Dense parts produced by uniaxial compressing an agglomerated spherical metal powder

• US 6,334,882 B1
• Filed: 07/12/2000
• Issued: 01/01/2002
• Est. Priority Date: 01/13/1998
• Status: Expired due to Term

• Current Assignee: Metals Process Systems
• Original Assignee: Metals Process Systems, Scandinavian Powdertech AB
• Inventors: Åslund, Christer
• Primary Examiner(s): MAI, NGOCLAN THI
• Application Number:
  US09/600,119
• Time in Patent Office: 538 Days
• Field of Search: 752/28, 419/38, 419/65
• US Class Current: 75/228
• CPC Class Codes: B22F 1/065 Spherical particles
• CPC Class Codes: B22F 1/10 Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B22F 2998/10 Processes characterised by the sequence of their steps
• CPC Class Codes: B22F 3/02 Compacting only
• CPC Class Codes: B22F 3/087 using high energy impulses, e.g. magnetic field impulses
• CPC Class Codes: B22F 3/10 Sintering only
• CPC Class Codes: B22F 3/15 Hot isostatic pressing

Abstract

The invention refers to a process for compressing a spherical metal powder, agglomerated with at least 0.5% by weight of a thermo-reversible hydrocolloid as a binder, in a uniaxial press operation with a ram speed of over 2 m/s to a green body having a high density. More particularly the invention also refers to a process for sintering said green bodies to products with full or near full density. The products obtained can be high resistant, high strength details or parts of stainless steel or other alloys.

Claims

1. A process for compressing an agglomerated spherical metal powder including at least 0.5% by weight of a thermo-reversible hydrocolloid as a binder, comprising:

pressing the agglomerated spherical metal powder in a uniaxial press operation with a ram speed of over 2 m/s to a green body having a high density.

2. A process according to claim 1, wherein the ram speed of the press during the pressing operation is 4 m/s or higher.

3. A process according to claim 1 or 2, wherein the amount of binder in the agglomerated metal powder does not exceed 1.5% by weight.

4. A process according to claim 1, wherein the thermo-reversible hydrocolloid is gelatine.

5. A process according to claim 4, wherein the uniaxial press operation is performed at a temperature ranging from 40°

C. to 55°

C.

6. A process according to claim 1, further comprising sintering said green body to full or near full density to form a sintered product.

7. A process according to claim 6, wherein the sintered product is subsequently subjected to hot isostatic pressing without being encapsulated.

12. A green body formed by the process according to any of claims 1, 2, 4, or 5.

13. A process according to claim 5, wherein the uniaxial press operation is performed at a temperature ranging from 45°

C. to 55°

C.

14. A green body formed by the process of claim 1, wherein the amount of binder in the agglomerated metal powder does not exceed 1.5% by weight.

8. A sintered product comprising an agglomerated spherical metal powder including at least 0.5% by weight of a thermo-reversible hydrocolloid as a binder, the agglomerated spherical metal powder being pressed in a uniaxial press operation with a ram speed of over 2 m/s to a green body that is subsequently sintered to full or near full density.

9. A sintered product according to claim 8, wherein the ram speed of the press during the pressing operation is 4 m/s or higher.

10. A sintered product according to claim 8 or 9, wherein the amount of binder in the agglomerated spherical metal powder does not exceed 1.5%.

11. A sintered product according to claim 8, wherein the thermo-reversible hydrocolloid is gelatine.