drive center (see Patent RU No. 2429102) and the thrust center of the lathe.

Then this billet with internal chamfers is based in the centers of the lathe and the dimensions are obtained: from D _o = 44 mm of the existing auxiliary surface, a lead-in cone with an angle of inclination β = 15 ° is formed, turning its base into a machined cylinder with a diameter of D _l = 53 mm. As a result, a billet-tube was formed for radial compression.

мм, D_o до $${D^{\prime }}_o=39$$

мм, D_l до $${D^{\prime }}_l$$

в пределах с 47,5 до 49,6 мм на длине lкч=210 мм, l_o до $${l^{\prime }}_o=1100$$

мм, а в поводковой части остается необработанный участок длиной l>12 мм и D_l=53 мм, которому предшествует переходная зона ~40 мм от конусов заходной части бойков РОМы (см фиг. 2).The first radial compression change the shape and dimensions: d _o to $${d^{\prime }}_o=16,5$$

mm, D _o to $${D^{\prime }}_o=39$$

mm, D _l to $${D^{\prime }}_l$$

in the range from 47.5 to 49.6 mm for a length lкч = 210 mm, l _o to $${l^{\prime }}_o=1100$$

mm, and in the lead part there remains an untreated section with a length l> 12 mm and D _l = 53 mm, which is preceded by a transition zone of ~ 40 mm from the cones of the lead-in part of the ROMs (see Fig. 2).

мм до $$d{п}^{\prime }<31$$

мм, вспомогательной поверхности с α=0°, переходящей во вновь выполненный заходный конус с углом β=15° и основанием $${D^{‴}}_o>39$$

мм; в поводковой части дорабатывают D_l до $${D^{″}}_l=51$$

мм, диаметр казенной части ствола, с подрезкой торца на длине не более 0,5 мм для удаления отпечатков зубьев поводкового центра.Then, intermediate tempering of the formed forgings is carried out to relieve stresses and softening of its metal, and its mechanical treatment follows: cleaning of the inner and outer surfaces from oxide films and turning in the centers on the existing internal chamfers under the second radial compression (see Fig. 3) with a change in lp before $$l{P}^{\prime }<5,5$$

mm to $$d{P}^{\prime }<31$$

mm, an auxiliary surface with α = 0 °, turning into a newly made entry cone with an angle β = 15 ° and the base $${D^{‴}}_o>39$$

mm; in the lead part modify D _l to $${D^{″}}_l=51$$

mm, the diameter of the breech of the barrel, with the cutting of the end on a length of not more than 0.5 mm to remove the imprints of the teeth of the lead center.

The second radial compression gives the final forging with a hole d = 14.82 mm for chrome plating, in the input part an external diameter of 32 mm, in the breech part its own diameter, varying from 45.5 to 48.4 mm over a length of 210 mm, and the total length forgings ~ 1385 mm; after that, the end of the lead part is cut to remove newly formed prints with a depth of not more than 0.5 mm of the teeth of the lead center and then the technological profit is removed from the opposite part in the form of a lead-in length of lp, an auxiliary surface I _o and an adjacent zone in which it has not formed suitable guide part, getting the barrel length lс = 1350 mm. Next, the final processing of the barrel is carried out with putting on the breech of the coupling and then the formation of the chamber, getting the barrel bore ready for chrome plating.

The proposed billet-pipe with a deformable cylindrical part reduces the amount of metal removed from the initial billet and the volume of its mechanical processing with an increase in the utilization of its metal to 90%, including due to the absence of a small cylinder weighing up to 0.5 kg in the lead part of the billet -pipes available for the formed prototype forgings.

For the first radial reduction, a retaining center with a maximum diameter of the working surface Dpc <D _o = 39 mm is used due to the equality of the angles of the technological chamfer and the auxiliary surface. Therefore, the maximum contact area of the mating surfaces of it and the inlet part of the pipe billet is provided with an increase in the strength of these elements during the first compression of this billet and a decrease in the pressure acting between these surfaces, which increases the resistance of this center.

Thus, the proposed method for manufacturing the barrel unifies the design of the billet-pipe, simplifies its manufacture, reduces its mass and the number of tools and accessories used to form the barrel, as well as its complexity, increases the strength of the entrance of this billet under the retaining center.

Claims (1)

A method of manufacturing a barrel, including the formation and heat treatment of the initial billet, its preliminary machining to obtain a billet-pipe, the manufacture of a billet-pipe by radial compression on a radial crimping machine of the finished forging of the barrel and its final machining, whereby a billet-pipe having at one end, the lead-in under the retaining center of the radial crimping machine, made in the form of an external technological chamfer passing at its base into an auxiliary surface and in the deformable part of the specified radial crimping machine, a part in the form of a lead-in cone and a cylinder, which is a lead part located on the other end of the pipe billet, having a technological insert at the end in the billet-pipe hole under the center of the radial crimp machine, characterized in that in the manufacture of the finished forgings of the barrel, the first radial compression of the billet-pipe is carried out with the intermediate forging of the barrel, its subsequent intermediate heat and mechanical processing and the second e radial compression, while under the first radial compression receive the workpiece-pipe with a lead-in in the form of an external technological chamfer with a generatrix located at an angle α <90 ° to the longitudinal plane, passing at its base into an auxiliary surface made with a diameter around the periphery D ₀ and with a generatrix which is inclined to the longitudinal plane at an angle equal to the angle of inclination of the generatrix of the outer chamfering process, and forging a second intermediate radial crimping made from the auxiliary generator dressing rhnosti which is inclined to the longitudinal plane at an angle of 0 °, and has a diameter at the periphery D ₀ ''<D _0.

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