EP0114591B1 - Process for the production of arm barrels - Google Patents

Abstract

The weapon barrel comprises a liner and at least one jacket tube. The liner is made of a highly wear-resistant material, like a cobalt or nickel base alloy, and the jacket tube is made of a tough alloy, like steel. In the manufacturing process the liner material is packed into the jacket tube in the form of a powdery material which may be pre-pressed or pre-sintered. The packing is arranged such as to leave a central free space in the jacket tube, and the jacket tube may be surrounded by an encapsulating tube. The jacket tube or the encapsulating tube is closed either before or after evacuation, and the closed tube arrangement is subjected to a combined heat and pressure treatment at temperatures of at least 900 DEG C., but below the melting point of the relevant materials and at pressures of at least 900 bar. The compound body thus obtained is formed with a full-area metallic bond between the liner and the jacket tube. After eventual heat treatment the compound body is further machined and a rifling is worked thereinto as, for example, by forging.

Description

The invention relates to a method for producing gun barrels with incorporated trains for guns or handguns, the gun barrels having a core barrel and a jacket barrel made of different metallic materials.

Gun barrels are subject to two completely different stresses: on the one hand, the explosion of the propellant charge of a projectile creates a high pressure inside the barrel, which the gun barrel must be able to withstand, and on the other hand the projectile is driven through the barrel at high speed, thereby stabilizing the bullet trajectory the projectile is rotated by the cables in the gun barrel, which creates an extremely abrasive load on the barrel interior. However, these two loads place different demands on the material. One way to meet these different requirements is to provide the gun barrels with a correspondingly large dimension, as a result of which the mobility of the weapons suffers and an extremely high amount of material is required.

A method for the manufacture of gun barrels has already become known, wherein a core tube is inserted into a casing tube in a snug fit. The disadvantage of this method is that particularly precise machining of both the inner hollow of the casing tube and the outer casing of the core tube is required. If the inner tube is damaged, for example as a result of cracks that can be attributed to the pressure, a major change in the caliber can occur, which can lead to the projectile being destroyed by the projectile.

It has also become known to provide a fiber-reinforced layer as a connecting tube between a core tube made of steel and an outer tube made of steel. Such constructions have become known both for a gun barrel and for handguns, although a gun barrel with a low weight can be produced with such a construction; However, the usability of such a tube is very limited due to the thermal sensitivity of the material arranged between these two tubes, since the thermal stress on the barrel via the projectile cannot be subject to narrow limits, particularly in an emergency.

According to DE-3 114 659, a method is described which is suitable for lining cavities, including pipes. In this case, a gap is created in a casing tube, for example made of steel, by introducing a thin-walled metal part, into which metal powder is filled, the gap is then evacuated and then the body with the metal part and powder contained therein at approx. 1150 ° C. and 103 N / mm ^{2 is} compressed. A final post-processing is possible.

No. 4,327,154 discloses a method for producing tubular parts, a composite part being produced by applying a powder component to a tubular metal shell with hot isostatic pressing between 1000 ° C. to 1400 ° C. and pressures from 10 to 1000 bar.

Furthermore, it is known from US Pat. No. 3,753,704 to subject composite pipes produced by isostatic pressing to hot deformation by hot extrusion prior to further mechanical processing.

The present invention had for its object to provide a method for producing gun barrels that are suitable for guns as well as for hand and handguns that have a core tube and at least one jacket tube made of different metallic materials, which allows a to produce a particularly light and resistant weapon barrel.

The method according to the invention for the manufacture of weapon tubes, which have a core tube and at least one jacket tube made of different metallic materials, consists essentially in the fact that in a sleeve tube, which is arranged in a capsule tube, a filling made of a bulk density of a tough alloy at least 60% of the density of the compact, powdery, highly wear-resistant or corrosion-resistant material is introduced and compacted with the exception of a central hollow area by a filler made of free-cutting steel, is closed at the ends of the casing or capsule tube, whereupon the tube is evacuated and the sealed tube in a protective gas atmosphere , at least 900 ° C, but below the melting point of the metallic materials and a pressure of at least 900 bar and that after a heat treatment of the composite body thus obtained, which between a full-surface metallic composite n has a casing tube and compressed material, is then subjected to at least 1.3 times the hot deformation, mechanically processed and trains are created. A weapon barrel manufactured according to this method has the advantage that it takes account of both the high pressure and the abrasive stresses in a particularly favorable manner, a particularly advantageous combination of a melt-metallurgical and powder-metallurgical method being provided.

If a tube is used as the packing, the manipulation can be carried out particularly easily, since the weight of the composite can be kept particularly low.

If titanium or a titanium alloy is used as a tough material, a particularly low-weight weapon barrel can be produced.

For gun barrels for guns or the like with a particularly elongated shot trajectory is considered to be high wear-resistant alloy uses a cobalt-based alloy.

In guns in which particularly corrosive propellant charges are used, a nickel-based alloy is used as the material for filling the casing tube.

According to a further feature of the method according to the invention, a sleeve tube is used which has a coating of an adhesion promoter, e.g. Nickel or the like.

The invention is explained in more detail below with the aid of the examples.

Example 1:

For further processing as a gun barrel of a machine gun, a composite metal tube part was produced by using X40CrMoV51 (with 0.38% C, 1.1% Si, 0.38% Mn, 5.20% Cr, 1.30% Mo and 1.2% V, the rest essentially iron) of the dimension: 46 mm outer diameter, 15 mm wall thickness and 650 mm length, a rod of the same length made of free-cutting steel is inserted centrally and in the remaining cavity a metal powder made of a heat-resistant nickel-based alloy with the composition 0, 12% C, 20.0% Cr, 18.1% Co, 2.5% Ti, 1.5% Al, 1.5% Fe, the rest essentially nickel. After the powder had been compacted by evacuation, the tube ends were sealed gas-tight by welding circular sheet metal disks onto the jacket tube and the hot isostatic pressing process was carried out at 1080 ° C. and a gas pressure of 1100 bar for 3 hours. After cooling, the central core made of free-cutting steel was completely drilled out and then the further mechanical processing was carried out to produce the trains and to complete the run.

Example 2:

In a capsule tube with a base plate made of unalloyed structural steel with an outer diameter of 68 mm, an inner diameter of 62 mm and a length of 800 mm, a sleeve tube made of an alloy of the following composition in wt .-% C 0.33, Si 0.28, Mn 0.50, Cr 3.0, Mo 1.2, V 0.27 and remainder iron with an outer diameter of 60 mm and an inner diameter of 40 mm and a length of 800 mm. A core cylinder made of free-cutting steel with an outer diameter of 18 mm and a length of 800 mm was inserted centrally into this tube. The hollow cylindrical space was filled with a powder of a cobalt-based alloy with the following composition in% by weight C 0.17, Si 0.35, Mn 0.65, Cr 28.9, Mo 5.6, Ni max. 0.5, Co 66.0 and Fe max. 0.5 filled, a density of 6.5 g / cm ^{3 was} achieved by shaking. Degassing was carried out at 350 ° C., whereupon an upper cover with a suction opening was welded onto the capsule tube. Then it was evacuated and the suction opening was closed. The encapsulated body was hot-isostatically pressed for 3 hours in an argon atmosphere at 1150 ° C. and at a pressure of 1000 bar. This composite body was then forged on a long forging machine to an outer diameter of approx. 35 mm, which corresponds to an approximate triple deformation. After forging, solution annealing was carried out at 1100 ° C for one hour, after which a barrel for a heavy machine gun was made by mechanical processing and cold forging of the trains.

Example 3:

In a capsule tube with a base plate made of unalloyed structural steel with an outer diameter of 215 mm, an inner diameter of 210 mm and a length of 900 mm, a hollow cylinder made of tempered steel with the following composition C 0.41, Si 0.3, Mn 0.7, Cr 1 , 1, Mo 0.2 introduced with an outer diameter of 210 mm and an inner diameter of 160 mm and a length of 900 mm. A cylindrical rod made of free-cutting steel with an outside diameter of 45 mm and a length of 900 mm was inserted in the center of the casing tube. The hollow cylindrical space was filled with a powder of a cobalt-based alloy with the following composition in% by weight C 0.17, Si 0.35, Mn 0.65, Cr 28.0, Mo 5.5, Ni max. 0.5, Co 66.0 and Fe max. 0.5 filled, a density of 6.7 g / cm ^{3 was} achieved by shaking. Degassing was carried out at 340 ° C., whereupon an upper cover with a suction opening was welded on. It was then evacuated and hot-isostatically pressed according to Example 2. The composite body thus obtained was forged on a long forging machine to a diameter of 105 mm or 35 mm or 23 mm and a length of 3500 mm, which corresponds to a fourfold deformation. The further processing was carried out analogously to Example 2, but a tensile strength of 900-1100 N / m ^{2 was} set by tempering the jacket tube. The tube obtained had a caliber of 1 "and was used for a rapid-fire cannon.

Example 4:

In a capsule tube provided with a bottom, a sleeve tube made of TiA16V4 with an outer diameter of 210 mm and an inner diameter of 160 mm and a length of 900 mm was introduced. A core rod made of free-cutting steel with a diameter of 45 mm and a length of 900 mm was then introduced into this casing tube. The intermediate space was filled with a powder of the following composition in% by weight C 0.34, Cr 1.2, Mo 0.2, Al 0.95, remainder Fe. It was compressed to 70% of the density. The procedure was then as in Example 3 and the composite body was forged to a diameter of 105 mm or 35 mm and a length of 350 mm, which corresponds to a fourfold deformation. This composite was heated at 940 ° C for one hour and then cooled in oil and tempered at 520 ° C for four hours. After processing, the inner Surface nitrided in a manner known per se to a depth of 0.3 to 0.4 mm.

Instead of the capsule tube, the sleeve tube can also be welded directly to the cover, since the powder can not act radially due to the material thickness of the sleeve tube. The core can also be formed by a hollow cylinder, in which case, which is particularly suitable for larger calibers, forging can be carried out using a mandrel.

A cladding tube can also be used which has an inner coating, e.g. B. electrodeposited from nickel or the like., Which can occur as an adhesion promoter between the material of the cladding tube and the powder.

In all of the examples cited, a full-area bond between the cladding tube and the core tube had occurred, the following property improvements, for example in the case of the cobalt hard alloy according to Example 2, being able to be achieved by hot-isostatic pressing or by hot-isostatic pressing and forging.

Claims (8)

1. A method for manufacturing weapon barrels with rifling for guns or manual firearms, the weapon barrels having a liner and a casing tube made of different metal materials, characterised in that a filler made of a highly-abrasion-resistant or corrosion-proof powdered material, which has a bulk density of at least 60% of the density of the compact material, is inserted and compressed in a casing, which is disposed in a capsule tube and is made of a tough alloy, by a filling body made of machining steel, hollowing out a central hollow region, the filling is sealed at the casing or capsule tube ends, then evacuated and the sealed tube is compressed in a protective gas atmosphere at a temperature of at least 900°C, but below the melting point of the metal materials, and at a pressure of at least 900 bar, and in that, after heat-treatment, the compound body thus obtained, which has a holohedral metallic connection between the casing tube and the compressed material, is subjected to at least a 1.3-fold hot-forming, machined, and riflings are provided.

2. A method according to claim 1, characterised in that a tube is used as a filling body.

3. A method according to claim 1 and 2, characterised in that titanium or a titanium alloy is used as a tough alloy.

4. A method according to one of claims 1 to 3, characterised in that steel is used as a tough alloy.

5. A method according to one of claims 1 to 4, characterised in that a cobalt-based alloy is used as a highly-abrasion-resistant alloy.

6. A method according to one of claims 1 to 5, characterised in that a nickel-based alloy is used as a highly-abrasion-resistant-alloy.

7. A method according to one of claims 1 to 6, characterised in that the powdered material is pre-compressed and/or pre-sintered.

8. A method according to one of claims 1 to 7, characterised in that the casing tube has a lining made of an ahesion agent, e.g. nickel.