US4568393A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Carburized high chrome liner
Assignee: National Oilwell Varco LP
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Filing: 1984-12-06
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Granted: 1986-02-04
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Expires: 2004-12-06
Abstract
Abstract A hard corrosion resistant surface is provided on a ferrous substrate by first overlay welding onto the substrate surface a chromium containing ferrous material. The deposited overlay can then be machined. It is thereafter subjected to a carburization treatment at a temperature and for a time sufficient to cause the overlay to become converted to an austenitic material containing iron chromium carbides. After cooling, the carburized overlay material is heated for a time and at a temperature sufficient to cause the austenitic matrix material to precipitate secondary carbides and convert to a martensite matrix material upon cooling. It is also contemplated to initiate the aforesaid treatment with a suitably selected chromium containing ferrous material that thereby is not overlay welded.
Inventors
- 👤 Robert F. Kane
- 👤 William D. Van Arnam, III
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:27
CPC Classifications
C; C23; C23C; C23C26/00; B; B23; B23K; B23K35/00; B23K35/22; B23K35/24; B23K35/30; B23K35/3053; B23K35/308
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
161 words
A method of producing a hard corrosion resistant coating on a surface of a ferrous substrate which method comprises: providing a ferrous substrate; depositing a layer of chromium containing ferrous material on a surface of said substrate by overlay welding, said overlay ferrous material containing from about 15 to about 35 weight percent chromium, with the remainder being iron plus residuals; subjecting the surface of the deposited chromium containing ferrous overlay material to a carburization treatment at a temperature ranging from about 1900° F. to about 2050° F. for a period of time sufficient to cause said chromium containing ferrous material to become converted to an austenitic material containing iron chromium carbides; cooling the carburized overlay material to a temperature of less than about 1800° F.; and, heating said cooled overlay material for a period of time and at a temperature sufficient to cause said austenitic matrix material to precipitate secondary carbides and convert to a martensite matrix material upon cooling.
Claim 2
Independent Claim
161 words
A method of producing a hard corrosion resistant coating on a surface of a ferrous substrate which method comprises: providing a ferrous substrate; depositing a layer of chromium containing ferrous material on a surface of said substrate by overlay welding, said overlay ferrous material containing from about 15 to about 35 weight percent chromium, with the remainder being iron plus residuals; subjecting the surface of the deposited chromium containing ferrous overlay material to a carburization treatment at a temperature ranging from about 1900° F. to about 2050° F. for a period of time sufficient to cause said chromium containing ferrous material to become converted to an austenitic material containing iron chromium carbides; cooling the carburized overlay material to a temperature of less than about 1800° F.; and, heating said cooled overlay material for a period of time and at a temperature sufficient to cause said austenitic matrix material to precipitate secondary carbides and convert to a martensite matrix material upon cooling.
Claim 3
Dependent Claim
36 words
The method of claim 1 further characterized by machining the surface of the deposited chromium containing ferrous overlay material to essentially the final surface condition desired prior to subjecting said machined surface to a carburization treatment.
Claim 4
Dependent Claim
30 words
The method of claim 1 wherein said ferrous substrate is a carbon or low alloy steel substrate in wrought or cast condition having an 0.50 weight percent maximum carbon content.
Claim 5
Dependent Claim
38 words
The method of claim 1 wherein said overlay welding deposits a ferrous material containing up to about 4 weight percent silicon and up to about 3 weight percent molybdenum, with the balance being chromium and iron plus residuals.
Claim 6
Dependent Claim
22 words
The method of claim 4 wherein said residuals are selected from the group consisting of carbon, manganese, nickel, phosphorous, sulphur and vanadium.
Claim 7
Dependent Claim
23 words
The method of claim 1 wherein said overlay welding deposits a ferrous material containing from about 15 to about 35 weight percent chromium.
Claim 8
Dependent Claim
38 words
The method of claim 1 wherein said overlay welding deposits a ferrous material to a depth not greater than about 1/8 inch by plasma transferred arc, gas metal arc or gas tungsten arc welding of said ferrous substrate.
Claim 9
Dependent Claim
27 words
The method of claim 1 wherein said ferrous overlay material surface is carburized by partial pressure carburizing, or conventional gas carburizing, or plasma carburizing or pack carburizing.
Claim 10
Dependent Claim
61 words
The method of claim 1 wherein said ferrous overlay material surface is carburized at a temperature ranging from about 1900° F. to about 2000° F. for a period of time from about 3 hours to about 24 hours thereby providing a carburized depth in said overlay ranging from about 0.010 inch to about 0.040 inch from the surface of said overlay.
Claim 11
Dependent Claim
18 words
The method of claim 1 wherein the carburized overlay material contains at least about 2.3 weight percent carbon.
Claim 12
Dependent Claim
17 words
The method of claim 1 wherein the carburized overlay material is thereby hardened to about HRC 45.
Claim 13
Dependent Claim
22 words
The method of claim 1 further characterized by burnishing said ferrous overlay material prior to subjecting said material to said carburization treatment.
Claim 14
Dependent Claim
41 words
The method of claim 1 wherein said cooled substrate is heated to a temperature of about 1800° F. for a time of about one hour and after cooling provides martensite matrix material with a resulting hardness of about HRC 61 minimum.
Claim 15
Dependent Claim
28 words
The method of claim 1 wherein after carburization the microstructure of said overlay ferrous material contains above about 30 percent hard iron chromium carbides in an austenitic matrix.
Claim 16
Dependent Claim
15 words
The method of claim 1 wherein said ferrous substrate is an interior pump liner surface.
Claim 17
Dependent Claim
12 words
The hard, corrosion resistant article prepared by the method of claim 1.
Claim 18
Independent Claim
137 words
A method adapted for producing a liner article having a hard and corrosion resistant interior surface which method comprises: establishing said article from chromium containing ferrous material containing from about 15to about 35 weight percent chromium, with the remainder being iron plus residuals; subjecting said chromium containing article to a carburization treatment at a temperature ranging from about 1900° F. to about 2050° F. for a period of time sufficient to cause said chromium containing ferrous material to become converted to an austenitic material containing iron chromium carbides; cooling the carburized overlay material to a temperature of less than about 1800° F.; and, heating said cooled overlay material for a period of time and at a temperature sufficient to cause said austenitic matrix material to precipitate secondary carbides and convert to a martensite matrix material upon cooling.
Claim 19
Independent Claim
137 words
A method adapted for producing a liner article having a hard and corrosion resistant interior surface which method comprises: establishing said article from chromium containing ferrous material containing from about 15to about 35 weight percent chromium, with the remainder being iron plus residuals; subjecting said chromium containing article to a carburization treatment at a temperature ranging from about 1900° F. to about 2050° F. for a period of time sufficient to cause said chromium containing ferrous material to become converted to an austenitic material containing iron chromium carbides; cooling the carburized overlay material to a temperature of less than about 1800° F.; and, heating said cooled overlay material for a period of time and at a temperature sufficient to cause said austenitic matrix material to precipitate secondary carbides and convert to a martensite matrix material upon cooling.
Claim 20
Dependent Claim
19 words
The method of claim 17 wherein said article is a pump liner established from a chromium containing ferrous material.
Claim 21
Dependent Claim
20 words
The method of claim 17 wherein said article is established from material containing silicon and molybdenum along with said chromium.
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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) | 1989-02-03 | 1989-08-05 | 1990-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-03 | 1993-08-05 | 1994-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-03 | 1997-08-05 | 1998-02-04 | $7700.00 | Window Closed / Lapsed |