GB2461351A - Process for Producing Components made from Austenitic-ferritic Cast Iron and such Components - Google Patents
Process for Producing Components made from Austenitic-ferritic Cast Iron and such Components Download PDFInfo
- Publication number
- GB2461351A GB2461351A GB0823569A GB0823569A GB2461351A GB 2461351 A GB2461351 A GB 2461351A GB 0823569 A GB0823569 A GB 0823569A GB 0823569 A GB0823569 A GB 0823569A GB 2461351 A GB2461351 A GB 2461351A
- Authority
- GB
- United Kingdom
- Prior art keywords
- austenitic
- hardening
- components
- cast iron
- ferritic
- 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- Withdrawn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 24
- 229910001018 Cast iron Inorganic materials 0.000 title claims abstract description 15
- 238000006243 chemical reaction Methods 0.000 claims abstract description 9
- 238000010438 heat treatment Methods 0.000 claims abstract description 6
- 238000010894 electron beam technology Methods 0.000 claims abstract description 5
- 230000006698 induction Effects 0.000 claims abstract description 4
- 229910001141 Ductile iron Inorganic materials 0.000 abstract description 2
- 238000005279 austempering Methods 0.000 abstract description 2
- 239000000463 material Substances 0.000 description 5
- 229910000831 Steel Inorganic materials 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 229910001566 austenite Inorganic materials 0.000 description 3
- 230000035515 penetration Effects 0.000 description 3
- 238000010791 quenching Methods 0.000 description 3
- 230000000171 quenching effect Effects 0.000 description 3
- 230000000717 retained effect Effects 0.000 description 3
- 229910001563 bainite Inorganic materials 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- 238000001816 cooling Methods 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000002986 polymer concrete Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/06—Surface 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/06—Surface hardening
- C21D1/09—Surface hardening by direct application of electrical or wave energy; by particle radiation
-
- 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
- C21D1/06—Surface hardening
- C21D1/09—Surface hardening by direct application of electrical or wave energy; by particle radiation
- C21D1/10—Surface hardening by direct application of electrical or wave energy; by particle radiation by electric induction
-
- 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
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C37/00—Cast-iron alloys
-
- 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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/001—Austenite
-
- 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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/005—Ferrite
-
- 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/25—Process efficiency
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
A process for producing components made from austenitic-ferritic cast iron, also known as Austempered Ductile Iron (ADI), in which a pearlitic initial structure is converted to an austenitic-ferritic structure by a multi-stage heat treatment, in particular austempering. The components are surface-hardened at least partly (local/selective surface hardening) after the conversion to the austenitic-ferritic structure, e.g. by one of the local surface hardening methods known as induction hardening or electron-beam hardening. The components made by this process are used for many applications, in particular for gears of heavy machines.
Description
Process for producing components made from austenitic-ferritic cast iron and such component
Description
The invention relates to a process for producing components made from austenitic-ferritic cast iron according to the preamble of patent claim 1. The invention also relates to a component made from such cast iron according to patent claim 4.
Austenitic-ferritic cast iron (AOl -Austempered Ductile Iron) is produced from cast iron with pearlitic initial structure by a special, multi-stage heat treatment, in particular austempering. The pearlitic initial structure is thus converted to a structure made from retained austenite which is stabilised at room temperature and needle-like ferrite incorporated therein. Differing from steel production, so-called bainitisation does not start during the production of ADI after the heat treatment, so that the structure produced does not contain carbides. This is achieved in that in the region of a certain process window, that is before reaching the bainite stage, the conversion process is stopped. Components made from such cast iron have a high strength with good expansion properties, wherein the ratio of retained austenite to ferrite considerably influences the material properties.
For mechanically greatly stressed components, the material properties which can be achieved with ADI are not always adequate to satisfy the increased requirements of service life and safety.
The object of the invention is therefore to indicate a process for producing components made from austenitic-ferritic cast iron having improved material properties, and such a component.
According to the invention, this object is achieved with regard to the process by the object of patent claim 1 and with regard to the component by the object of patent claim 4.
The concept of the invention is to indicate a process for producing components made from austenitic-ferritic cast iron, in which a pearlitic initial structure is converted to an austenitic-ferritic structure by a multi-stage heat treatment, wherein the component is surface-hardened at least partly after the conversion to the austenitic-ferritic structure.
The invention has the advantage that due to the surface hardening following the multi-stage heat treatment, an ADI material is provided which combines the known advantages with regard to the ductility, tensile strength and expansion properties with a hard and wear-resistant surface. Due to the combination of a ductile core with a hard surface, it is possible to substitute steel components which are mechanically processed hitherto expensively and with high material wear or steel components which are cast with considerable expense, with a cast iron produced by the process of the invention. A cast iron produced by the process of the invention is thus more cost-effective in production than comparable steel components.
The surface hardening is preferably effected by induction hardening. Particularly cost-effective and rapid surface hardening is possible in this manner, wherein a relatively high hardness penetration depth may be achieved.
In a preferred embodiment of the process of the invention, the surface hardening is effected by electron-beam hardening. Electron-beam hardening has the advantage that selective, in particular local, hardening is possible, wherein hardening may be effected in temperature-controlled manner and also with complex geometries. Electron-beam hardening is also designated as laser-beam hardening.
The concept of the invention is also to indicate a component made from cast iron with an austenitic-ferritic structure, wherein the component is surface-hardened. The advantages mentioned in connection with the process apply equally to the component claimed within the framework of the invention.
Components produced by the process of the invention are preferably used where high mechanical stresses are to be expected. Such highly stressed components, which may be produced particularly advantageously by the process of the invention, are for example gearwheels, rollers, worms, in particular for gears of heavy machines, or segments for polymer concrete manufacture.
In a preferred exemplary embodiment of the process of the invention, the components with a pearlitic initial structure are initially heated in a furnace under protective atmosphere to an austenitisation temperature of about 850° to 950° Celsius. Depending on wall thickness and chemical composition of the components, the austenitisation temperature is maintained over a certain period of time, the holding time. After the pearlitic initial structure has been converted completely to an austenitic structure, the casting is placed very quickly in a quenching bath and cooled there. Quenching is usually effected in a water bath, in particular salt-water bath. The casting is cooled by quenching to a conversion temperature, under the influence of which an isothermal transformation of the cast structure is effected. The conversion temperature is preferably 2200 Celsius to 450° Celsius maximum. Generally the component is aged for several hours at conversion temperature. It is thus possible to carry out the isothermal conversion either in a salt bath or a furnace. As soon as stable retained austenite is formed and even before bainite is formed, the conversion process is stopped by further cooling of the component to room temperature.
The ADI component now existing is subsequently subjected to a hardening process, for example by induction hardening. The hardness penetration depth is about 0.2 mm according to an exemplary embodiment of the invention. Other hardness penetration depths are likewise possible. A martensitic structure, which is characterised by high wear resistance, is formed on the component surface by hardening. Components which have improved wear resistance with at the same time high ductility and good expansion properties are thus provided by the process of the invention.
Claims (4)
- Claims 1. Process for producing components made from austenitic-ferritic cast iron, in which a pearlitic initial structure is converted to an austenitic-ferritic structure by a multi-stage heat treatment, characterised in that the component is surface-hardened at least partly after the conversion to the austenitic-ferritic structure.
- 2. Process according to claim 1, characterised in that the surface hardening is effected by induction hardening.
- 3. Process according to one of claims 1 or 2, characterised in that the surface hardening is effected by electron-beam hardening.
- 4. Component made from cast iron with an austenitic-ferritic structure, characterised in that the component is surface-hardened.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102007062664A DE102007062664B3 (en) | 2007-12-24 | 2007-12-24 | Method for producing components made of austenitic-ferritic cast iron and such a component |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0823569D0 GB0823569D0 (en) | 2009-01-28 |
| GB2461351A true GB2461351A (en) | 2010-01-06 |
Family
ID=40344224
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0823569A Withdrawn GB2461351A (en) | 2007-12-24 | 2008-12-24 | Process for Producing Components made from Austenitic-ferritic Cast Iron and such Components |
Country Status (2)
| Country | Link |
|---|---|
| DE (1) | DE102007062664B3 (en) |
| GB (1) | GB2461351A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104946858A (en) * | 2015-07-29 | 2015-09-30 | 山东伊莱特重工有限公司 | High-temperature short-time heating surface strengthening processing process |
| WO2022146334A1 (en) * | 2020-12-29 | 2022-07-07 | Gazi Universitesi | A new heat treatment method to produce hard surface austempered materials |
| WO2022146335A3 (en) * | 2020-12-29 | 2022-08-04 | Gazi Universitesi | Hard surface austempered materials |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102389960B (en) * | 2011-10-27 | 2013-03-20 | 王怀林 | Casting and heat treatment production method of mechanical concrete pump piping |
| DE102015214261A1 (en) * | 2015-07-28 | 2017-02-02 | Siemens Aktiengesellschaft | Method for producing a component |
| CN112251579B (en) * | 2020-10-22 | 2022-06-17 | 安徽工业大学 | Method for reducing quenching retained austenite of pearlite-based gray cast iron |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6293361A (en) * | 1985-10-18 | 1987-04-28 | Toyota Motor Corp | Manufacture of surface hardened gear made of cast iron |
| JPH01225745A (en) * | 1988-03-03 | 1989-09-08 | Daikin Ind Ltd | Sliding member |
| JPH02149617A (en) * | 1988-11-29 | 1990-06-08 | Mazda Motor Corp | Manufacture of ferrous member |
| US5246510A (en) * | 1992-06-01 | 1993-09-21 | Applied Process | Method for producing a selectively surface hardened cast iron part |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH360701A (en) * | 1957-09-19 | 1962-03-15 | Tiroler Roehren & Metallwerk | Process for surface hardening of cast iron |
-
2007
- 2007-12-24 DE DE102007062664A patent/DE102007062664B3/en active Active
-
2008
- 2008-12-24 GB GB0823569A patent/GB2461351A/en not_active Withdrawn
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6293361A (en) * | 1985-10-18 | 1987-04-28 | Toyota Motor Corp | Manufacture of surface hardened gear made of cast iron |
| JPH01225745A (en) * | 1988-03-03 | 1989-09-08 | Daikin Ind Ltd | Sliding member |
| JPH02149617A (en) * | 1988-11-29 | 1990-06-08 | Mazda Motor Corp | Manufacture of ferrous member |
| US5246510A (en) * | 1992-06-01 | 1993-09-21 | Applied Process | Method for producing a selectively surface hardened cast iron part |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104946858A (en) * | 2015-07-29 | 2015-09-30 | 山东伊莱特重工有限公司 | High-temperature short-time heating surface strengthening processing process |
| WO2022146334A1 (en) * | 2020-12-29 | 2022-07-07 | Gazi Universitesi | A new heat treatment method to produce hard surface austempered materials |
| WO2022146335A3 (en) * | 2020-12-29 | 2022-08-04 | Gazi Universitesi | Hard surface austempered materials |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0823569D0 (en) | 2009-01-28 |
| DE102007062664B3 (en) | 2009-06-10 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |