US5409551A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for minimizing surface roughening of tungsten-containing rolls and other metallic articles
Assignee: Nippon Steel Corp
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Filing: 1992-11-04
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Granted: 1995-04-25
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Expires: 2012-11-04
Abstract
Abstract A method for improving the resistance to surface roughening of tungsten-containing metallic articles such as cutting tools and hot mill rolls made of a cemented carbide or high-speed steel and extending the lifetime thereof. The method comprises treating a metallic article with an aqueous alkaline solution containing calcium ions and optionally tungstate ions having a pH greater than 8 so as to form a coating of calcium tungstate on the surface of the metallic article. In hot rolling with tungsten-containing rolls, the aqueous solution can be used as at least part of a cooling water to cool the rolls, thereby extending the period before roll replacement becomes necessary due to surface roughening and decreasing the frequency of roll dressing required during hot rolling.
Inventors
- 👤 Shigeki Azuma
- 👤 Yoshiaki Kusaba
- 👤 Hideaki Miyuki
- 👤 Hideo Yamamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:07
CPC Classifications
C; C23; C23C; C23C22/00; C23C22/05; C23C22/60; C23C22/64; B; B21; B21B; B21B45/00; B21B45/02; B21B45/0203; C23C22/68
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
50 words
A method for improving the resistance to surface roughening of tungsten-containing metallic articles, comprising treating a tungsten-containing metallic article with an aqueous alkaline solution containing calcium ions and having a pH greater than 8 so as to form a coating of calcium tungstate on the surface of the metallic article.
Claim 2
Independent Claim
50 words
A method for improving the resistance to surface roughening of tungsten-containing metallic articles, comprising treating a tungsten-containing metallic article with an aqueous alkaline solution containing calcium ions and having a pH greater than 8 so as to form a coating of calcium tungstate on the surface of the metallic article.
Claim 3
Dependent Claim
20 words
The method of claim 1, wherein the tungsten content of the metallic article is about 8% by weight or more.
Claim 4
Dependent Claim
20 words
The method of claim 1, wherein the tungsten content of the metallic article is about 20% by weight or more.
Claim 5
Dependent Claim
18 words
The method of claim 3, wherein the metallic article is made of a cemented tungsten carbide hard alloy.
Claim 6
Dependent Claim
13 words
The method of claim 1, wherein the aqueous solution further contains tungstate ions.
Claim 7
Dependent Claim
20 words
The method of claim 5, wherein the tungsten content of the metallic article is less than about 20% by weight.
Claim 8
Dependent Claim
16 words
The method of claim 6, wherein the metallic article is made of a tungsten-containing high-speed steel.
Claim 9
Dependent Claim
19 words
The method of claim 1, wherein the aqueous solution has a pH in the range of 8.5 to 9.
Claim 10
Dependent Claim
20 words
The method of claim 1, wherein the content of calcium ions in the aqueous solution is at least 10 ppm.
Claim 11
Dependent Claim
21 words
The method of claim 9, wherein the content of calcium ions is in the range of 30 ppm to 80 ppm.
Claim 12
Dependent Claim
20 words
The method of claim 5, wherein the content of tungstate ions in the aqueous solution is at least 10 ppm.
Claim 13
Dependent Claim
18 words
The method of claim 11, wherein the content of tungstate ions is in the range of 20-50 ppm.
Claim 14
Dependent Claim
24 words
The method of claim 1, wherein the metallic article is treated with the aqueous solution at a temperature in the range of 80°-200° C.
Claim 15
Dependent Claim
15 words
The method of claim 13, wherein the temperature is in the range of 120°-180° C.
Claim 16
Dependent Claim
18 words
The method of claim 1, wherein the metallic article is treated with the aqueous solution for 3-24 hours.
Claim 17
Independent Claim
45 words
A method for retarding surface roughening of tungsten-containing hot mill rolls, comprising substituting an aqueous alkaline solution which contains calcium ions and which has a pH greater than 8 for at least part of the cooling water used to cool the rolls during hot rolling.
Claim 18
Independent Claim
45 words
A method for retarding surface roughening of tungsten-containing hot mill rolls, comprising substituting an aqueous alkaline solution which contains calcium ions and which has a pH greater than 8 for at least part of the cooling water used to cool the rolls during hot rolling.
Claim 19
Dependent Claim
13 words
The method of claim 16, wherein the aqueous solution further contains tungstate ions.
Claim 20
Dependent Claim
47 words
The method of claim 16, wherein the rolls are treated with an aqueous calcium ion-containing solution containing calcium ions and having a pH greater than 8 so as to form a coating of calcium tungstate on the surface of the rolls prior to use in hot rolling.
Claim 21
Dependent Claim
17 words
The method of claim 16, wherein the rolls are made of a cemented tungsten carbide hard alloy.
Claim 22
Dependent Claim
15 words
The method of claim 17, wherein the rolls are made of a tungsten-containing high-speed steel.
References Cited (Backward Citations)
US2653882A
Cited
GB698910A
Cited
GB1011715A
Cited
US4355079A
Cited
EP0008211A1
Cited
EP0146284A1
Cited
US4818572A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-04-24 | 1998-10-24 | 1999-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-04-24 | 2002-10-24 | 2003-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-04-24 | 2006-10-24 | 2007-04-25 | $7700.00 | Window Closed / Lapsed |