WO1986001541A1 - Shallow case hardening process - Google Patents
Shallow case hardening process Download PDFInfo
- Publication number
- WO1986001541A1 WO1986001541A1 PCT/US1985/001687 US8501687W WO8601541A1 WO 1986001541 A1 WO1986001541 A1 WO 1986001541A1 US 8501687 W US8501687 W US 8501687W WO 8601541 A1 WO8601541 A1 WO 8601541A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- order
- magnitude
- preferred
- furnace
- workpieces
- Prior art date
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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
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
-
- 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/34—Methods of heating
- C21D1/53—Heating in fluidised beds
Definitions
- Diffusion plates are underneath the sand, in the sense that the top of a coffee percolator has little holes in it for diffusing water, except that the holes in this case are filled with small screws that are countersunk but not entirely screwed in, and they are oversized holes with respect to the shafts of the countersunk screws, so that a small passageway is created for flow of gasses through the diffusion plate underneath the bed of alumi ⁇ num oxide.
- These fluidized beds are utilized to facilitate carborizing, nitrocarbonizing, carboni triding, and nitro-hardening.
- tem ⁇ peratures of approximately 1500 degrees Fahrenheit are utilized, in an Austenitizing type process, to provide core-hardening as opposed to case-hardening of parts.
- temperatures of approximately 1750 degrees Fahrenheit are utilized to provide case-hardening at a high temperature with high carbon content.
- Nitrocarborizing refers to providing case-hardening with a relatively larger nitrogen content at temperatures of approximately 1050 degrees Fahrenheit. Carbonitriding is provided at temperatures of approximately 1600 degrees " Fahrenheit fo-r a higher carbon content of the mixture of carbon and nitrogen in providing the case-hardening for high Rockwells at surface. Nitrocarborizing is a light case process at light case process at low temperature, high surface hardnesses, and not a lot of depth; the opposite is true of carbonitriding, with a higher temperature,, and a deeper case hardening. Carborizing is 60 thousandths deep, carbonitriding is 15 to 20 thousandths deep, and nitrocarborizing is 3 to 5 thousandths deep. 5" Another process for finishing metal is the
- Quench-Polish-Quench (or Q.P.Q.) Process for applying corrosion resistance.
- the Q.P.Q. Process is in part inadequate, because, while it provides excellent corrosion characteristics, it destroys the hardening 3 characteristics required, and this has dramatic results affecting tool life and possible failure.
- This invention relates generally to nitrocarborizing, carborizing and the like, and more particularly, it relates to case-hardening with corrosion resistance characteristics achieved by passing gas through a bed of sand a specified rates of flow, type of gas, time prior to diffusion, and diffusion time, and temperature.
- the time is 3 hours in nitrogen and other gas atmosphere. 800 pounds of work ⁇ pieces will be dropped into the furnace. It will take about a half hour for the furnace to restore its initial temperature of 980 degrees Fahrenheit.
- the preferred gas atmosphere is then introduced. It comprises the following: at the rate of 250 cubic feet of nitrogen per hour, 700 cubic feet of ammonia per hour, 350 oubic feet of natural gas per hour; held at temperature at those atmospheres for 3 hours. This phase is followed by an hour and a half of humidified nitrogen.
- Humidified nitrogen is obtained by passing dry nitrogen through a humidifier, in a manner well known in the humdifying art. Nitrogen, being hygroscopic, absorbing moisture through a humidifier, then is passed through the bed at 300 cubic feet an hour, humidified to approximately 10 to 20 percent. This forms an oxidized
- the oxide layer is highly porous, which allows for its lubri ⁇ cation properities, and underneath it is the nitrocarbide layer, which is extremely non-porous.
- the depth of the oxide layer is approximately 5 tenths of a thousandth of an inch.
- White layer is between one and one-and-one-half thousandths pure nitrogen. Below that is six thousandths of diffused nitrogen zone.
- This invention provides an extraordinarily deep loading of fifty to a hundred times what it would ordi ⁇ narily be of the case-hardened depth, which gives signi ⁇ ficantly greater hardening and corrosion resistant properties
- the parameters would change for a cutting-type tool, such as an end mill, in which temperature would be lowered
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
Abstract
A shallow case hardening process comprising passing selected mixtures of gases for prescribed times through sand in which workpieces are imbedded at temperatures substantially different from recommended levels in normal nitriding.
Description
SHALLOW CASE HARDENING PROCESS
SPECIFICATIONS In the past» it has been a common practice in heat treating of metal workpieces to utilize fluid beds, such as those made by Procedyne Corporation of New
Brunswick, New Jersey. An example of these fluidized beds is designated 18502048HT, standing respectively for: 1850 degress Fahrenheit, 20 inch diameter, 48 inch depth. These are essentially, furnaces that have a sand- like bed, where the sand is made of aluminum oxide.
Diffusion plates are underneath the sand, in the sense that the top of a coffee percolator has little holes in it for diffusing water, except that the holes in this case are filled with small screws that are countersunk but not entirely screwed in, and they are oversized holes with respect to the shafts of the countersunk screws, so that a small passageway is created for flow of gasses through the diffusion plate underneath the bed of alumi¬ num oxide. These fluidized beds are utilized to facilitate carborizing, nitrocarbonizing, carboni triding, and nitro-hardening. In the case of ni tro-hardening, tem¬ peratures of approximately 1500 degrees Fahrenheit are utilized, in an Austenitizing type process, to provide core-hardening as opposed to case-hardening of parts. As to carborizing, temperatures of approximately 1750 degrees Fahrenheit are utilized to provide case-hardening at a high temperature with high carbon content.
TE SHEET
Nitrocarborizing refers to providing case-hardening with a relatively larger nitrogen content at temperatures of approximately 1050 degrees Fahrenheit. Carbonitriding is provided at temperatures of approximately 1600 degrees " Fahrenheit fo-r a higher carbon content of the mixture of carbon and nitrogen in providing the case-hardening for high Rockwells at surface. Nitrocarborizing is a light case process at light case process at low temperature, high surface hardnesses, and not a lot of depth; the opposite is true of carbonitriding, with a higher temperature,, and a deeper case hardening. Carborizing is 60 thousandths deep, carbonitriding is 15 to 20 thousandths deep, and nitrocarborizing is 3 to 5 thousandths deep. 5" Another process for finishing metal is the
Quench-Polish-Quench (or Q.P.Q.) Process for applying corrosion resistance. The Q.P.Q. Process, is in part inadequate, because, while it provides excellent corrosion characteristics, it destroys the hardening 3 characteristics required, and this has dramatic results affecting tool life and possible failure.
Past experience with the Procedyne Process in the way it has been utilized provides excellent increases in Rockwell and case-hardening, as opposed to _f core-hardening. Prior to the subject invention, it had
not been considered using processes analogous to the Procedyne Process for achieving not only case-hardening but simultaneously, corrosion resistance.
Accordingly, it is an object of this invention to combine the two objectives and manipulate and change parameters involving gas flow and temperature, for obtaining simultaneously the appropriate corrosion resistance and case-hardening for the particular product. Previous to this time, a blanket rule of thumb had been recommended by procedyne, and utilized throughout the industry, which was a standard half-hour saturation in the bed at fluid flows of approximately, or a least not exceeding 800 cubic feet per hour. This cookbook was a standard flow, standard diffusion at the end of the cycle, standard temperature, and standard time within the furnace prior to diffusion: two hours in a nitrocarborizing atmosphere, one half hour diffusion time, 800 cubic feet per hour total gas flows its various components are as follows: 35% ammonia, 45% natural gas, 10% nitrogen.
It is another object of this invention to achieve case hardening and corrosion resistance in an integral heat-treating process in an uncomplicated, inexpensive, readily utilizable manner. These and other objects of this invention may be more readily understood from the following specifications and claims.
This invention relates generally to nitrocarborizing, carborizing and the like, and more particularly, it relates to case-hardening with corrosion resistance characteristics achieved by passing gas through a bed of sand a specified rates of flow, type of gas, time prior to diffusion, and diffusion time, and temperature.
For example, in making parts, specifically a chain for a front-wheel drive, the time is 3 hours in nitrogen and other gas atmosphere. 800 pounds of work¬ pieces will be dropped into the furnace. It will take about a half hour for the furnace to restore its initial temperature of 980 degrees Fahrenheit. The preferred gas atmosphere is then introduced. It comprises the following: at the rate of 250 cubic feet of nitrogen per hour, 700 cubic feet of ammonia per hour, 350 oubic feet of natural gas per hour; held at temperature at those atmospheres for 3 hours. This phase is followed by an hour and a half of humidified nitrogen. Humidified nitrogen is obtained by passing dry nitrogen through a humidifier, in a manner well known in the humdifying art. Nitrogen, being hygroscopic, absorbing moisture through a humidifier, then is passed through the bed at 300 cubic feet an hour, humidified to approximately 10 to 20 percent. This forms an oxidized
SUBSTITUT
layer on top of the previous nitrocarborized layer. The oxide layer is highly porous, which allows for its lubri¬ cation properities, and underneath it is the nitrocarbide layer, which is extremely non-porous. The depth of the oxide layer is approximately 5 tenths of a thousandth of an inch. White layer is between one and one-and-one-half thousandths pure nitrogen. Below that is six thousandths of diffused nitrogen zone.
This contrasts with the Procedyne process described above, where there would be no oxide layer, white layer would be one to two-tenths of a thousandths of an inch, nitride layer would be two to three thousandths.
This invention provides an extraordinarily deep loading of fifty to a hundred times what it would ordi¬ narily be of the case-hardened depth, which gives signi¬ ficantly greater hardening and corrosion resistant properties
In an alternative embodiment of this invention, the parameters would change for a cutting-type tool, such as an end mill, in which temperature would be lowered
(950 degrees Fahrenheit)-, atmosphere total flows would be the same, time in the atmosphere would be 30 minutes (a 30 minute diffuse on humidified nitrogen), it would give an oxide depth of 5 tenths or a thousandth, the white layer would be one to two tenths of a thousandth, and a
nitride layer of 5 to 7 tenths of a thousandth. The oxide layer cuts down the welding effect of chips on the cutting edge*
Claims
1. In a heat treating method for case hardening metal workpieces utilizing gaseous entities flowing through a fluidized sand bed at temperatures substantially above the boiling point of moisture and substantially below the freezing point of the metal workpieces, the improvements comprising: heating a fluidizable sand bed furnace to a first temperature; introducing workpieces into said furnace; allowing the combined mass of the workpieces and the furnace to recover to said first temperature; after said temperature recovery, introducing a first preferred atmosphere into said furnace; said first preferred atmosphere comprising ammonia; said first preferred atmosphere comprising nitrogen; said first preferred atmosphere comprising natural gas; * maintaining said first preferred atmosphere in said furnace at said first temperature with said mass of workpieces for a first preferred period of time; passing nitrogen through a humidifier in such a manner as to obtain a resultant mixture of nitrogen humidified; replacing said first preferred atmosphere with a second preferred atmosphere; said second preferred atmosphere comprising said humidified nitrogen mixture being introduced into said furnace; and maintaining said second preferred atmosphere in said furnace with said mass of workpieces for a second preferred period of time.
2. In the method of Claim 1, wherein said first preferred period of time is of an order of magnitude corresponding to three hours and said second preferred period of time corresponds to an order of magnitude in the range of one to one and one half hours.
3. A product obtained from a workpiece pro- cessed from the method of Claim 1, wherein said first preferred period of time is of an order of magnitude corresponding to three hours and said second preferred period of time corresponds to an order of magnitude in the range of one to one and one half hours, having: an outer layer that is substantially porous and operable to hold petroleum product in measurable amounts and having a coefficient of friction substantially lower than the outer surface of said workpiece prior subjection to said method.
4. A product obtained from a workpiece pro- cessed from them method of Claim 1, wherein said first preferred period of time is of an order of magnitude corresponding to three hours and said second preferred 5 period of time corresponds to an order of magnitude in
6 the range of one to one and one half hours, having:
7 an outer layer that is substantially porous and
8 operable to hold petroleum product in measurable amounts
9 and having a coefficient of friction substantially lower 0 that the outer surface of said workpiece prior subjection 1 to said method; and 2 a second layer adjacent said outer layer being 3 substantially nonporous and inoperable to transmit 4 further interiorly or to hold any petroleum product.
1 5. A product obtained from a workpiece processed
2 from the method of Claim 1, wherein said first preferred
3 period of time is of an order of magnitude corresponding
4 to three hours and said second preferred period of time
5 corresponds to an order of magnitude in the range of one
6 to one and one half hours, having:
7 an outer layer that is substantially porous and
8 operable to hold petroleum product in measurable amounts
9 and having a coefficient of friction substantially lower 0 that the outer surface of said workpiece prior subjection 1 to said method; - a second layer adjacent said outer layer being 3 substantially nonporous and inoperable to transmit - further interiorly or to hold any petroleum product; and ^ a third layer interior from and adjacent to said 6 second layer, and having a substantial amount of diffused 7 nitrogen throughout therein. 1 6. A product obtained from a workpiece pro-
2 cessed from the method of Claim 1, wherein said first
3 preferred period of time is of an order of magnitude
4 corresponding to three hours and said second preferred
5 period of time corresponds to an order of magnitude in
6 the range of one to one and one half hours, havings
7 an outer layer that has oxide portions substan-
8 tially uniformly distributed therein and is substantially
9 porous and operable to hold petroleum product in
10 measurable amounts and having a coefficient of friction
II. substantially lower than the outer surface of said work-
12 piece prior subjection to said method;
13 a second layer adjacent said outer layer being
14 substantially nonporous and inoperable to transmit
15 further interiorly or to hold any petroleum product;
16 and a third layer interior from and adjacent to
17 said second layer, and having a substantial amount of
18 diffused nitrogen throughout therein; and
19 said outer layer having a thickness of an order 2.0 of magnitude of five tenths of a thousandths of an inch;
21 said second layer having a thickness of an order of
22 magnitude of one and one-half thousandths of an inch; and
23 said third layer having thickness of an order of magni-
24 tude of six thousandths of an inch.
1 7. A product obtained from a workpiece pro-
2- cessed from the method of Claim 1, wherein said first preferred period of time is of an order of magnitude corresponding to three hours and said second preferred period of time corresponds to an order of magnitude in the range of one to one and one half hours, having: and outer layer that has oxide portions substan- tially uniformly distributed therein and is substantially porous and operable to hold petroluem product in 0 measurable amounts and having a coefficient of friction 1 substantially lower than the outer surface of said work- 2 piece prior subjection to said method; 3 a second layer adjacent said outer layer being 4 substantially nonporous and inoperable to transmit 5 further interiorly or to hold any petroleum product; 6 and a third layer interior from and adjacent to T said second layer and having a substantial amount of 8 diffused nitrogen throughout therein; and 9 the surface of said outer layer having a 0 substantially greater hardness as measured by Rockwell -1 test than the surface of said workpiece prior to subjec- 2 tion to said method.
1 8. In apparatus for heat treating metal
2 workpieces, the improvements comprising:
3 a fluidizable sand bed furnace;
4 means holding metal workpieces within the sand
5 of said furnace;
BSTITUTE SHEET means conducting gas through said sand and said workpieces; a source of gas flows means humidifying said gas flow; and means transmitting said humidified gas flow to said conducting means. 9. In the apparatus of Claim 8, said gas flow being nitrogen flow, and said humidifying means operable to humidify said gas flow with 1O per cent to 20 per cent moisture, and said metal workpieces being made of ferrous metal. 10. In the method of Claim 1, the improvements comprising: said first temperature being measurably below 1000 degrees Fahrenheit and substantially above 900 degrees Fahrenheit; said workpieces having a mass on the order of magnitude exceeding one quarter ton, when said furnace has an interior diameter of the order of magnitude of 20 inches and a depth of the order of magnitude of 48 inches; said first preferred atmosphere comprising a total flow exceeding the order of magnitude of 1200 cubic feet per hour; said first preferred atmosphere comprising nitrogen flowing at an order of magnitude corresponding to 700 cubic feet per hour;
SUBS 16 said first preferred atmosphere comprising
17 nitrogen flowing at an order of magnitude corresponding
18 to 250 cubic feet per hour;
' 19 said first preferred atmosphere comprising
20 natural gas flowing at an order of magnitude corresponding
21 to 350 cubic feet per hour;
22 passing nitrogen through a humidifier in such a
23 manner as to obtain a resultant mixture of nitrogen humi-
24 dified in the range of 10 percent to 20 percent;
25 said second preferred atmosphere comprising
26 said humidified nitrogen mixture being introduced into
27 said furnace at a rate having an order of magnitude of
28 300 cubic feet per hour; and
29 maintaining said second preferred atmosphere in
30 said furnace with said mass of workpieces for a second
31 preferred period of time.
1 11. In the method of Claim 1, the improvements
2 comprising:
3 said first temperature being measurably below
4 1000 degrees Fahrenheit and substantially above 900
5 degrees Fahrenheit;
6 said workpieces having a mass on the order of
7 magnitude exceeding one quarter ton, when said furnace
8 has an interior diameter of the order of magnitude of 20 ' inches and a depth of the order of magnitude of 48
10 inches;
SUBSTITUTE SHEET 14
said first preferred atmosphere comprising a total flow exceeding the order of magnitude of 1200 cubic ; feet per hour; said first preferred atmosphere comprising ammo- nia flowing at an order of magnitude corresponding to 700 cubic feet per hour; said first preferred atmosphere comprising nitrogen flowing at an order of magnitude corresponding to 250 cubic feet per hour; said first preferred atmosphere comprising natural gas flowing at an order of magnitude corresponding to 350 cubic feet per hour; passing nitrogen through a humidifier in such a manner as to obtain a resultant mixture of nitrogen humi- dified in the range of 10 percent to 20 percent; said second preferred atmosphere comprising said humidified nitrogen mixture being introduced into said furnace at a rate having an order of magnitude of 300 - cubic feet per hour; and maintaining said second preferred atmosphere in said furnace with said mass of workpieces for a second preferred period of time; said first period of time having an order of magnitude of 3 hours; said second period of time having an order of magnitude in the range of one hour to one and one half hours . 12. In a heat treating method for case har- dening metal workpieces utilizing gaseous entities flowing through a fluidized sand bed at temperatures substantially above the boiling point of moisture and substantially below the freezing point of the metal workpieces, the improvements comprising: heating a fluidizable sand bed furnace to a first temperature, said first temperature being measurably below 1000 degrees Fahrenheit and substan- tially above 900 degrees Fahrenheit; introducing workpieces into said furnace; allowing the combined mass of the workpieces and the furnace to recover to said first temperture; said workpieces having a mass on the order of magnitude exceeding one quarter ton, when said furnace has an interior diameter of the order of magnitude of 20 inches and a depth of the order of magnitude of 48 inches; after said temperature recovery, introducing a first preferred atmosphere into said furnace; said first preferred atmosphere comprising a total flow exceeding the order of magnitude of 1200 cubic feet per hour; said first preferred atmosphere comprising ammo- nia flowing at an order of magnitude corresponding to 700 cubic feet per hour;
SUBSTITUTE SHEET 7 said first preferred atmosphere comprising 8 nitrogen flowing at an order of magnitude corresponding 9 to 250 cubic feet per hour; 0 said first preferred atmosphere comprising f natural gas flowing at an order of magnitude 2 corresponding to 350 cubic feet per hour; 3 maintaining said first preferred atmosphere in 4 said furnace at said first temperature with said mass of 5 workpieces for a first preferred period of time; 6 passing nitrogen through a humidifier in such a 7 manner as to obtain a resultant mixture of nitrogen humi- 8 dified in the range of 10 percent to 20 percent; 9 replacing said preferred atmosphere with a second 0 preferred atmosphere; 1 said second preferred atmosphere comprising said - humidified nitrogen, mixture being introduced into said -3 furnace at a rate having an order of magnitude of 300 -4 cubic feet per hour; and -5 maintaining said second preferred atmosphere in 6 said furnace with said mass or workpieces for a second 7 preferred period of time.
SUBSTITUTE SHEET
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US64656484A | 1984-09-04 | 1984-09-04 | |
| US646,564 | 1984-09-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO1986001541A1 true WO1986001541A1 (en) | 1986-03-13 |
Family
ID=24593539
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/US1985/001687 WO1986001541A1 (en) | 1984-09-04 | 1985-09-04 | Shallow case hardening process |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0192745A1 (en) |
| AU (1) | AU4780085A (en) |
| CA (1) | CA1258609A (en) |
| WO (1) | WO1986001541A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2615868A1 (en) * | 1987-05-30 | 1988-12-02 | Schwing Ewald | PROCESS FOR THE HEAT TREATMENT OF METAL PARTS IN A FLUIDIZED LAYER CROSSED BY A GAS |
| EP0605444A1 (en) * | 1991-09-20 | 1994-07-13 | Kemp Dev Corp | Process and apparatus for surface hardening of refractory metal workpieces. |
| WO2007009190A1 (en) * | 2005-07-21 | 2007-01-25 | Hard Technologies Pty Ltd | Duplex surface treatment of metal objects |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3658602A (en) * | 1968-12-30 | 1972-04-25 | Usinor | Method for quenching steel rails in a fluidized powder medium |
| US4249889A (en) * | 1979-06-05 | 1981-02-10 | Kemp Willard E | Method and apparatus for preheating, positioning and holding objects |
| US4410373A (en) * | 1981-09-30 | 1983-10-18 | Kemp Willard E | Process for heat treatment of a metal workpiece |
-
1985
- 1985-09-03 CA CA000489938A patent/CA1258609A/en not_active Expired
- 1985-09-04 WO PCT/US1985/001687 patent/WO1986001541A1/en unknown
- 1985-09-04 EP EP19850904552 patent/EP0192745A1/en not_active Withdrawn
- 1985-09-04 AU AU47800/85A patent/AU4780085A/en not_active Abandoned
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3658602A (en) * | 1968-12-30 | 1972-04-25 | Usinor | Method for quenching steel rails in a fluidized powder medium |
| US4249889A (en) * | 1979-06-05 | 1981-02-10 | Kemp Willard E | Method and apparatus for preheating, positioning and holding objects |
| US4410373A (en) * | 1981-09-30 | 1983-10-18 | Kemp Willard E | Process for heat treatment of a metal workpiece |
Non-Patent Citations (3)
| Title |
|---|
| Die Casting Engineer, Vol. 27 No. 3 issued 1983, May/June, J.E. JAPKA "Fluidized Bed Furnace Heat Treating Applications for the Die Casting Industry". * |
| Heat Treating, issued 1983 August K. BOIKO, "Tool and die Specialists aim to Out-Fox the Slump in Detroit", pages 76-29 * |
| Metal Progress, Vol. 123 No. 2, issued 1983 February J.E. JAPKA, "Using the Fluidized Bed for Nitriding-Type Processes". * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2615868A1 (en) * | 1987-05-30 | 1988-12-02 | Schwing Ewald | PROCESS FOR THE HEAT TREATMENT OF METAL PARTS IN A FLUIDIZED LAYER CROSSED BY A GAS |
| EP0605444A1 (en) * | 1991-09-20 | 1994-07-13 | Kemp Dev Corp | Process and apparatus for surface hardening of refractory metal workpieces. |
| EP0605444A4 (en) * | 1991-09-20 | 1994-11-17 | Kemp Dev Corp | Process and apparatus for surface hardening of refractory metal workpieces. |
| WO2007009190A1 (en) * | 2005-07-21 | 2007-01-25 | Hard Technologies Pty Ltd | Duplex surface treatment of metal objects |
| US8317926B2 (en) | 2005-07-21 | 2012-11-27 | Hard Technologies Pty Ltd. | Duplex surface treatment of metal objects |
Also Published As
| Publication number | Publication date |
|---|---|
| AU4780085A (en) | 1986-03-24 |
| EP0192745A1 (en) | 1986-09-03 |
| CA1258609A (en) | 1989-08-22 |
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