Surface treatment for ferrous components

• US 20030106617A1
• Filed: 12/10/2001
• Published: 06/12/2003
• Est. Priority Date: 12/10/2001
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Black, Jared A., Biltgen, Gary Leroy, Kiser, Matthew Thomas
• Granted Patent: US 6,656,293 B2
• Time in Patent Office: Days
• US Class Current: 148/219
• CPC Class Codes: C23C 8/22 of ferrous surfaces
• CPC Class Codes: C23C 8/32 of ferrous surfaces
• CPC Class Codes: C23C 8/80 After-treatment

Abstract

A method for treating a surface of a first component wherein at least a portion of the surface of the first component contacts a surface of a second component. The method includes forming a compound layer at at least a portion of the surface of the first component by a thermochemical diffusion treatment and isotropically finishing the at least a portion of the surface of the first component that contacts the surface of the second component.

Claims

1. A method for treating a surface of a first component, wherein at least a portion of the surface of the first component contacts a surface of a second component comprising:

forming a compound layer at at least a portion of the surface of the first component by a thermochemical diffusion treatment; and

isotropically finishing the at least a portion of the surface of the first component that contacts the surface of the second component.

2. The method of claim 1, wherein the thermochemical diffusion treatment is at least one of nitriding and ferritic nitrocarburizing.

3. The method of claim 1, wherein the isotropic finishing provides a surface roughness of Ra≦

0.1 μ

m.

4. The method of claim 1, wherein the isotropic finishing provides a surface roughness of Ra≦

0.05 μ

m.

5. The method of claim 1, further including providing a physical vapor deposition layer on the isotropically finished portion of the surface of the first component.

6. The method of claim 5, wherein the physical vapor deposition layer is formed by at least one of sputtering, electron beam deposition, laser deposition, vacuum evaporation, ion-beam-assisted deposition, arc vapor deposition, ion plating, thermal evaporation, and ion assisted deposition.

7. A method for treating a surface of a track bushing, wherein at least a portion of the surface of the track bushing contacts a polymeric component to form a seal, the method comprising:

subjecting the surface of the track bushing to a thermochemical diffusion treatment to form a compound layer; and

isotropically finishing at least the portion of the surface of the track bushing that contacts the polymeric component to a surface roughness of Ra≦

0.1 μ

m.

8. The method of claim 7, wherein the thermochemical diffusion treatment is at least one of nitriding and ferritic nitrocarburizing.

9. The method of claim 7, further including providing a physical vapor deposition layer on the isotropically finished portion of the surface of the track bushing.

10. The method of claim 9, wherein the physical vapor deposition coating is formed by at least one of sputtering, electron beam deposition, laser deposition, vacuum evaporation, ion-beam-assisted deposition, arc vapor deposition, ion plating, thermal evaporation, and ion assisted deposition.

11. A track bushing comprising a surface, wherein at least a portion of the surface is isotropically finished and includes a compound layer.

12. The track bushing of claim 11, wherein the compound layer includes at least one of γ

′

(Fe₄N) and ε

(Fe_2-3 N) microstructures.

13. The track bushing of claim 11, wherein the portion of the surface that is isotropically finished has a surface roughness of Ra≦

0.1 μ

m.

14. The track bushing of claim 11, wherein the portion of the surface that is isotropically finished has a surface roughness of Ra≦

0.05 μ

m or less.

15. The track bushing of claim 11, wherein the portion of the surface that is isotropically finished further includes a physical vapor deposition layer on the compound layer.

16. The track bushing of claim 15, wherein the physical vapor deposition layer is at least one of chrome nitride, metal containing diamond-like carbon, amorphous diamond-like carbon, TiCN, and TiBN.

21. The track of claim 16, wherein the isotropically finished end surface has a surface roughness of Ra≦

0.05 μ

m.

17. A track comprising:

a plurality of track links, each of the plurality of track links including a bore at a first end and a second end;

a plurality of bushing assemblies, wherein the plurality of bushing assemblies join adjacent track links by residing in the bore at the second end of a first track link and the bore at the first end of a second track link, and wherein each of the plurality of bushing assemblies includes,

a steel bushing having an isotropically finished surface, wherein the isotropically finished surface includes a compound layer, and

a pin that fits in the steel bushing; and

polymeric seals that contact the isotropically finished surface of the steel bushing and an inside surface of the bore of at least one of the adjacent track links.

18. The track of claim 17, wherein the compound layer is formed by at least one of nitriding and ferritic nitrocarburizing.

19. The track of claim 17, wherein the surface further includes a physical vapor deposition layer of at least one of chrome nitride, metal containing diamond-like carbon, amorphous diamond-like carbon, TiCN, and TiBN.

20. The track of claim 17, wherein the isotropically finished end surface has a surface roughness of Ra≦

0.1 μ

m.