Projectiles made from tungsten and iron

• US 6,112,669 A
• Filed: 06/05/1998
• Issued: 09/05/2000
• Est. Priority Date: 06/05/1998
• Status: Expired due to Term

• Current Assignee: OLIN Corporation
• Original Assignee: OLIN Corporation
• Inventors: Robinson, Peter W., Mravic, Brian
• Primary Examiner(s): Jenkins, Daniel J.
• Application Number:
  US09/092,301
• Time in Patent Office: 823 Days
• Field of Search: 102/501, 420/122, 148/337
• US Class Current: 102/501
• CPC Class Codes: F42B 12/74 of the core or solid body

Abstract

A lead-free projectile made from a composition containing about 5-25% by weight tungsten and more than about 97% by weight tungsten plus iron.

Claims

1. A lead-free projectile comprising:

(1) a composition of tungsten and iron;

(2) wherein the tungsten content in the composition is from about 5% to about 25% by weight;

(3) wherein the iron plus tungsten content of the composition is at least about 97% by weight, said percentages based on the total weight of the composition; and

(4) wherein said composition is lead-free and is shaped like a projectile and is made from a solid solution of tungsten and ferritic iron that is substantially free of a second phase of hard intermetallic iron-tungsten particles.

2. The projectile of claim 1 wherein said projectile is a bullet.

3. The projectile of claim 2 wherein the bullet is a penetrating bullet and the tungsten content is from about 20% to about 25% by weight.

4. The projectile of claim 2 wherein said composition has a Brinell hardness of about 100 to about 400.

5. The projectile of claim 4 wherein said composition has a tungsten content of about 20-25% by weight and a Brinell hardness of about 325 to 400.

6. The projectile of claim 1 wherein the projectile has a density of about 70-95% of lead.

7. The projectile of claim 1 wherein said composition additionally contains no more than about 1% by weight, each based on the total weight of the composition, of silicon, manganese, and aluminum or mixtures thereof.

8. A lead-free projectile comprising:

(a) a composition of tungsten and iron;

(b) wherein the tungsten content in the composition is from about 5% to about 25% by weight;

(c) wherein the iron plus tungsten content of the composition is at least about 97% by weight, said percentages based on the total weight of the composition; and

(d) wherein said composition is lead-free and is shaped like a projectile and is made from a solid solution of tungsten and ferritic iron that is substantially free of a second phase of hard intermetallic iron-tungsten particles, and

(e) wherein the projectile is made by the steps of;

(1) forming a liquid mixture of tungsten and iron;

(2) cooling that liquid mixture into a solid composition of tungsten and iron;

(3) subjecting said solid composition to at least one cycle of a heat treatment followed by rapid cooling to form a solid solution of tungsten and ferritic iron that is substantially free of a second phase of hard intermetallic iron-tungsten particles; and

(4) forming a projectile shape with that solid solution.

9. The projectile of claim 8 wherein said composition has a Brinell hardness of about 100 to about 400.

10. The projectile of claim 8 wherein said composition has a tungsten content of about 20-25% by weight and a Brinell hardness of about 325 to 400.

11. The projectile of claim 8 wherein the projectile has a density of about 70-95% of lead.

12. The projectile of claim 8 wherein the projectile is a bullet.

13. The projectile of claim 12 wherein the bullet is a penetrating bullet and the tungsten content is from about 20% to about 25% by weight.

14. The projectile of claim 8 wherein said composition additionally contains no more than about 1% by weight, each based on the total weight of the composition of silicon, manganese and aluminum or mixtures thereof.

15. The projectile of claim 8 wherein the projectile is a shot.

16. The projectile of claim 12 wherein the projectile is a shot.

17. The process for making a lead-free projectile wherein said projectile comprises:

(a) a composition of tungsten and iron;

(b) wherein the tungsten content in the composition is from about 5% to about 25% by weight;

(c) wherein the iron plus tungsten content of the composition is at least about 97% by weight, said percentages based on the total weight of the composition; and

(d) wherein said composition is lead-free and is shaped like a projectile and is made from a solid solution of tungsten and ferritic iron that is substantially free of a second phase of hard intermetallic iron-tungsten particles, and said process comprises the steps of;

(1) forming a liquid mixture of tungsten and iron;

(2) cooling that liquid mixture into a solid composition of tungsten and iron;

(3) subjecting said solid composition to at least one cycle of a heat treatment followed by rapid cooling to forma solid solution of tungsten and ferritic iron that is substantially free of a second phase of hard intermetallic iron-tungsten particles; and

(4) forming a projectile shape with that solid solution.

18. The process of claim 17 wherein the projectile shape formed is for a shot.

19. The process of claim 17 wherein the projectile shape formed is for a bullet.

20. The process of claim 19 wherein the bullet is a penetrating bullet and the tungsten content is from about 20% to about 25% by weight.