Cutting blade for an agricultural implement, and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-11060176-B2
Application number	US-201916662081-A
Country	US
Kind code	B2
Filing date	Oct 24, 2019
Priority date	Oct 24, 2019
Publication date	Jul 13, 2021
Grant date	Jul 13, 2021

Abstract

The disclosure provides a method of manufacturing a cutting blade for an agricultural implement. The method includes forming the cutting blade to define a final shape having an exterior surface. The cutting blade is treated with a surface diffusion hardening process to form a surface hardened layer disposed over a core layer. The surface hardened layer is very thin, approximately 0.1 mm, and exhibits an apparent hardness equal to or greater than 1000 HV. After the surface diffusion hardening process, the cutting blade is treated with a through hardening process, such that the core layer exhibits a Rockwell Hardness C Scale value between the range of thirty five (35) and fifty five (55).

First claim

The invention claimed is:

1. A method of manufacturing a cutting blade for an agricultural implement, the method comprising:
forming the cutting blade to define a final shape having an exterior surface;
treating the final shape of the cutting blade with a surface diffusion hardening process, whereby atoms are diffused into the exterior surface of the cutting blade to form a surface hardened layer disposed over a core layer;
treating the final shape of the cutting blade with a through hardening process, such that the core layer exhibits a Rockwell Hardness C Scale value between the range of thirty five and fifty five.

2. The method set forth in claim 1 , wherein forming the cutting blade is further defined as forming the cutting blade from a steel blank.

3. The method set forth in claim 1 , wherein treating the final shape of the cutting blade with the surface diffusion hardening process is further defined as treating the final shape of the cutting blade with the surface diffusion hardening process such that the surface hardened layer includes a thickness between the range of 0.00 mm and 0.2 mm.

4. The method set forth in claim 3 , wherein the thickness of the surface hardened layer is between the range of 0.05 mm and 0.15 mm.

5. The method set forth in claim 1 , wherein treating the final shape of the cutting blade with the surface diffusion hardening process is further defined as treating the final shape of the cutting blade with the surface diffusion hardening process such that the surface hardened layer exhibits a hardness having a Vickers Hardness number greater than 1000 HV when tested using the Vickers Hardness Test.

6. The method set forth in claim 5 , wherein the hardness of the surface hardened layer exhibits a Vickers Hardness number greater than 1200 HV when tested using the Vickers Hardness Test.

7. The method set forth in claim 1 , wherein treating the final shape of the cutting blade with the through hardening process is further defined as treating the final shape of the cutting blade with the through hardening process after treating the final shape of the cutting blade with the surface diffusion hardening process.

8. The method set forth in claim 1 , wherein forming the cutting blade to define a final shape includes forming the cutting blade to define a first exterior surface and a second exterior surface that intersect each other to define a cutting edge.

9. The method set forth in claim 8 , wherein only one of the first exterior surface and the second exterior surface is treated with the surface diffusion hardening process.

10. The method set forth in claim 8 , further comprising masking one of the first exterior surface and the second exterior surface to define a masked surface, whereby the masked surface blocks diffusion of atoms into the exterior surface of the cutting blade.

11. The method set forth in claim 1 , wherein treating the final shape of the cutting blade with the through hardening process includes:
heating the final shape of the cutting blade to a defined uniform temperature throughout the core layer;
quenching the cutting blade in a liquid after heating the core layer of the cutting blade to the defined uniform temperature; and
tempering the cutting blade after the cutting blade has been quenched.

12. The method set forth in claim 1 , wherein treating the final shape of the cutting blade with the through hardening process is further defined as treating the final shape of the cutting blade with an austempering process.

13. The method set forth in claim 1 , wherein the cutting blade does not include a coating layer disposed over the exterior surface of the final shape of the cutting blade.

14. The method set forth in claim 1 , wherein the surface diffusion hardening process is a boronizing process, whereby boron atoms are diffused into the exterior surface of the cutting blade.

15. The method set forth in claim 1 , wherein the surface diffusion hardening process is one of a boronizing process, a nitriding process, or a nitrocarburizing process.

16. A cutting blade for an agricultural implement, the cutting blade comprising:
a body having a first exterior surface intersecting a second exterior surface to define a cutting edge therebetween;
wherein the body includes a surface hardened layer at least partially defining at least one of one of the first exterior surface and the second exterior surface, and a core layer disposed immediately adjacent to the surface hardened layer;
wherein the surface hardened layer includes a thickness between the range of 0.00 mm and 0.2 mm and exhibits a hardness having a Vickers Hardness number greater than 1000 HV when tested using the Vickers Hardness Test; and
wherein the core layer exhibits a Rockwell Hardness C Scale value between the range of thirty five and fifty five.

17. The cutting blade set forth in claim 16 wherein the hardness of the surface hardened layer exhibits a Vickers Hardness number greater than 1200 HV when tested using the Vickers Hardness Test.

18. The cutting blade set forth in claim 16 , wherein the thickness of the surface hardened layer is between the range of 0.05 mm and 0.15 mm.

19. The cutting blade set forth in claim 16 , wherein the surface hardened layer includes a first portion disposed adjacent to the first exterior surface and a second portion disposed adjacent to the second exterior surface, with the core layer disposed between the first portion and the second portion of the surface hardened layer.

20. The cutting blade set forth in claim 16 , wherein one of the first exterior surface and the second exterior surface includes serrations.

21. The cutting blade set forth in claim 16 , wherein the body is shaped to form a pre-cutter knife for a crop harvesting implement.

22. The cutting blade set forth in claim 16 , wherein the surface hardened layer includes boron atoms.

Assignees

• Deere & Co

Inventors

• Derscheid Daniel E
• Augustine Brent A

Classifications

• C23C8/04

  Treatment of selected surface areas, e.g. using masks · CPC title

• C21D9/18

  for knives, scythes, scissors, or like hand cutting tools · CPC title

• C23C8/32

  of ferrous surfaces · CPC title

• C23C8/26 Primary

  of ferrous surfaces · CPC title

• C23C8/70 Primary

  of ferrous surfaces · CPC title