FRANGIBLE BULLET AND ITS MANUFACTURING METHOD

• US 20100242778A1
• Filed: 03/25/2010
• Published: 09/30/2010
• Est. Priority Date: 03/25/2009
• Status: Active Grant

• Current Assignee: Aleaciones de Metales Sinterizados, S.A. (Ames Tamarite SA)
• Original Assignee: Aleaciones de Metales Sinterizados, S.A. (Ames Tamarite SA)
• Inventors: Morato Ribas, Joan, Allut Grillot, Luis, Calero Martinez, Jose Antonio
• Granted Patent: US 8,365,672 B2
• Time in Patent Office: Days
• US Class Current: 102/517
• CPC Class Codes: F42B 12/74 of the core or solid body

Abstract

This invention describes a frangible bullet made from particles of a copper-based metal powder with the aid of an organic lubricant, which have been pressed so that the pressed particles have a density of more than 6.9 g/cm³, where the composition has been treated with thermal oxidation.

Claims

1. A frangible bullet comprising pressed particles of a copper-based metal powder, the particles having been pressed including an organic lubricant, the particles having a density of more than about 6.9 g/cm³ and having been subsequently treated in an oxidizing medium.

2. A frangible bullet according to claim 1, wherein the pressed particles have a density of about 7.2 g/cm³ to about 7.5 g/cm³.

3. A frangible bullet according to claim 1, wherein the organic lubricant is a polymer chosen from the group comprising polyethylenes, polyamides and polyvinyl alcohols.

4. A frangible bullet according to claim 3, wherein the organic lubricant is high-density polyethylene.

5. A frangible bullet according to claim 1, wherein the copper-based powder consists in particles of a homogeneous pre-alloy of copper, tin and zinc, with a content of less than 41% by weight of Zn and/or less than 12% by weight of Sn.

6. A frangible bullet according to claim 1, wherein the copper-based powder has an irregular shape with a particle size distribution of more than 120 micrometers.

7. A frangible bullet according to claim 1, wherein the pressed powder has been oxidised at a temperature of not more than 400°

C.

8. A method for producing a frangible bullet, wherein it comprises the steps of:

providing a copper-based metal powder;

pressing the particles with the aid of an organic lubricant up to a density of more than 6.9 g/cm³ thereby favoring the cold welding of the particles; and

subjecting the pressed particles to an oxidative heat treatment thereby allowing physical bonds between the polymer chain with oxygen as well as the growth of the oxidised layer of the pressed particles.

9. A method for producing a frangible bullet according to claim 8, wherein the organic lubricant is a polymer chosen from the group comprising polyethylenes, polyamides or polyvinyl alcohols.

10. A method for producing a frangible bullet according to claim 8, wherein the heat treatment is performed at a temperature of less than 400°

C.

11. A method for producing a frangible bullet according to claim 8, wherein the heat treatment is performed in the presence of air.

12. A method for producing a frangible bullet according to claim 8, wherein during pressing up to 1% by weight of the organic lubricant is used with respect to the metal powder.

13. A method for producing a frangible bullet according to claim 8, wherein the copper-based powder is bronze or brass.