Brake disc and manufacturing method thereof

Patent metadata

Field	Value
Publication number	US-11215251-B2
Application number	US-201916534433-A
Country	US
Kind code	B2
Filing date	Aug 7, 2019
Priority date	Dec 14, 2018
Publication date	Jan 4, 2022
Grant date	Jan 4, 2022

Abstract

The present disclosure relates a brake disc and a method of manufacturing the same, in which the depth of the coating layer containing a nitride is adjustable and corrosion resistance and wear resistance can be improved. A brake disc according to an embodiment of the present disclosure includes: a disc base material made of gray cast iron; and a coating layer formed on a surface of the disc base material and including a nitride produced as nitrogen is diffused into a ferrite matrix structure.

First claim

The invention claimed is:

1. A brake disc comprising:
a disc base material made of gray cast iron; and
a coating layer formed on a surface of the disc base material and including a nitride produced as nitrogen is diffused into a ferrite matrix structure;
wherein the coating layer is formed by burnishing a sprayed layer formed by thermal spraying a coating material including pure iron powder and other unavoidable impurities onto the surface of the disc base material and then nitriding the burnished sprayed layer; and
wherein the coating material further contains 1 wt % or less of one or more strengthening elements selected from Cr, Al, Ti, and V.

2. The brake disc of claim 1 , wherein the coating layer includes a nitrogen-diffused region in which nitrogen is diffused through the nitriding, and
the nitrogen-diffused region includes a strengthened phase region in which the nitride of at least one of an epsilon (ε) phase and a gamma prime (γ′) phase is formed.

3. The brake disc of claim 2 , wherein the strengthened phase region formed in the coating layer is formed by at least 20 μm from the surface.

4. The brake disc of claim 1 , wherein the coating layer includes a strengthening nitride, which is formed by bonding nitrogen with at least one of the strengthening elements.

5. The brake disc of claim 4 , wherein the coating layer includes a nitrogen-diffused region in which nitrogen is diffused through the nitriding, and
the nitrogen-diffused region includes a strengthened phase region in which the nitride of at least one of an epsilon (ε) phase and a gamma prime (γ′) phase is formed.

6. A method of manufacturing a brake disc, the method comprising:
providing a disc base material made of gray cast iron;
thermal spraying a coating material containing pure iron powder and other unavoidable impurities onto the surface of the disc base material to form a sprayed layer of a ferrite matrix structure;
burnishing the sprayed layer; and
nitriding the burnished sprayed layer to form a coating layer on which a nitride is produced;
wherein the coating material sprayed in the thermal spraying further contains 1 wt % or less of one or more strengthening elements selected from Cr, Al, Ti, and V; and
the nitriding includes forming a strengthening nitride, which is formed by bonding nitrogen with at least one of the strengthening elements, in the coating layer.

7. The method of claim 6 , wherein the nitriding includes nitriding the burnished sprayed layer from a surface of the burnished sprayed layer to form a nitrogen-diffused region in which a nitride is formed by diffusing nitrogen in all or a part of the burnished sprayed layer, and
the nitrogen-diffused region includes a strengthened phase region in which at least one of an epsilon (ε) phase and a gamma prime (γ′) phase is formed.

8. The method of claim 7 , wherein the nitriding includes nitriding the burnished sprayed layer from a surface of the burnished sprayed layer to form a nitrogen-diffused region in which a nitride is formed by diffusing nitrogen in all of the burnished sprayed layer.

9. The method of claim 7 , wherein in the nitriding, the strengthened phase region is formed at least 20 μm from a surface of the coating layer.

10. The method of claim 6 , wherein the nitriding includes nitriding the burnished sprayed layer from a surface of the burnished sprayed layer to form a nitrogen-diffused region in which a nitride is formed by diffusing nitrogen in all or a part of the burnished sprayed layer, and
the nitrogen-diffused region includes the strengthening nitride.

11. The method of claim 6 , wherein the thermal spraying is performed in a reducing atmosphere.

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Kwon Soon Woo
• Lee Chung An
• Kang Min Woo
• Hong Seung Hyun

Classifications

• F16D2200/0008

  Ferro · CPC title

• F16D65/12

  Discs; Drums for disc brakes · CPC title

• F16D2200/0013

  Cast iron · CPC title

• F16D69/027

  Compositions based on metals or inorganic oxides · CPC title

• C23C4/08 Primary

  containing only metal elements (C23C4/073 takes precedence) · CPC title