Press-forming mold and method for manufacturing protective film for press-forming mold

Patent metadata

Field	Value
Publication number	US-9902093-B2
Application number	US-201214009522-A
Country	US
Kind code	B2
Filing date	Apr 3, 2012
Priority date	Apr 18, 2011
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

A press-forming mold has a protective film for preventing seizing during press-forming formed on at least a forming surface that comes into contact with a formed body. The protective film is formed by PVD. An arbitrary selection section extracted from the surface of the protective film is divided into a plurality of individual sections; and, when the gradient of the surface at the n th division point is represented by (dZn/dXn), taking N to represent the number of divisions, the root-mean-square RΔq calculated by the following numerical expression is no greater than 0.032.

R
⁢

⁢
Δ
⁢

⁢
q

=

1
N

⁢

∑

n
=
1

N

⁢

⁢

(

d
⁢

⁢

Z
n

d
⁢

⁢

X
n

)

2

It is thereby possible to improve the seizing resistance of a press-forming mold having a protective film formed by PVD.

First claim

What is claimed is:

1. A press-forming mold comprising:
a protective film for preventing seizing during press-forming, which is formed on at least a forming surface that comes into contact with a formed body, wherein:
said protective film is formed by PVD;
an arbitrary selection section extracted from the surface of the protective film is divided into a plurality of individual sections; and,
when the n th division point from an end of said selected section is defined as being located a distance of dXn in the direction of extension of said selected section and dZn in the height direction from the (n−1) th division point, and the gradient of the surface at said n th division point is represented by (dZn/dXn), taking N to represent the number of divisions, the root-mean-square RΔq calculated by the following expression is no greater than 0.032:

R
⁢

⁢
Δ
⁢

⁢
q

=

1
N

⁢

∑

n
=
1

N

⁢

⁢

(

d
⁢

⁢

Z
n

d
⁢

⁢

X
n

)

2

.

2. The press-forming mold according to claim 1 , wherein said protective film is one that is formed by PVD in which a metal material containing at least 50 atom % of Al is used as a target.

3. The press-forming mold according to claim 2 , wherein said protective film is one in which a first thin film comprising a TiAlN-based material is formed on a side that comes into contact with said formed body.

4. The press-forming mold according to claim 3 , wherein said protective film is one in which a second thin film comprising a CrN-based material is formed on said forming surface, and said first thin film formed on the second thin film.

5. A method for manufacturing a protective film for a press-forming mold in which a protective film for preventing seizing during press-forming is formed on at least a forming surface of the press-forming mold that comes into contact with a formed body,
the method comprising:
forming a protective film by PVD on said forming surface in a reaction gas atmosphere using, as a target, a metallic material to become said protective film; and
polishing the surface of the protective film;
wherein in said polishing the surface of the protective film, the polishing is performed so that:
an arbitrary selection section extracted from the surface of said protective film is divided into a plurality of individual sections; and
when the n th division point from an end of said selected section is defined as being located a distance of dXn in the direction of extension of said selected section and dZn in the height direction from the (n−1) th division point, and the gradient of the surface at said n th division point is represented by (dZn/dXn), the root-mean-square RΔq calculated by the following expression is no greater than 0.032:

R
⁢

⁢
Δ
⁢

⁢
q

=

1
N

⁢

∑

n
=
1

N

⁢

⁢

(

d
⁢

⁢

Z
n

d
⁢

⁢

X
n

)

2

.

6. The press-forming mold according to claim 1 , wherein the protective film comprises:
a first film formed on the forming surface and comprising a CrN-based material and having a thickness in range from 2μ to 5μ; and
a second film formed on the first film and comprising a TiAlN-based material and having a thickness in range from 1μ to 5μ.

7. The press-forming mold according to claim 1 , wherein the root-mean-square RΔq is equal to or less than 0.030.

8. The press-forming mold according to claim 1 , wherein the PVD comprises arc ion plating.

9. A method for manufacturing a protective film for a press-forming mold, the method comprising:
forming a thin film on the mold comprising:
placing the mold on a rotary table connected to a bias power source in a chamber;
supplying a process gas into the chamber;
placing a target comprising a metal material and connected to an arc power source in the chamber;
supplying power from the bias and arc po

Assignees

• KASHI Takaharu
• Yamamoto Kenji
• Nippon Koshuha Steel Co Ltd
• Kobe Steel Ltd

Inventors

• KASHI Takaharu
• Yamamoto Kenji

Classifications

• C23C14/0641

  Nitrides (C23C14/0617 takes precedence) · CPC title

• B21D37/01 Primary

  Selection of materials · CPC title

• B29C33/68 Primary

  Release sheets · CPC title

• C23C14/5886

  Mechanical treatment (involving removal of material C23C14/588) · CPC title

• C23C14/32 Primary

  by explosion; by evaporation and subsequent ionisation of the vapours {, e.g. ion-plating}(C23C14/34 - C23C14/48 take precedence) · CPC title