US2740730A - Method for preparing valve parts for apparatus for handling molten calcium - Google Patents
Method for preparing valve parts for apparatus for handling molten calcium Download PDFInfo
- Publication number
- US2740730A US2740730A US395841A US39584153A US2740730A US 2740730 A US2740730 A US 2740730A US 395841 A US395841 A US 395841A US 39584153 A US39584153 A US 39584153A US 2740730 A US2740730 A US 2740730A
- Authority
- US
- United States
- Prior art keywords
- valve
- calcium
- seat
- plug
- molten calcium
- 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
- 229910052791 calcium Inorganic materials 0.000 title claims description 48
- 239000011575 calcium Substances 0.000 title claims description 48
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 title claims description 45
- 238000000034 method Methods 0.000 title claims description 17
- 229910052751 metal Inorganic materials 0.000 claims description 24
- 239000002184 metal Substances 0.000 claims description 24
- 238000005260 corrosion Methods 0.000 claims description 7
- 230000007797 corrosion Effects 0.000 claims description 7
- 238000009792 diffusion process Methods 0.000 claims description 6
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 12
- 229910045601 alloy Inorganic materials 0.000 description 11
- 239000000956 alloy Substances 0.000 description 11
- 238000009833 condensation Methods 0.000 description 8
- 230000005494 condensation Effects 0.000 description 8
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 229910052804 chromium Inorganic materials 0.000 description 6
- 239000011651 chromium Substances 0.000 description 6
- 229910052759 nickel Inorganic materials 0.000 description 6
- 238000004821 distillation Methods 0.000 description 5
- 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 4
- KEAYESYHFKHZAL-UHFFFAOYSA-N Sodium Chemical compound [Na] KEAYESYHFKHZAL-UHFFFAOYSA-N 0.000 description 4
- 229910052708 sodium Inorganic materials 0.000 description 4
- 239000011734 sodium Substances 0.000 description 4
- 229910000640 Fe alloy Inorganic materials 0.000 description 3
- -1 calcium metals Chemical class 0.000 description 3
- 239000000788 chromium alloy Substances 0.000 description 3
- 239000011261 inert gas Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000010802 sludge Substances 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- 239000010963 304 stainless steel Substances 0.000 description 2
- 229910000589 SAE 304 stainless steel Inorganic materials 0.000 description 2
- 238000011835 investigation Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 229910000599 Cr alloy Inorganic materials 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- UPHIPHFJVNKLMR-UHFFFAOYSA-N chromium iron Chemical compound [Cr].[Fe] UPHIPHFJVNKLMR-UHFFFAOYSA-N 0.000 description 1
- 238000004508 fractional distillation Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052987 metal hydride Inorganic materials 0.000 description 1
- 150000004681 metal hydrides Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 229910021652 non-ferrous alloy Inorganic materials 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B26/00—Obtaining alkali, alkaline earth metals or magnesium
- C22B26/20—Obtaining alkaline earth metals or magnesium
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K25/00—Details relating to contact between valve members and seats
- F16K25/04—Arrangements for preventing erosion, not otherwise provided for
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12729—Group IIA metal-base component
Definitions
- This invention relates to valves for an apparatus for handling molten calcium metal and, more particularly, to valves for apparatus for alternately handling molten sodium and calcium metals.
- the apparatus described in the above mentioned copending application comprises a vertical distillation retort communicating nearits upper end with a downwardly inclined condensation'receptacle.
- the condensing receptacle is provided with a discharge outlet at its lower end which may be opened and closed by a valve having a stationary valve seat and a movable engageable member adapted to be moved to open and close the valve.
- This valve preferably is of the type having a stationary valve seat and a plug valve adapted to be moved into and out of engagement with the valve seat.
- the discharge outlet communicates through a conduit with means for separately receiving molten sodium and calcium metals.
- the distillation and condensing receptacles as well as the associated parts which are contacted by the hot molten metal or metal vapors are formed of any suitable iron or non-ferrous alloy having good corrosion resistance at high temperatures, such as an iron-chromium alloy, chromiumnickel alloys or chromium-cobalt alloys, stainless steel, etc.
- movable valve member such as the plug valve, of type 304 stainless steel containing about 8 to 11 per cent nickel and 18 to 20 per cent chromium.
- the valve seat of the same material as that of the body of the condensing receptacle which may be the same or a dilferent material from that forming the movable valve member.
- the distillation receptacle is heated to cause the sodium metal to distill from the sludge therein in the presence of an inert gas at a suitable pressure, such as atmospheric pressure.
- the sodium vapors are condensed to liquid in the condensation receptacle and are caused to pass through the discharge outlet to a sodium metal receiving receptacle.
- the valve at the bottom of the condensation receptacle then is closed and the distillation receptacle is heated to cause calcium metal to distill from the calcium-rich residue therein.
- the calcium vapors are condensed to a solid muff in the condensation receptacle.
- the solid mufi of calcium metal is melted and the molten calcium collects in the bottom of the condensation receptacle.
- the valve controlling the discharge outlet of the condensation receptacle then is opened to permit 2,740,730 Patented Apr. 3, 1956 Ice the molten calcium to flow into a separate calcium receiving receptacle.
- the present invention contemplates a method for preparing valve means for an apparatus for handling molten calcium metal at a predetermined temperature by pretreating one or more of the cooperating valve parts with molten calcium at a temperature below that at which the alloy is substantially corroded but substantially above such predetermined temperature fora sufficient period of time to.
- the pool of molten calcium collecting in the bottom of the condensationreceptacle is maintained at a temperature between about 900 to 950. Consequently, in the practice of the present invention the temperature of the molten calcium used for pretreating one or more of the parts of the valve controlling the outlet of the condensation receptacle should be greater than 950 C.
- the valve means includes a plug valve movable toward and away from the valve seat and is formed of type 304 stainless steel containing about 8 to 11 per cent nickel and 18 to 20 per cent chromium, the valve means operates satisfactorily if the plug valve has been pretreated with molten calcium at a temperature of about 1000 C. for a few hours and, preferably for about 24 hours. Pretreatment with molten calcium at a temperature of about 1050 C. tends to corrode this material.
- the pretreatment may be conducted ina closed receptacle with an atmosphere of an inert gas under a pressure slightly greater than atmospheric pressure above the molten calcium. After the valve part has been immersed in the molten calcium for the desired period of time, it may be raised and permitted to cool in the inert gas. It then is removed from the receptacle and cleaned as by washing with dilute nitric acid.
- a method for preparing valve means for an apparatus for handling molten calcium at a predetermined'temperature said valve means including a valve seat and a valve plug rnoveable into and out of engagement with the seat, said seat and plug being formed of an alloy having good corrosion resistance at high temperature, said method comprising pretreating at least one of the valve parts consisting of said seat and plug by subjecting it to the action of molten calcium metal at a temperature below that at which the alloy is substantially corroded but greater than said predetermined temperaturefor a sufficient period of time to cause substantial difiusion of calcium metal into the surface thereof which is to engage the other valve part.
- valve means for an apparatus for handling molten calcium at a predetermined temperature
- said valve means including a valve seat and a valve plug moveable into and out of engagement With the seat, said seat and plug being formed of an alloy having good corrosion resistance at high temperature
- said method comprising pretreating said plug by subjecting it to the action of molten calcium at a temperature below that at which the alloy is substantially corroded but greater than saidpredetermined temperature for a sumcient period of time to cause substantial diffusion of calcium metal into the surface thereof which is to engage the valve seat.
- valve means for an apparatire for handling molten calcium at a predetermined temperature
- said valve means including a valve seat and a valve plug moveable into and out of engagement with the seat, said seat and plug being formed of an alloy having good corrosion resistance at high temperature
- said method comprising pretreating said seat and plug by subjecting them to the action of molten calcium at a temperature below that at which the alloy is substantially corroded but greater than said predetermined temperature for a sufficient period of time to cause substantial difiusion of calcium metal into the surfaces which are to engage one another.
- valve means for an ap paratus for handling molten calcium at a predetermined temperature
- said valve means including a valve seat and a valve plug moveable into and out of engagement with the seat, said seat and plug being formed of an iron alloy having good corrosion resistance at high temperatures
- said method comprising forming at least one of the valve parts selected from the group consisting of said seat and said plug of an alloy comprising essentially iron, chromium and nickel, and pretreating the selected part by subjecting it to the action of molten calcium metal at a temperature below-that at which the alloyis substantially corroded but greater than said predetermined temperature for a period of time suificient to cause substantial diffusion of calcium metal into the surface thereof which is to engage the other valve part.
- valve part is formed of stainless steel having a nickel content of about 8 to 11 per cent and a chromium content of about 18 to 20 per cent by weight.
- valve means for an apparatus for handling molten calcium at a predetermined temperature
- said valve means including a valve seat and a valve plug moveable into and out of engagement with the seat, said seat and plug being formed of an iron alloy having good corrosion resistance at high temperatures
- said method comprising forming said plug of an alloy comprising essentially iron, chromium and nickel, and pretreating said plug by subjecting it to the action of molten calcium metal at a temperature below that at which the alloy is substantially corroded but greater than said predetermined temperature for a period of time sufficient to cause substantial diffusion of calcium metal into the surface thereof Which is to engage the other valve part.
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Life Sciences & Earth Sciences (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Lift Valve (AREA)
Description
METHOD FOR PREPARING VALVE PARTS FOR APPARATUS FOR HANDLING MOLTEN CAL! CIUM Mario D. Banus, Topsfield, Mass, assignor to Metal Hydrides Incorporated, Beverly, Mass, a corporation of Massachusetts No Drawing. Application December 2, 1953,
' Serial N0. 395,841
7 Claims. (Cl. 117-131) This invention relates to valves for an apparatus for handling molten calcium metal and, more particularly, to valves for apparatus for alternately handling molten sodium and calcium metals.
In a copending application of Bernard A. Gruber, Emanuel Gordon and Robert A. Jermain, Serial No. 323,412, filed December 1, 1952, an apparatus is described which is adapted for the recovery of sodium and calcium metals by fractional distillation from the sludge obtained as a byproduct in the electrolytic production of sodium metal. This sludge contains about 70 per cent sodium metal and about 20 per cent calcium metal, the balance being essentially chlorides and oxides of these metals present as impurities.
The apparatus described in the above mentioned copending application comprises a vertical distillation retort communicating nearits upper end with a downwardly inclined condensation'receptacle. The condensing receptacle is provided with a discharge outlet at its lower end which may be opened and closed by a valve having a stationary valve seat and a movable engageable member adapted to be moved to open and close the valve. This valve preferably is of the type having a stationary valve seat and a plug valve adapted to be moved into and out of engagement with the valve seat. The discharge outlet communicates through a conduit with means for separately receiving molten sodium and calcium metals.
The distillation and condensing receptacles as well as the associated parts which are contacted by the hot molten metal or metal vapors are formed of any suitable iron or non-ferrous alloy having good corrosion resistance at high temperatures, such as an iron-chromium alloy, chromiumnickel alloys or chromium-cobalt alloys, stainless steel, etc. It is presently preferred to form the above mentioned movable valve member, such as the plug valve, of type 304 stainless steel containing about 8 to 11 per cent nickel and 18 to 20 per cent chromium. It is convenient to form the valve seat of the same material as that of the body of the condensing receptacle which may be the same or a dilferent material from that forming the movable valve member.
The distillation receptacle is heated to cause the sodium metal to distill from the sludge therein in the presence of an inert gas at a suitable pressure, such as atmospheric pressure. The sodium vapors are condensed to liquid in the condensation receptacle and are caused to pass through the discharge outlet to a sodium metal receiving receptacle.
The valve at the bottom of the condensation receptacle then is closed and the distillation receptacle is heated to cause calcium metal to distill from the calcium-rich residue therein. The calcium vapors are condensed to a solid muff in the condensation receptacle. When the calcium metal has been removed from the calcium-rich residue, the solid mufi of calcium metal is melted and the molten calcium collects in the bottom of the condensation receptacle. The valve controlling the discharge outlet of the condensation receptacle then is opened to permit 2,740,730 Patented Apr. 3, 1956 Ice the molten calcium to flow into a separate calcium receiving receptacle.
When the apparatus abovedescribed was first operated, difiiculty was experienced with the operation of the valve controlling the discharge outlet of the condensation receptacle. Thus, while the solid muff of calcium metal was being melted, the molten calcium collected in the bottom of the condenser and remained in contact with the valve closing the discharge outlet for a short period of time. When it was attempted to open the valve to permit the molten calcium to flow into its receiving receptacle, it was found that the plug could not be lifted from its seat.
Extensive subsequent investigations were conducted in an attempt to overcome this difficulty. As a result of these investigations, it has been discovered that this difficulty can be overcome by pretreating either the valve seat or the valve plug or both by subjecting the valve part to the action of molten calcium at a temperature below that at which the alloy is substantially corroded but substantially above the temperature at which the molten calcium contacts the valve part in actual use. The period of such pretreatment should be suflicient to cause substantial diffusion of calcium metal into the surface thereof which is to engage the other valve part in use. Thus, the present invention contemplates a method for preparing valve means for an apparatus for handling molten calcium metal at a predetermined temperature by pretreating one or more of the cooperating valve parts with molten calcium at a temperature below that at which the alloy is substantially corroded but substantially above such predetermined temperature fora sufficient period of time to.
cause substantial diffusion of calcium 'metal into the surface thereof which is to engage the cooperating valve part.
In the normal operation of the above described distillation apparatus, the pool of molten calcium collecting in the bottom of the condensationreceptacle is maintained at a temperature between about 900 to 950. Consequently, in the practice of the present invention the temperature of the molten calcium used for pretreating one or more of the parts of the valve controlling the outlet of the condensation receptacle should be greater than 950 C. When the valve means includes a plug valve movable toward and away from the valve seat and is formed of type 304 stainless steel containing about 8 to 11 per cent nickel and 18 to 20 per cent chromium, the valve means operates satisfactorily if the plug valve has been pretreated with molten calcium at a temperature of about 1000 C. for a few hours and, preferably for about 24 hours. Pretreatment with molten calcium at a temperature of about 1050 C. tends to corrode this material.
The pretreatment may be conducted ina closed receptacle with an atmosphere of an inert gas under a pressure slightly greater than atmospheric pressure above the molten calcium. After the valve part has been immersed in the molten calcium for the desired period of time, it may be raised and permitted to cool in the inert gas. It then is removed from the receptacle and cleaned as by washing with dilute nitric acid.
I claim:
1. A method for preparing valve means for an apparatus for handling molten calcium at a predetermined'temperature, said valve means including a valve seat and a valve plug rnoveable into and out of engagement with the seat, said seat and plug being formed of an alloy having good corrosion resistance at high temperature, said method comprising pretreating at least one of the valve parts consisting of said seat and plug by subjecting it to the action of molten calcium metal at a temperature below that at which the alloy is substantially corroded but greater than said predetermined temperaturefor a sufficient period of time to cause substantial difiusion of calcium metal into the surface thereof which is to engage the other valve part.
2. A method for preparing valve means for an apparatus for handling molten calcium at a predetermined temperature, said valve means including a valve seat and a valve plug moveable into and out of engagement With the seat, said seat and plug being formed of an alloy having good corrosion resistance at high temperature, said method comprising pretreating said plug by subjecting it to the action of molten calcium at a temperature below that at which the alloy is substantially corroded but greater than saidpredetermined temperature for a sumcient period of time to cause substantial diffusion of calcium metal into the surface thereof which is to engage the valve seat.
3. A method for preparing valve means for an apparatire for handling molten calcium at a predetermined temperature, said valve means including a valve seat and a valve plug moveable into and out of engagement with the seat, said seat and plug being formed of an alloy having good corrosion resistance at high temperature, said method comprising pretreating said seat and plug by subjecting them to the action of molten calcium at a temperature below that at which the alloy is substantially corroded but greater than said predetermined temperature for a sufficient period of time to cause substantial difiusion of calcium metal into the surfaces which are to engage one another.
4. A method for preparing valve means for an ap paratus for handling molten calcium at a predetermined temperature, said valve means including a valve seat and a valve plug moveable into and out of engagement with the seat, said seat and plug being formed of an iron alloy having good corrosion resistance at high temperatures, said method comprising forming at least one of the valve parts selected from the group consisting of said seat and said plug of an alloy comprising essentially iron, chromium and nickel, and pretreating the selected part by subjecting it to the action of molten calcium metal at a temperature below-that at which the alloyis substantially corroded but greater than said predetermined temperature for a period of time suificient to cause substantial diffusion of calcium metal into the surface thereof which is to engage the other valve part.
5. The method as described by claim 4 in which the selected valve part is formed of stainless steel having a nickel content of about 8 to 11 per cent and a chromium content of about 18 to 20 per cent by weight.
6. A method for preparing valve means for an apparatus for handling molten calcium at a predetermined temperature,'said valve means including a valve seat and a valve plug moveable into and out of engagement with the seat, said seat and plug being formed of an iron alloy having good corrosion resistance at high temperatures, said method comprising forming said plug of an alloy comprising essentially iron, chromium and nickel, and pretreating said plug by subjecting it to the action of molten calcium metal at a temperature below that at which the alloy is substantially corroded but greater than said predetermined temperature for a period of time sufficient to cause substantial diffusion of calcium metal into the surface thereof Which is to engage the other valve part.
7. The method as described by claim 6 in which the said plug is formed of stainless steel having a nickel con tent of about 8 to 11 per cent and a chromium content of about 18 to 20 per cent by weight.
References Cited in the file of this patent UNITED STATES PATENTS 2,400,255 Pfeil May 14, 1946 FOREIGN PATENTS 64,821 Russia May 31, 1945
Claims (1)
1. A METHOD FOR PREPARING VALVE MEANS FOR AN APPARATUS FOR HANDLING MOLTEN CALCIUM AT A PREDETERMINED TEMPERATURE, SAID VALVE MEANS INCLUDING A VALVE SEAT AND A VALVE PLUG MOVEABLE INTO AND OUT OF ENGAGEMENT WITH THE SEAT, SAID SEAT AND PLUG BEING FORMED OF AN ALLOY HAVING GOOD CORROSION RESISTANCE AT HIGH TEMPERATURE, SAID METHOD COMPRISING PRETREATING AT LEAST ONE OF THE VALVE PARTS CONSISTING OF SAID SEAT AND PLUG BY SUBJECTING IT TO THE ACTION OF MOLTEN CALCIUM METAL AT A TEMPERATURE BELOW THAT AT WHICH THE ALLOY IS SUBSTANTIALLY CORRODED BUT GREATER THAN SAID PREDETERMINED TEMPERATURE FOR A SUFFICIENT PERIOD OF TIME TO CAUSE SUBSTANTIAL DIFFUSION OF CALCIUM METAL INTO THE SURFACE THEREOF WHICH IS TO ENGAGE THE OTHER VALVE PART.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US395841A US2740730A (en) | 1953-12-02 | 1953-12-02 | Method for preparing valve parts for apparatus for handling molten calcium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US395841A US2740730A (en) | 1953-12-02 | 1953-12-02 | Method for preparing valve parts for apparatus for handling molten calcium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2740730A true US2740730A (en) | 1956-04-03 |
Family
ID=23564753
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US395841A Expired - Lifetime US2740730A (en) | 1953-12-02 | 1953-12-02 | Method for preparing valve parts for apparatus for handling molten calcium |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2740730A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3190749A (en) * | 1963-07-23 | 1965-06-22 | Du Pont | Alloy article having a porous outer surface and process of making same |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2400255A (en) * | 1941-05-27 | 1946-05-14 | Int Nickel Co | Electric resistance elements and the like |
-
1953
- 1953-12-02 US US395841A patent/US2740730A/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2400255A (en) * | 1941-05-27 | 1946-05-14 | Int Nickel Co | Electric resistance elements and the like |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3190749A (en) * | 1963-07-23 | 1965-06-22 | Du Pont | Alloy article having a porous outer surface and process of making same |
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