KR100950907B1 - Decoppering agent - Google Patents

Abstract

The present invention seeks to provide a copper remover incorporated into the propellant to remove copper from rifleing the inner diameter of the barrel. The copper remover consists essentially of ground additives that do not include lead mixed with other propellant compounds. Applicants have found that a mixture of tin and bismuth is a very good copper remover. Especially at a ratio of 42% Sn / 58% Bi, the melting point of this combination is 138 ° C. This is much lower than the individual components. It can be any type of suitable tin and bismuth compound. Bismuth and tin vaporize or liquefy on propellant ignition, are brittle and dissolve copper deposits to facilitate removal.

Description

Copper remover {DECOPPERING AGENT}             

Field of invention

The present invention relates to additives added to all types of propellants effective to remove copper deposits from the inner surface of the barrel. More specifically, the composite additive includes a ground copper remover that is mixed with the propellant.

Background of the Invention

Most firearms have barrels with rifle bore that give a stable spin to the fired projectile. This inner diameter is coated with a hard facing material, such as chromium, thereby increasing the number of projectiles that can be fired from the gun by minimizing corrosive wear.

Typically a large aperture projectile has a diameter slightly smaller than the diameter of the inner diameter. One or more closure devices, or turns, bands surround the projectile. In the band, the diameter of the projectile is slightly larger than the inner diameter of the barrel. When the projectile is fired, the rotating band is engraved by rifleing, and the rifleing through the length of the tube imparting the projectile comes into contact with the stabilized spin. Projectiles for rifle and pistols typically do not have a rotating band, but they have a jacket consisting primarily of tombbags carved by rifleing.             

The barrel is made of a material such as steel and is sometimes coated with a hard material such as chrome facing. The barrel is harder than the swivel band or jacket, which is typically copper or a copper alloy. As a result, a portion of the copper from the swivel band or jacket is deposited on the rifle inside the barrel. Such copper deposition is referred to as "copper contamination", which can affect the ballistics of the projectile, and major contamination can prevent the projectile from being properly inserted, installed, and placed in the barrel prior to launch.

Copper contamination has been a major problem for large artillery weapons, such as 155-mill howitzer, and has also been found to appear in small and medium-caliber cannons such as 20-mill cannons. This is a big problem today because it uses a primer that does not contain lead. Previously, primers contained lead, and small amounts of lead were used as copper removers. A common solution to copper removal is to include a copper remover in the propellant. Copper removers remove copper without damaging the barrel or rifle.

Typical copper removers are lead foil sheets deposited between propellants and projectiles. Lead ignites on ignition of the propellant charge, which diffuses into copper. The resulting alloy is brittle and easily scattered. The sum of the heat generated by the burning propellant and the mechanical movement of the propellant gas separates the brittle lead / copper alloy into the surface of the barrel. Such broken debris is blown away from the muzzle of the muzzle with the propellant gas.

A second theory as to why lead foil is effective as a copper remover is that heat is generated by the propellant melting the lead foil. The liquid lead comes into contact with the copper deposition and dissolves the copper, and the copper containing lead solution is released as liquid from the muzzle with the propellant gas.

Although metal lead and lead compounds are effective as copper removers, these materials are toxic to people working around inorganics. Thus there is a need for a copper remover that does not contain lead.

Among the copper removers which have been proposed to include no lead, there are bismuth, bismuth carbonate (BiCO ₃ ), tin, and tin alloys. Bismuth compounds are brittle, and even metal bismuth cannot be wound into thin foils such as lead. Alloys of bismuth metals with other metals can be wound in foil, but the alloys are very expensive and are not very effective as copper removers. There is also a solution, in particular, produced as pellets of bismuth in nitrocellulose binders and added to propellant loading.

Therefore, there is still a need for a method of effectively injecting lead-free copper remover into the propellant. Inclusion of a copper remover in the propellant composition is much easier and cheaper when specially prepared copper removal additives have to be added to the load.

Summary of the Invention

Provided is a copper remover incorporated into the propellant to remove copper by rifleing the barrel inner diameter. Such copper removers consist essentially of ground additives that do not contain lead mixed with other propellant compounds. Applicants have found that a mixture of tin and bismuth is a very good copper remover. In particular, the ratio of tin and bismuth is 10 to 62% Sn and 90 to 38% Bi. Especially at a ratio of 42% Sn / 58% Bi, the melting point of this combination is 138 ° C. This is much lower than the individual components. It can be any type of suitable tin and bismuth compound. It is suitably selected from the group consisting of metal bismuth, bismuth alloys, bismuth compounds, metal tin, tin alloys and tin compounds. Bismuth and tin vaporize or liquefy on propellant ignition, are brittle and dissolve copper deposits to facilitate removal.

Therefore, it is an object of the present invention to provide a substantially lead free copper remover comprised in the propellant. The present invention is characterized in that the copper remover becomes part of the propellant and is homogeneously distributed.

It is advantageous in the present invention that the copper remover is distributed in the barrel and trough, the barrel having a propellant gas. If a copper remover is included in the propellant, this means that the powder gas always contains the same amount of copper remover.

The greatest advantage of the present invention is that it is easier and cheaper to load because the copper remover is always present. This eliminates the need for a special container made specifically for copper removal.

Claims (2)

Pulverized additives containing no lead, consisting of a mixture of tin and bismuth compounds selected from the group consisting of metal bismuth, bismuth alloys, bismuth compounds, metal tins, tin alloys and tin compounds to effectively remove copper deposits from the barrel It is essentially a copper remover for propellants, which can be mixed with all types of propellants to produce the least amount of residue upon combustion, wherein the ratio between tin and bismuth is 10 to 62% Sn and 90 to 38% Bi. A copper remover characterized by the above. The copper remover of claim 1, wherein the mixture is Sn 42% and Bi 58%.