US3249456A - Diffusion coating process - Google Patents
Diffusion coating process Download PDFInfo
- Publication number
- US3249456A US3249456A US236691A US23669162A US3249456A US 3249456 A US3249456 A US 3249456A US 236691 A US236691 A US 236691A US 23669162 A US23669162 A US 23669162A US 3249456 A US3249456 A US 3249456A
- Authority
- US
- United States
- Prior art keywords
- substrate
- carbon
- steel
- alloy coating
- chromium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C10/00—Solid state diffusion of only metal elements or silicon into metallic material surfaces
- C23C10/28—Solid state diffusion of only metal elements or silicon into metallic material surfaces using solids, e.g. powders, pastes
- C23C10/34—Embedding in a powder mixture, i.e. pack cementation
- C23C10/36—Embedding in a powder mixture, i.e. pack cementation only one element being diffused
- C23C10/38—Chromising
- C23C10/40—Chromising of ferrous surfaces
Definitions
- the present invention relates to a process for providing metal substrates with a diffusion alloy coating. More particularly, the present invention relates to a diffusion alloy coating process in which decarburization of the substrate metal is avoided.
- Diffusion alloy coatings have been provided on metal substrates by heating the substrate in contact with coating metal, in elemental form, at low pressures. While a satisfactory diffusion alloy coating is obtained in this manner it has been found that the aforedescribed treatment causes decarburization of the substrate. In the case of steel, this develops a ferritic structure which is detrimental in that it leads to loss of hardness and strength in the coated article.
- diffusion coated articles have properties which make them advantageous for use in structural applications, in addition to such uses as automobile bumpers and trim, it would be of significant industrial benefit if impairment of the substrate material by carbon depletion could be avoided.
- a process in accordance with the present invention for providing a metal substrate with a diffusion alloy coating comprises heating a metal substrate in intimate contact with a carbon bearing alloy of the coating metal, the heating being conducted at a pressure of less than 2,000 microns in the temperature range of about 1000 to 1500 C. for a period of time sufficient to provide the substrate with the desired depth of diffusion alloy coating.
- a steel substrate in the form of plate, for example, is placed in a vacuum furnace and carbon bearing chromium metal is placed in intimate contact with the substrate.
- carbon bearing chromium metal is placed in intimate contact with the substrate.
- This can be conveniently accomplished by packing the steel substrate in comminuted high carbon ferrochromium alloy.
- the aforementioned materials are then heated at a temperature between 1000" C. and 1500 C., at a pressure of less than about 2000 microns, for a time sufficient to provide the desired depth of alloy coating in the substrate. Heating periods of from about 20 to 60 hours have been found to be sufficient to provide alloy coated articles suitable for use in such application as automobile trim, automobile bumpers and the like with the longer heating periods providing greater coating depths of up to about 0.15 inch or more.
- the alloy surface in the articles produced in this manner are high in chromium, e.g., up to 40%, at the surface of the article with decreasing chromium contents at increasing distances from the surface. Also, importantly, there is substantially no loss of carbon in the substrate as a result of the alloy coating treatment.
- the proportion of carbon in the source of coating metal e.g., ferrochrome
- the proportion of carbon in the source of coating metal should be at least about 25 times the proportion of carbon in the substrate. This can be conveniently provided most often with the use of commercially available ferroalloys such as high carbon ferrochrome which contain from 4-9 percent carbon.
- Example 1 A /2 inch plate of 1020 steel was packed in high carbon ferrochrome alloy powder (325 meshXD) and heated in a vacuum furnace at 1300 C. for 36 hours. The average pressure in the furnace during heating was 70 microns.
- Another plate of 1020 having the same dimensions as the first was packed in low carbon (vacuum grade chromium metal powder) (325 meshX D) and heated under the same conditions, i.e., 1300" C. for 36 hours at 70 microns pressure. Both steel plates were provided with a diffusion alloy coating of chromium as a result of this treatment.
- the carbon of the steel plate processed with high carbon ferrochrome was substantially unaffected while the carbon content of the steel plate processed with chromium was depleted to about 10% of its original value as shown in the data of Table I.
- Example 2 A /2 inch plate of 1020 steel was pack-ed in high carbon ferrochrome alloy powder meshXD) and heated in a vacuum furnace at 1175 C. for 48 hours. The average pressure in the furnace during heating was 60 microns.
- Another plate of 1020 having the same dimensions as the first was packed in low carbon ferrochrome (20 meshXD) and heated under the same conditions, i.e., 1175 C. for 48 hours .at 60 microns pressure. Both steel plates were provided with a diffusion alloy coating of chromium as a result of this treatment.
- This carbon content of the steel plate processed with high carbon ferrochrome was substantially unaffected while the carbon content of the steel plate processed with low carbon ferrochrome was depleted to about 30% of its original value as shown in the data of Table II.
- a process for providing a steel substrate with a diffusion alloy coating of chromium metal and avoiding decarburization of steel substmate which comprises heating the steel substrate in intimate contact with ferrochrome having a carbon content of 49%, said heating being conducted at a pressure of less than about 2,000 microns in the temperature range of 1000 C. to 1500 C. for a period of time sufficient to provide the desired depth of alloy coating whereby the substrate is provided with a diffusion alloy coating of chromium and decarburization of the steel substrate is avoided.
- earburization of steel substrate which comprises heating 2,141,640 12/1938 Cooper 117-22 the steel substrate in intimate contact with carbon bearing 2,205,864 6/1940 Sghwarzkopt 117 22 X chromium metal, the proportion of earbonin the chro- 5 mium metal being at least about 25 times the proportion OTHER REFERENCES of carbon in the substrate.
Description
Claims (1)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US236691A US3249456A (en) | 1962-11-09 | 1962-11-09 | Diffusion coating process |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US236691A US3249456A (en) | 1962-11-09 | 1962-11-09 | Diffusion coating process |
Publications (1)
Publication Number | Publication Date |
---|---|
US3249456A true US3249456A (en) | 1966-05-03 |
Family
ID=22890556
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US236691A Expired - Lifetime US3249456A (en) | 1962-11-09 | 1962-11-09 | Diffusion coating process |
Country Status (1)
Country | Link |
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US (1) | US3249456A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3485595A (en) * | 1965-09-10 | 1969-12-23 | Wmf Wuerttemberg Metallwaren | Metal fiber bodies |
US3717444A (en) * | 1970-12-14 | 1973-02-20 | Inland Steel Co | Chromized steel product |
FR2370106A1 (en) * | 1976-11-04 | 1978-06-02 | Gen Electric | PROCESS FOR IMPROVING THE RESISTANCE TO OXIDATION AND TO HOT CORROSION OF SUPERALALLIES |
FR2483468A2 (en) * | 1980-05-29 | 1981-12-04 | Creusot Loire | IMPROVEMENT IN THE CHROMIZATION OF STEELS BY GAS |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1155974A (en) * | 1911-10-04 | 1915-10-05 | Gen Electric | Treatment of metals. |
US1365499A (en) * | 1919-10-23 | 1921-01-11 | Gen Electric | Surface-alloyed metal |
US1672444A (en) * | 1926-03-17 | 1928-06-05 | Electro Metallurg Co | Producing corrosion-resistant surfaces on metals |
US1902092A (en) * | 1931-03-10 | 1933-03-21 | Electro Metallurg Co | Production of castings with coatings composed of high-chromium alloys |
US2141640A (en) * | 1936-11-11 | 1938-12-27 | Cooper Products Inc | Method of chromizing |
US2205864A (en) * | 1940-06-25 | Method of manufacturing hard |
-
1962
- 1962-11-09 US US236691A patent/US3249456A/en not_active Expired - Lifetime
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2205864A (en) * | 1940-06-25 | Method of manufacturing hard | ||
US1155974A (en) * | 1911-10-04 | 1915-10-05 | Gen Electric | Treatment of metals. |
US1365499A (en) * | 1919-10-23 | 1921-01-11 | Gen Electric | Surface-alloyed metal |
US1672444A (en) * | 1926-03-17 | 1928-06-05 | Electro Metallurg Co | Producing corrosion-resistant surfaces on metals |
US1902092A (en) * | 1931-03-10 | 1933-03-21 | Electro Metallurg Co | Production of castings with coatings composed of high-chromium alloys |
US2141640A (en) * | 1936-11-11 | 1938-12-27 | Cooper Products Inc | Method of chromizing |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3485595A (en) * | 1965-09-10 | 1969-12-23 | Wmf Wuerttemberg Metallwaren | Metal fiber bodies |
US3717444A (en) * | 1970-12-14 | 1973-02-20 | Inland Steel Co | Chromized steel product |
FR2370106A1 (en) * | 1976-11-04 | 1978-06-02 | Gen Electric | PROCESS FOR IMPROVING THE RESISTANCE TO OXIDATION AND TO HOT CORROSION OF SUPERALALLIES |
FR2483468A2 (en) * | 1980-05-29 | 1981-12-04 | Creusot Loire | IMPROVEMENT IN THE CHROMIZATION OF STEELS BY GAS |
EP0043742A1 (en) * | 1980-05-29 | 1982-01-13 | Creusot-Loire | Method of gas-chromizing steels |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: ELKEM METALS COMPANY, 270 PARK AVE., NEW YORK, NY Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:UNION CARBIDE CORPORATION;REEL/FRAME:003882/0752 Effective date: 19810626 Owner name: ELKEM METALS COMPANY, 270 PARK AVENUE, NEW YORK, N Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:UNION CARBIDE CORPORATION, A NY CORP.;REEL/FRAME:003882/0761 Effective date: 19810626 Owner name: ELKEM METALS COMPANY, A GENERAL PARTNERSHIP OF NY, Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:UNION CARBIDE CORPORATION;REEL/FRAME:003882/0752 Effective date: 19810626 Owner name: ELKEM METALS COMPANY, A NEW YORK GENERAL PARTNERSH Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:UNION CARBIDE CORPORATION, A NY CORP.;REEL/FRAME:003882/0761 Effective date: 19810626 |