Steel cord and method for producing the same

Patent metadata

Field	Value
Publication number	US-10914015-B2
Application number	US-201615768728-A
Country	US
Kind code	B2
Filing date	Oct 13, 2016
Priority date	Oct 16, 2015
Publication date	Feb 9, 2021
Grant date	Feb 9, 2021

Abstract

There is provided a steel cord including a steel wire and a plating layer that covers the steel wire and has Cu, Zn, and Co, wherein Cu and Zn are alloyed and a region covered with Co and a region not covered with Co are mixed on the outermost surface of the plating layer.

First claim

The invention claimed is:

1. A steel cord comprising a steel wire and a plating layer that covers the steel wire, wherein
the plating layer has Cu, Zn, and Co,
the Cu and the Zn are alloyed, and
a region covered with Co which is in an island shape and is not alloyed and a region not covered with Co coexist in the outermost surface of the plating layer.

2. The steel cord according to claim 1 , wherein the ratio of the area of the region covered with Co to the area of the region not covered with Co is a range from 2:98 to 30:70.

3. The steel cord according to claim 1 , wherein the content of Co in the plating layer is a range from 2 to 8 wt %.

4. The steel cord according to claim 1 , wherein, in at least a part of the region not covered with Co, Co is not present between the outermost surface of the plating layer and an interface with the steel wire.

5. The steel cord according to claim 1 , wherein, in a plan view of the plating layer, at least a part of the region covered with Co is present in an island shape on the outermost surface of the plating layer.

6. The steel cord according to claim 1 , wherein, in a sectional view of the steel cord, Co is present at a position apart from the steel wire.

7. A tire comprising the steel cord according to claim 1 .

8. A method for producing a steel cord comprising a plating layer that has Cu, Co, and Zn, which comprises:
a first plating step of plating the Cu to a steel wire,
a second plating step of plating the Co and the Zn on the Cu to obtain a plated wire, and
a wire-drawing step of drawing the plated wire to obtain a steel cord, wherein
after the wire-drawing step, a region covered with Co which is in an island shape and is not alloyed and a region not covered with Co coexist in the surface of the steel cord.

9. The method for producing a steel cord according to claim 8 , wherein a region where the Zn comes into direct contact with the Cu is formed in the second plating step.

10. The method for producing a steel cord according to claim 8 , wherein, after the second plating step, a heat treatment is performed at a temperature equal to or higher than alloying temperature of the Cu and the Zn to expose a part of the Co on the surface of the plated wire.

11. The method for producing a steel cord according to claim 10 , wherein the heat treatment is performed at a temperature equal to or higher than the temperature at which Zn becomes a liquid phase.

12. The method for producing a steel cord according to claim 8 , wherein, in the second plating step, the Zn is plated after the Co is plated.

13. The steel cord according to claim 1 , wherein at least 95 wt % of the Co present on the outermost surface of the plating being not alloyed.

Assignees

• Sumitomo Electric Tochigi Co Ltd
• Sumitomo Electric Industries
• Sumitomo Rubber Ind
• Nippon Steel Corp

Inventors

• Nakajima Tetsuya
• Yamashita Kenichi
• Tokuyama Takashi
• Takamura Shinei
• Suzuki Masumi
• Fujisawa Koji
• Kodama Junichi

Classifications

• C21D8/06

  during manufacturing of rods or wires · CPC title

• D10B2505/12

  Vehicles (D10B2505/08 takes precedence) · CPC title

• D07B2205/3089

  Brass, i.e. copper (Cu) and zinc (Zn) alloys · CPC title

• D07B2205/3067

  Copper (Cu) · CPC title

• D07B2205/3025

  Steel · CPC title