US1864083A - Method of annealing nitrided steel - Google Patents
Method of annealing nitrided steel Download PDFInfo
- Publication number
- US1864083A US1864083A US424727A US42472730A US1864083A US 1864083 A US1864083 A US 1864083A US 424727 A US424727 A US 424727A US 42472730 A US42472730 A US 42472730A US 1864083 A US1864083 A US 1864083A
- Authority
- US
- United States
- Prior art keywords
- nitrogen
- nitrided
- annealing
- metal
- ferrous
- 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
Links
- 238000000034 method Methods 0.000 title description 17
- 229910000831 Steel Inorganic materials 0.000 title description 3
- 239000010959 steel Substances 0.000 title description 3
- 238000000137 annealing Methods 0.000 title description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 32
- 229910052757 nitrogen Inorganic materials 0.000 description 16
- 229910045601 alloy Inorganic materials 0.000 description 11
- 239000000956 alloy Substances 0.000 description 11
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 10
- 239000000463 material Substances 0.000 description 10
- 150000003839 salts Chemical class 0.000 description 8
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 5
- 150000001805 chlorine compounds Chemical class 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 229910000975 Carbon steel Inorganic materials 0.000 description 3
- 229910052783 alkali metal Inorganic materials 0.000 description 3
- 150000001342 alkaline earth metals Chemical class 0.000 description 3
- 239000010953 base metal Substances 0.000 description 3
- 239000010962 carbon steel Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 150000001340 alkali metals Chemical class 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000005121 nitriding Methods 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 229910001514 alkali metal chloride Inorganic materials 0.000 description 1
- -1 alkali-metal salts Chemical class 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 229910001338 liquidmetal Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910001510 metal chloride Inorganic materials 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M potassium chloride Inorganic materials [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 1
- 235000011164 potassium chloride Nutrition 0.000 description 1
- 239000001103 potassium chloride Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D3/00—Diffusion processes for extraction of non-metals; Furnaces therefor
- C21D3/02—Extraction of non-metals
- C21D3/08—Extraction of nitrogen
Definitions
- Another object of my invention is to pro vide a process which comprises treating nitrided ferrous products with a chemical reagent that is capable of reacting with the nitrogen without attacking the physical characteristics of the base metal which, as a rule,
- Another and more specific object of my invention is to provide a process of treating nitrided ferrous products which comprises subjecting them to the action of a fused alka,- line salt, the metal constituent of which is capable of reacting with the nitrogen present in a the surface portion of the ferrous material.
- ferrous products having an outer surface portion containing nitrogen may be annealed or softened to such an extent that they may be machined by the ordinary carbon-steel tools by a simple process which involves treating the material with a fused salt bath.
- the nitrided ferrous product is immersed in a bath comprising an alkaline metal chloride, such as potassium or sodium chloride or a mixture of such salts, which is maintained in afused state by the application of heat.
- an alkaline metal chloride such as potassium or sodium chloride or a mixture of such salts
- the reactionv between the alkali metal and the nitrogen in the surface material of the ferrous product will take place if the salt or mixture of salts are maintained in a fused state. Approximately fifteen minutes to one hour is requiredto effect complete reaction, depending upon the temperature.
- the nitrogen has been removed from the surface material of the ferrous product, it is withdrawn from the bath, and the salt remaining upon its surface niay be remove by washingor in any other desired manner.
- the alkali or alkaline-earth metal reacts chemically with the nitrogen and removes it from the surface portion of the ferrous material, liberating chlorine.
- the ferrous product may be again subjected to one of the usual nitriding processes, and, since the physical properties of the base alloy are not affected by the process, a nitrided product may be again produced having properties similar to the original nitrided material.
- the nitrogen was not removed, and any softening that occurred was caused by a dilution of the nitrogen throughout the surface KW materialk
- Such processes are not commercially feasible because they have the tendency to destroy the characteristics of the base metal. Since it is possible, by my improved 5 process, however, to remove the nitrogen Without impairing the physical properties of the base metal, it may be again nitrided with the usual good results.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
Description
Patented June 21, 1932 UNITED STATES P-ATENT" OFFICE WILLIAM J. MERTEN, OF PITTSBURGH, PENNSYLVANIA, ASSIG-NOR TO WESTINGHOUSE ELEOTRIG & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.-
METHOD OF ANNEALING NITRIDED STEEL No Drawing.
Another object of my invention is to pro vide a process which comprises treating nitrided ferrous products with a chemical reagent that is capable of reacting with the nitrogen without attacking the physical characteristics of the base metal which, as a rule,
contains alloys that are capable of being readily nitrided.
Another and more specific object of my invention is to provide a process of treating nitrided ferrous products which comprises subjecting them to the action of a fused alka,- line salt, the metal constituent of which is capable of reacting with the nitrogen present in a the surface portion of the ferrous material.
It has heretofore been the practice to subject ordinary carbon-steel alloys, or those containing special alloying ingredients, such as molybdenum, aluminum, chromium or vanadium or acombination of two or more of such elements, to the action of compounds containingflnitrogen at an elevated temperature for the purpose of hardening the surface and preventing corrosion. In such processes, the compoundsTzontaining nitrogen are de- 5 composed, and nitrogen is liberated in the nascent state.
Steel or other special alloys which have been subjected to such process, however, are difficult to machine, when employing the usual 0 carbon-steel tools, because of the extreme hardness of .the nitrided surface material. Attempts have heretofore been made to anneal or soften the nitrided products by subjecting them to a high temperature or by heating them in one of the usual liquid metal baths but the results have not been satisfactory. For example, subjecting them to temperatures as high as 2000 Fahrenheit or heating them in the usual lead baths have not been effective.
Application filed January 30, 1930. Serial No. 424,727.
I have made the discovery,however, that ferrous products having an outer surface portion containing nitrogen may be annealed or softened to such an extent that they may be machined by the ordinary carbon-steel tools by a simple process which involves treating the material with a fused salt bath.
In practicing my invention, the nitrided ferrous product is immersed in a bath comprising an alkaline metal chloride, such as potassium or sodium chloride or a mixture of such salts, which is maintained in afused state by the application of heat. I have foundthat, when the bath is maintained at a temperature of 1000 to 1400 Fahn, satisfactory results may be obtained, although it is understood that higher temperatures may be utilized. The reactionv between the alkali metal and the nitrogen in the surface material of the ferrous product will take place if the salt or mixture of salts are maintained in a fused state. Approximately fifteen minutes to one hour is requiredto effect complete reaction, depending upon the temperature. After the nitrogen has been removed from the surface material of the ferrous product, it is withdrawn from the bath, and the salt remaining upon its surface niay be remove by washingor in any other desired manner.
In my process, the alkali or alkaline-earth metal reacts chemically with the nitrogen and removes it from the surface portion of the ferrous material, liberating chlorine. After the nitrogen has been removed and the necessary marching operations performed, the ferrous product may be again subjected to one of the usual nitriding processes, and, since the physical properties of the base alloy are not affected by the process, a nitrided product may be again produced having properties similar to the original nitrided material.
My process'has the distinct advantage that the nitrogen is chemically removed from the surface material. When attempts have heretofore been made to anneal or soften the nitrided surface material of a ferrous product, the nitrogen was not removed, and any softening that occurred was caused by a dilution of the nitrogen throughout the surface KW materialk Such processes are not commercially feasible because they have the tendency to destroy the characteristics of the base metal. Since it is possible, by my improved 5 process, however, to remove the nitrogen Without impairing the physical properties of the base metal, it may be again nitrided with the usual good results.
While I have described my invention in considerable detail, it will be understood that it is not limited to the specific details set forth in the foregoing examples, which should be construed as illustrative and not by way of limitation. For example, the chlorides of one or more of the alkaline-earth metals, such as calcium, barium or strontium, or a mixture of one or more of such salts, with one or more of alkali-metal salts may be employed. It is, therefore, desired that only such limitations shall be imposed as are indicated in the appended claims.
claim as my invention: 1. In the process of removing nitrogen from alloys which have been subjected to a nitriding process, the steps which comprise heating the alloy in a bath comprising one or more chlorides of the alkali or alkaline-earth metals for a sufficient length of time to cause a reaction between the metal constituent of 80 the salt and the nitrogen in the surface ma terial of the alloy.
2. The process of treating alloys having a nitrided surface which comprises placing the alloy in a bath containing one or more of the 5 alkali-metal chlorides and maintaining the bath in a fused state by the application of heat for a sufiicient length of time-to cause a reaction between the alkali metal and the nitrogen in the surface material.
.40 3. The process of treating alloys having a nitrided surface which comprises subjecting the alloy to the action of a bath containing a mixture of sodium andpotassium chlorides while the chlorides are maintained in a fused state.
In testimony whereof, I have hereunto subscribed my name this 2lst day of January,
WILLIAM J. MERTEN. so
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US424727A US1864083A (en) | 1930-01-30 | 1930-01-30 | Method of annealing nitrided steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US424727A US1864083A (en) | 1930-01-30 | 1930-01-30 | Method of annealing nitrided steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US1864083A true US1864083A (en) | 1932-06-21 |
Family
ID=23683645
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US424727A Expired - Lifetime US1864083A (en) | 1930-01-30 | 1930-01-30 | Method of annealing nitrided steel |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US1864083A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3265541A (en) * | 1963-09-16 | 1966-08-09 | Armco Steel Corp | Elimination of enamel fishscaling in iron and steel sheets |
| DE102021104448A1 (en) | 2021-02-24 | 2022-08-25 | Lixil Corporation | Process for manufacturing a workpiece |
-
1930
- 1930-01-30 US US424727A patent/US1864083A/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3265541A (en) * | 1963-09-16 | 1966-08-09 | Armco Steel Corp | Elimination of enamel fishscaling in iron and steel sheets |
| DE102021104448A1 (en) | 2021-02-24 | 2022-08-25 | Lixil Corporation | Process for manufacturing a workpiece |
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