US4467016A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Aluminized chromized steel
Assignee: Alloy Surfaces Co Inc
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Filing: 1982-07-16
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Granted: 1984-08-21
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Expires: 2002-07-16
Abstract
Abstract Low alloy steel tubing is decarburized, chromized and then aluminized with or without masking at the sites at which the tubing is to be welded in place, to greatly increase resistance of the tubing to high temperature oxidation and sulfidation. Low surface aluminum content after aluminizing makes it easier to weld at that surface.
Inventors
- 👤 Alfonso L. Baldi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:55
CPC Classifications
B; B01; B01J; B01J25/00; B01J25/02; B01J23/00; B01J23/70; B01J23/89; B01J23/892; B01J35/00; B01J35/50; B01J35/58; B01J37/00; H; H05; H05K; H05K2201/00; H05K2201/02; H05K2201/0203; H05K2201/0206; H05K2201/0209; Y; Y10; Y10S; Y10S138/00; Y10S138/06; Y10T; Y10T428/00; Y10T428/12; Y10T428/12354; Y10T428/12493; Y10T428/12736; Y10T428/12743; Y10T428/12771; Y10T428/12806; Y10T428/12826; Y10T428/12847; Y10T428/12854
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
62 words
The process of protecting against hot sulfidation a low alloy steel tube that is to be welded in place, which process is characterized by the steps of subjecting the tube to a heavy diffusion chromizing, followed by a diffusion aluminizing in which the aluminizing is arranged to leave the welding sites with a surface aluminum content less than about 10% without masking.
Claim 2
Dependent Claim
62 words
The process of protecting against hot sulfidation a low alloy steel tube that is to be welded in place, which process is characterized by the steps of subjecting the tube to a heavy diffusion chromizing, followed by a diffusion aluminizing in which the aluminizing is arranged to leave the welding sites with a surface aluminum content less than about 10% without masking.
Claim 3
Dependent Claim
26 words
The combination of claim 1 in which the chromizing is sufficiently heavy to leave the aluminized surface with a chromium content of at least about 25%.
Claim 4
Dependent Claim
15 words
The combination of claim 1 in which the surface aluminum content is less than 5%.
Claim 5
Dependent Claim
15 words
The combination of claim 1 in which the low alloy steel is a chromium steel.
Claim 6
Dependent Claim
22 words
The combination of claim 4 in which the chromium steel has its surface decarburized before it is subjected to the diffusion chromizing.
Claim 7
Dependent Claim
9 words
The product produced by the process of claim 1.
References Cited (Backward Citations)
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Cited
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US3694255A
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US3764371A
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US3936539A
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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) | 1987-08-21 | 1988-02-20 | 1988-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-21 | 1992-02-20 | 1992-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-21 | 1996-02-20 | 1996-08-21 | $7700.00 | Window Closed / Lapsed |