CA2044226C - Method and apparatus for producing a surface layer on a metallic workpiece - Google Patents
Method and apparatus for producing a surface layer on a metallic workpiece Download PDFInfo
- Publication number
- CA2044226C CA2044226C CA002044226A CA2044226A CA2044226C CA 2044226 C CA2044226 C CA 2044226C CA 002044226 A CA002044226 A CA 002044226A CA 2044226 A CA2044226 A CA 2044226A CA 2044226 C CA2044226 C CA 2044226C
- Authority
- CA
- Canada
- Prior art keywords
- workpiece
- surface layer
- accordance
- temperature
- region
- 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 - Fee Related
Links
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
- C23C26/00—Coating not provided for in groups C23C2/00 - C23C24/00
- C23C26/02—Coating not provided for in groups C23C2/00 - C23C24/00 applying molten material to the substrate
Abstract
The surface of a workpiece is provided with a surface layer. Initially, the workpiece is inductively heated by a HF/MF generator to a first temperature and subsequently heated further by a laser beam with coating material being applied to the region of the laser beam in an amount sufficient to form a surface layer on the workpiece. The generator and the laser source are able to operate simultaneously to effect a high duality surface layer of relatively thin thickness.
Description
~9 A METHOD AND APPARATUS FOR PRODUCING
A SURFACE LAYER ON A METALLIC WORKPIECE
This invention relates to a method and apparatus for producing a surface layer on a metallic workpiece.
For the most various reasons, workpieces have been provided wholly or partially with surface layers. For example, surface layers have been provided at places on workpieces which are particularly heavily loaded thermally, chemically or mechanically. These layers may moreover be produced by alteration of the structure of the surface regions of a workpiece, e.g., by hardening by, say, heat treatment, or by the incorporation of foreign substances. Surface layers are also generated by the application of actual surface layers, such as by melting them on or by galvanic surface treatment.
In the case of coated workpieces which are subjected, e.g., to alternating thermal loading, the life of surface layers suitable in themselves is inadequate for certain applications. For example, the surface layer or parts thereof may loosen from the workpiece. In other cases, cracks may form in the surface layer which lead to a breakdown of the surface layer and also of the workpiece.
By way of example, European Patent Application 0 190 3?8 describes a method for surface-alloying metal with a high-density energy beam and an alloy steel. In one described embodiment, a second heat source comprising a burner or an induction heater is disposed in front of and/or behind the irradiation area of the high-density energy beam. This second heat source provides a supplementary heat source .for decreasing the energy of the high-density beam and/or for enhancing the working ability and is intended to prevent thermal cracks. However, such a technique still allows the overall workpiece to be subjected to alternating thermal loading. That is to say, while the area under the influence of the second heat source and high density energy beam, i.e, a laser beam, is significantly heated, the adjacent areas of the workpiece are not. Thus, there is an uneven temperature over the working area of the workpiece. Hence, residual stresses occur during the thermal treatment of workpieces. These residual stresses, in turn, may result in deformations such as localized buckling, within the workpiece and in the surface layer thereon.
Accordingly, it is an object of the invention to improve the quality of a surface layer on a workpiece.
It is another object of the invention to provide a relatively simple technique for forming high quality surface layers on a workpiece.
It is another object of the invention to form relatively thin surface layers on a workpiece with minimal melting of the workpiece.
Briefly, the invention provides a method and apparatus for producing a surface layer on a metallic workpiece.
In accordance with the method, at least one part of a metallic workpiece to be coated is inductively heated through a first range of temperatures and thereafter a laser beam is directed onto a limited surface heated part in order to melt the surface for generating a surface layer on a workpiece.
In one embodiment, the laser beam may be used to directly heat the surface of the workpiece followed by a ~~~4~~~
A SURFACE LAYER ON A METALLIC WORKPIECE
This invention relates to a method and apparatus for producing a surface layer on a metallic workpiece.
For the most various reasons, workpieces have been provided wholly or partially with surface layers. For example, surface layers have been provided at places on workpieces which are particularly heavily loaded thermally, chemically or mechanically. These layers may moreover be produced by alteration of the structure of the surface regions of a workpiece, e.g., by hardening by, say, heat treatment, or by the incorporation of foreign substances. Surface layers are also generated by the application of actual surface layers, such as by melting them on or by galvanic surface treatment.
In the case of coated workpieces which are subjected, e.g., to alternating thermal loading, the life of surface layers suitable in themselves is inadequate for certain applications. For example, the surface layer or parts thereof may loosen from the workpiece. In other cases, cracks may form in the surface layer which lead to a breakdown of the surface layer and also of the workpiece.
By way of example, European Patent Application 0 190 3?8 describes a method for surface-alloying metal with a high-density energy beam and an alloy steel. In one described embodiment, a second heat source comprising a burner or an induction heater is disposed in front of and/or behind the irradiation area of the high-density energy beam. This second heat source provides a supplementary heat source .for decreasing the energy of the high-density beam and/or for enhancing the working ability and is intended to prevent thermal cracks. However, such a technique still allows the overall workpiece to be subjected to alternating thermal loading. That is to say, while the area under the influence of the second heat source and high density energy beam, i.e, a laser beam, is significantly heated, the adjacent areas of the workpiece are not. Thus, there is an uneven temperature over the working area of the workpiece. Hence, residual stresses occur during the thermal treatment of workpieces. These residual stresses, in turn, may result in deformations such as localized buckling, within the workpiece and in the surface layer thereon.
Accordingly, it is an object of the invention to improve the quality of a surface layer on a workpiece.
It is another object of the invention to provide a relatively simple technique for forming high quality surface layers on a workpiece.
It is another object of the invention to form relatively thin surface layers on a workpiece with minimal melting of the workpiece.
Briefly, the invention provides a method and apparatus for producing a surface layer on a metallic workpiece.
In accordance with the method, at least one part of a metallic workpiece to be coated is inductively heated through a first range of temperatures and thereafter a laser beam is directed onto a limited surface heated part in order to melt the surface for generating a surface layer on a workpiece.
In one embodiment, the laser beam may be used to directly heat the surface of the workpiece followed by a ~~~4~~~
rapid cool down of the workpiece in order to form a surface layer therein.
In another embodiment, a coating material is fed into a region of the laser beam striking the surface of the heated part of the workpiece in an amount sufficient to effect fusing of the coating material with the workpiece surface in order to foam a surface layer thereat.
The apparatus includes a high-frequency/medium-frequency generator, an inductive coil electrically connected to the generator for inductively heating at least a part of a metallic workpiece to be coated through a first range of temperature and a laser source for directing a laser beam onto a limited surface of the heated part of the workpiece for melting of said surface.
In the embodiment where the surface layer is formed by a coating material, a suitable means is provided for feeding the coating material into the region of the laser beam for fusion with the workpiece surface.
By the inductive high-frequency/medium-frequency generator, it is possible to heat the workpiece to which the surface layer is to be applied, up to a well defined temperature and - what is of importance for the quality of the surface layer - to maintain this temperature precisely even during the production of the surface layer. The inductive preheat temperature may be maintained without problem exactly within _+l0°C. The improved quality is, inter alia, to be attributed to the fact that the temperature difference between the workpiece and the fusion region, that is, the region where the surface layer is generated continuously by the laser beam, may first be chosen and secondly be kept relatively low, and thirdly even during the production of the surface layer may be well maintained. The character of the surface layer, in particular its thickness, surface, structure, crystalline structure, ductility, hardness, etc. thereby becomes more uniform and therefore the surface layer becomes quite generally better. By the method, thinner surface layers may also be produced.
The method thus makes it possible to position the work area of the laser beam directly into the center of the inductively heated area or near the center of the inductively heated area. The inductive heating permits, over and above that, the production of an essentially equal temperature over relatively large areas of the workpiece, that is, a homogeneous temperature field.
This serves to keep the residual stress which may occur during thermotreatment at extremely low values. The consequence of this is that deformations of the treated workpiece, the so-called buckling remains minor or practically fail to materialize at all.
Basically, the following possibilities exist of producing surface layers: By hardening in the solid state, in which in principle the workpiece is heated and thereupon rapidly cooled down; through fusion and restructuring of the material of the workpiece; through fusion and incorporation of foreign material, i.e., alloying the surface layer of the workpiece; through melting on a layer of a material which differs from that of the workpiece, the surface layer and workpiece being connected only in a thin fusion region. Moreover, the cooling down process has in the case of all kinds of production of surface layers, an influence upon their properties.
In the case of surface layers of a material differing from that of the workpiece, the coefficient of thermal expansion of the layer material may be chosen to be lower than that of the material of the workpiece.
Because of the exact choice of temperature possible in the coating process, the temperature of the workpiece during coating may be chosen to be higher than the operating temperature foreseen for the workpiece so that, at operating temperature, the surface layer experiences in operation a definite compressive force which is exerted upon and transmitted to the surface layer from the workpiece. Inherent compressive stresses of that kind in the surface lays;r oppose crack-formation, material fatigue and also corrosion of the part and in particular of the surface layer. Thus, the life and quality of the part and in particular of the surface layer are improved. This is the case, for example, with a stellite 6 layer on a workpiece of X2 CrNiMo 18 12 (chrome-nickel-molybdenum) stainless steel.
The possibility of rapid inductive preheating of the workpiece through a first range of temperature up to a discretionary first temperature also reduces the troublesome processes of oxidation on the workpiece surface during coating or avoids these altogether if the heating is effected under protective gas.
Through appropriate adaptation of the induction coil connected to the HF/MF generator, the inductive heating permits very different temperature profiles over the whole workpiece. This enables the distortion and deformation of the workpiece to be reduced and also allows the progress of the hardening over the surface layer to be kept uniform. Moreover, annealing, i.e., the resoftening of parts of a hardened workpiece or surface may be prevented or influenced through the choice of the inductive heating profile, possibly in, combination with a cooling process. Then, on the surface which, for example, may be heated inductively to a temperature of 800°C, the surface layer may be melted on by the laser source at a temperature of 1800°C.
The HF/MF generator which preferably works in the frequency range from 0.5 kHz to 1 MHz in the power range from 5 to some tens of kW has as heating, above all, a depth or volume effect whilst the superimposed heating by the laser source has, above all, a point by point surface action, that is, in the region of the preheated surface, where the actual surface layer is generated at still higher temperature by melting on foreign material or merely the uppermost layers of the workpiece to be coated. In that case, the layer material, for example, may be blown in powder form and by protective gas as the medium of conveyance into the region of the laser beam striking the surface of the workpiece. There the powder is fused and blended with the thinnest and smallest fused part possible of the surface of the workpiece.
For example, by the method, thin surface layers may be generated in the range of thickness from 0.2 - 0.4 millimeters (mm).
In order not to overhead certain regions of workpieces and/or to keep them within a certain temperature range, individual regions of the workpiece and/or of the surface layer may be cooled by a cooling means which works with, e.g., air, oil, water or some other cooling medium. By cooling, it is also possible to keep the character of the surface layer of a workpiece constantly improved. The character of a surface is in many cases dependent upon cooling processes which may be maintained better and more exactly by a cooling device. By the cooling means, it is possible both to avoid overheating and to improve, i.e., to maintain more exactly the time slope of the cooling process.
Under the method, the workpiece to be provided with the surface layer or parts of the workpiece, are heated by the inductive HF/MF generator to a first temperature.
By the laser source limited regions of the heated surface to be treated are further heated and the surface layer generated on the workpiece. The laser source and the HF/MF generator, allow the workpiece to be influenced by both simultaneously. Workpieces with surface layers generated according to the method exhibit a higher, i.e., an improved quality since the method allows and makes possible a clearly improved maintenance of the temperature time slope and also the temperature distribution in the workpiece.
These and other objects and advantages of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawing wherein:
The figure schematically illustrates an apparatus constructed in accordance with the invention.
Referring to the drawing, in the simplest form, the apparatus for producing a surface layer 101 on a workpiece 10 includes a holding device for the workpiece 10, a HF or MF generator 2 (HF = high frequency; MF =
medium frequency) with an induction coil 20 which together form essentially an inductive heating means, and a laser source 3 with a deflecting mirror 31 and optical system 32 for focusing a laser beam 30.
As shown, the workpiece 10 may, for example, be a valve for a combustion engine. The edge regions 10" of the valve head 10' which forms the annular sealing region in the valve seating are to be provided with a surface layer 101.
The inductive heating means functions to heat the entire workpiece edge region 10", as indicated by the coil to being concentrically disposed about this workpiece 10 so as to envelop this edge region 10"
circumferentially. For example, the entire edge region 10" is heated to a temperature of 800°C.
The laser beam 30 is focused by the deflecting mirror 31 and the optical focusing system 32 onto the working point 30' of the edge region 10" of the valve 10' which is to be coated. That is, the beam 30 is directed onto a limited surface of the heated edge region 10" to meet the surface thereat.
The surface layer 101 may, for example, be generated through mere fusion and restructuring of the workpiece (hardening) of regions of the valve head 10' or through application of a layer of another material, _g_ e.g., stellite 6. The stellite .6 in powder form may, e.g., by means of a powder conveyor 4 with a powder nozzle 41 which generates a powder jet 40, be blown at the working point 30' into the region of the laser beam 30. Conveyance of the powder may be effected by argon which simultaneously acts as protective gas about the heated surface during generation of the surface layer 101.
For the coating of axially symmetrical workpieces 10 and axially symmetrical surface layers 101, the workpiece 10 may be turned by means such as a turning mechanism 100. It would also be possible to move the working point 30' of the laser beam 30 together with the powder jet 40 along the surface of the workpiece l0. It would again be conceivable to move all four, workpiece 10, laser beam 30, and powder jet 40 as well as the coil or else just one or a number of them. This might confer advantages if, for example, complicated surface layer patterns have to be generated on workpieces with 20 complicated contours.
In many applications, the quality of the surface layer is influenced by maintaining exact limits to the temperature of the workpiece 10 and the surface layer 101 in the region of the working point 30' of the laser beam 30. In just the same way, the cooling process may be decisive for the character and properties of the surface layer and the coated workpiece. For this purpose, the apparatus may include a control and regulating device 5 by which the HF/MF generator 2 heating power and also the power of the laser source 3 may be controlled and regulated. In the example shown, two temperature sensors 51, 52 are provided as control quantities which determine the temperature of the surface layer 101 in the region of the working point 30' of the laser 30 or respectively the surface temperature of the valve head 10'. The control and regulating device 5 may set the power of the HF/MF and/or the laser _g_ heating sources 2,3 to desired values which are predetermined, for example, at a temperature-desired-value transmitter 53.
For maintaining particular temperature profiles on the workpiece 10 or parts thereof, e.g., on the valve head 10', a cooling means 6, for example, may be provided which cools the valve head by a jet 60 of cooling fluid of, e.g., air, a protective gas or a liquid such as water. The temperatures might also be regulated, i.e., influenced by the speed of rotation of the turning mechanism 100 for the workpiece 10 and/or by the cooling fluid jet 60 being varied or respectively switched on and off. The control and regulating means 5 may be programmable within wide limits in order, depending upon the surface layer which is to be produced, to create other surface coating conditions.
Thus, the apparatus may be constructed at the induction coil 20, the temperature sensors 51, 52, e.g., radiation pyrometers and the laser source 3 with the laser beam 30 are moved with respect to one another and/or to the workpiece 16 which in turn is likewise moved. The possible signal flow from the regulating and control device 5 is indicated in the diagrammatic Figure by arrows. ,All of these relative motions may likewise be determined by the regulating and control device 5.
The invention thus provides a relatively simple technique for forming relatively thin surface layers on metallic workpieces. In this respect, the surface layer is to be distinguished from an alloy layer which may be formed on a workpiece, for example, as described in European Patent Application 0190378. As described therein, the surface of a base metal is alloyed by means of a laser or electron beam which locally melts the surface of the base metal while additive material is delivered into the melted base metal. A distinguishing feature of a surface layer made in accordance with the above described process is the formation of a very thin fusion region between an applied surface layer and the workpiece.
The fusion region between an applied surface layer and the workpiece is typically thinner than the surface layer itself and lies in most cases between two and twenty um.
In the sence of this invention the term surface layer can either mean a layer of the basic material of a workpiece having a different structure or a layer of different material fused onto the original surface layer of the workpiece. Different structures of the surface layer can for instance be produced by defined fast and~or slow cooling.
In another embodiment, a coating material is fed into a region of the laser beam striking the surface of the heated part of the workpiece in an amount sufficient to effect fusing of the coating material with the workpiece surface in order to foam a surface layer thereat.
The apparatus includes a high-frequency/medium-frequency generator, an inductive coil electrically connected to the generator for inductively heating at least a part of a metallic workpiece to be coated through a first range of temperature and a laser source for directing a laser beam onto a limited surface of the heated part of the workpiece for melting of said surface.
In the embodiment where the surface layer is formed by a coating material, a suitable means is provided for feeding the coating material into the region of the laser beam for fusion with the workpiece surface.
By the inductive high-frequency/medium-frequency generator, it is possible to heat the workpiece to which the surface layer is to be applied, up to a well defined temperature and - what is of importance for the quality of the surface layer - to maintain this temperature precisely even during the production of the surface layer. The inductive preheat temperature may be maintained without problem exactly within _+l0°C. The improved quality is, inter alia, to be attributed to the fact that the temperature difference between the workpiece and the fusion region, that is, the region where the surface layer is generated continuously by the laser beam, may first be chosen and secondly be kept relatively low, and thirdly even during the production of the surface layer may be well maintained. The character of the surface layer, in particular its thickness, surface, structure, crystalline structure, ductility, hardness, etc. thereby becomes more uniform and therefore the surface layer becomes quite generally better. By the method, thinner surface layers may also be produced.
The method thus makes it possible to position the work area of the laser beam directly into the center of the inductively heated area or near the center of the inductively heated area. The inductive heating permits, over and above that, the production of an essentially equal temperature over relatively large areas of the workpiece, that is, a homogeneous temperature field.
This serves to keep the residual stress which may occur during thermotreatment at extremely low values. The consequence of this is that deformations of the treated workpiece, the so-called buckling remains minor or practically fail to materialize at all.
Basically, the following possibilities exist of producing surface layers: By hardening in the solid state, in which in principle the workpiece is heated and thereupon rapidly cooled down; through fusion and restructuring of the material of the workpiece; through fusion and incorporation of foreign material, i.e., alloying the surface layer of the workpiece; through melting on a layer of a material which differs from that of the workpiece, the surface layer and workpiece being connected only in a thin fusion region. Moreover, the cooling down process has in the case of all kinds of production of surface layers, an influence upon their properties.
In the case of surface layers of a material differing from that of the workpiece, the coefficient of thermal expansion of the layer material may be chosen to be lower than that of the material of the workpiece.
Because of the exact choice of temperature possible in the coating process, the temperature of the workpiece during coating may be chosen to be higher than the operating temperature foreseen for the workpiece so that, at operating temperature, the surface layer experiences in operation a definite compressive force which is exerted upon and transmitted to the surface layer from the workpiece. Inherent compressive stresses of that kind in the surface lays;r oppose crack-formation, material fatigue and also corrosion of the part and in particular of the surface layer. Thus, the life and quality of the part and in particular of the surface layer are improved. This is the case, for example, with a stellite 6 layer on a workpiece of X2 CrNiMo 18 12 (chrome-nickel-molybdenum) stainless steel.
The possibility of rapid inductive preheating of the workpiece through a first range of temperature up to a discretionary first temperature also reduces the troublesome processes of oxidation on the workpiece surface during coating or avoids these altogether if the heating is effected under protective gas.
Through appropriate adaptation of the induction coil connected to the HF/MF generator, the inductive heating permits very different temperature profiles over the whole workpiece. This enables the distortion and deformation of the workpiece to be reduced and also allows the progress of the hardening over the surface layer to be kept uniform. Moreover, annealing, i.e., the resoftening of parts of a hardened workpiece or surface may be prevented or influenced through the choice of the inductive heating profile, possibly in, combination with a cooling process. Then, on the surface which, for example, may be heated inductively to a temperature of 800°C, the surface layer may be melted on by the laser source at a temperature of 1800°C.
The HF/MF generator which preferably works in the frequency range from 0.5 kHz to 1 MHz in the power range from 5 to some tens of kW has as heating, above all, a depth or volume effect whilst the superimposed heating by the laser source has, above all, a point by point surface action, that is, in the region of the preheated surface, where the actual surface layer is generated at still higher temperature by melting on foreign material or merely the uppermost layers of the workpiece to be coated. In that case, the layer material, for example, may be blown in powder form and by protective gas as the medium of conveyance into the region of the laser beam striking the surface of the workpiece. There the powder is fused and blended with the thinnest and smallest fused part possible of the surface of the workpiece.
For example, by the method, thin surface layers may be generated in the range of thickness from 0.2 - 0.4 millimeters (mm).
In order not to overhead certain regions of workpieces and/or to keep them within a certain temperature range, individual regions of the workpiece and/or of the surface layer may be cooled by a cooling means which works with, e.g., air, oil, water or some other cooling medium. By cooling, it is also possible to keep the character of the surface layer of a workpiece constantly improved. The character of a surface is in many cases dependent upon cooling processes which may be maintained better and more exactly by a cooling device. By the cooling means, it is possible both to avoid overheating and to improve, i.e., to maintain more exactly the time slope of the cooling process.
Under the method, the workpiece to be provided with the surface layer or parts of the workpiece, are heated by the inductive HF/MF generator to a first temperature.
By the laser source limited regions of the heated surface to be treated are further heated and the surface layer generated on the workpiece. The laser source and the HF/MF generator, allow the workpiece to be influenced by both simultaneously. Workpieces with surface layers generated according to the method exhibit a higher, i.e., an improved quality since the method allows and makes possible a clearly improved maintenance of the temperature time slope and also the temperature distribution in the workpiece.
These and other objects and advantages of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawing wherein:
The figure schematically illustrates an apparatus constructed in accordance with the invention.
Referring to the drawing, in the simplest form, the apparatus for producing a surface layer 101 on a workpiece 10 includes a holding device for the workpiece 10, a HF or MF generator 2 (HF = high frequency; MF =
medium frequency) with an induction coil 20 which together form essentially an inductive heating means, and a laser source 3 with a deflecting mirror 31 and optical system 32 for focusing a laser beam 30.
As shown, the workpiece 10 may, for example, be a valve for a combustion engine. The edge regions 10" of the valve head 10' which forms the annular sealing region in the valve seating are to be provided with a surface layer 101.
The inductive heating means functions to heat the entire workpiece edge region 10", as indicated by the coil to being concentrically disposed about this workpiece 10 so as to envelop this edge region 10"
circumferentially. For example, the entire edge region 10" is heated to a temperature of 800°C.
The laser beam 30 is focused by the deflecting mirror 31 and the optical focusing system 32 onto the working point 30' of the edge region 10" of the valve 10' which is to be coated. That is, the beam 30 is directed onto a limited surface of the heated edge region 10" to meet the surface thereat.
The surface layer 101 may, for example, be generated through mere fusion and restructuring of the workpiece (hardening) of regions of the valve head 10' or through application of a layer of another material, _g_ e.g., stellite 6. The stellite .6 in powder form may, e.g., by means of a powder conveyor 4 with a powder nozzle 41 which generates a powder jet 40, be blown at the working point 30' into the region of the laser beam 30. Conveyance of the powder may be effected by argon which simultaneously acts as protective gas about the heated surface during generation of the surface layer 101.
For the coating of axially symmetrical workpieces 10 and axially symmetrical surface layers 101, the workpiece 10 may be turned by means such as a turning mechanism 100. It would also be possible to move the working point 30' of the laser beam 30 together with the powder jet 40 along the surface of the workpiece l0. It would again be conceivable to move all four, workpiece 10, laser beam 30, and powder jet 40 as well as the coil or else just one or a number of them. This might confer advantages if, for example, complicated surface layer patterns have to be generated on workpieces with 20 complicated contours.
In many applications, the quality of the surface layer is influenced by maintaining exact limits to the temperature of the workpiece 10 and the surface layer 101 in the region of the working point 30' of the laser beam 30. In just the same way, the cooling process may be decisive for the character and properties of the surface layer and the coated workpiece. For this purpose, the apparatus may include a control and regulating device 5 by which the HF/MF generator 2 heating power and also the power of the laser source 3 may be controlled and regulated. In the example shown, two temperature sensors 51, 52 are provided as control quantities which determine the temperature of the surface layer 101 in the region of the working point 30' of the laser 30 or respectively the surface temperature of the valve head 10'. The control and regulating device 5 may set the power of the HF/MF and/or the laser _g_ heating sources 2,3 to desired values which are predetermined, for example, at a temperature-desired-value transmitter 53.
For maintaining particular temperature profiles on the workpiece 10 or parts thereof, e.g., on the valve head 10', a cooling means 6, for example, may be provided which cools the valve head by a jet 60 of cooling fluid of, e.g., air, a protective gas or a liquid such as water. The temperatures might also be regulated, i.e., influenced by the speed of rotation of the turning mechanism 100 for the workpiece 10 and/or by the cooling fluid jet 60 being varied or respectively switched on and off. The control and regulating means 5 may be programmable within wide limits in order, depending upon the surface layer which is to be produced, to create other surface coating conditions.
Thus, the apparatus may be constructed at the induction coil 20, the temperature sensors 51, 52, e.g., radiation pyrometers and the laser source 3 with the laser beam 30 are moved with respect to one another and/or to the workpiece 16 which in turn is likewise moved. The possible signal flow from the regulating and control device 5 is indicated in the diagrammatic Figure by arrows. ,All of these relative motions may likewise be determined by the regulating and control device 5.
The invention thus provides a relatively simple technique for forming relatively thin surface layers on metallic workpieces. In this respect, the surface layer is to be distinguished from an alloy layer which may be formed on a workpiece, for example, as described in European Patent Application 0190378. As described therein, the surface of a base metal is alloyed by means of a laser or electron beam which locally melts the surface of the base metal while additive material is delivered into the melted base metal. A distinguishing feature of a surface layer made in accordance with the above described process is the formation of a very thin fusion region between an applied surface layer and the workpiece.
The fusion region between an applied surface layer and the workpiece is typically thinner than the surface layer itself and lies in most cases between two and twenty um.
In the sence of this invention the term surface layer can either mean a layer of the basic material of a workpiece having a different structure or a layer of different material fused onto the original surface layer of the workpiece. Different structures of the surface layer can for instance be produced by defined fast and~or slow cooling.
Claims (9)
1. Method for the manufacture of surface layers on workpieces which can be heated inductively and in which at least the part of the workpiece to be coated is inductively heated in a first temperature range, and the surface layer is produced by further heating up or melting on of the inductively heated surface region of the workpiece to be coated using laser light and laser energy, characterised in that the material to be melted on for the surface layer to be produced, and which differs from the material of the workpiece, is brought during the inductive heating to the working point of the laser beam which is disposed at the centre of or in the vicinity of the centre of the RF/MF heated region, with the surface layer being formed by the added material which differs from the material of the workpiece.
2. Method in accordance with claim 1, wherein the thermal coefficient of expansion of the material of the workpiece is greater than that of the material of the surface layer.
3. Method in accordance with claim 2, wherein the thermal coefficient of expansion of the material of the surface layer is smaller than that of the workpiece and the first temperature range is higher than the operating temperature provided for the workpiece.
4. Method in accordance with claim 1, 2 or 3 in which the production of the surface layer takes place under inert gas.
5. Method in accordance with any one of claims 1 to 4, wherein the inductive heating up of the workpiece takes place with the RF/MF generator in accordance with a selectable thermal profile.
6, Method in accordance with claim 5, wherein the inductive thermal profile of the workpiece is additionally influenced by a cooling system.
7. Apparatus for carrying out the method in accordance with any one of the claims 1 to 6, comprising an RF/MF
generator and transmission means for the inductive heating of the workpiece to be coated with the surface layer into a first temperature range and also with a laser device for the further heating of the surface region of the workpiece to be coated, characterised by an apparatus for the supply of powder-like or wire-like material for the surface layer different from the material of the workpiece to the working point of the laser beam, which is disposed in the centre of or close to the centre of the region which can be inductively heated by means of the RF/MF generator, with the surface layer being formed by a supplied material which differs from the material of the workpiece.
generator and transmission means for the inductive heating of the workpiece to be coated with the surface layer into a first temperature range and also with a laser device for the further heating of the surface region of the workpiece to be coated, characterised by an apparatus for the supply of powder-like or wire-like material for the surface layer different from the material of the workpiece to the working point of the laser beam, which is disposed in the centre of or close to the centre of the region which can be inductively heated by means of the RF/MF generator, with the surface layer being formed by a supplied material which differs from the material of the workpiece.
8. Apparatus in accordance with claim 7 comprising means for the movement of the workpiece, and/or means for the determination of the temperature of the workpiece and/or of the temperature in the laser heated region of the surface layer, and/or means for the supply of protective gas and/or means for the cooling of regions of the workpiece.
9. Apparatus in accordance with claim 7 or 8, comprising a regulating and control device for the controlling and/or regulation of the RF/MF generator and/or of the laser device and/or of the cooling device and/or of its movement and/or the movement of the workpiece to be coated and/or of the laser device and/or of the means for the determination of the temperature and/or of the movement of parts thereof.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH1992/90-2 | 1990-06-13 | ||
| CH199290 | 1990-06-13 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2044226A1 CA2044226A1 (en) | 1991-12-14 |
| CA2044226C true CA2044226C (en) | 2001-03-13 |
Family
ID=4223380
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002044226A Expired - Fee Related CA2044226C (en) | 1990-06-13 | 1991-06-10 | Method and apparatus for producing a surface layer on a metallic workpiece |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US5224997A (en) |
| EP (1) | EP0462047B1 (en) |
| JP (1) | JP3034079B2 (en) |
| CA (1) | CA2044226C (en) |
| DE (1) | DE59108894D1 (en) |
| ES (1) | ES2110985T3 (en) |
| PT (1) | PT97946B (en) |
Families Citing this family (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5554837A (en) * | 1993-09-03 | 1996-09-10 | Chromalloy Gas Turbine Corporation | Interactive laser welding at elevated temperatures of superalloy articles |
| JP3550575B2 (en) * | 1994-10-21 | 2004-08-04 | フジオーゼックス株式会社 | Manufacturing method of engine valve |
| DE19529928A1 (en) * | 1995-08-01 | 1997-02-06 | Wago Verwaltungs Gmbh | Mfg. electrotechnical components provided with contact coating - with selective induction heating of predetermined contact regions of the component before contact materials are melted onto them |
| DE19701483A1 (en) * | 1997-01-17 | 1998-07-23 | Zahnradfabrik Friedrichshafen | Raised structure production on sintered component(s) |
| DE10137776C1 (en) * | 2001-08-02 | 2003-04-17 | Fraunhofer Ges Forschung | Process for the production of wear-resistant surface layers |
| DE10353473B4 (en) * | 2003-11-15 | 2007-02-22 | Daimlerchrysler Ag | Component of an internal combustion engine and method for its production |
| JP2007169761A (en) * | 2005-12-26 | 2007-07-05 | Delta Kogyo Co Ltd | Method for manufacturing reclining component |
| JP5189824B2 (en) * | 2007-11-02 | 2013-04-24 | 本田技研工業株式会社 | Method and apparatus for depositing valve seat |
| DE102011113551A1 (en) * | 2011-09-15 | 2013-03-21 | Robert Bosch Gmbh | Method for applying a bearing layer on a sliding bearing component body and sliding bearing component |
| JP6050141B2 (en) * | 2013-02-22 | 2016-12-21 | 三井造船株式会社 | Hardfacing welding apparatus and method |
| CN103276394A (en) * | 2013-06-17 | 2013-09-04 | 铜陵学院 | Laser remelting one-step reinforcing processing method and device thereof for plasma sprayed thermal barrier coating with double-layer structure |
| CN105555442B (en) * | 2013-06-20 | 2018-07-03 | Mtu飞机发动机有限公司 | For being additionally formed the device and method of at least one component region of component |
| CN104195543A (en) * | 2014-08-18 | 2014-12-10 | 苏州克兰兹电子科技有限公司 | In-light coaxial composite wire-feeding and powder-feeding laser cladding system |
| DE102014222055A1 (en) * | 2014-10-29 | 2016-05-04 | Siemens Aktiengesellschaft | Apparatus for build-up welding with cooled inert gas and method |
| CN108136498A (en) * | 2015-08-04 | 2018-06-08 | 自动工程公司 | Reinforcement structure component |
| CN105154875B (en) * | 2015-09-14 | 2017-08-11 | 温州大学 | A kind of laser induction composite covers process equipment |
| KR101779104B1 (en) | 2017-03-20 | 2017-09-18 | 창원대학교 산학협력단 | thermally assisted apparatus using multi heat source |
| JP6289713B1 (en) * | 2017-06-12 | 2018-03-07 | 南海鋼材株式会社 | Welding system and welding method |
| CN110283973B (en) * | 2019-07-29 | 2021-05-14 | 无锡众望四维科技有限公司 | Valve stem neck annealing production line |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1035675A (en) * | 1974-01-07 | 1978-08-01 | Avco Everett Research Laboratory | Formation of surface layer casings on articles |
| CA1051288A (en) * | 1974-03-04 | 1979-03-27 | Caterpillar Tractor Co. | Method and apparatus for fusibly bonding a coating metal powder to a metal article |
| DE2811400C3 (en) * | 1978-03-16 | 1981-12-17 | Aeg-Elotherm Gmbh, 5630 Remscheid | Process for remelt hardening of workpieces |
| EP0190378B1 (en) * | 1985-02-05 | 1990-05-23 | Nippon Steel Corporation | Method for surface-alloying metal with a high-density energy beam and an alloy steel |
| JPS6252975A (en) * | 1985-08-30 | 1987-03-07 | Mitsubishi Electric Corp | Amorphous solar battery |
| US4780590A (en) * | 1985-11-21 | 1988-10-25 | Penn Research Corporation | Laser furnace and method for zone refining of semiconductor wafers |
| CH674650A5 (en) * | 1988-04-28 | 1990-06-29 | Castolin Sa | Heat-treating coated surfaces - with high energy beam and pre- or post-heat treatment using induction heating devices to prevent cracking in high hardness alloys |
| US5015492A (en) * | 1989-04-03 | 1991-05-14 | Rutgers University | Method and apparatus for pulsed energy induced vapor deposition of thin films |
-
1991
- 1991-05-03 ES ES91810343T patent/ES2110985T3/en not_active Expired - Lifetime
- 1991-05-03 EP EP91810343A patent/EP0462047B1/en not_active Expired - Lifetime
- 1991-05-03 DE DE59108894T patent/DE59108894D1/en not_active Expired - Fee Related
- 1991-06-05 US US07/710,815 patent/US5224997A/en not_active Expired - Fee Related
- 1991-06-10 CA CA002044226A patent/CA2044226C/en not_active Expired - Fee Related
- 1991-06-12 JP JP3139929A patent/JP3034079B2/en not_active Expired - Fee Related
- 1991-06-12 PT PT97946A patent/PT97946B/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| EP0462047B1 (en) | 1997-11-26 |
| EP0462047A1 (en) | 1991-12-18 |
| DE59108894D1 (en) | 1998-01-08 |
| PT97946B (en) | 1998-11-30 |
| US5224997A (en) | 1993-07-06 |
| JPH07148585A (en) | 1995-06-13 |
| CA2044226A1 (en) | 1991-12-14 |
| JP3034079B2 (en) | 2000-04-17 |
| ES2110985T3 (en) | 1998-03-01 |
| PT97946A (en) | 1993-07-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2044226C (en) | Method and apparatus for producing a surface layer on a metallic workpiece | |
| US10285222B2 (en) | Method and device for generatively producing at least one component area | |
| USRE29815E (en) | Cladding | |
| US6843866B2 (en) | Process for producing wear-resistant surface layers | |
| US6925346B1 (en) | Closed-loop, rapid manufacturing of three-dimensional components using direct metal deposition | |
| US7094988B1 (en) | Laser welding heat treat process | |
| US6197386B1 (en) | Method for applying a coating by means of plasma spraying while simultaneously applying a continuous laser beam | |
| US4157923A (en) | Surface alloying and heat treating processes | |
| EP0147190B1 (en) | Method and apparatus for laser gear hardening | |
| US20090283501A1 (en) | Preheating using a laser beam | |
| EP2444194A1 (en) | Method for beam welding on components | |
| US5993915A (en) | Fusing thermal spray coating and heat treating base material using infrared heating | |
| US5698273A (en) | Electron beam physical vapor deposition method | |
| US20210213565A1 (en) | Additive manufacturing device | |
| JPS6293028A (en) | Bending method for plate stock by laser | |
| JP3934679B2 (en) | Cutting die and method for manufacturing the same | |
| AU660240B2 (en) | Process for recharging a part by means of a plasma transferred arc | |
| Bloehs et al. | Recent progress in laser surface treatment: II. Adopted processing for high efficiency and quality | |
| JP4953172B2 (en) | Method to refine ferrite structure by laser irradiation | |
| Folkes | Surface modification and coating with lasers | |
| Son et al. | High-temperature properties of hot-work tool steel (AISI H13) deposited via direct energy deposition | |
| EP4104962A1 (en) | Electron beam welding | |
| Wetzig et al. | Induction assisted laser-cladding a new and effective method for producing high wear resistant coatings on steel components | |
| Zediker et al. | High power laser diode system for surface treatment | |
| Díaz et al. | Laser Powder Welding with a Co-based alloy for repairing steam circuit components in thermal power stations |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |