Method and device for welding parts from heat-resistant alloys

FIELD: metallurgy.

SUBSTANCE: device comprises source 3 to form heat feed zone 11 on part surface 10, device 5 to feed welding filler 13 into said zone 11 and device 15 to displace heat source 3 and filler feed device 5 relative to part surface 10. Control unit 17 with control program controls displacement so that welding power and heat feed zone diameter are set to ensure cooling rate of at least 8000 K per second at material crystallisation. Depth of remelting previous layer is set proceeding from the condition of formation of polycrystalline weld seam.

EFFECT: rules out cracks.

14 cl, 6 dwg

 

The present invention relates to a method and apparatus for welding parts, in particular parts of gas turbines, such as gas turbine blades.

Rotor blades of gas turbines in operation are exposed to high temperatures and severe mechanical loads. Therefore, these parts preferably are applied heat-resistant alloys based on Nickel, which can prosnetsja by precipitation of γ'-phase. However, in rotor blades can cause cracks, which expanded over time. These cracks can occur due to extreme mechanical loads during operation of the gas turbine, but they can also occur during the manufacturing process. Since the production of turbine blades and other parts made of such heat-resistant alloys is costly and expensive, strive to produce as little as possible of the defects in the manufacture and guarantee long service life of the existing products.

In the process of working blades of gas turbines are regularly maintenance and, if necessary, replaced, if due to operation of the load flawless operation cannot easily be guaranteed. To allow further use of substitutions is the R turbine blades, last, as far as possible, restored. They can then again be used in a gas turbine. Within this recovery may, for example, be necessary build-up layer in the damaged areas to restore the original wall thickness.

Also the turbine blades that are already in the process of manufacturing received the cracks, can be made suitable for use with the fuse cover, so that the defects in the manufacture can be reduced.

However, in the case of γ'-strengthened heat-resistant Nickel-based alloys using traditional welding methods with related filler materials welding is realized only with difficulty. The reason for this is that you should avoid microlocally, i.e. microscopic bundles of mixtures of melts. Moreover, the welding process can lead to the generation of cracks in the weld zone during subsequent heat treatment. The reasons for this are their own welding voltage due to plastic deformation during the heat input during the welding process.

To overcome the difficult weldability γ'-strengthened heat-resistant Nickel-based alloys, often welding is performed with plastic weld filler materials, such as Nickel-based alloys without γ'-hardening. A typical representative of this alloy is as Nickel base without γ'-hardening is for example, IN625. Plasticity is not γ'-hardened filler material can reduce welding stresses due to plastic deformation during the heat treatment after welding. In any case, non-reinforced alloys in comparison with the γ'-strengthened heat resistant Nickel-based alloys have lower high-temperature strength (as a lower tensile strength and less fatigue strength (yield strength)). Therefore, preferably used welding methods without plastic filler materials. These methods can be divided into two classes, namely the ways in which the aging of the base material to improve the ductility by coarsening of γ'-phase, and the ways in which the welding process is carried out in a preheated substrate. Carrying out the welding process on the pre-heated substrate reduces own welding voltage due to recovery (return of the metal during the welding process. The welding process with the previous aging is described, for example, in US 6120624, and the welding process, which takes place on preheated details described, for example, in US 5319179.

However, both of these welding methods without plastic welding filler materials have disadvantages. For example, in the case held before PR is the process of welding aging, before welding is carried out to heat treatment of the γ'-hardened heat-resistant alloy based on Nickel, in order to carry out the aging γ'-phase. While the ductility of the base material is noticeable. This increase plasticity enables welding of the material at room temperature. In addition, it can be cold straightened. In addition, this heat treatment enables the use of heat-resistant Nickel-based alloys, as, for example, Rene41 or Haynes282 as a welding filler material. They form, however, the γ'-phase in the structure, but only at significantly lower volume fraction than the typical γ'-containing heat-resistant Nickel-based alloys, which currently are used for hot gas components gas turbines such as blades of gas turbines (for example, IN738LC, IN939, Rene80, IN6203DS, PWA1483X, Alloy 247 and so on). Therefore, even in the case when the welding process is carried out aging cannot happen fully structural welding.

If you are pre-heating the turbine blades, the temperature difference and, thus, the resulting stress gradient between the weld area and the rest of the turbine blade is reduced, making it possible to avoid the formation of welding cracks in the parts of garorock the x alloys on a Nickel basis. Such methods, in which heating of the turbine blades to temperatures between 900°C and 1000°C by the induction coils must be performed, however, in a protective gas atmosphere, which complicates and increases the cost of the welding process. Besides, this way due to the lack of availability of parts in the tank with an inert gas, can be carried out in all areas of the part.

There is therefore a need for alternative welding method for fusion of the coating, which is particularly well suited for γ'-strengthened heat-resistant Nickel-based alloys and does not have the above-mentioned disadvantages or has them only to a small extent. Another objective of the present invention is the provision of a welding device suitable for performing a method corresponding to the invention.

The first problem is solved by a method for surfacing under paragraph 1 of the claims, and the second task using a welding device according to paragraph 10 of the claims. The dependent claims contain preferred embodiments of the invention.

In accordance with the invention method for welding of parts made of heat-resistant heat-resistant alloys by the application of welding filler material on the surface of the part through a zone of heat input and the zone is filing for supplying welding filler material in the area of heat input. Area of heat input and the zone during welding are moved along the workpiece surface. Movement can be along the direction of welding, for example, on a linear trajectory, or the trajectory oscillating relative to the direction of welding. In accordance with the invention method, the welding parameters are selected so that the cooling rate during solidification (crystallization) of the material is at least 8000 K/S.

The main options available when installing a cooling rate of at least 8000/s during crystallization of the material, are parameters of the method relative to the welding power and the diameter of the zone of heat input, for example, in the form of the laser power and the diameter of the laser beam, the feed speed of the process) and, if necessary, the current on the applied welding filler material. Depending on the type of laser source can be achieved through appropriate coordination of these parameters to set the desired cooling rate for the welded material. The speed of the process could be at least 250 mm/min, in particular more than 500 mm/min. for Example, when the speed of the process more than 500 mm/min parameters of the method relative to the welding power and the diameter of the zone of heat input can be set so that the cooling rate is for men is our least 8000 K/S.

Due to the high cooling rate and high speed of crystallization of the distribution coefficient increases so that microlocally, i.e. microscopic bundles of the mixture of the melt can be avoided to a great extent. Melt in Shrivenham the material solidifies as dendritic, that is, in the tree structure, and direction of growth of dendrites vary along the weld, because the orientation of the possible directions of growth of dendrites in relation to temperature gradients varies according to the crystallization front. The direction of growth with the lowest propensity to temperature gradients or with the lowest rate of growth is predominant. In addition, the formation of crystallization nuclei before the crystallization front, which during crystallization dostigayutsya the solidification front. These centers initiate crystallization direction of growth of dendrites, which are statistically distributed.

Corresponding to the invention the method is suitable for welding parts of γ'-containing heat-resistant Nickel-based alloys by welding filler material, which is γ'-forming material heat resistant alloy based on Nickel. Then you can be ensured of the highest strength in Shrivenham the material on the basis of application related filler material is material and acceptable weld quality, that is a very small percentage of cracks and very small average length of the cracks.

Based on the capabilities of the welding process at room temperature with locally available bath melt a protective gas atmosphere corresponding to the invention the welding method achieves a very high efficiency.

The method may be implemented, in particular, as a method of welding by means of welding, in which the application of welding filler material layer-by-layer. The direction of welding successive layers can be rotated relative to each other, in particular, on the 90about. Due to the rotation direction of the welding of various layers, you can avoid binding between the layers especially in the case when the area of the heat input and the input area is moved on the surface of the component along the direction of welding on the trajectory oscillating relative to the direction of welding.

Unevenly distributed orientation of the dendrites is predominantly in the upper half of the weld. Therefore, the preferred manner of the invention the method is applied before the layer is less than half of its thickness of a layer of melted again. When crystallization is acquired crystal structure of the newly molten zone. Due to the small depth of repeat Rapla the population is guaranteed by the fact that the solidification front is coming to the area with irregularly distributed dendritic orientations. This results in two-layer welding that is generated polycrystal grains, the diameter of which is on average very small. The grain boundaries are in General weak spot with respect to the formation of cracks at transient stresses during the welding process or the subsequent heat treatment. Due to the small length of the grain boundaries in the plane and their irregular orientation in the weld seam obtained by an appropriate invention of the method, the welding seam is towards the formation of cracks is more insensitive, so that the welding process can be carried out at room temperature.

Corresponding to the invention the method can be used polycrystalline and directionally crystallized or single crystal substrates. In all these cases, as a welding filler material can be used γ'-containing superalloy based on Nickel.

In the framework of the invention, a welding method after application of the welding filler material may be heat-treated. Through harmonized with weld metal heat treatment may, therefore, ustanavlivaetsya γ'-morphology. This serves to further improve the strength of the weld metal.

Corresponding to the invention a welding device for welding heat-resistant superalloy, which is suitable for implementing the invention, the device contains a source of heat for the formation of a zone of heat input to the part surface, a feeder for feeding a welding filler material, the heat source and the transfer unit for the formation of the relative movement between the injection zone heat and feeder, on the one hand, and the surface of the part with the other hand. The transfer unit preferred way connected with the heat source and the feeder for welding filler material, in order to achieve relative movement to move the heat source and the feeder. It is usually less costly than moving parts. As the heat source of the invention, the welding device can be used, in particular, the laser. Corresponding to the invention the welding device also includes a control unit with a control program that sets the welding parameters so that the cooling rate during crystallization of the material is at least 8000 To in a second. In particular, the control unit mouthstraight parameters of the method relative to the welding power and the diameter of the zone of heat input thus the cooling rate during crystallization of the material is at least 8000 To in a second. In this welding can be performed with a process speed of at least 250 mm per minute, especially with the speed of more than 500 mm per minute.

The relative movement may, in particular, be managed in such a way that the area of heat input and the zone along the direction of welding is moved along the trajectory, oscillating relative to the direction of welding, the surface of the part. In addition, the control unit can carry out a relative movement with or without oscillations so that the direction of welding successive layers are rotated relative to each other, for example, 90°.

Corresponding to the invention the welding device provides the ability to perform appropriate the invention, a method of welding by applying a control program, which contains within the technique of welding parameters, such as the trajectory of the relative motion between the heat source and the feeder, on the one hand, and the item, on the other hand, the process speed, laser power, beam diameter, etc. of the welding process. Described in the framework of the method parameters of the method and mechanisms contribute to suppress the formation of cracks, such as solidification cracks or cracks the re-melting, in the base material and the melt. This is, in particular, when as a base material and weld filler material is γ'-forming the heat-resistant Nickel-based alloys. Hence it is necessary welding quality achievable with the relevant invention and method corresponding to the invention the welding device, which is acceptable for structural welding, for example, for repair or Assembly in the high-load zone of the turbine blades or other parts.

Other features, properties and advantages of the proposed invention are presented in the following description of examples with reference to the attached drawings.

Fig. 1 shows as an example a gas turbine in longitudinal section.

Fig. 2 shows a turbine blade in the spatial representation.

Fig. 3 shows a combustion chamber of a gas turbine in partial cross-section in the spatial representation.

Fig. 4 shows in schematic representation corresponding to the invention the welding device.

Fig. 5 shows the welding seam for the first layer on the weld filler material.

Fig. 6 shows the welding seam for the second layer on the weld filler material.

Fig. 1 shows as an example the gas turbine 100 in longitudinal section.

Gas the turbine 100 includes inside the rotor 103, mounted rotatably around the axis 102 of the rotation shaft 101, which is also referred to as the turbine rotor.

Along the rotor 103 to each other, followed by the housing 104 air intake, a compressor 105, the camera 110 of the combustion in the example shown toroidal shape, in particular an annular combustion chamber, with a number of coaxially arranged burners 107, a turbine 108 and the housing 109 of the exhaust system.

Annular chamber 110 combustion reported, for example, with the channel 111 of hot gases ring shape. There is formed, for example, four included for each other stage 112 of the turbine the turbine 108.

Each stage turbine 112 is formed, for example, of two wheels with blades. When considering in the direction of flow of the working medium 113, the channel 111 of hot gases over the next 115 vanes followed by a row 125 formed of blades 120.

Guide vanes 130 is fixed on the inner housing 138 of a stator 143, whereas the rotor blades 120 of a row 125 are placed through the turbine wheel 133 on the rotor 103.

With the rotor 104 is connected to the generator or a working machine (not shown).

During operation of the gas turbine 100 135 air is sucked by the compressor 105 through the housing 104 of the inlet and is compressed. Compressed air is provided on facing the turbine end compressor 105, is supplied to the burners 107 and there is mesiwala with fuel. This mixture then with the formation of a working medium 113 is burned in the chamber 110 of combustion. From there, the working medium 113 flows along the channel 111 of hot gases to the guide vanes 130 and the working blades 120. On the rotor blades 120, the working medium 113 expands, passing the working pulse so that the rotor blades 120 actuate the rotor 103, which, in turn, actuates an associated working machine.

Posted in hot working medium 113 components are subjected during operation of the gas turbine 100 thermal loads. Guide vanes 130 and rotor blades 120 when considering in the direction of flow of the working medium 113 of the first stage turbine 112 most thermally loaded along with heat-insulating cladding annular combustion chamber 110.

To counteract existing there temperatures, they should be cooled using a chiller.

Also the substrate component may have a directional structure, i.e. they are either single-crystal (SX structure)or have only longitudinally directed grains (DS structure).

As a material for components, in particular for the blades 120, 130 turbines and components of the combustion chamber 110, are used, for example, heat-resistant alloys based on iron, Nickel or cobalt.

These heat-resistant alloys are known, for example, from EP 120476 B1, EP 1306454, EP 1319729 A1, WO 99/67435 or WO 00/44949; these publications concerning the chemical composition of the alloys are part of the present disclosure.

Also the blades 120, 130 may have a coating to protect against corrosion (MCrAlX; M is at least one element from the group iron (Fe), cobalt (Co), Nickel (Ni), X is an active element, meaning yttrium (Y) and/or silicon, scandium (Sc) and/or at least one rare earth element, or hafnium). Such alloys are known from EP 0486489 B1, EP 0786017 B1, EP 0412397 B1 or EP 1306454 A1, which is about the chemical composition of the alloys are part of the present disclosure.

On the MCrAlX, you may have a heat-insulating layer, which consists, for example of ZrO2, Y2O3-ZrO2i.e. it is not stabilized or is partially or fully stabilized by yttrium oxide and/or calcium oxide and/or magnesium oxide.

Using a suitable method of coating, as, for example, electron beam deposition (EB-PVD), in the insulating layer are formed sterjnevye grain.

Guide vane 130 is directed to the inner housing 138 of the turbine 108 base (foot) of the guide vanes (not shown here) and located opposite the base of the guide vanes head of the guide vanes. The head of the guide vanes facing toward the rotor 103 and mounted on the ring 140 fastening the stator 143.

F is, 2 shows a spatial representation of the working blade 120 or the guide vane 130 of the turbomachine, which is oriented along the longitudinal axis 121.

The turbomachine may be a gas turbine aircraft or power plant for electricity generation, steam turbine or a compressor.

The blade 120, 130 contains along the longitudinal axis 121 each other an area of 400 mounting, adjacent the platform 403 vanes, as well as working side of the blade and the top of 415 of the scapula.

As a guide blades 130 blade 130 at its top 415 may have an additional platform (not shown).

In the area of 400 mounting formed the base 183 of the scapula, which is used to fasten the blades 120, 130 on the shaft or disk (not shown).

The base 183 vanes, for example, in a T-shape. There might also be other forms of execution, such as multi-tiered base or base type dovetail.

The blade 120, 130 has a front edge 406 and the rear edge 412 for environment, ambient working side 406 of the scapula.

In conventional blades 120, 130, in all zones 400, 403, 406 of the blade 120, 130 are used, for example, dense metallic materials, such as heat-resistant alloys.

Such heat-resistant alloys are known, for example, from EP 1204776 B1, EP 1306454, EP 1319729 A1, WO 99/67435 or WO 00/44949; these publications Casa is part of the chemical composition of the alloys are part of the present disclosure.

This blade 120, 130 may be manufactured from these alloys by the method of casting and directional solidification, by means of forging, milling, or a combination of these methods.

Details with single-crystal structure or structures are used as parts of machines, which in the process are exposed to high mechanical, thermal and/or chemical loads.

The production of such single-crystal components is carried out, for example, by crystallization from a melt. When it comes to casting methods in which the liquid metal alloy is crystallized with the formation of a monocrystalline structure, i.e. monocrystalline details, or crystallizes directed.

While dendritic crystals are oriented along the heat flow and form either starinavity crystalline grain structure (columnar, i.e. grains which are held throughout the length of the part and here denoted, according to the generally accepted term, as obtained directional solidification)or a monocrystalline structure, i.e. the entire workpiece consists of a single crystal. In this way it is necessary to prevent the transition to globular (polycrystalline) solidification, as non-directional growth with the need arise poperen the e and longitudinal grain boundaries, cancelling out the good properties of directionally crystallized or monocrystalline details.

If in the General case we are talking about directionally crystallized structures, this is understood as a single crystal, which has no grain boundaries or has a maximum grain boundaries with small angle and rod-like crystal structure, which have grain boundaries, passing in the longitudinal direction, but do not have grain boundaries, which run in the transverse direction. In the case of the second named crystal structures indicate directionally crystallized structures.

Such methods are known from U.S. patent 6024792 and EP 0892090 A1, these publications about the way the crystallization form part of the present disclosure.

Also the blades 120, 130 may have a coating, for example, for protection against corrosion or oxidation (MCrAlX; M is at least one element from the group iron (Fe), cobalt (Co), Nickel (Ni), X is an active element, denoting yttrium (Y) and/or silicon and/or at least one rare earth element, or hafnium (Hf)). Such alloys are known from EP 0486489 B1, EP 0786017 B1, EP 0412397 B1 or EP 1306454 A1, which is about the chemical composition of the alloys are part of the present disclosure.

The thickness is preferably 95% of theoretical thickness.

On the MCrAlX layer (as an intermediate in the Loya or as the outer layer) is formed a protective layer of aluminum oxide (TGO - thermally grown oxide layer).

Preferred, the composition layer is a Co-30Ni-28Cr-8Al-0,6Y-0,7Si or Co-28Ni-24Cr-10Al-0,6Y. Along with these protective coatings on cobalt basis also apply protective layers on Nickel-based, such as Ni-10Cr-12Al-0,6Y-3Re or Ni-12Co-21Cr-11Al-0,4Y-2Re or Ni-25Co-a 17cr-10Al-0,4Y-1,5Re.

On the MCrAlX, you may have a heat-insulating layer, which is preferably the outermost layer and consists, for example of ZrO2, Y2O3-ZrO2i.e. it is not stabilized or is partially or fully stabilized by yttrium oxide and/or calcium oxide and/or magnesium oxide. The insulating layer preferably covers the entire MCrAlX layer.

Using a suitable method of coating, as, for example, electron beam deposition (EB-PVD), in the insulating layer are formed sterjnevye grain.

There may be other methods of coating, for example, plasma spraying in the atmosphere (APS, LPPS, VPS or CVD. The insulating layer may be porous, micro - or macroscopic grains for better thermal shock resistance. Thus, the insulating layer is preferably more porous than the MCrAlX layer.

Recovery means that components 120, 130 after their use should, if necessary, to be released from their protective layers (for example, by pescos ruinous processing). Then remove corrosion or oxidation layers or products. If necessary, another repaired cracks in parts 120, 130. Then re-coating of the components 120, 130 and new components.

The blades 120, 130 may be made hollow or solid. If the blades 120, 130 should be cool, they are hollow and are, if necessary, another hole film cooling.

In Fig. 3 shows the camera 110 of the combustion gas turbine. The camera 110 combustion is performed, for example, as a so-called annular combustion chamber, in which the many located on a circle around the axis 102 of the rotation of burners 107, forming a torch 156, are communicated with a common space 154 of the combustion chamber. To do this, the camera 110 of combustion in its entirety is designed as an annular structure which is positioned relative to the axis 102 of the rotation.

To achieve a comparatively high efficiency, the camera 110 of the combustion is performed with the expectation of high temperature working medium M of approximately 1000aboutWith -1600aboutC. and under these unfavorable for materials operating parameters to ensure the possibility of a relatively long life, wall 153 of the combustion chamber on its side facing the working medium M, equipped with an inner lining formed of heat-shielding elements 155.

It is jdy heat shield element 155 made of an alloy on the side addressed to the working environment, equipped with a particularly heat-resistant heat-resistant protective layer (MCrAlX layer and/or ceramic coating) or made of heat-resistant material (solid ceramic bricks).

These protective layers may be similar to the turbine blades, thus, for MCrAlX have the following notation: M is at least one element from the group iron (Fe), cobalt (Co), Nickel (Ni), X is an active element, meaning yttrium (Y), and/or silicon and/or at least one rare earth element, or hafnium (Hf)). Such alloys are known from EP 0486489 B1, EP 0786017 B1, EP 0412397 B1 or EP 1306454 A1, which is about the chemical composition of the alloys are part of the present disclosure.

On the MCrAlX, you may have a heat-insulating layer, which consists, for example of ZrO2, Y2O3-ZrO2i.e. it is not stabilized or is partially or fully stabilized by yttrium oxide and/or calcium oxide and/or magnesium oxide.

Using a suitable method of coating, as, for example, electron beam deposition (EB-PVD), in the insulating layer are formed sterjnevye grain.

There may be other methods of coating, such as plasma spraying in the atmosphere (APS, LPPS, VPS or CVD. The insulating layer may be porous, micro - or macroscopic grains for better resistance to thermal shock is in.

Recovery means that the heat-shielding elements 155, after their use should, if necessary, to be released from their protective layers (for example, by sandblasting). Then remove corrosion or oxidation layers or products. If necessary, another repaired cracks in the heat-shielding element 155. Then re-coating of the heat-shielding elements 155 and the new use of heat-shielding elements 155.

Based on the high temperatures inside the combustion chamber 110 to the heat-shielding elements 155 or to the holders may be provided by the cooling system. Heat-shielding elements 155 are, for example, hollow and have holes for cooling, which communicate with the space 154 of the combustion chamber.

Figure 4 shows a schematic representation corresponding to the invention the welding device 1. It contains the laser 3 and the device 5 of the feed powder, which powder welding filler material may be submitted in the welding zone part 9. By means of laser radiation on the surface of the part formed area 11 of the heat input, which also introduces the powder 13 from the device 5 powder supply.

The laser 3 and the device 5 of the supply of powder is placed on the scanning device 15, which provides the ability to shift the manhole is RA 3 and 5 of the supply of powder in two dimensions along the surface details (directions x and y in Fig. 4) to be welded area 7. In addition, the scanning device 15 according to this exemplary embodiment, allows the shift of the laser device 3 and 5 of the powder supply is perpendicular to the part surface (z-direction in Fig. 4). Using the scanning device 15 can thus move the zone of heat input and the zone of contact of the powder along the given trajectory. As the scanning device can be used, for example, the robot arm.

The motion control performed by the scanning device 15 is performed by the block 17 control, which also controls other parameters of the welding process. In contrast to the presented exemplary embodiment, the other parameters of the welding process can also be carried out at the expense of additional control that is separate from the process control movement. In addition, in contrast to the presented exemplary embodiment, instead of the scanning device 15 to move the laser device 3 and 5 of the powder feeder can also be used movable holder component. In the framework of the invention, the value is only relative movement between the laser 3 and the device 5 powder supply, on the one hand, and item 9.

Corresponding to the invention a method of welding workpiece surface may find application is for their application; in particular for multilayer material to be welded zone 7 part 9. Item 9 is not required nor heat, nor be subjected to aging by heat treatment.

The following describes a method of hardfacing on the surface 10 blade turbine 9 for details. The turbine blade in the present exemplary embodiment consists of a γ'-strengthened heat-resistant alloy based on Nickel, for example, IN738LC, IN939, Rene80, IN6203DS, PWA1483SX, Alloy 247, etc. Subject to the welding zone 7 on the surface 10 of the blade 9 of the turbine is directed in layers, and the area of the input heat with zone into powder for powder 13 is moved along the direction of welding on the subject welding zone 7 blades 9 of the turbine. Powder 13 in this case is a powder of γ'-containing heat-resistant alloy based on Nickel or of IN738LC, IN939, Rene80, IN6203DS, PWA 1483, Alloy 247, etc.

Path P1, which is the area 11 of the heat input, and the area of contact of the powder 13 when overlaying the first layer underlying the welding zone 7 schematically represented in Fig. 5. The drawing shows the blade 9 of the turbine to be welding area 7 and the direction S1 welding when the welding of the first layer 19. Area 11 of the heat input, which simultaneously represents the area of contact of the powder 13, moves linearly along the direction S1 welding, and oscillates at offset along the direction of the ing the welding simultaneously in the direction perpendicular to the direction of welding. Due to this, the area 11 of the heat input zone and into powder 13 follow meander path P1 on the subject welding zone 7.

For deposition of the second layer 21 (Fig. 4) laser 3 and the device 5 powder supply several are shifted along the z-direction scanning device 15. In addition, in this example, the execution direction S2 of the weld relative to the direction S1 welding for the first layer rotated 90about. Path P2 zone 11 of the heat input and zone contact for powder 13 when overlaying the second layer 21 shown in Fig. 6. Also when overlaying the second layer zone 21 11 input heat with zone into powder 13 oscillates in the direction perpendicular to S2 welding. So get together meander path P2 zone 11 of the heat input and zone contact for powder 13 to be welded zone 7.

Described in the framework of sample trajectories represent only one of various possible options. In principle, there are many possibilities welding: 1 - non-directional or 2 - bi-directional (for example, in the form of a meander) surfacing. In each of these variants traces (trajectory) of the second layer can welding be displaced parallel to or perpendicular to the traces (paths) of the first layer. All these options can be used to frame the way corresponding to the invention.

When moving the laser and feeder powder oscillations can be chosen so that with a single trajectory along the direction of the weld overlaps all be welding area 7, as shown in Fig. 5, or in such a way that overlaps only a portion to be welded zone 7, and for surfacing the entire zone must undergo several adjacent trajectories P2 in the direction S1 welding, as shown in Fig. 6.

Moving zone 11 of the heat input and zone into powder 13 along the path P1 or P2 is in this example of execution with process speed of at least 500 mm/min laser Power, beam diameter and the flow of powder is selected when you do this so that the cooling rate of the passable zone during crystallization of more than 8000 K/S. If you apply a second layer 21 of the process parameters on the laser power and beam diameter, in addition, are selected so that the depth of re-melting, to which the first layer 19 is again melted, is less than 50% of the height of the seam of the first layer 19. The depth of the re-melting is shown in Fig. 4 by the dotted line, but in principle also possible other than shown in the present example, the speed of the process, and then the remaining parameters: laser power, beam diameter and the flow is orosco must be properly aligned.

Due to the high cooling rate and high speed of crystallization of the distribution coefficient increases so that microlocal largely prevented. Called area 11 of the heat input to the melt crystallizes dendritic way, and crystal structure in the newly molten zone receives this crystal structure. Thus vary the direction of growth of dendrites along the path P1, P2. The reason for this is that the orientation of the possible directions of growth of dendrites varies relative to the temperature gradient, preferably implemented the direction of growth with the least tendency to temperature gradients or with the lowest growth rate. In addition, the crystallization nuclei, which are formed prior to crystallization front during crystallization dostigayutsya the crystallization front, initiate directions dendritic growth, which is statistically distributed. These irregularly distributed orientation of the dendrites are mostly in the upper half of the layer 19. Therefore, the smaller the depth of re-melting guaranteed by the fact that the solidification front is superimposed on the area with irregularly distributed orientations of dendrites that after several layers leads to the fact that there is a polycrystal the grains, the diameters are on average very small. Due to this welded area of the vanes 9 of the turbine is insensitive to the formation of cracks.

After applying the desired number of layers 19, 21 and the shoulder 9 of the turbine may be subjected to heat treatment, which leads to desirable set γ'-morphology. This serves to further improve the strength of the welded zone of the blades 9 of the turbine.

Using the appropriate the invention, a method is possible to carry out welding at room temperature and without pre-aging of the workpiece, and suppresses the occurrence of cracks crystallization and cracking re-melting. In turn, this leads to the welding quality, acceptable for structural welding, in particular, in high-load areas of blades of a gas turbine or other details. At the same time be only a small effect on the core material, since due to the small area of heat (there is no pre-heating) and the suppression of cracks re-melt in the zone of the input heat is only a very small input of heat into the substrate.

1. The method of welding parts (9) of the γ'-containing heat-resistant Nickel-based alloys, in which by the application of multiple layers of weld filler material (13), which is is γ'-forming superalloy based on Nickel, on the surface (10) parts by zone (11) of the heat input generated by a laser, and the zone for feeding the welding filler material in the zone (11) of heat input, and area (11) of heat input and the feed area, on the one hand, and the surface (10) items, on the other hand, are moved relative to each other, characterized in that the welding parameters are selected so that the cooling rate during crystallization of the material is at least 8000 K/s, at a depth of re-melting of the previous layer such that is formed of polycrystalline weld.

2. The method according to claim 1, characterized in that the welding parameters relative to the welding power and the diameter of the zone of heat input are set such that the cooling rate during crystallization of the material is at least 8000 K/S.

3. The method according to claim 1, characterized in that the process speed is at least 250 mm/min

4. The method according to claim 1, characterized in that the application of welding filler material (13) is carried out in layers.

5. The method according to claim 4, characterized in that applied before the layer (19) is again melted less than half its thickness.

6. The method according to claim 2 or 5, characterized in that for each layer (19, 21) zone (11) of heat input and the input area is moved along the direction S1, S2) welding relative to the surface (10) details and directions (S1, S2) welding successive layers (19, 21) are rotated relative to each other.

7. The method according to claim 2 or 5, characterized in that the zone (11) of heat input and the input area is moved along the direction (S1, S2) welding along a path (P1, P2), oscillating with respect to the direction (S1, S2) welding, relative to the surface (10) items.

8. The method according to claim 1, characterized in that after application of the welding filler material (13) is heat treatment.

9. Welding device for welding parts (9) of the γ'-containing heat-resistant Nickel-based alloys containing
source (3) heat of formation by laser radiation zone (11) of heat input at the surface (10) items,
the device (5) feeder for feeding a welding filler material (13), which is γ'-forming superalloy based on Nickel, in the zone (11) of heat input and
the transfer unit (15) to generate the relative movement between the source (3) heat and a device (5) filing, on the one hand, and the surface (10) items, on the other hand, characterized in that it includes a block (17) control, which sets the welding parameters so that the cooling rate during crystallization of the material is at least 8000 K/S.

10. Swaro is a great device according to claim 9, characterized in that the block (17) control sets the welding parameters relative to the welding power and zone diameter (11) of the heat input so that the cooling rate during crystallization of the material is at least 8000 K/S.

11. The welding device according to claim 9 or 10, characterized in that the block (17) control performs relative movement with a process speed of at least 250 mm/min

12. The welding device according to claim 9, characterized in that the control program moves the zone (11) of heat input and the zone along the direction (S1, S2) welding along a path (P1, P2), oscillating with respect to the direction (S1, S2) welding, surface (10) items.

13. The welding device according to claim 9, characterized in that the source (3) heat is a laser.

14. The welding device according to claim 9, characterized in that the control program when the layer-by-layer welding turning direction (S1, S2) welding successive layers (19, 21) with respect to each other.



 

Same patents:

FIELD: process engineering.

SUBSTANCE: invention relates to machine building and may be used in welding different materials by laser radiation. Plane of but joint between said parts is inclined along tangential line to segment of welded seam thermal effect. Laser radiation is focused to material with higher heat resistance at a distance from butt plane. But joint plane inclination angle and focus distance are determined with due allowance for inhibiting evaporation of low-melting metal. Laser radiation is fed onto welded surfaces to heat welding zone to melting temperature to produce, thereafter, a welded seam.

EFFECT: possibility to weld different metals together.

3 dwg

FIELD: electricity.

SUBSTANCE: method includes fixation of polarised flat piezoceramic plate and cutting with laser beam. Fixation is carried out in cuvette on surface of cooling liquid or on gasket from porous material impregnated with cooling liquid, amount of which is maintained at the level of gasket. Cutting is done by focused interrupting laser beam along circuit of cut item in one or more stages with simultaneous cooling of cutting circuit. Device comprises laser, control system, mechanisms of optical elements moving, technological table with cuvette of soft magnetic material installed on it and partially filled with water, on bottom of which there is a porous material intended to locate cut flat piezoceramic plate, and fixation device of specified plate.

EFFECT: simplified technology of manufacturing of flat piezoceramic items of various configuration and dimensions and improvement of their properties and parametres due to provision of usage of whole surface of piezoelement.

7 cl, 3 dwg

FIELD: technological processes.

SUBSTANCE: invention may be used for creation of different single crystal processing tools, medical tools, for creation of electric contacts with metal on the surface of semiconductor and other diamonds. Preliminarily surface of diamond single crystal is polished to 5th class of roughness (according to state standard GOST 2789-73) and degreased. Degreased surface of diamond single crystal is coated with intermediate layer with thickness of 0.05÷0.4 mm from mixture of nanodispersed powders of ferric oxides with size of particles of 20÷40 nm and fullerene C60. Ratio of ferrous oxides content to fullerene C60 makes 10-50:90-50 wt %. Then place of contact is exposed to pressure of 2.0÷5.0 GPa and simultaneously to shift effect by rotation at the angle of 100÷1000 degrees.

EFFECT: higher strength and quality of diamond single crystal binding to metal.

3 cl, 3 ex

FIELD: physics; lasers.

SUBSTANCE: present invention pertains to laser technology, particularly to the method of cutting pyrographite using laser, and can be used in instrument making, and mainly in electronics. Laser radiation with central mode TEM00 is focused on the material. The focus of the beam is directed on the surface of the material, while keeping the density of the incident power within the 106-107 W/cm2 range. The work piece is moved at speed ranging from 1 to 3 mm/s. The cutting process parameters are determined by the expression , where K is the coupling factor of parameters, chosen from the condition 7·10-5≤K≤12·10-5; f is the repetition frequency of the laser radiation, τ is the pulse duration of the laser radiation, d is the diameter of the spot of focused laser radiation, and h is the thickness of the work piece. A laser with yttrium aluminium garnet active element, with controlled distribution of power in the section of the beam is used.

EFFECT: high quality of cutting material with a smaller heat affected zone during optimum process modes.

2 cl, 1 ex

The invention relates to wear-resistant and optimized tribological working surface of the cylinder

FIELD: process engineering.

SUBSTANCE: invention relates to laser facing and alloying and may be used in stereolithography with application of powder materials. Proposed device comprises laser coupled optically with circular beam generation system and focusing system, and system to feed material to be applied in the form of tube. Focusing system represents conical prism to produce conical laser beam. Material feed system is arranged along focusing system optical axis. Said focusing system has annular spherical lens with optical axis aligned with that of conical laser beam. Its focus is located on article surface.

EFFECT: higher efficiency powder utilisation factor.

1 dwg

FIELD: machine building.

SUBSTANCE: method to manufacture a circular comb (10) for a labyrinth seal is characterised by formation of a protruding part of the comb (10) by serial application of layers onto a base (12). The following stages are carried out: a) a substrate (20) is made in the form of a solid of revolution around a longitudinal axis, with the base (12) of the circular comb (10), b) a spray nozzle (38) is installed as capable of displacement relative to the substrate (20), and is connected to the first source (35) of the first powdery material, which is identical to the substrate material, and the second source (45) of the second powdery material, c) used as connected with an optical head (34) of the laser source installed as capable of displacement relative to the substrate (20) to focus a laser beam at the point of the substrate surface (20), d) the optical head (34) and a nozzle (38) are adjusted along one and the same point of the surface of the base top (12) of the comb (10), e) the laser source and sources (35, 45) of the powdery material are activated, at the same time a molten pool is developed as localised at the level of the specified point, where a powdery material is sprayed, as a result a localised boss is created, f) the optical head (34) and the nozzle (38) are adjusted along another point of the surface of the base top (12), adjacent with the localised boss, and the stage e) is repeated to form a layer substantially along the entire width of the base top (12), g) at least one section of the protruding part of the comb (10) is formed by means of serial application of narrower and narrower layers in longitudinal direction on the base top (12). Each layer is produced as a result of performance of stages d) - e).

EFFECT: no necessity to do mechanical treatment, combs are produced with higher wear resistance.

13 cl, 4 dwg

FIELD: process engineering.

SUBSTANCE: invention relates to metal processing by laser and may be used in machine building. Part to be processed is placed in sealed chamber filled with inert gas and modifying gas. Laser beam with spot power density on part surface making (106-107) W/cm2 is used to affect steel part surface to produce optical discharge surface plasma in fused metal vapors. Laser beam is displaced at the speed of 0.1-2 m/s at gas pressure in the chamber equal to 1.5-2 atm.

EFFECT: improved mechanical properties, higher wear and heat resistance.

2 cl, 1 dwg, 1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to technology of resurfacing monocrystalline metal component or metal component obtained through directional crystallisation, having thickness Ws less than 2 mm, in which a laser beam and a stream of metal powder of the same nature as the metal component are directed onto the component using a nozzle to obtain at least one layer of monocrystalline metal component or metal component subjected to directional crystallisation. The laser beam has power P and moves along the component at speed v. The laser beam and the stream of metal powder are directed onto the component coaxially and the ratio P/v is in a defined range. Supply of the power on the axis of the laser beam ensures high manoeuvrability of the nozzle and increases uniformity of the speed and melting for resurfacing. In case of resurfacing the component without pre-heating, the invention enables to significantly save time and simplify the process.

EFFECT: if pre-heating is used, the obtained components are more accurate.

11 cl, 5 dwg

FIELD: engines and pumps.

SUBSTANCE: proposed method of restoring bladed disk with at least one damaged zone comprises preparing said zone, building up metal on appropriate machine tool and finishing restored zone. In preparing, damaged zone is subjected to machining to produce preset profile restored zone. Then meat is built up on test piece, called initial test piece, with said preset profile using laser built-up tool with preset operating parametres. After build-up, test piece quality is checked and, if it complies with acceptance criterion, metal build-up is performed in zone to be restored using the same laser tool without changing its operating parametres. Other inventions of the set relate to test pieces intended for above described method and made from titanium alloy. In compliance with one version, shape of said test pieces imitates the tip of aerodynamic profile, while, in compliance with another version, it imitates the angle of front or rear edge of aerodynamic profile tip subjected to machining to preset model.

EFFECT: longer life and higher reliability of turbo machine restored disk.

17 cl, 9 dwg

FIELD: machine building.

SUBSTANCE: invention relates to machine building field, particularly to pipe rolling. Method includes pre-heating of treated surface, following treatment by focused laser beam up to melting of surface coating and introduction into melt of alloy additions. Invention provides in the capacity of pre-heating of pipe to use standard intermediate heating of tubular billet at its rolling, after the final redistribution of tubular billet to limit access of oxygen into inner cavity of pipe, following treatment by laser beam to implemented at pipe temperature not lower than 850 degrees, and into content of alloying mixture to add deoxidisers.

EFFECT: increase of corrosion resistance of hot-rolled pipes generally and tubing pipes particularly.

FIELD: process engineering.

SUBSTANCE: proposed method comprises applying filler material onto surface to be processed and irradiating it by focused laser beam. Scanning comprises moving laser beam along circular trajectory. Note here that scanning diametre makes beam step makes and beam frequency of motion in melt bath makes

where dl is the laser beam spot diametre, D is the laser beam rotation diametre, P is the laser radiation power, λm is main material heat conduction, Tm is the melting temperature of built-up material, °C, α is the factor equal to 1.0, when h<dl, and equal to 3.0, when h>dl, h is the laser step, γ is beam frequency of motion in melt bath, Hz, n is the number of laser steps at one melt point (n≥3), νn is hard-facing rate.

EFFECT: higher strength of built-up layer.

2 cl, 1 ex, 1 tbl

FIELD: metallurgy.

SUBSTANCE: invention relates to laser surfacing process of corrosion protection coating and can be used in mechanical engineering at treatment of working surfaces of parts made of aluminium bronzes including details of ship reinforcement. Method includes delivery of metallic powder and simultaneous treatment of surface by laser ray with power radiant density 104-106 watt/cm2 during 0.0005-2.0 s. Preliminary on part surface it is created intermediate layer of depth not less two diametres of laser ray by means of surface treatment by laser ray with power radiant density 104-106 watt/cm2 and traverse speed 0.2-10.0 mm/s. During the process of overlaying welding depth of metal penetration is kept in the range not more 0.8 of intermediate layer depth.

EFFECT: providing of cracks absence in built-up material and fusion area at laser building-up on aluminium bronze of copper-nickel alloys with content of nickel more than 10%.

1 ex, 1 tbl

FIELD: processes for forming metallic portion on metallic substrate by superimposing deposited layers one on other, possibly manufacture of articles with laminate coating.

SUBSTANCE: method comprises steps of generating heat beam of heat power source and directing said beam to metallic powder fed from powdered metal source; moving substrate relative to beam along formed portion while creating propagating zone of melt; during process of forming group of metallic layers reading parameters of melt zone in group of selected coordinates; storing read parameters in each of selected coordinate group and processing stored parameters while determining respective power of laser for applying next layer. Power change for applying next layers is realized in such a way that to create melt zone corresponding to those formed for applying lower optimal layer. It compensates heating of substrate caused by layer deposition and causing increased melt zone dimension or temperature in upper layers.

EFFECT: enhanced quality of metallic substrates.

12 cl, 4 dwg

FIELD: artistic working of metals for decorating metal parts of arms, souvenirs and jewelry.

SUBSTANCE: method involves preparing steel surface of work piece to be processed to predetermined degree of surface finish for making artistic pattern; applying pattern to surface; positioning part to be worked; simultaneously directing laser beam with fused metal over pattern. After smoothing, master-engraver performs additional working of pattern by removing excessively fused metal. Final working involves polishing and oxidizing processes.

EFFECT: increased efficiency and decorative effect.

FIELD: process engineering.

SUBSTANCE: proposed method may be used in nuclear power engineering and other branches of machine building. Proposed method comprises focusing laser beam at material and feeding protective inert gas into cutting zone. Inert gas is fed via nozzle at its outlet pressure of, at least, 3.5·10-5 MPa. Note here that laser beam with wavelength of 1.06-1.07 mcm is used and directed via said nozzle coaxially with its lengthwise axis.

EFFECT: higher efficiency and quality, ruled out metal corrosion.

2 cl, 1 dwg, 2 ex

FIELD: physics.

SUBSTANCE: method involves deposition of particles of a substance from gas phase through local heating of the deposition region with laser radiation. The substance in gas phase is dispersed in form of an aerosol. The deposition region is locally heated with pulsed laser radiation and the aerosol particles are baked onto the substrate. The pulse duration of the laser radiation is not shorter than that when the heat wavelength in particle is greater than the dimension of the particle in the direction of radiation. Material of said particles absorbs laser radiation.

EFFECT: high efficiency of depositing coatings while maintaining high resolution power of the method.

5 cl, 4 dwg

FIELD: process engineering.

SUBSTANCE: proposed method comprises welding in atmosphere of inert gas with simultaneous effects of laser and arc in one welding bath. In welding, arc torch is arranged ahead of laser beam along its path. Welding wire is directed to the points whereat laser beam crosses welded parts surface. Laser beam is inclined through 30-40 degrees in opposite sides with respective to normal to welded parts surface.

EFFECT: higher quality of welded seam.

FIELD: physics.

SUBSTANCE: proposed method comprises continuous action of laser light spot on part surface. Parallel overlapped hardening paths are applied on vertical or inclined surfaces. Hardening paths are applied by beam directed at processed surface at angle and, at increased flow rate of process gas, said beam passed through nozzle. Laser beam is turned from perpendicular upward to surface in part processing plane through angle equal to 0.5-5°. Laser unit incorporates 5-coordinate laser head. Said paths are applied in different hardening spaced apart bands.

EFFECT: higher wear resistance and processing efficiency.

3 cl, 4 dwg, 1 ex

Welding tool // 2393945

FIELD: process engineering.

SUBSTANCE: invention relates to welding tool for arc-welding by tungsten electrode in inert gas, or for plasma welding, or for laser welding. Proposed tool comprises appliances to feed inert gas into welding tool head. Welding head is surround by skirt made from semi-rigid refractory material. Said skirt comprises front section shaped so that envelope welding seam with clearance over a certain length and appliances to allow detachable joint of said skirt on welding head. Said skirt is made by pressing or hot forming of composite material based on ceramic fibers and elastomer that sustains high temperatures. Skirt lower edge is located nearby welded parts, its shape and clearance mating those of jointed parts.

EFFECT: reliable protection of welded seam in automatic welding.

7 cl, 6 dwg

FIELD: machine building.

SUBSTANCE: method includes feeding of laser beam on treated surface, feeding co-axially to laser beam of process gas, collimation of laser beam, its embedding into treated product and movement by specified program. Cutting is implemented in liquid field. Product is located in bath with water on cone-shaped pins with exceeding of water level over surface of product equal to 10-15 mm. Cutting is implemented by ytterbium laser with laser beam embedding into treated product for 0.2-0.4 of its thickness. Movement of laser beam is implemented at a rate 1.2-1.8 m/min.

EFFECT: enhancement of manufacturing capabilities and improvement of ecology at treatment of composite materials and it is provided high quality of cutting.

1 dwg, 2 ex

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