US3582055A - Furnace plants for heat treatment of workpieces under protective gas atmospheres - Google Patents
Furnace plants for heat treatment of workpieces under protective gas atmospheres Download PDFInfo
- Publication number
- US3582055A US3582055A US830729A US3582055DA US3582055A US 3582055 A US3582055 A US 3582055A US 830729 A US830729 A US 830729A US 3582055D A US3582055D A US 3582055DA US 3582055 A US3582055 A US 3582055A
- Authority
- US
- United States
- Prior art keywords
- prechamber
- heat
- workpieces
- furnace
- treating chambers
- 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
- 230000001681 protective effect Effects 0.000 title claims abstract description 15
- 238000010438 heat treatment Methods 0.000 title claims abstract description 10
- 238000010791 quenching Methods 0.000 claims description 5
- 230000000171 quenching effect Effects 0.000 claims description 5
- 239000002826 coolant Substances 0.000 claims description 4
- 229910052751 metal Inorganic materials 0.000 abstract description 3
- 239000002184 metal Substances 0.000 abstract description 3
- 238000005255 carburizing Methods 0.000 description 9
- 238000001816 cooling Methods 0.000 description 6
- 238000000034 method Methods 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 238000005496 tempering Methods 0.000 description 1
Images
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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
-
- 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
- C21D1/62—Quenching devices
- C21D1/63—Quenching devices for bath quenching
Definitions
- metal workpieces are carburizcd, carbonitrided, gas nitrided, normalized, brazed, sintered, steam treated and hardened or tempered.
- furnaces are designed as continuous furnaces or as furnaces for intermittent operation, for example as chamber or pit furnaces.
- the single process steps take place in a closed unit logically one after the other.
- preheating carburizing
- lowering of the temperature to hardening temperature quenching and tempering.
- the intermittently operating furnaces are known as single furnaces and consist in general of a prechamber and the true carburizing or hardening furnace.
- the prechamber serves once as loading assist means in order that the protective gas atmosphere in the carburizing or hardening furnace is not influenced in the charging operation.
- the prechamber is provided with the quenching tank and a cooling station for cooling the workpieces under protective gas.
- a lifting device in the prechamber serves to lower and lift the treated goods.
- a mechanical conveyor arrangement passes the loaded charging support into the furnace and onto the loading or unloading table before the furnace. The mentioned conveyor is a constituent of the prechamber.
- the prechamber is found behind the carburizing or hardening furnace.
- the protective gas atmosphere in the carburizing or hardening furnace is partially disturbed during the period of charging.
- furnace designs are known according to which two heat-treating chambers are arranged one behind the other, in order, for example, to be able to work in the first chamber at carburizing temperature and in the second chamber at the lower hardening temperature.
- One or two heat-treating chambers work as carburizing furnaces, while in a further heat-treating chamber the workpiece is brought to hardening temperature prior to cooling, for example in oil.
- the first heat-treating chamber is used for carburizing, in the second heat-treating chamber the workpieces are transformed into the pearlitic structure and in the third heat-treating chamber the workpieces are reheated to hardening temperature prior to quenching.
- FIG. 1 is a diagrammatic front view of a furnace plant according to the invention.
- FIG. 2 is a diagrammatic plan view of the furnace plant of FIG. 1.
- the furnace plant of the invention consists of two or more heat-treatin chambers l, a gastight prechamber 2 and a loading or unloa ing table 3.
- the prechamber there is shown by the numeral 4 the position of a loaded charging table before being carried on into a heat-treating chamber or before being discharged onto the unloading table 3.
- the numeral 5 shows the charging table in the cooling medium and the numeral 6 the position of the charging table during the cooling period under protective gas atmosphere which becomes strongly circulated by a gas circulation device 7 to increase the convection.
- the rotary-lifting device 8 also carries the mechanical conveyor 9 firmly mounted on it.
- the door 10 seals the prechamber tight against the outside atmosphere.
- the bottom part of the prechamber which contains the cooling medium, is able to be moved out.
- the protective gas in the proper formulation depending on the intended use is passed separately and under controlled pressure to the prechamber and the heat-treating chambers.
- the heat-treating chambers can be provided on their backwalls with doors 11 through which the heat-treated workpieces can be immersed in additional cooling baths or withdrawn for press hardening, further machining, etc.
- the furnace plant can be provided with automatic switch potentiometers and gas meter instruments so that the entire heat treatment cycle takes place automatically.
- a furnace plant for the heat treatment of workpieces under a protective gas atmosphere comprising: means defining a single gastight unheated prechamber having a horizontally facing loading and unloading door for workpieces; means defining at least two heat-treating chambers disposed in a common horizontal plane and adjacent said prechamber; a separate door between said prechamber and each of said heattreating chambers; conveying means wholly within said prechamber, said conveying means being adapted to be turned to align workpieces with any of said separate doors so that the workpieces can subsequently be moved between said prechamber and any of said heat-treating chambers.
- a furnace plant according to claim ll having a quenching bath in the bottom portion of the prechamber in movable arrangement so as to assure an easy change of a cooling medi- 3.
- a furnace plant according to claim 1 wherein at least two of the heat-treating chambers connected to a single prechamber are maintained at different temperatures.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Tunnel Furnaces (AREA)
- Furnace Details (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
Abstract
Furnace plants for the heat treatment of metal workpieces under protective atmospheres are provided with one prechamber servicing two or more heat treating chambers.
Description
United States Patent [72] Inventors Karl-Heinz Winter Domigheim; Friedrich Eysell, Frankfurt am Main; Rolf Schuster. Hanau (Main), all of, Germany [2| Appl, No. 830,729
[22] Filed June 5,1969
[45] Patented June l, [971 [73] Assignee Deutsche Gold-und Silber Sheideanstalt normals Rossler Frankfurt, am Main, Germany [32] Priority June 5, 1968 [3 3 Germany [54] FURNACE PLANTS FOR HEAT TREATMENT OF WORKPIECES UNDER PROTECTIVE GAS [5]] lnt.Cl C2ld 1/00, F27b 9/02 [50] Field of Search 263/36, 37, 3s, 39; 266/4 [56] References Cited UNITED STATES PATENTS 2,000,664 5/1935 Hayes 263/36 2,978,237 4/! 961 Frank 263/6 3,] 37,485 6/1964 Johnson et a]. 263/6 3,431,346 3/1969 Westeren et al. 263/36X Primary Examiner-John .l. Camby Attorney-Cushman, Darby & Cushman ABSTRACT: Furnace plants for the heat treatment of metal workpieces under protective atmospheres are provided with one prechamber servicing two or more heat treating chambers.
PATENTEUJUH nan 3,582,055
SHEET 1 OF 2 INVENTORS flBL- 42 #1025? zi'exfzze/o/ 27/5544 N BY @AF 621/0575 ATTORNEYS PATENTEDJUN H97! 3582.055
SHEET 2 0F 2 FiQZ ATTORNEY 5 FURNACE PLANTS FOR HEAT TREATMENT OF WORKI'IECES UNDER PROTECTIVE GAS ATMOSPHERES There are known furnaces in which metal workpieces are carburizcd, carbonitrided, gas nitrided, normalized, brazed, sintered, steam treated and hardened or tempered. These furnaces are designed as continuous furnaces or as furnaces for intermittent operation, for example as chamber or pit furnaces.
In a continuous furnace, the single process steps take place in a closed unit logically one after the other. As examples there can be mentioned: preheating, carburizing, lowering of the temperature to hardening temperature, quenching and tempering.
The intermittently operating furnaces are known as single furnaces and consist in general of a prechamber and the true carburizing or hardening furnace. The prechamber serves once as loading assist means in order that the protective gas atmosphere in the carburizing or hardening furnace is not influenced in the charging operation. In addition, the prechamber is provided with the quenching tank and a cooling station for cooling the workpieces under protective gas. A lifting device in the prechamber serves to lower and lift the treated goods. A mechanical conveyor arrangement passes the loaded charging support into the furnace and onto the loading or unloading table before the furnace. The mentioned conveyor is a constituent of the prechamber.
By another of the known furnace designs, the prechamber is found behind the carburizing or hardening furnace. With this furnace design, however, the protective gas atmosphere in the carburizing or hardening furnace is partially disturbed during the period of charging.
Also furnace designs are known according to which two heat-treating chambers are arranged one behind the other, in order, for example, to be able to work in the first chamber at carburizing temperature and in the second chamber at the lower hardening temperature.
In the last described furnace designs for intermittent operation there is the drawback that on account of the necessary, thin walled internal doors no definite temperature and protective gas conditions (dewpoint or CO, value) can be accurately maintained. Besides with all of these furnace types it is only possible to work at the same time cycle in both chambers, i.e. the programmed heat treatment conditions (treating time, temperature and type of protective gas) cannot be different for the two chambers. Furthermore the cooling medium (protective gas, oil, salt, water) cannot be varied.
According to the invention it is proposed with use of a single conveyor, for example following German Pat. No. 1,279,706 (application P 14 58987.8), to fit several heat-treating chambers on only one prechamber and thereby to eliminate the portrayed drawbacks and limitations of the known'types of furnace. Without difficulty, for example, the following heat treatment processes can be accomplished according to the invention.
1. All of the heat-treating chambers fitted to the gastight prechamber are used as carburizing furnaces.
2. One or two heat-treating chambers work as carburizing furnaces, while in a further heat-treating chamber the workpiece is brought to hardening temperature prior to cooling, for example in oil.
-3. The first heat-treating chamber is used for carburizing, in the second heat-treating chamber the workpieces are transformed into the pearlitic structure and in the third heat-treating chamber the workpieces are reheated to hardening temperature prior to quenching.
The invention will be understood best in connection with the drawings wherein:
FIG. 1 is a diagrammatic front view of a furnace plant according to the invention; and
FIG. 2 is a diagrammatic plan view of the furnace plant of FIG. 1.
Referring now specifically to the drawings, the furnace plant of the invention consists of two or more heat-treatin chambers l, a gastight prechamber 2 and a loading or unloa ing table 3. In the prechamber there is shown by the numeral 4 the position of a loaded charging table before being carried on into a heat-treating chamber or before being discharged onto the unloading table 3. The numeral 5 shows the charging table in the cooling medium and the numeral 6 the position of the charging table during the cooling period under protective gas atmosphere which becomes strongly circulated by a gas circulation device 7 to increase the convection. The rotary-lifting device 8 also carries the mechanical conveyor 9 firmly mounted on it. The door 10 seals the prechamber tight against the outside atmosphere. In order to be able to cool altematively in oil, salt or water the bottom part of the prechamber, which contains the cooling medium, is able to be moved out. The protective gas in the proper formulation depending on the intended use is passed separately and under controlled pressure to the prechamber and the heat-treating chambers.
The heat-treating chambers can be provided on their backwalls with doors 11 through which the heat-treated workpieces can be immersed in additional cooling baths or withdrawn for press hardening, further machining, etc.
The furnace plant can be provided with automatic switch potentiometers and gas meter instruments so that the entire heat treatment cycle takes place automatically.
We claim:
1. A furnace plant for the heat treatment of workpieces under a protective gas atmosphere comprising: means defining a single gastight unheated prechamber having a horizontally facing loading and unloading door for workpieces; means defining at least two heat-treating chambers disposed in a common horizontal plane and adjacent said prechamber; a separate door between said prechamber and each of said heattreating chambers; conveying means wholly within said prechamber, said conveying means being adapted to be turned to align workpieces with any of said separate doors so that the workpieces can subsequently be moved between said prechamber and any of said heat-treating chambers.
2. A furnace plant according to claim ll having a quenching bath in the bottom portion of the prechamber in movable arrangement so as to assure an easy change of a cooling medi- 3. A furnace plant according to claim 1 wherein the heattreating chambers are provided on their backwalls with doors through which the heat-treated workpieces can be passed for further treatment.
4. A furnace plant according to claim I wherein the prechamber includes means for lifting and lowering the goods being treated in said chamber.
5. A furnace plant according to claim 1 wherein at least two of the heat-treating chambers connected to a single prechamber are maintained at different temperatures.
Claims (5)
1. A furnace plant for the heat treatment of workpieces under a protective gas atmosphere comprising: means defining a single gastight unheated prechamber having a horizontally facing loading and unloading door for workpieces; means defining at least two heat-treating chambers disposed in a common horizontal plane and adjacent said prechamber; a separate door between said prechamber and each of said heat-treating chambers; conveying means wholly within said prechamber, said conveying means being adapted to be turned to align workpieces with any of said separate doors so that the workpieces can subsequently be moved between said prechamber and any of said heat-treating chambers.
2. A furnace plant according to claim 1 having a quenching bath in the bottom portion of the prechamber in movable arrangement so as to assure an easy change of a cooling medium.
3. A furnace plant according to claim 1 wherein the heat-treating chambers are provided on their backwalls with doors through which the heat-treated workpieces can be passed for further treatment.
4. A furnace plant according to claim 1 wherein the prechamber includes means for lifting and lowering the goods being treated in said chamber.
5. A furnace plant according to claim 1 wherein at least two of the heat-treating chambers connected to a single prechamber are maintained at different temperatures.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19681758460 DE1758460B1 (en) | 1968-06-05 | 1968-06-05 | OVEN SYSTEM FOR HEAT TREATMENT OF WORKPIECES UNDER PROTECTIVE GAS ATMOSPHERES |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3582055A true US3582055A (en) | 1971-06-01 |
Family
ID=5695048
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US830729A Expired - Lifetime US3582055A (en) | 1968-06-05 | 1969-06-05 | Furnace plants for heat treatment of workpieces under protective gas atmospheres |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US3582055A (en) |
| DE (1) | DE1758460B1 (en) |
| FR (1) | FR2010507A1 (en) |
| GB (1) | GB1273393A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080314203A1 (en) * | 2007-06-20 | 2008-12-25 | Longyear Tm, Inc. | Process of drill bit manufacture |
| EP2685193A1 (en) * | 2012-07-11 | 2014-01-15 | LOI Thermprocess GmbH | Method and rotary hearth furnace for heat treating workpieces |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2583774B1 (en) * | 1985-06-25 | 1992-08-14 | Stein Heurtey | INSTALLATION OF THERMOCHEMICAL TREATMENTS AT DIFFERENT TEMPERATURES AND ATMOSPHERES, PARTICULARLY FOR THE AUTOMOTIVE INDUSTRY |
| DE3538958A1 (en) * | 1985-11-02 | 1987-05-14 | Ruhrgas Ag | Furnace installation for the heat treatment of workpieces |
| DE3935014A1 (en) * | 1989-10-20 | 1991-04-25 | Pfeiffer Vakuumtechnik | MULTI-CHAMBER VACUUM SYSTEM |
| JP2697364B2 (en) * | 1991-04-30 | 1998-01-14 | 株式会社村田製作所 | Heat treatment system |
-
1968
- 1968-06-05 DE DE19681758460 patent/DE1758460B1/en active Pending
-
1969
- 1969-05-20 FR FR6916372A patent/FR2010507A1/fr not_active Withdrawn
- 1969-06-02 GB GB27767/69A patent/GB1273393A/en not_active Expired
- 1969-06-05 US US830729A patent/US3582055A/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080314203A1 (en) * | 2007-06-20 | 2008-12-25 | Longyear Tm, Inc. | Process of drill bit manufacture |
| US7905161B2 (en) * | 2007-06-20 | 2011-03-15 | Longyear Tm, Inc. | Process of drill bit manufacture |
| EP2685193A1 (en) * | 2012-07-11 | 2014-01-15 | LOI Thermprocess GmbH | Method and rotary hearth furnace for heat treating workpieces |
| CN103540943A (en) * | 2012-07-11 | 2014-01-29 | 洛伊热处理有限公司 | Method and rotary hearth furnace for heat treating workpieces |
| CN103540943B (en) * | 2012-07-11 | 2017-03-01 | 洛伊热处理有限公司 | Load and unload equipment and the method for heat-treatment furnace |
Also Published As
| Publication number | Publication date |
|---|---|
| GB1273393A (en) | 1972-05-10 |
| DE1758460B1 (en) | 1971-05-06 |
| FR2010507A1 (en) | 1970-02-20 |
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