EP0281249A1 - Verfahren zur Wärmebehandlung von Teilen aus Eisenwerkstoffen - Google Patents
Verfahren zur Wärmebehandlung von Teilen aus Eisenwerkstoffen Download PDFInfo
- Publication number
- EP0281249A1 EP0281249A1 EP88300891A EP88300891A EP0281249A1 EP 0281249 A1 EP0281249 A1 EP 0281249A1 EP 88300891 A EP88300891 A EP 88300891A EP 88300891 A EP88300891 A EP 88300891A EP 0281249 A1 EP0281249 A1 EP 0281249A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- castings
- furnace
- temperature
- austempering
- cooling
- 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.)
- Withdrawn
Links
- 238000000034 method Methods 0.000 title claims abstract description 17
- 239000002184 metal Substances 0.000 title description 3
- 229910052751 metal Inorganic materials 0.000 title description 3
- -1 ferrous metals Chemical class 0.000 title 1
- 238000005266 casting Methods 0.000 claims abstract description 59
- 238000005279 austempering Methods 0.000 claims abstract description 29
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 16
- 239000012530 fluid Substances 0.000 claims abstract description 8
- 238000001816 cooling Methods 0.000 claims description 22
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 4
- 239000000126 substance Substances 0.000 claims 6
- 239000002826 coolant Substances 0.000 claims 1
- 239000007788 liquid Substances 0.000 abstract description 5
- 238000011065 in-situ storage Methods 0.000 abstract 1
- 239000010959 steel Substances 0.000 description 11
- 229910001018 Cast iron Inorganic materials 0.000 description 10
- 229910001208 Crucible steel Inorganic materials 0.000 description 10
- 229910001563 bainite Inorganic materials 0.000 description 7
- 238000005242 forging Methods 0.000 description 6
- 229910001562 pearlite Inorganic materials 0.000 description 6
- 150000003839 salts Chemical class 0.000 description 6
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 5
- 229910001566 austenite Inorganic materials 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 229910000734 martensite Inorganic materials 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000010791 quenching Methods 0.000 description 3
- 230000000171 quenching effect Effects 0.000 description 3
- 239000011819 refractory material Substances 0.000 description 3
- 229910001141 Ductile iron Inorganic materials 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000000717 retained effect Effects 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 235000011089 carbon dioxide Nutrition 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000004901 spalling 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
- C21D1/18—Hardening; Quenching with or without subsequent tempering
- C21D1/19—Hardening; Quenching with or without subsequent tempering by interrupted quenching
- C21D1/20—Isothermal quenching, e.g. bainitic hardening
-
- 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
- C21D5/00—Heat treatments of cast-iron
-
- 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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
Definitions
- This invention relates to methods of heat treating cast iron or steel. More particularly, it relates to an improved method of treatment to produce a bainite structure and improved mechanical and physical characteristics.
- cast iron or steel may be cooled from an elevated temperature where it is austenitic in structure, at such a rate that normal formation of pearlite is suppressed and austenite and martensite occur instead.
- the austenite and martensite are stable at lower temperatures, such as room temperature.
- a structure of bainite is formed instead. This bainite may contain varying quantities of pearlite, austenite or martensite, depending on the exact cooling conditions that prevail and the exact composition of the cast iron or steel.
- austempering This process of producing bainite by heat treatment is known as austempering.
- Conventional procedures involve heating the cast iron or steel to a temperature in excess of 1300 degrees F so that it becomes austenitic in structure. This temperature is known as the austenitizing temperature.
- this austenizing temperature is held to a maximum value of 1900 degrees F and the period of time is usually 1 hour plus 30 minutes for every one inch of casting section. This time period is also somewhat dependent on the total mass of casting shapes in the furnace load and on the heat input into the furnace.
- the cast iron or steel is then cooled rapidly to the holding temperature called the austempering temperature usually between 400 degrees F and 800 degrees F. After holding at this temperature for 1 to 4 hours, depending on mass section and composition, the cast iron or steel is then cooled to room temperature.
- Austempering is usually conducted in a bath of hot salt or hot oil or any liquid medium that can be maintained at the austempering temperature. Shapes in cast iron or steel are transferred from a furnace at austenizing temperature and are quenched in the austempering bath. Such treatment involves two furnace systems as well as the handling of hot shapes, such as forgings or castings, in cast iron or steel. Further, after cooling to room temperature, the castings or forgings have to be washed or cleaned to remove all residual salts or traces of the quenching medium used. Because salt baths are quite expensive there is usually a limit to the size of the castings or shapes that can be austempered in the conventional manner.
- Our invention is based on the discovery that fine jets or water or a gaseous medium like liquid nitrogen or carbon dioxide gas can be applied directly to castings or forgings while in position in the furnace so that the castings or forgings may be cooled and the furnace itself may be cooled down to the austempering temperature. This avoids the necessity of transferring the castings or forgings to a second furnace for austempering.
- one object of our invention is to reduce the cost of the austempering process.
- a further object is to provide a means of using only one furnace for the complete austempering process.
- a further object is to economically allow the austempering of large castings or forgings.
- the furnace is raised above the castings or is tilted back in order to expose the castings. This makes it easier to cool the furnace and to cool the castings. As soon as both the furnace and the castings have reached the required austempering temperature, the furnace is lowered or tilted back over the castings and the temperature of the furnace is then maintained for the desired length of time at the austempering temperature.
- the whole process of austempering may in this manner be conducted without the necessity of moving the castings or of having a second furnace.
- Figure 1 is a diagrammatic illustration of the preferred method of the invention.
- Position (a) shows a furnace containing a casting on the furnace bottom plate and with the furnace in the austenitizing mode.
- Position (b) shows the furnace tilted back for cooling and the quenching mode.
- Position (c) shows the furnace back in position over the casting and the casting in the austempering mode.
- Figure 2 shows a typical temperature time cooling curve when a given casting, in this case a 3 ⁇ diameter bar, is quenched in a salt bath and is subsequently held in this bath to produce bainite. Shown also is a curve indicating the cooling rate obtained when water is applied to the casting in a furnace and the casting as well as the furnace are cooled by air circulation to the austempering temperature. We have found that manipulation of the amount of water used as well as the amount of air circulated will allow the cooling rate in the casting to be varied over a relatively wide range of cooling rates.
- the curve A represents the cooling rate obtained in a salt bath where the line CC is the austenitizing temperature and line DD is the austempering temperature.
- the austempering temperature is reached in a 10 minute time period. F and at this time the furnace was tilted back to cover the castings after cutting off air and water circulation.
- the furnace was maintained at a temperature of 620 degrees F for a period of 2 hours and the casting load was then removed from the furnace.
- the temperatures, velocities and amounts of the fluids applied to the mass of the castings will determine the rate of cooling in a manner known to or easily determinable by those skilled in the art. That rate must suffice to cool the castings within a ten to twenty minute period in order to avoid the formation of pearlite and thereby to obtain the desired bainitic structure. While the rate of cooling required to suppress pearlite will vary according to the composition of the ferrous metal involved and may be exactly determined by means of a time-temperature-transformation diagram for the particular metal involved, the time required for cooling normally will be less than 20 minutes.
- Curve B represents the cooling rate when air was circulated in the furnace while water was applied to the casting. In this case the austempering temperature was reached in a 12 minute time period.
- Figure 3 shows the bainite structure resulting from a nodular iron bar cooled by water treatment at the rate indicated in Figure 2.
- a load of castings consisting of twelve bars ranging in diameter from 2 ⁇ to 4 ⁇ and about 24 ⁇ in length were placed in a furnace 3′ ⁇ 4′ and 4′ high.
- the furnace was lined with fibre refractory and was pivoted at its back end so it could be tilted back from the castings placed on a fixed floor.
- the furnace had as a heat source a series of propane-air burners.
- the furnace load was headed to 1650 degrees F and was held at this temperature for 2 hours when the propane was shut off and the furnace was tilted back to expose the casting load.
- the air was circulated from the burners while the furnace was tilted back and an additional fan was used to blow air on the furnace to cool it down to 620 degrees F.
- a fan was used to blow air directly on the casting and water was introduced by pressure jet so as to impinge directly on the casting load.
- a thermocouple placed strategically in the casting load was used to indicate when this load had reached an approximate temperature of 600 degrees
Landscapes
- 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)
- Heat Treatments In General, Especially Conveying And Cooling (AREA)
- Heat Treatment Of Articles (AREA)
- Control Of Heat Treatment Processes (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US2272087A | 1987-03-06 | 1987-03-06 | |
| US22720 | 1987-03-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP0281249A1 true EP0281249A1 (de) | 1988-09-07 |
Family
ID=21811087
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP88300891A Withdrawn EP0281249A1 (de) | 1987-03-06 | 1988-02-03 | Verfahren zur Wärmebehandlung von Teilen aus Eisenwerkstoffen |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0281249A1 (de) |
| JP (1) | JPS63317620A (de) |
| CN (1) | CN88101145A (de) |
| DK (1) | DK68788A (de) |
| FI (1) | FI880858L (de) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2697535A1 (fr) * | 1992-11-02 | 1994-05-06 | Schissler Jean Marie | Procédé amélioré de traitement thermique d'alliages ferreux ou non-ferreux, et son application à l'élaboration de fonte bainitique. |
| AU707536B2 (en) * | 1996-02-16 | 1999-07-15 | Australian Wool Research & Promotion Organisation | Improvements in shearing combs and cutters |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111041164B (zh) * | 2019-12-25 | 2022-01-25 | 浙江金固股份有限公司 | 辊型模具的热处理修复方法 |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE848203C (de) * | 1949-10-04 | 1952-09-01 | Walter Sellerbeck | Ofen fuer zu erwaermende und regelbar beschleunigt abzukuehlende Werkstuecke |
| DE863070C (de) * | 1951-04-22 | 1953-01-15 | Ofu Ofenbau Union G M B H | Verfahren und Vorrichtung zum Abschrecken von Stahlgegenstaenden mittels gasfoermiger Medien |
| DE1228643B (de) * | 1965-05-19 | 1966-11-17 | Ofag Ofenbau Ges M B H | Verfahren und Ofenanlage zur Waermebehandlung von zylindrischen Koerpern aus Gusseisenwerkstoffen nach bestimmten Zeittemperaturkurven |
| DE1433715A1 (de) * | 1964-01-17 | 1968-12-12 | Breitenbach Gmbh Ed | Verfahren zur Waermebehandlung von schweren Werkstuecken aus Schmiede- oder Gussstahl |
| FR2379607A1 (fr) * | 1977-02-03 | 1978-09-01 | Vide & Traitement Sa | Procede pour le traitement thermique de metaux |
| EP0087634A1 (de) * | 1982-03-01 | 1983-09-07 | Pont-A-Mousson S.A. | Schleudergussröhren aus Gusseisen mit Kugelgraphit und Verfahren zur Herstellung derselben |
| DD219268A1 (de) * | 1983-11-18 | 1985-02-27 | Beimler Lokomotivbau | Einrichtung zum spruehabschrecken im muffelofen |
-
1988
- 1988-02-03 EP EP88300891A patent/EP0281249A1/de not_active Withdrawn
- 1988-02-10 DK DK068788A patent/DK68788A/da not_active Application Discontinuation
- 1988-02-24 FI FI880858A patent/FI880858L/fi not_active Application Discontinuation
- 1988-03-04 JP JP63049905A patent/JPS63317620A/ja active Pending
- 1988-03-05 CN CN88101145A patent/CN88101145A/zh active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE848203C (de) * | 1949-10-04 | 1952-09-01 | Walter Sellerbeck | Ofen fuer zu erwaermende und regelbar beschleunigt abzukuehlende Werkstuecke |
| DE863070C (de) * | 1951-04-22 | 1953-01-15 | Ofu Ofenbau Union G M B H | Verfahren und Vorrichtung zum Abschrecken von Stahlgegenstaenden mittels gasfoermiger Medien |
| DE1433715A1 (de) * | 1964-01-17 | 1968-12-12 | Breitenbach Gmbh Ed | Verfahren zur Waermebehandlung von schweren Werkstuecken aus Schmiede- oder Gussstahl |
| DE1228643B (de) * | 1965-05-19 | 1966-11-17 | Ofag Ofenbau Ges M B H | Verfahren und Ofenanlage zur Waermebehandlung von zylindrischen Koerpern aus Gusseisenwerkstoffen nach bestimmten Zeittemperaturkurven |
| FR2379607A1 (fr) * | 1977-02-03 | 1978-09-01 | Vide & Traitement Sa | Procede pour le traitement thermique de metaux |
| EP0087634A1 (de) * | 1982-03-01 | 1983-09-07 | Pont-A-Mousson S.A. | Schleudergussröhren aus Gusseisen mit Kugelgraphit und Verfahren zur Herstellung derselben |
| DD219268A1 (de) * | 1983-11-18 | 1985-02-27 | Beimler Lokomotivbau | Einrichtung zum spruehabschrecken im muffelofen |
Non-Patent Citations (1)
| Title |
|---|
| H[RTEREI-TECHNISCHE MITTEILUNGEN, vol. 41, no. 1, January-February 1986, pages 28-32, Munich; P. LISTEMANN "Gestuftes Abk}hlen zum H{rten und isothermes Umwandeln im Bainitbereich zur verzugsarmen W{rmebehandlung in Vakuumanlagen" * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2697535A1 (fr) * | 1992-11-02 | 1994-05-06 | Schissler Jean Marie | Procédé amélioré de traitement thermique d'alliages ferreux ou non-ferreux, et son application à l'élaboration de fonte bainitique. |
| AU707536B2 (en) * | 1996-02-16 | 1999-07-15 | Australian Wool Research & Promotion Organisation | Improvements in shearing combs and cutters |
Also Published As
| Publication number | Publication date |
|---|---|
| DK68788D0 (da) | 1988-02-10 |
| DK68788A (da) | 1988-09-07 |
| CN88101145A (zh) | 1988-09-14 |
| JPS63317620A (ja) | 1988-12-26 |
| FI880858L (fi) | 1988-09-07 |
| FI880858A0 (fi) | 1988-02-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
| AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): BE CH DE GB LI LU NL SE |
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| STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
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| 18D | Application deemed to be withdrawn |
Effective date: 19890308 |