DE1242127B - Process for applying an oxide layer to lead shot - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

F42b

German class: 72d-5

Number: 1 242 127

File number: D 340851 c / 72 d

Filing date: August 24, 1960

Open date: June 8, 1967

The lead shot used in the hunting cartridges tends to be affected by the high combustion temperatures the propellant powder to clump, d. i.e., several pellets flow together, and larger lead formations are formed. This results in a bad hit pattern, i. that is, the coverage value of the shot becomes smaller. Furthermore, the lead shot sticking together poses a danger, since such structures fly further than the individual ones Shot pellets. A further disadvantage is barrel lead, which can only be achieved by means of a wire spiral or Wire brush can be eliminated.

To avoid these disadvantages, use has already been made of the measure, the surface special treatment of the shot. For example, you have a harder coating Metal applied like copper, for which it is also known to compress it during application. Apart from the fact that the production of the copper coating is very complex and expensive, this has Measure did not bring the desired success. As practice teaches, they are with these Instead of the usual lead residues, a lot of copper residues deposited in the barrel were grinded more difficult to remove than the lead residue.

It is also known to apply a molybdenum sulfide layer to the surface of the shot, by the meal in the presence of the molybdenum sulfide present, for example, in an oily suspension in a polishing drum are circulated. However, this method of shot handling has never been practical Obtained importance, in particular probably because the sulfide in atmospheric humidity reacts sourly, which in turn causes it to become significant and, above all, no longer to be eliminated Damage can occur in the internal polish of the barrels.

It is also known to metallize the shot on the surface in a bath using known methods, to oxidize or otherwise change. Regarding metallization, the difficulties are in essentially the same as in the known method of application mentioned above a metal coating. Finally, however, the application of an oxide layer according to this has also become known Method proved to be ineffective because the oxide layer on the one hand is not sufficiently strong on the The surface of the shot adheres and on the other hand against the stresses occurring during the shot is not sufficiently resistant

The invention is also concerned with applying a layer of oxide to the surface of

Process for applying an oxide layer
on lead shot

Applicant:

Dynamit Nobel Aktiengesellschaft,

Troisdorf (district of Cologne)

Named as inventor:

Walter Kreuzer, Rottweil / Neckar

»5 lead shot, in contrast to the one above mentioned known method the lead shot into a common in ammunition production Steel drum is used and several, for example 4 hours at a low speed

for example 60 rev / min. is drummed.

As on the basis of investigations and bombardment

attempt could be determined in this way on the surface of the lead shot an extremely dense and firmly adhering oxide protective layer achieved,

«5 as they neither according to the known method nor by the per se conceivable, but not feasible in practice, oxidation of the shot surface can be achieved in air. As a result of this extremely effective insulating oxide protective layer, it becomes a real one Passivation of the individual lead shot achieved, d. i.e., the shot is against both the hot powder gases that may pass them as well as those that occur when the shot is fired mechanical stress insensitive, so that both the previously unavoidable deformation the edge shot as well as the clumping of several shot and finally the barrel lead are avoided.

In an expedient embodiment of the invention it is proposed to drum the shot until an oxide layer with a thickness of 5 to 40 μ has formed. As has been shown, those are above The disadvantages mentioned hitherto occurring with a layer of this thickness are definitely completely avoided.

In addition to the application of the oxide layer by drums, the application of the oxide layer according to a further proposal of the invention also be carried out in a known manner by a chemical, where lead oxide is used as the chemical in an amount of less than 0.1 percent by weight. on In this way, the drum can then be reduced in time.

example 1

50 kg of normal lead shot (96.3% metallurgical soft lead, 3.5% antimony and 0.2% arsenic) are used in a hexagonal steel drum with 68 rev / min. Drummed for 4 hours. The individual pellets have a surface layer of 30 μ thickness, which is resistant up to over 820 ° C and is predominantly made of There is lead oxide.

Example 2

The same experiment was anticipated with the addition of 20 g of lead oxide. After a After an hour of drumming, the surface layer was in place.

Claims (3)

Patent claims: 1. Method for applying an oxide; layer on lead shot, thus identifiable 10 shows that the lead shot is inserted into a steel drum that is customary in ammunition production and that it takes several hours, for example 4 hours, at a low number of revolutions of for example 60 revolutions / min. is drummed. 2. The method according to claim 1, characterized in that the drumming to emerge an oxide layer of 5 to 40 μ is extended. 3. The method according to claim 1 or 2, characterized in that in addition the application the oxide layer is carried out in a known manner by means of a chemical, the chemical being lead oxide is used in an amount less than 0.1 percent by weight. Considered publications:
German Patent Nos. 554 288, 387 992;
French patent specification No. 1127 501.