RU2246684C1 - Cartridge case and method for application of protective coating on its surface - Google Patents

Abstract

FIELD: manufacture of cartridge cases of small arms of various purpose, can be realized mainly for manufacture of steel cartridge cases of small arms.

SUBSTANCE: the cartridge case manufactured of steel, has a polymeric coating on the basis of polyorgansiloxane and copolymer of butadium with styrene. The coating is made composite consisting of successively applied zink-phosphate layer, polymeric layer on the basis of polyorganiloxane and copolymer of butadion with styrene and an external layer obtained from water-soluble film-forming substances. The method includes chemical deposition of a protective layer. Originally a zink-phosphate layer is formed on the outer surface of the cartridge case by phosphate treating with a water-soluble zinc-phosphate concentrate with concentration of 40 to 100 ml/l with addition of sodium nitrite at the rate of 0.05 to 1.0 g/l during 3 to 20 min at a temperature of 30 to 70C, after washing of the cartridge case the polymeric layer is formed by treating of the cartridge case during at least 1 min in an aqueous solution on the basis of polyorgansiloxane and copolymer of butadion with styrene with concentration of 80 to 140 g/l at a temperature of 15 to 30C, then the cartridge case is treated in an aqueous solution of a film-forming substance with formation of an outer film layer, after that the cartridge case is subjected to drying at a temperature of 160 to 220C.

EFFECT: enhanced anticorrosive properties of the cartridge case and resistance of the coating to grinding, improved decorative appearance of the product and enhanced operating properties of the weapon when cartridges with the given cartridge case are used; besides, simplified process of application of the protective coating on the cartridge cases, reduced health hazard of the given manufacturing process.

8 cl, 2 dwg, 1 ex

Description

The invention relates to the field of production of small arms cartridges for various purposes and can be implemented mainly for the manufacture of steel shells for small arms cartridges, cartridges for construction cartridges and similar parts.

Known cartridge casings made of steel and having a metal protective coating, RF patent No. 2062166, IPC 6 B 21 D 51/54, 06/20/96, as well as cartridge casings made of steel and having a protective galvanic coating with non-ferrous metal, patent RF №2120344, IPC 6 B 21 D 51/54, 10.20.98. The disadvantages of these sleeves include the difficulty of applying a protective metal coating, its high cost in case of using copper as a coating, as well as the insufficient resistance of these coatings to corrosion and abrasion.

Known cartridge case made of steel and having a coating based on a water-soluble polymer of polyorganansiloxane and a copolymer of butadiene with styrene (water-soluble composition FPSM-51) according to the second version of the certificate for utility model of the Russian Federation No. 6441, IPC 6 F 42 B 5/26, 04/16/98 g., which is taken as a prototype for the design of the cartridge case.

The water-soluble composition for applying this coating is low toxic, does not require special means of personnel protection, and the process of applying this coating to an already manufactured sleeve is simple.

The disadvantages of this sleeve include the fact that the protective coating based on the water-soluble composition FPSM-51 has low anticorrosion properties and low abrasion resistance than the coatings described above. In addition, this coating has an oily “loose” smearing character. This drawback leads to the fact that in the manufacturing process of the entire product - the cartridge: capsule encapsulation, cartridge assembly, sealing, transport operations, etc., dust adheres to the surface of the liners, consisting mainly of coating particles. During the operation of cartridges with this sleeve, the user's hands become dirty, as well as the bolt of the weapon, reducing its operational properties, which lead to jamming of the weapon. In addition, the gray color of the sleeve with a coating having a “loose" oily character worsens the presentation of the cartridges with this sleeve.

A known method of applying an anti-corrosion coating on the outer surface of cartridge cases during their manufacture according to the patent of the Russian Federation No. 2120344, IPC 6 B 21 D 51/54, 10/20/98. According to this patent, in the manufacture of a cartridge case made of steel after the first operation, drawing is applied to its surface galvanic protective coating with non-ferrous metal 1 ... 5 μm thick by deposition from an electrolyte. After applying the plating, carry out the subsequent stages of drawing and trimming the sleeve in size. The disadvantages of this method of applying a protective coating include the complexity of the equipment for coating, the complexity of the electrochemical technology of applying a protective coating, high safety requirements of the technology and the harmfulness of production. The application of a protective coating between the stages of exhaust hoods reduces the productivity of the manufacturing process, complicates the setup of automated equipment, which actually does not allow to implement this method in the manufacture of liners on high-performance rotor lines. In addition, the application of a protective coating after the first extraction of the semi-finished product leads to the fact that after the subsequent stages of the hoods, the protective coating loses its continuity, which significantly impairs the anticorrosive properties of the protective coating in the finished product.

There is a method of applying a protective coating on the outer surface of a metal hunting sleeve when it is manufactured according to the patent of the Russian Federation No. 2062166, IPC 6 B 21 D 51/54, 06/20/96, which is taken as a prototype for a method of applying a protective coating on the outer surface of a cartridge case . According to claim 2 of this invention, a metal coating is applied to the surface of the stamped shells by chemical copper plating at room temperature for 3 ... 5 minutes in a solution of sulfuric acid and copper sulfate. The disadvantages of this method include the fact that it is applicable only to sleeves made of steel plated with tompak. In addition, this technology relates to hazardous industries and requires special protective equipment for personnel and special equipment.

The present invention solves the problem of increasing the corrosion protective properties of the cartridge case, increasing the abrasion resistance of the cartridge case coating, as well as the task of improving the decorative appearance of the product and improving the operational properties of the weapon when using cartridges with this cartridge case. In addition, the invention solves the problem of simplifying the technology of applying a protective coating on cartridge cases made of steel, and reducing the harmfulness of this process.

The problem is solved in that for a cartridge case made of steel and having a polymer coating based on polyorganansiloxane and a copolymer of butadiene with styrene, the coating is composite, consists of a successively deposited zinc phosphate layer, a polymer layer based on polyorganansiloxane and a copolymer of butadiene with styrene and an external film a layer obtained from water-soluble film-forming substances.

As the outer film layer can be used films, for example, based on polyvinyl alcohol, or films based on water-soluble varnishes and paints, or films based on liquid glass.

When implementing the proposed method for applying a protective coating to the surface of the cartridge case by chemical deposition, the zinc phosphate layer is initially formed on the outer surface of the cartridge sleeve by phosphating with a water-soluble zinc phosphate concentrate with a concentration of 40 ... 100 ml / l with the addition of sodium nitrite at the rate of 0.05 .. .1.0 g / l for 3 ... 20 min at a temperature of 30 ... 70 ° C, after washing the liner the polymer layer is formed by treating the liner for at least 1 min in an aqueous solution based on polyorganansil xan and copolymer of butadione with styrene with a concentration of 80 ... 140 g / l at a temperature of 15 ... 30 ° C, and then the sleeve is treated in an aqueous solution of a film-forming substance with the formation of an outer film layer, after which the sleeve is dried at a temperature of 160. ..220 ° C.

To enhance the anti-corrosion properties of the coating after applying the zinc phosphate layer, it is advisable to passivate it, for example, for at least 1 min in an aqueous solution of potassium dichromate at a concentration of 0.1 ... 10.0 g / l at a temperature of 20 ... 70 ° C.

Enhance the anti-corrosion properties of the sleeve can also be passivation of the outer film layer, for example, corrosion inhibitors on a chromate or organic basis, for example, on the basis of potassium dichromate at a concentration of it in the film-forming substance solution of 0.1 ... 10.0 g / l, or based on cyclohexylamine chromate at a concentration in the solution of a film-forming substance equal to 0.1 ... 0.5 g / l.

It is advisable to add corrosion inhibitors to the aqueous solution of the film-forming substance immediately before its application to the surface of the cartridge case.

Passivation of the outer film layer can be carried out both using passivation of the phosphate layer, and instead of it.

Figure 1 presents the cartridge sleeve, figure 2 is a fragment I of a protective corrosion-resistant and wear-resistant coating of the sleeve shown in figure 1.

On the outer surface of the sleeve 1 made of steel, a composite coating 2 is applied. The composite coating consists of a phosphate layer 3 successively applied, a polymer layer 4 and an outer film layer 5 obtained from water-soluble film-forming substances.

Composite coating can be carried out on one automated screw drum unit, consisting of sequentially placed drums connected by a screw conveyor, i.e. the coating is carried out by simply dipping into the appropriate solutions with the tedding of cartridge cases.

Phosphate coating 3 is applied by dipping and agitating cartridge cases in a solution of zinc phosphate concentrate.

The polymer layer 4 is applied by dipping and turning the sleeves in a water-soluble composition based on polyorganansiloxane and a copolymer of butadiene with styrene - the industrial name of this composition: FPSM-51.

To fix the polymer protective layer 4 and improve the decorative appearance of the sleeve over the polymer layer 4, an outer film layer 5 is applied, obtained on the basis of water-soluble film-forming substances, including the use of water-soluble paints.

Instead of passivation of the phosphate layer or in addition to it, passivation of the outer film layer can be carried out, for example, with chromate or organic based inhibitors.

Additional passivation of at least one of the layers of the composite coating of the cartridge case allows for the storage of cartridges in a humid atmosphere to inhibit the development of corrosion processes in the composite coating of cartridge cases.

Example.

The surface of cartridge cases made of 18YuA steel was previously prepared for applying a protective coating according to traditional technology:

- to remove pollution and ensure uniformity of further chemical treatment, the surface of the shells was chemically degreased for 5 minutes with trisodium phosphate with a technical twelve-water concentration of 120 ... 130 g / l at a temperature of 60 ... 70 ° C, after which the shells were washed countercurrent in warm water;

- to remove oxidized metal sections from the surface of the sleeves and to activate the surface layer of metal, the sleeves were subjected to chemical etching for 3 min in sulfuric acid at a concentration of 120 ... 130 g / l at a temperature of 40 ... 50 ° C, followed by washing with a countercurrent in cold water.

The surface of the cartridge case prepared for the application of a protective anticorrosive coating was coated with the first zinc phosphate layer. Phosphating was carried out for 5 ... 10 min in a water-soluble zinc phosphate concentrate with a concentration of 60 ... 80 ml / l at a temperature of 40 ... 45 ° C with the addition of sodium nitrite at a rate of 0.3 ... 0.5 g / l .

In the process of applying the zinc phosphate layer 3 on the steel surface of the sleeve 1, a metal dissolution process takes place and iron and zinc phosphates are deposited on the surface of the sleeve with the formation of the first preparatory porous zinc phosphate layer 3, which is necessary for penetration into this layer and fixing the protective polymer layer 4, t .e. for better adhesion to the outer surface of the sleeve subsequent to the zinc phosphate layer of the protective polymer layer 4.

After phosphating, the sleeves were washed in cold running water.

To enhance the corrosion protection of the composite coating 2, the zinc phosphate layer 3 was passivated for 1 min in an aqueous solution of potassium dichromate with a concentration of 0.3 ... 0.5 g / l at a temperature of 60 ... 70 ° C, followed by washing in running cold water.

All of the above operations were performed on a single automated screw drum unit.

Then the sleeves were transferred to another automated unit for applying the second layer of the composite protective coating — polymer layer 4. Before applying this layer to ensure its uniformity on the surface, the phosphate layer 3 of the sleeves 1 was moistened with water. To form a second protective layer, the sleeve was treated for 3 min in an aqueous solution of organosilicon polymer - in an aqueous composition based on polyorganansiloxane and a butadiene-styrene copolymer (FPSM-51) with a concentration of 90 ... 100 g / l at a temperature of 18 ... 23 ° FROM.

To enhance the corrosion protection of composite coating 2, before applying the outer film layer 5 to an aqueous solution of a film-forming substance, polyvinyl alcohol (PVA) with a concentration of 2.0 ... 3.0 g / l, a corrosion inhibitor, potassium dichromate, was added to a concentration in the solution equal to 0.3 ... 0.5 g / l.

The outer film layer 5 was formed by treating the liner for 2 min in the resulting aqueous solution of polyvinyl alcohol (PVA) with a corrosion inhibitor at a temperature of 18 ... 23 ° C. The outer film layer 5 made it possible to eliminate the smearing property of the previous polymer layer 4.

Thus, in the process of applying an external film coating, it was passivated.

After that, the liners were dried at a temperature of 185 ± 5 ° C for at least 5 min and cooled to room temperature.

The claimed cartridge shells with a three-layer coating with alternative external film coatings were manufactured at the Tula Cartridge Plant and were tested for corrosion and abrasion resistance of the coating, as well as for the reliability of the operation of weapons using cartridges with the declared cartridge case. The experiments showed that the cartridge is not inferior to the standard one in terms of combat and operational characteristics, and significantly exceeds the coating of the cartridge case by the prototype in terms of anti-corrosion properties and abrasion resistance. In addition, externally, the cartridges using the declared cartridges have a more attractive decorative appearance, which is important when using these cartridges in hunting cartridges. The use of water-soluble paints as an external film coating allows marking of cartridges according to one or another parameter, including their combat characteristics.

Claims (8)

1. A cartridge case made of steel, having a polymer coating based on polyorganansiloxane and a copolymer of butadiene with styrene, characterized in that the coating is made of composite, consisting of a successively deposited zinc phosphate layer, a polymer layer based on polyorganansiloxane and a copolymer of butadiene with styrene and an outer film layer obtained from water-soluble film-forming substances. 2. The sleeve according to claim 1, characterized in that films based on polyvinyl alcohol are used as the film layer. 3. The sleeve according to claim 1, characterized in that as a film layer use films based on water-soluble varnishes and paints. 4. The sleeve according to claim 1, characterized in that as the film layer use films based on liquid glass. 5. The method of applying a protective coating to the surface of the cartridge case, including chemical deposition of the protective coating, characterized in that initially on the outer surface of the cartridge sleeve form a zinc phosphate layer by phosphating with a water-soluble zinc phosphate concentrate with a concentration of 40 ... 100 ml / l with the addition of sodium nitrite from calculation of 0.05 ... 1.0 g / l for 3 ... 20 min at a temperature of 30 ... 70 ° C, after washing the liner the polymer layer is formed by treating the liner for at least 1 min in an aqueous solution on sex based organopolysiloxane and copolymer of butadiene with styrene with a concentration of 80 ... 140 g / l at a temperature of 15 ... 30 ° C, then the sleeve is treated in an aqueous solution of a film-forming substance with the formation of an outer film layer, after which the sleeve is dried at a temperature of 160 .. .220 ° C. 6. The method according to claim 5, characterized in that the outer film layer is formed by processing the liner for at least 1 min in an aqueous solution of polyvinyl alcohol with a concentration of 0.2 ... 15.0 g / l at a temperature of 15 ... 30 ° C. 7. The method according to claim 5, characterized in that after applying the zinc phosphate layer it is passivated for at least 1 min in an aqueous solution of potassium dichromate at a concentration of 0.1 ... 10.0 g / l at a temperature of 20 ... 70 ° C. 8. The method according to claim 5 or 7, characterized in that at the same time as the formation of the outer film layer, it is passivated by the addition of a corrosion inhibitor on a chromate or organic basis in an aqueous solution of a film-forming substance.

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