US4775599A
Expired / Lapsed
US
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Cold rolled steel sheets having an improved press formability
Assignee: JFE Steel Corp
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Filing: 1986-12-19
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Granted: 1988-10-04
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Expires: 2006-12-19
Abstract
Abstract A cold rolled steel sheet or plated steel sheet having an improved press formability as well as excellent phosphatability, resistance to galling and spot weldability is produced by controlling a surface roughness pattern of the steel sheet so as to satisfy a center-line average surface roughness of 0.3-2.0 μm and a regularity parameter in at least one direction of not more than 0.25 defining the regularity of surface roughness.
Inventors
- 👤 Saiji Matsuoka
- 👤 Takashi Obara
- 👤 Kozo Tsunoyama
- 👤 Shunichi Tsugawa
- 👤 Shigeru Kobayashi
- 👤 Toshio Ichida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:10
CPC Classifications
C; C21; C21D; C21D9/00; C21D9/46; C21D8/00; C21D8/02; C21D8/04; C21D8/0421; C21D8/0436; B; B21; B21B; B21B1/00; B21B1/22; B21B1/227; C21D8/0478; C21D9/38; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/923; Y10S428/924; Y10S428/925; Y10T; Y10T428/00; Y10T428/12; Y10T428/12389; Y10T428/12993
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
75 words
A cold rolled steel sheet having an improved press formability, characterized in that said steel sheet has a surface roughness pattern satisfying a center-line average surface roughness (Ra, μm) of 0.3-2.0 and a regularity parameter (S) in at least one direction of not more than 0.25 showing a regularity of surface roughness represented by the following equations: ##EQU6## wherein Xi is a distance between peaks of convex portions at the surface of the steel sheet.
Claim 2
Dependent Claim
75 words
A cold rolled steel sheet having an improved press formability, characterized in that said steel sheet has a surface roughness pattern satisfying a center-line average surface roughness (Ra, μm) of 0.3-2.0 and a regularity parameter (S) in at least one direction of not more than 0.25 showing a regularity of surface roughness represented by the following equations: ##EQU6## wherein Xi is a distance between peaks of convex portions at the surface of the steel sheet.
Claim 3
Dependent Claim
35 words
The cold rolled steel sheet according to claim 1, wherein said surface roughness pattern further satisfies a mean area per one convex portion at center plane of surface roughness (SGr, μm 2 ) of 2,000-30,000.
Claim 4
Dependent Claim
56 words
The cold rolled steel sheet according to claim 1, wherein said surface roughness pattern further satisfies a mean area per one convex portion at center plane of surface roughness (SGr, μm 2 ) of 2,000-30,000 and a product of center-line average surface roughness (Ra, μm) and mean concave distance (Lmv, μm) of not less than 50.
Claim 5
Dependent Claim
54 words
The cold rolled steel sheet according to claim 1, wherein said surface roughness pattern further satisfies a mean area per one convex portion at center plane of surface roughness (SGr, μm 2 ) of 2,000-30,000 and a ratio of mean concave radius (Rmv, μm) to mean convex radius (Rmp, μm) of more than 1.
Claim 6
Dependent Claim
56 words
The cold rolled steel sheet according to claim 1, wherein said surface roughness pattern further satisfies a mean area per one convex portion at center plane of surface roughness (SGr, μm 2 ) of 2,000-30,000 and a mean area ratio of convex portions at center plane of surface roughness (SSr, %) of not less than 45.
Claim 7
Dependent Claim
74 words
The cold rolled steel sheet according to claim 1, wherein said surface roughness pattern further satisfies a mean area per one convex portion at center plane of surface roughness (SGr, μm 2 ) of 2,000-30,000, a product of center-line average surface roughness (Ra, μm) and mean concave distance (Lmv, μm) of not less than 50, and a ratio of mean concave radius (Rmv, μm) to mean convex radius (Rmp, μm) of more than 1.
Claim 8
Dependent Claim
74 words
The cold rolled steel sheet according to claim 1, wherein said surface roughness pattern further satisfies a mean area per one convex portion at center plane of surface roughness (SGr, μm) of 2,000-30,000, a product of center-line average surface roughness (Ra, μm) and mean concave distance (Lmv, μm) of not less than 50, and a mean area ratio of convex portions at center plane of surface roughness (SSr, %) of not less than 45.
Claim 9
Dependent Claim
74 words
The cold rolled steel sheet according to claim 1, wherein said surface roughness pattern further satisfies a mean area per one convex portion at center plane of surface roughness (SGr, μm 2 ) of 2,000-30,000, a ratio of mean concave radius (Rmv, μm) to mean convex radius (Rmp, μm) of more than 1, and a mean area ratio of convex portions at center plane of surface roughness (SSr, %) of not less than 45.
Claim 10
Dependent Claim
94 words
The cold rolled steel sheet according to claim 1, wherein said surface roughness pattern further satisfies a mean area per one convex portion at center plane of surface roughness (SGr, μm 2 ) of 2,000-30,000, a product of center-line average surface roughness (Ra, μm) and mean concave distance (Lmv, μm) of not less than 50, a ratio of mean concave radius (Rmv, μm) to mean convex radius (Rmp, μm) of more than 1, and a mean area ratio of convex portions at center plane of surface roughness (SSr, %) of not less than 45.
Claim 11
Dependent Claim
74 words
A plated steel sheet having an improved press formability, characterized in that said steel sheet has a surface roughness pattern satisfying a center-line average surface roughness (Ra, μm) of 0.3-2.0 and a regularity parameter (S) in at least one direction of not more than 0.25 showing a regularity of surface roughness represented by the following equations: ##EQU7## wherein Xi is a distance between peaks of convex portions at the surface of the steel sheet.
Claim 12
Dependent Claim
74 words
A plated steel sheet having an improved press formability, characterized in that said steel sheet has a surface roughness pattern satisfying a center-line average surface roughness (Ra, μm) of 0.3-2.0 and a regularity parameter (S) in at least one direction of not more than 0.25 showing a regularity of surface roughness represented by the following equations: ##EQU7## wherein Xi is a distance between peaks of convex portions at the surface of the steel sheet.
Claim 13
Dependent Claim
34 words
The plated steel sheet according to claim 10, wherein said surface roughness pattern further satisfies a mean area per one convex portion at center plane of surface roughness (SGr, μm 2 ) of 2,000-30,000.
Claim 14
Dependent Claim
55 words
The plated steel sheet according to claim 10, wherein said surface roughness pattern further satisfies a mean area per one convex portion at center plane of surface roughness (SGr, μm 2 ) of 2,000-30,000 and a product of center-line average surface roughness (Ra, μm) and mean concave distance (Lmv, μm) of not less than 50.
Claim 15
Dependent Claim
53 words
The plated steel sheet according to claim 10, wherein said surface roughness pattern further satisfies a mean area per one convex portion at center plane of surface roughness (SGr, μm 2 ) of 2,000-30,000 and a ratio of mean concave radius (Rmv, μm) to mean convex radius (Rmp, μm) of more than 1.
Claim 16
Dependent Claim
55 words
The plated steel sheet according to claim 10, wherein said surface roughness pattern further satisfies a mean area per one convex portion at center plane of surface roughness (SGr, μm 2 ) of 2,000-30,000 and a mean area ratio of convex portions at center plane of surface roughness (SSr, %) of not less than 45.
Claim 17
Dependent Claim
73 words
The plated steel sheet according to claim 10, wherein said surface roughness pattern further satisfies a mean area per one convex portion at center plane of surface roughness (SGr, μm 2 ) of 2,000-30,000, a product of center-line average surface roughness (Ra, μm) and mean concave distance (Lmv, μm) of not less than 50, and a ratio of mean concave radius (Rmv, μm) to mean convex radius (Rmp, μm) of more than 1.
Claim 18
Dependent Claim
73 words
The plated steel sheet according to claim 10, wherein said surface roughness pattern further satisfies a mean area per one convex portion at center plane of surface roughness (SGr, μm) of 2,000-30,000, a product of center-line average surface roughness (Ra, μm) and mean concave distance (Lmv, μm) of not less than 50, and a mean area ratio of convex portions at center plane of surface roughness (SSr, %) of not less than 45.
Claim 19
Dependent Claim
73 words
The plated steel sheet according to claim 10, wherein said surface roughness pattern further satisfies a mean area per one convex portion at center plane of surface roughness (SGr, μm 2 ) of 2,000-30,000, a ratio of mean concave radius (Rmv, μm) to mean convex radius (Rmp, μm) of more than 1, and a mean area ratio of convex portions at center plane of surface roughness (SSr, %) of not less than 45.
Claim 20
Dependent Claim
92 words
The plated steel sheet according to claim 10, wherein said surface roughness pattern further satisfies a mean area per one convex portion at center plane of surface roughness (SGr, μm 2 ) of 2,000-30,000, a product of center-line average surface roughness (Ra, μm) and mean concave distance (Lmv, μm) of not less than 50, a ratio of mean concave radius (Rmv, μm) to mean convex radius (Rmp, μm) of more than 1, and a mean ratio of convex portions at center plane of surface roughness (SSr, %) of not less than 45.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-10-04 | 1992-04-04 | 1992-10-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-04 | 1996-04-04 | 1996-10-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-04 | 2000-04-04 | 2000-10-04 | $7700.00 | Window Closed / Lapsed |