Claims
- 1. Process for the preparation of a powder metallurgical body characterised by the steps ofunaxially compacting metal powder; subjecting the obtained body to shot peening or rolling at an intensity and for a period of time sufficient for establishing a densification surface layer in the range of 90 to 100 percent of full density within a deformation depth of at least 0.1 mm; optionally subjecting the obtained body to an additional compacting step; and sintering the surface densified body.
- 2. Process according to claim 1, characterised in that the compacted body is presintered at a temperature of at least 500° C. before shot peening or rolling.
- 3. Process according to claim 2, characterised in that the metal powder is an iron-based powder.
- 4. Process according to claim 3, characterised in that the iron-based powder includes one or more elements selected from the group consisting of C, Cr, Mn, Mo, Cu, Ni, P, V, S, B, Nb, Ta, N and inevitable impurities in addition to Fe.
- 5. Process according to claim 2, characterised in that the iron-based powder is selected from the group consisting of substantially pure iron particles, pre-alloyed iron-based particles, diffusion alloyed iron-based particles and mixtures of iron particles and alloying elements.
- 6. Process according to claim 1, characterised in that the powder is unaxially compacted and presintered to a bending strength of at least 15 MPa.
- 7. Process according to claim 2, characterised in that the powder is unaxially compacted and presintered to a bending strength of at least 15 Mpa.
- 8. Process according to claim 3, characterised in that the powder is unaxially compacted and presintered to a bending strength of at least 15 Mpa.
- 9. Process according to claim 4, characterised in that the powder is unaxially compacted and presintered to a bending strength of at least 15 Mpa.
- 10. Process according to claim 5, characterised in that the powder is unaxially compacted and presintered to a bending strength of at least 15 Mpa.
- 11. Process according to claim 1, wherein a deformation depth of at least 0.2 mm is achieved in said surface densification layer.
- 12. Process according to claim 1, wherein the compacted powder is presintered to a bending strength of at least 20 MPa.
- 13. Process according to claim 1, wherein the compacted powder is presintered to a bending strength of at least 25 MPa.
- 14. Process according to claim 2, wherein the compacted powder is presintered to a bending strength of at least 20 MPa.
- 15. Process according to claim 2, wherein the compacted powder is presintered to a bending strength of at least 25 MPa.
- 16. Process according to claim 3, wherein the compacted powder is presintered to a bending strength of at least 20 MPa.
- 17. Process according to claim 3, wherein the compacted powder is presintered to a bending strength of at least 25 MPa.
- 18. Process according to claim 4, wherein the compacted powder is presintered to a bending strength of at least 20 MPa.
- 19. Process according to claim 4, wherein the compacted powder is presintered to a bending strength of at least 25 MPa.
- 20. Process according to claim 5, wherein the compacted powder is presintered to a bending strength of at least 25 MPa.
Priority Claims (1)
Number |
Date |
Country |
Kind |
9602376 |
Jun 1996 |
SE |
|
Parent Case Info
This is a continuation of International Application No. PCT/SE97/01027, filed Jun. 12, 1997, which designates the United States of America and claims priority from Swedish Application No. 9602376-7, filed Jun. 14, 1996.
US Referenced Citations (8)
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GB |
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JP |
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JP |
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JP |
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SE |
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WO |
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Non-Patent Literature Citations (2)
Entry |
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“Process Controls the Key to Reliability of Shot Peening”, J. Mogul et al., Industrial Heating, No. 11 (Nov. 1995) pp. 34-35. |
Continuations (1)
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Number |
Date |
Country |
Parent |
PCT/SE97/01027 |
Jun 1997 |
US |
Child |
09/208499 |
|
US |