RU2572113C1 - Method of barrel production - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: initial billet is machined over the outer surface after thermal processing. Then, the first radial reduction is performed to get the forged piece for its intermediate thermal treatment. Then, through bore is drilled in said forged piece to machine its outer surface. Produced forged piece is subjected to second radial reduction and, then, to machining.

EFFECT: lower metal input, reduced machining steps and machining volume.

4 dwg, 1 ex

Description

The invention relates to the field of metal forming and is suitable for the manufacture of trunks with threaded guiding parts.

A known method for the manufacture of trunks: the forgings are pre-treated on the outer surface, their ends are cut, centering necks and control belts are made and deep drilling is carried out. Then it is heat-treated, a deep hole is drilled, grooves are made in it, then the chamber is finished and finally processed on the outer surface to obtain a finished barrel (see the book by N. Troitsky, Deep Drilling. - M.: Mechanical Engineering, 1971, p. 140-141 )

With this method, the length of the initial billet is greater than the length of the barrel, taking into account the trimming of the ends and the separation of the template from the muzzle under the sample witnesses. Therefore, the volumes of preliminary and final machining are significant, and the metal utilization factor (KIM - the ratio of the mass of the barrel to the mass of the initial billet - η) is not more than 30%.

There is another method for the manufacture of trunks (see patent for the invention No. 2069594 RU from 11.27.1996 g), adopted for the prototype, containing the receipt and heat treatment of the original billet (rolled or forged). Then it is machined before the 1st radial crimp, after it is forged, and after the 2nd radial crimp, the barrel forgings are finally processed, and intermediate heat treatment of the forgings after the 1st radial crimp is also performed.

The advantage of this prototype method over the analogue: due to a smaller by about 2 times the length of the initial billet compared to the barrel length, the volumes of metal and preliminary machining to obtain a billet-pipe for radial compression are reduced and the metal utilization rate increases to 67-70% due to its rational distribution along the length of the forging of the barrel and the receipt of some finally processed sections of the outer surface and the inner surface (guide part) ready for chrome plating.

The disadvantages of the prototype: the removal of technological profits in the breech of the forging of the barrel; the larger diameter of the initial billet required to eliminate the difference between the longitudinal axis of the billet and the hardness of its metal formed as a result of through-hole drilling due to the misalignment of the end centering (the axis of the centering hole does not coincide with the longitudinal axis of the billet); increased energy consumption for the rotation of the original workpiece during through drilling to machining; the presence of finishing of the outer and inner surfaces of the forgings of the barrel after intermediate heat treatment.

The task of the invention is to reduce material, labor and energy costs for the manufacture of the barrel.

The technical result from the implementation of the invention in comparison with the prototype is to reduce up to 18% of the metal consumption on the barrel, reducing its complexity on the order of one norm-hour by reducing the number of operations and the volume of machining of the initial billet and the resulting forgings after the 1st and 2nd radial compression, lower energy consumption during the formation of a through hole in the forging of the barrel.

The specified technical result is achieved by the fact that in the method of manufacturing the barrel, including the formation and heat treatment of the original billet, machining it and forging before the 1st radial compression, after it and after the 2nd radial compression, as well as the intermediate heat treatment of the forging between them is NEW that until the first radial crimping, the workpiece is processed only on the outer surface, and after the intermediate heat treatment, a through hole is made at the forging and the outer surface is machined.

By machining the initial billet up to the 1st radial crimp, centering holes are obtained at its ends for the subsequent formation of its external lead-in, lead parts and side surfaces, and also its mass is reduced, therefore, the energy consumption for rotation during through drilling obtained by the 1st radial crimp forgings and finishing the formed hole.

The first radial compression increases the length of the machined billet, but its transverse parameters and grain sizes of the metal decrease, and its hardness increases, which minimizes the mismatch between its longitudinal axes and the metal hardness and minimizes or eliminates the axis of the through hole formed in forging.

Subsequent machining of the outer surface of the obtained forgings-pipes (after the 1st radial crimping) reduces its difference before the 2nd radial crimping to a minimum or zero and the quality of the guiding part of the resulting barrel forging is guaranteed.

By performing a through hole in the forging after intermediate heat treatment, the operations of cleaning it and the outer surface before the second radial compression are eliminated to remove metal oxide films generated from this heat treatment.

A technical solution with features distinguishing the claimed solution from the prototype is unknown and does not explicitly follow from the prior art. This allows us to consider that the claimed solution is industrially applicable, new and therefore has an inventive step.

The proposed method is illustrated by drawings (Fig. 1-4).

In FIG. 1 shows an example of a blank for a first radial compression. It has base surfaces - centering holes at the ends - for machining the initial workpiece in the centers of the lathe, which receive the lead-in with parameters D ₂ , l ₃ and D ₁ in the muzzle and the lead part with parameters D ₀ , l ₁ and D ₁ breech, as well as a lateral cylindrical surface with a length of l ₂ and a diameter of D ₁ .

, D₄<D₁, D₃<D₁ и $$l_2<l_2^{\text{'}}$$

, после чего она подверглась промежуточной термообработке.In FIG. 2 shows the forging of the barrel obtained by the first radial compression, in which D ₀ , D ₁ , l ₁ , D ₂ remained unchanged and changed $$l_3^{\text{'}\text{'}}<{\mathrm{<figure-callout\; id="3"\; label="l"\; filenames="00000036.png"\; state="\{\{state\}\}">l</figure-callout>}}_3$$

, D ₄ <D ₁ , D ₃ <D ₁ and $$l_2<l_2^{\text{'}\text{'}}$$

then it underwent an intermediate heat treatment.

, $$l_3^{\text{'}\text{'}}<l_3^{\text{'}}$$

, $$D_4^{\text{'}}<D_4$$

, $$D_3^{\text{'}}<D_3$$

, $$l_1<l_1^{\text{'}}$$

.In FIG. 3 shows a forging-pipe obtained from a forging with a through axial hole d _{0 being} made therein and then external machining it, in which $$D_2^{\text{'}\text{'}}<D_2$$

, $$l_3^{\text{'}\text{'}\text{'}\text{'}}<l_3^{\text{'}\text{'}}$$

, $$D_{\mathrm{four}}^{\text{'}\text{'}}<D_{\mathrm{four}}$$

, $$D_3^{\text{'}\text{'}}<{\mathrm{<figure-callout\; id="3"\; label="D"\; filenames="00000036.png"\; state="\{\{state\}\}">D</figure-callout>}}_3$$

, $$l_{\mathrm{one}}<l_{\mathrm{one}}^{\text{'}\text{'}}$$

.

, $$l_3^{"\text{'}}<l_3^{\text{'}\text{'}}$$

, $$D_3^{\text{'}\text{'}}<D_3^{\text{'}}$$

, $$l_2^{\text{'}\text{'}}<l_2^{\text{'}\text{'}\text{'}}$$

ствола или максимально приближенным к ним.In FIG. 4 shows the forging of the barrel obtained by the second radial compression, in which a guide part with a diameter d and an outer surface with ready-made parameters were formed $$D_{\mathrm{four}}^{"}<D_{\mathrm{four}}^{\text{'}\text{'}}$$

, $${\mathrm{<figure-callout\; id="3"\; label="l"\; filenames="00000036.png"\; state="\{\{state\}\}">l</figure-callout>}}_3^{"\text{'}\text{'}}<l_3^{\text{'}\text{'}\text{'}\text{'}}$$

, $$D_3^{\text{'}\text{'}\text{'}\text{'}}<D_3^{\text{'}\text{'}}$$

, $$l_2^{\text{'}\text{'}\text{'}\text{'}}<l_2^{\text{'}\text{'}\text{'}\text{'}\text{'}\text{'}}$$

trunk or as close to them.

The proposed method is implemented as follows. At a metallurgical enterprise, the initial billet-rolling or forging is manufactured and heat treated. Then, at the weapon manufacturing plant, it is cut into billets less than about 2 times the length of the barrel (for example, with a Kord machine gun of 12.7 mm caliber, the latter is 1100 mm.). Next, the ends are cut and centered at this blank, the lateral surface is machined with a diameter of D ₁ and a length of l ₂ , and also the lead-in part of a length of l ₃ and diameters D ₂ and D ₁ and a lead part with a diameter of D ₀ and D ₁ and a length l ₁ ( see Fig. 1), and the driver can be in the form of a cylinder with a technological chamfer in the axial hole from the side of the breech end (see patent for invention No. 2429102 RU dated 08.20.2010) or in the form of a large cylinder or small diameter ≥ breech diameter parts of the barrel (see patent for the invention No. 2156670 RU from 09/27/2000), and this option The lead part excludes its removal to the technological waste after radial crimping (one or two times) of the workpiece and is used as the breech part of the trunk shown in FIG. one.

(см. фиг. 2) и повышенной твердости металла (для вышеуказанного ствола она равна HB=350-380 единиц). Затем поковку подвергают промежуточной термообработке - отпуску, чем понижают эту твердость до НВ<340 единиц. 1-м радиальным обжатием и этой термообработкой сводится к минимуму или к нулю несовпадение продольных осей ее и разнотвердости металла.After that, the workpiece is subjected to the 1st radial compression and get an intermediate conical forging of the barrel with transverse dimensions D ₃ and D ₄ smaller than D ₁ but of greater length $$l_2<l_2^{\text{'}\text{'}}$$

(see Fig. 2) and increased hardness of the metal (for the above barrel it is equal to HB = 350-380 units). Then the forging is subjected to intermediate heat treatment - tempering, which reduces this hardness to HB <340 units. 1st radial compression and this heat treatment minimizes or to zero the mismatch of its longitudinal axes and the hardness of the metal.

After heat treatment in the forging, it is preferable from the input side to perform and then process the through hole to the required purity and accuracy with the diameter d ₀ > d (barrel caliber) and, based on it, process the forging pipe along the outer surface, eliminating the bore axis formed during drilling from its longitudinal axis, if it is due to the hardness of the forging metal (the permissible rate of withdrawal of this axis is ≤0.6 mm / m, see MA Minkov’s book, Production of deep precise holes. - M.: Mechanical Engineering, 1964, p. 11).

, устраняя увод от отверстия, и подрезают в поводковой части торец, образованный диаметрами D₀ и $$D_3^{\text{'}}$$

, для удаления отпечатков торцевых зубьев поводкового центра, образовавшихся при первом радиальном обжатии (при этом длина $$l_1^{\text{'}}>l_1$$

; так как снимается слой металла толщиной 1-1,5 мм) и, если это необходимо, в заходной части противоположный торец поковки для удаления остатков его центровочного отверстия, и тогда $$l_3^{\text{'}\text{'}}<l_3^{\text{'}}$$

, а также протачивая в $$D_2^{\text{'}}>D_2$$

. При этом длина конической части поковки-трубы будет $$l_2^{\text{'}\text{'}}<l_2^{\text{'}}$$

.In addition, the resulting forgings-pipes are sharpened in $$D_0^{\text{'}\text{'}}$$

, eliminating the withdrawal from the hole, and cut in the leash part of the end face formed by diameters D ₀ and $$D_3^{\text{'}\text{'}}$$

, to remove the imprints of the end teeth of the lead center formed during the first radial compression (the length $$l_{\mathrm{one}}^{\text{'}\text{'}}>l_{\mathrm{one}}$$

; since a metal layer 1-1.5 mm thick is removed) and, if necessary, the opposite end of the forging in the inlet part to remove the remains of its centering hole, and then $$l_3^{\text{'}\text{'}\text{'}\text{'}}<l_3^{\text{'}\text{'}}$$

as well as $$D_2^{\text{'}\text{'}}>D_2$$

. The length of the conical part of the forging pipe will be $$l_2^{\text{'}\text{'}\text{'}\text{'}}<l_2^{\text{'}\text{'}}$$

.

, $$D_4^{"\text{'}}<D_4^{\text{'}}$$

, $$l_3^{\text{'}\text{'}\text{'}}<l_3^{\text{'}\text{'}}$$

, $$l_2^{\text{'}\text{'}\text{'}}>l_2^{\text{'}\text{'}}$$

по наружной поверхности и направляющую часть калибром d (см. фиг. 4). Далее у нее удаляют только дульную часть длиной, большей $$l_3^{\text{'}\text{'}\text{'}}$$

, при использовании решений вышеуказанных изобретений.Then it is subjected to a second radial compression and get the forging of the barrel with the appropriate dimensions $$D_3^{\text{'}\text{'}\text{'}\text{'}}\le D_3^{\text{'}\text{'}}$$

, $$D_{\mathrm{four}}^{"\text{'}\text{'}}<D_{\mathrm{four}}^{\text{'}\text{'}}$$

, $$l_3^{\text{'}\text{'}\text{'}\text{'}\text{'}\text{'}}<l_3^{\text{'}\text{'}\text{'}\text{'}}$$

, $$l_2^{\text{'}\text{'}\text{'}\text{'}\text{'}\text{'}}>l_2^{\text{'}\text{'}\text{'}\text{'}}$$

on the outer surface and the guide part with caliber d (see Fig. 4). Then she removes only the muzzle longer $$l_3^{\text{'}\text{'}\text{'}\text{'}\text{'}\text{'}}$$

using solutions of the above inventions.

An example of the implementation of this method in the manufacture of the barrel of the machine gun "Cord".

Its standard workpiece with a diameter of ⌀ 60 mm and a length of 1180 mm is cut into workpieces with a length of l ₂ ≈590 mm, the ends are cut and centered, machined at the centers of the lathe in a diameter of D ₁ = 57 mm, and the corresponding lead-in and drive parts with lengths of l ₃ > 20 mm, l ₁ ≤10 mm, D ₂ > 32 mm and D ₀ > 38 mm, and the breech diameter of this trunk is 38 mm.

и непроковом металла заготовки на участке между D₁ и D₃, удаляемым последующей механической обработкой. Далее ее подвергают промежуточной термообработке для снятия напряжений и понижения твердости металла до НВ<340 единиц. После этого в ней выполняют предпочтительнее с заходной части сверлением и чистовой обработкой сквозное отверстие диаметром d₀=15 мм и, базируя на нем, в центрах такую поковку-трубу обтачивают по наружной поверхности, получая $$D_4^{\text{'}}=\mathrm{39,5}\text{ мм}$$

, $$D_3^{\text{'}}=\mathrm{49,5}\text{ мм}$$

, дорабатывают заходную часть в размеры $$D_2^{\text{'}}=\mathrm{31,8}\text{ мм}$$

и $$l_3^{\text{'}\text{'}}\approx 30\text{ мм}$$

, а также поводковую часть в размеры $$D_0^{\text{'}}=38\text{ мм}$$

и $$l_1^{\text{'}}=l_1+\left(1-\mathrm{1,5}\right)\text{ мм}$$

для устранения увода оси отверстия и удаления отпечатков зубьев поводкового центра, оставшихся на торце при первом радиальном обжатии. Механической обработкой ее также удаляют и окисленный поверхностный слой металла от промежуточной термообработки после первого радиального обжатия, а также устраняют увод оси просверленного отверстия, если это имело место из-за несовпадения этой оси и продольной оси разнотвердости металла поковки.Then the first radial compression receive an intermediate forging in the form of a truncated cone with diameters D ₃ = 50 mm and D ₄ = 40 mm, length $$l_2^{\text{'}\text{'}}\le 890\text{mm}$$

and non-structural metal billet in the area between D ₁ and D ₃ , removed by subsequent machining. Then it is subjected to intermediate heat treatment to relieve stresses and lower the hardness of the metal to HB <340 units. After that, a through hole with a diameter of d ₀ = 15 mm is preferably drilled and finished with a drill part in it and, based on it, in the centers such a forging-pipe is machined on the outer surface, obtaining $$D_{\mathrm{four}}^{\text{'}\text{'}}=39.5\text{mm}$$

, $$D_3^{\text{'}\text{'}}=49.5\text{mm}$$

Modify the lead-in size $$D_2^{\text{'}\text{'}}=31.8\text{mm}$$

and $$l_3^{\text{'}\text{'}\text{'}\text{'}}\approx \mathrm{thirty}\text{mm}$$

as well as the leash in size $$D_0^{\text{'}\text{'}}=38\text{mm}$$

and $$l_{\mathrm{one}}^{\text{'}\text{'}}=l_{\mathrm{one}}+\left(\mathrm{one}-\mathrm{1,5}\right)\text{mm}$$

to eliminate the removal of the axis of the hole and to remove the imprints of the teeth of the leash center remaining on the end face during the first radial reduction. By machining it, the oxidized surface layer of the metal is also removed from the intermediate heat treatment after the first radial reduction, and also the axis of the drilled hole is removed if this has occurred due to a mismatch between this axis and the longitudinal axis of the hardness of the forging metal.

с $$D_4^{\text{'}\text{'}}=\mathrm{32,2}\text{ мм}$$

, $$D_3^{\text{'}\text{'}}=\mathrm{46,5}\text{ мм}$$

и размером d=13,03 мм по полям направляющей части.Further, such a forging pipe is subjected to a second radial compression, obtaining a forged barrel length $$l_2^{\text{'}\text{'}\text{'}\text{'}\text{'}\text{'}}<1150\text{mm}$$

from $$D_{\mathrm{four}}^{\text{'}\text{'}\text{'}\text{'}}=\mathrm{32,2}\text{mm}$$

, $$D_3^{\text{'}\text{'}\text{'}\text{'}}=46.5\text{mm}$$

and size d = 13.03 mm in the fields of the guide part.

, а на токарных станах с ЧПУ ее обрабатывают окончательно по наружной поверхности и выполняют патронник, изготовив в итоге ствол под хромирование, сборку, испытания и эксплуатацию.Subsequent machining removes technological profits only in the muzzle (which also reduces barrel processing time) and obtain a forged barrel $$l_2^{\text{'}\text{'}\text{'}\text{'}\text{'}\text{'}}+l_{\mathrm{one}}^{\text{'}\text{'}}=1100\text{mm}$$

and on CNC lathes it is finally treated on the outer surface and the chamber is performed, eventually producing a barrel for chrome plating, assembly, testing and operation.

The above method is also suitable for other barrel calibers (5.45; 7.62; 14.5; 23 and others), the blanks and forgings of which are crimped on radial crimping machines in the cold state.

When using the proposed method, the utilization rate of the metal of the initial billet increases to 85% due to the lack of technological profits weighing more than 0.5 kg in the forging part of the forging and reducing the diameter from ⌀ 60 to ⌀ 58 mm of the original billet of the Kord machine gun barrel due to minimizing or zero the axis of the through hole formed after the 1st radial compression; reduced: the complexity of the barrel up to 1 standard hour due to the lack of operations to clean the through hole and the outer surface of the forgings after the intermediate heat treatment, as well as the energy consumption for processing forgings with a mass of less than the mass of the original billet, in the operations of drilling a through hole in it and its finishing, as well as grinding of its outer surface with minimal or zero difference, which ensures the quality of the guide part of the barrel.

Thus, the proposed solution increases the utilization rate of the metal of the initial billet, reduces the complexity of the barrel and energy consumption in operations performed after the 1st radial compression of the forgings, and also ensures the quality of its guide part.

Claims (1)

A method of manufacturing a barrel, including the manufacture and heat treatment of the initial billet, the first radial compression of the billet to obtain a forgings, the second radial compression of the forgings, the mechanical treatment that is carried out after heat treatment of the initial billet before the first radial compression, after it and after the second radial compression, and the intermediate heat treatment of the forgings between the first and second radial compression, characterized in that the machining of the workpiece to the first radial compression is carried out according to the outer surface, and in the process of machining the forgings between the first and second radial reductions, which is carried out after the intermediate heat treatment, a through hole is made in the forging and the outer surface is machined.

Images