Method of welding the billets of high-refractory super alloys at definite filler material feed weight rate

FIELD: process engineering.

SUBSTANCE: invention relates to laser welding of billets (9) from high-refractory super alloys. Heat laser source (3) creates generates zones (11) of heat feed to billet surface (10). Welding filler (13) is fed by device (5) to heat feed zone (11) and driven by transfer device (15) between heat source (3) and feed device (5) on one side and, on opposite side, and billet surface (10). Welding filler is fed at weight rate ≤350 mg/min.

EFFECT: set is one of the following laser welding parameters: laser power of 100 W to 300 W, laser beam diameter of 500 mcm to 800 mcm, welding rate of at least 250 mm/min.

18 cl, 6 dwg

The present invention relates to a method of welding workpieces, in particular workpieces 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, such structural elements are preferably used superalloys based on Nickel, which can prosnetsja by separating the γ'-phase. With time in the working blades there are cracks, which are further extended. 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 pieces of such superalloys is time-consuming and costly, strive to manufacture producing less waste and ensure a long service life of products.

In operation the blades of gas turbines are subjected to regular maintenance and, if necessary, the replacement when due to operation of the load is no longer possible to ensure perfect functioning fully. To enable further application of the replacement turbine blades on the and, to the extent possible, are then re-processed. They can then again be used in a gas turbine. Within this kind of recovery, for example, in the damaged areas may need welding to restore the original wall thickness.

Also the turbine blades, which are already in the process of manufacturing a crack, for example, by welding can be made usable so you can reduce defects in manufacturing.

However, reinforced by the allocation of the γ'-phase superalloys based on Nickel currently can only with difficulty be welded by conventional welding methods with similar composition of filler materials. The reason for this is that you should avoid microlocally, i.e. microscopic redistribution of the melt. Moreover, the welding process can lead to the formation of cracks in the welded region during subsequent heat treatment. The reason for this lies in the internal stresses generated during welding due to plastic deformation during the heat during the welding process.

In order to cope with difficult weldability hardened allocation γ'-phase superalloys based on Nickel, welding is often performed with plastic weld filler materials, n is the sample with alloys based on Nickel without quenching the allocation of γ'-phase. A typical representative of such an alloy based on Nickel without quenching the allocation of γ'-phase is, for example, IN625. The plasticity of the filler material without heat treatment allocation γ'-phase reduces occurs during welding the internal stresses by plastic deformation during the heat treatment after welding. However, soft alloys compared to the hardened secretion of γ'-phase superalloys based on Nickel has a lower vysokozharoprochnyh (as low tensile strength and low fatigue strength). Therefore, preferably used welding methods without plastic filler materials. These methods can be divided into two classes, namely, the ways in which perestiani base material with the aim of increasing the plasticity through consolidation of γ'-phase, and the ways in which the welding process when the pre-heated substrate. The implementation of the welding process on the pre-heated substrate reduces occurs during welding internal stress due to relaxation during the welding process.

The welding process with a preliminary pedestrianism described, for example, in US 6120624, the welding process, which is carried out on a preheated workpiece is described, for example, in US 5319179.

Both of these methods sarkies plastic welding consumables however, also have disadvantages. For example, when running before the welding process perestiani before welding is carried out, the corresponding heat-treated tempered allocation γ'-phase supersplash Nickel-based, to make perestiani γ'-phase. While the ductility of the base material is significantly increased. This increase plasticity allows welding material at room temperature. In addition, it can be cold straightened. In addition, such heat treatment enables the application of superalloys based on Nickel, such as, for example, Rene41 or Haynes282, as a welding filler material. These alloys, although the form γ'-phase in the structure, but only with much lower volume fractions than the characteristic containing a γ'-phase superalloys based on Nickel, are used for contact with the hot gas of the gas turbine components, such as, for example, blades of gas turbines (for example, IN738LC, IN939, Rene80, IN6203DS, PWA1483SX, Alloy 247 and the like). Therefore, even when the welding process carried out perestiani, full structural welding does not occur.

When preheating the turbine blades, the temperature difference and emerging along with the voltage gradient between the weld area and the rest of the lo is atki turbine is reduced, thanks to that education occurs during welding of cracks in structural components made of superalloys based on Nickel can be prevented. Such methods, in which preheating the turbine blades to temperatures from 900°C to 1000°C by means of the inductors must, however, be carried out in inert gas, which complicates and increases the cost of the welding process. Moreover, this method due to the poor availability of the workpiece in the chamber with an inert gas, can be carried out in all regions of the workpiece.

There is therefore a need for alternative welding method welding, which, in particular, suitable for seasoned allocation γ'-phase superalloys based on Nickel and does not have the abovementioned disadvantages or has them only to a limited extent.

This problem is solved by using a welding method welding according to claim 1 of the claims.

The dependent claims contain preferred embodiments of the invention and are the preferred way to arbitrarily combined with each other.

In the invention method of welding workpieces made of highly temperature-resistant superalloys is the application of welding filler material on the surface of the workpiece through the zone heat and zone, SL is relevant to supply welding filler material in the area of heat supply. The area of heat supply and the supply zone during welding are moved along the surface of the workpiece. This movement can be in the direction of welding, for example, on a straight-line trajectory direction of welding, or sweep, oscillating around the direction of welding.

The invention of the mass feed rate is ≤350 mg/min In one of the advanced options method, the welding parameters are chosen so that the cooling rate during crystallization of the material is at least 8000 K/S.

Major available options to set the cooling rate equal to at least 8000/s, during crystallization of the material are parameters of the method relating to the performance of welding and diameter of the zone of heat, for example, represents the laser power and the diameter of the laser beam, submission (process speed), and if necessary, the current supplied to the welding filler material. Depending on the type of laser source by proper coordination of these parameters it is possible to set the required cooling rate intended for welding 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 is equal to more than 500 mm/min, the parameters of the method relating to the hearth is emeu power and diameter of the zone of heat, can be set so that the cooling rate during crystallization of the material was at least 8000 K/S.

Due to the high cooling rate and high speed of crystallization of the distribution coefficient increases so that microlevel, i.e. microscopic redistribution of the melt is largely prevented. In the weld material is dendritic, i.e. tree structure, crystallization of the melt, the direction of growth of dendrites along surfacing roller varies as the orientation of the possible directions of growth of dendrites varies relative to the temperature gradient at the solidification front. The predominant direction of growth with the least direction to the temperature gradient or, respectively, with the lowest growth rate. In addition, before the crystallization front are formed centers of crystallization, which during crystallization captured by the crystallization front. These centers of crystallization initiate statistically distributed direction of growth of dendrites.

The invention method is suitable, for example, for welding workpieces of containing γ'-phase superalloys based on Nickel by welding filler material, which is forming the γ'-phase material supersplash onbased on Nickel. Then in the weld material, thanks to the use of similar composition filler material, it is possible to achieve high strength and acceptable quality of welding, i.e. a very small amount of cracks and very small average crack length. Due to the possible execution of the welding process at room temperature in a protective gas atmosphere, locally in the weld pool, the invention a method of welding ensures high profitability.

The method can, in particular, to provide a welding method welding, in which the application of welding filler material occurs in layers. The direction of welding successive layers can be rotated relative to each other, in particular by 90°. Thanks to the rotation direction of the welding of various layers, you can avoid defects connections between layers, in particular when the feed area of the body and feed area move, besides, in the direction of welding for oscillating around the direction of the welding trajectory on the surface of the workpiece.

Unevenly distributed orientation of the dendrites is mainly in the upper half of the facing roller. Therefore, it is preferable in the invention method previously applied layer melted again less than half of their thickness. When Christ is lisali adopted the structure of the re-crystallization of the melted regions. Thanks to the depth of re-melting is provided by the imposition of the solidification front in the region with non-uniformly distributed orientation of the dendrites. As a result, when the multi-layer welding this leads to the fact that the formed polycrystalline with grains, the diameter of which is on average very small. The grain boundaries in General are weak in terms of crack formation during transient stresses during welding and subsequent heat treatment. With a small expansion of the grain boundary in the plane and its uneven orientation in the weld by the invention method, the material of the deposited material becomes insensitive to cracking, so that the welding process can be performed at room temperature.

The invention method can be used polycrystalline and directed crystallising or single-crystal substrates. In all these cases you can use as a welding filler material containing a γ'-phase superalloys based on Nickel.

In the proposed invention the welding method after application of the welding filler material may be heat-treated. Using the selected in accordance with the deposited material those is morabadi can set the desired morphology of the γ'-phase. This serves to further improve the strength of the weld material.

By the invention a welding device, which serves for welding of highly temperature-resistant superalloys, which is intended to carry out the proposed invention the method includes a heat source that is used to create a zone of heat on the surface of the workpiece feeder used to feed the welding filler materials, the heat source and the transport device, which serves for the implementation of the relative movement between the area of heat supply and feeder on the one hand and the surface of the workpiece with the other hand. The transport device is preferably connected with a source of heat and feeder welding filler material, in order to implement the relative movement to move the heat source and the feeder. It is usually less time-consuming than moving the workpiece. As a heat source in the proposed invention, the welding device can, in particular, to apply the laser. The invention of the welding device includes in addition the control unit with the control program, which sets the welding parameters so that the cooling rate during crystallization of the material was at least 8000/SV particular, the control unit may set the welding parameters relating to the supplied power, and the diameter of the zone of heat to the cooling rate during crystallization of the material was at least 8000 K/S. In this welding can be performed with the speed of the process, component, at least 250 mm per minute, in particular with the speed of the process, part of more than 500 mm per minute.

Control the relative movement may, in particular, to occur so that the area of heat supply and feed area moved in the direction of welding for oscillating around the direction of the welding trajectory on the surface of the workpiece. In addition, the control unit may perform control relative movement with oscillation or without so that the direction of welding successive layers were rotated relative to each other, for example, 90°.

Other features, properties and advantages of the present invention are contained in the subsequent description of embodiments with reference to the accompanying drawings.

Figure 1 as an example gas turbine in partial longitudinal section.

Figure 2 shows the turbine blade on the form in the future.

Figure 3 shows a combustion chamber of a gas turbine in a partially dissected image in the future.

Figure 4 shows in schematic picture is the invention of the welding device.

Figure 5 shows the trajectory of the welding for the first layer welding filler material.

Figure 6 shows the trajectory of the welding for the second layer welding filler material.

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

A gas turbine 100 inside there is mounted rotatably around the axis 102 of rotation of the rotor 103 with the shaft 101, which is also known as the rotating part of the turbine.

Along the rotor 103 are consistently located the intake casing 104, a compressor 105, having, for example, the torus form of combustion chamber 110, in particular an annular combustion chamber, provided with several spaced coaxial burners 107, a turbine 108 and the housing 109 flue system.

The annular combustion chamber 110 reported, for example, with the annular channel 111 of hot gases. There is, for example, four cascaded stages of turbine 112 to form the turbine 108.

Each stage turbine 112 is formed, for example, of the two rings of blades. If you look in the direction of flow of the working medium 113, the channel 111 of hot gases, for the next 115 vanes should be formed from rotor blades 120 of a row 125.

Guide vanes 130 thus fixed to the inner housing 138 of a stator 143, in contrast to which the rotor blades 120 of a row 125 are installed, for example, a group is a rotary disk 133 of the turbine to the rotor 103.

With the rotor 103 is connected to a generator or a working machine (not illustrated).

During operation of the gas turbine 100 135 air sucked by the compressor 105 through the intake casing 104 and compressed. Get turned on to the turbine end compressor 105 compressed air is sent to the burners 107 and there mixed with a combustible medium. This mixture is then burned in the combustion chamber 110 with the formation of a working medium 113. From there, the working medium 113 flows through the channel 111 of hot gases along the guide vanes 130 and the working blades 120. On the rotor blades 120, the working medium 113 expands with momentum transfer, so that the rotor blades 120 drive the rotor 103 and the rotor is connected with him working machine.

Under the influence of hot working medium 113 structural elements during operation of the gas turbine 100 is exposed to thermal loads. Guide vanes 130 and rotor blades 120 of the first, if you look in the direction of flow of the working medium 113, steps 112 of the turbine, along with the liner elements heat shield annular combustion chamber 110, are subjected to thermal loads in the highest degree.

To sustain arising there temperature, they can be cooled by using the cooling means.

The substrates of structural elements may also be directed to the article is ucture, i.e. they are single-crystal (SX structure) or have only longitudinally directed grains (DS structure).

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

Such superalloys are known for example from document EP 1 204 776 B1, EP 1 306 454, EP 1 319 729 A1, WO 99/67435 or WO 00/44949.

The blades 120, 130 may also be provided with coatings against corrosion, for example (MCrAlX; M is at least one element from the group iron (Fe), cobalt (Co), Nickel (Ni), X is an active element and represents yttrium (Y), and/or silicon, scandium (Sc), and/or at least one element of the rare earths, or hafnium). Such alloys are known from the documents EP 0 486 489 B1, EP 0 786 017 B1, EP 0 412 397 B1 or EP 0 306 454 A1.

On the MCrAlX may also contain an insulating layer, which preferably is an extreme outer layer consists, for example of ZrO₂, Y₂O₃-ZrO₂i.e. it is not stabilized, partially or completely, by yttrium oxide and/or calcium oxide and/or magnesium oxide.

Using appropriate methods of coating, such as, for example, electron beam coating method vapour deposition (EB-PVD), the resulting grain stabilizatory in the insulating layer.

The guide vanes 130 has brought to the inner housing 138 of the turbine 108 leg of the guide vanes (not here shown), and opposite legs of the guide vanes, the head of the guide vanes. The head of the guide vanes facing toward the rotor 103 and mounted on the mounting ring 140 of the stator 143.

Figure 2 shows a perspective view of the working vanes 120 or guide vanes 130 hydraulic machines, which extends along the longitudinal axis 121.

Hydraulic machine can be a gas turbine aircraft or power plant, designed to produce electricity, steam turbine or a compressor.

The blades 120, 130 along the longitudinal axis 121 has, consistently, area 400 mounting, adjacent to the platform 403 vanes, as well as working part 406 of the blade and the top of 415 of the scapula.

If the blade 130 is a guide vane 130, it may be provided at its top 415 vanes another platform (not illustrated).

In the area of 400 mounting made leg 183 of the scapula, which is used to fasten the blades 120, 130 to the shaft or disk (not illustrated).

Leg 183 vanes, for example, in a T-shape. Other choices are possible implementation in the form of a Christmas tree or dovetail.

The blade 120, 130 has a leading edge 409 of crowding and edge 412 began the I for environment, which flows through the working part 406 of the scapula.

Traditional blades 120, 130 in all regions 400, 403, 406 of the blades 120, 130 are used, for example, a solid metal material, in particular superalloys.

Such superalloys are known for example from document EP 1 204 776 B1, EP 1 306 454, EP 1 319 729 A1, WO 99/67435 or WO 00/44949.

When the blade 120, 130 may be fabricated by casting, in particular by means of directional solidification, by a forging method, a milling method or combinations thereof.

Billets with a monocrystalline structure or structures are used as structural elements of machines, which during operation is exposed to high mechanical, thermal and/or chemical loads.

The manufacture of such monocrystalline workpieces is carried out, for example, by crystallization from a melt. When it comes to casting methods in which the liquid metal alloy crystallizes with obtaining monocrystalline structure, i.e. monocrystalline workpiece or directed.

While dendritic crystals are oriented along the heat flow and form either stalked crystalline granular structure (colonialismo, i.e. grains that pass through the entire length of the workpiece and here, in common language, called directionally crystal is used) or a monocrystalline structure, i.e. the entire workpiece consists of a single crystal. In this way, you need to avoid the transition to globular (polycrystalline) solidification, as in directional growth necessarily formed transverse and longitudinal grain boundaries, which negates the good properties of directionally crystallized or single-crystal structural element.

If we are talking about directionally crystallized structures in General, they are as single crystals, which have no grain boundaries or, at least, have the grain boundaries with small angles, and stalked crystal structure, which can be are passing in the longitudinal direction of grain boundaries, but no transverse grain boundaries. In the case of those named in the second place the crystal structures also indicate directionally crystallized structures (directionally solidified structures).

Such methods are known from the document US-PS 6024792 and EP 0 892 090 A1.

The blades 120, 130 may also be provided with coatings against corrosion or oxidation, for example (MCrAlX; M is at least one element from the group iron (Fe), cobalt (Co), Nickel (Ni), X is an active element and represents yttrium (Y), or silicon and/or at least one element of the rare earths or, respectively, hafnium (Hf)). Such alloys from the local document EP 0 486 489 B1, EP 0 786 017 B1, EP 0 412 397 B1 or EP 0 306 454 A1.

The density is preferably about 95% theoretical density.

Of the MCrAlX layer (as the intermediate layer or the extreme outer layer) is formed a protective layer of aluminum oxide (TGO = thermal grown oxide layer).

Preferably 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 based on cobalt are also preferably the protective coating based on Nickel, 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 may also contain an insulating layer, which preferably is an extreme outer layer consists, for example of ZrO₂, Y₂O₃-ZrO₂i.e. it is not stabilized, partially or completely, by yttrium oxide and/or calcium oxide and/or magnesium oxide.

The insulating layer covers the entire MCrAlX layer. Using appropriate methods of coating, such as, for example, electron beam coating method vapour deposition (EB-PVD), the resulting grain stalked form in the insulating layer.

Other coating methods, for example, atmospheric plasma spraying (APS, LPPS, VPS or CVD. To improve thermal shock resistance of the insulating layer may contain a porous, having micro - or macro-cracking of the grain. That is, t is playsessions layer is preferably more porous, than the MCrAlX layer.

Refurbishment means that structural elements 120, 130 after their application, if necessary, must be released from protective layers (for example by sandblasting). Then remove corrosion and/or oxide layers or, respectively, of products. If necessary, the repair of cracks in structural elements 120, 130. After this is repeated coating on the structural element 120, 130 and re-application of the structural element 120, 130.

The blade 120, 130 may be made hollow or solid. If necessary, cooling the blades 120, 130 it is hollow and, if necessary, provided with holes 418 for film cooling (indicated by the dashed line).

Figure 3 shows a combustion chamber 110 of a gas turbine. Combustion chamber 110 is made, for example, in the form of a so-called annular combustion chamber, in which many are located in the circumferential direction around the axis 102 of the rotation of burners 107, which create a flame 156, into one common space 154 of the combustion chamber. For this combustion chamber 110 is made together in the form of a ring-shaped structure, which is located around the axis 102 of the rotation.

To achieve a relatively high efficiency of combustion chamber 110 R is scatana at a relatively high temperature of the working medium M, approximately from 1000°C to 1600°C. So that even under these unfavourable for materials operating parameters to provide the opportunity for a relatively long service life, wall 153 of the combustion chamber on its facing the working medium M side provided with an inner lining formed from elements 155 of the heat shield.

Each element 155 of the heat shield, made of alloy, equipped with the working environment is particularly heat-resistant protective layer (MCrAlX layer and/or ceramic coating) or made of highly temperature-resistant material (solid ceramic bricks).

These protective layers may be similar to the turbine blades, that is, MCrAlX, for example, means: M represents at least one element from the group iron (Fe), cobalt (Co), Nickel (Ni), X is an active element and represents yttrium (Y), or silicon and/or at least one element of the rare earths, or hafnium (Hf). Such alloys are known from the documents EP 0 486 489 B1, EP 0 786 017 B1, EP 0 412 397 B1 or EP 0 306 454 A1.

On the MCrAlX may also be, for example, a ceramic insulating layer, consisting for example of ZrO₂, Y₂O₃-ZrO₂i.e. it is not stabilized, partially or completely, by yttrium oxide and/or calcium oxide and/or magnesium oxide.

Using appropriate methods of coating, such is AK, for example, electron beam coating method vapour deposition (EB-PVD), the resulting grain stalked form in the insulating layer.

Other coating methods, for example, atmospheric plasma spraying (APS, LPPS, VPS or CVD. To improve thermal shock resistance of the insulating layer may contain a porous, having micro - or macro-cracking of the grain.

Refurbishment means that elements 155 of the heat shield after their application, if necessary, must be released from protective layers (for example by sandblasting). Then remove corrosion and/or oxide layers or, respectively, of products. If necessary, the repair of cracks in item 155 of the heat shield. After this is repeated coating on the element 155 of the heat shield and re-use elements 155 of the heat shield.

Due to the high temperatures inside the combustion chamber 110 for items 155 heat shield or, respectively, for their fastening elements may be provided by the cooling system. Elements 155 of the heat shield are, for example, hollow and, if necessary, is supplied also into the space 154 of the combustion chamber holes for cooling are not depicted).

Figure 4 in a strongly schematized image shows the welding device 1.

This device includes a laser 3 and the device 5 of the feed powder, which powder welding filler material may be applied to intended for welding region of the workpiece 9. By means of laser radiation on the surface of the workpiece creates a zone 11 of heat, into which the powder 13 by means of the device 5 of the powder feeder. The laser is preferably a laser at 300 watts, in particular the Nd-Yag laser (solid state laser whose active medium is used alumina-yttrium aluminium garnet "YAG", Y₃Al₅O₁₂with the addition of neodymium Nd), in a very special case with λ=1.06 µm. The laser power ranges from 100 watts to 300 watts, and preferably from 100 watts to 200 watts, in a very special case from 100 watts to 150 watts. Thus, the welding filler material preferably is well melted and partially melted base to get the tight spot welding.

The laser 3 and the device 5 for feeding powder located on the scanning device 15, which provides the possibility of moving the laser device 3 and 5 of the supply of powder in two directions on the surface of the structural element (directions x and y in figure 4) is intended for welding region 7. The speed of the process and the sa is at least 250 mm/min, in particular from 400 to 600 mm/min, in a very special case of 500 mm/min. Thus possible preferred heat input in the welding material and the substrate.

In addition, the scanning device 15 of the present embodiment allows the movement of the laser device 3 and 5 of the powder supply is perpendicular to the surface of the structural element (z-direction figure 4). Using the scanning device 15, the area of heat supply and the area of contact of the powder can thus move along a given trajectory. As the scanning device may, for example, be applied to the robot arm. The diameter of the laser beam is, in particular, from 500 μm to 700 μm, in a very special case of 600 μm. Thus, the possible heating of the welding material supplied.

The control carried out by the scanning device 15, with unit 17 of the control, which also controls other parameters of the welding process. But unlike the present embodiment, control other parameters of the welding process may also be performed using an additional control that is separate from the process control movement. In addition, in contrast to the presented embodiment, instead of the scanning device 15, which serves to move the Oia laser device 3 and 5 of the powder feeder, can also be used movable fastening of the structural element. 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 the workpiece 9.

By the invention a method of welding welding on the surface of the workpiece can be used for application, in particular for multilayer material designed for welding region 7 structural element 9. It does not require any preheating or perestiani by heat treatment of structural element 9.

Following the method described in example deposition on the surface 10 of the blade 9 of the turbine, which is a workpiece. The turbine blade of the present embodiment consists of a reinforced allocation of γ'-phase supersplash Nickel-based, for example, IN738LC, IN939, Rene80, IN6203DS, PWA1483SX, Alloy 247, etc. Intended for welding region 7 in the surface 10 of the blade 9 of the turbine is subjected to layer-by-layer deposition, the zone of heat together with the region into powder 13 in the direction of welding move around intended for welding region 7 blades 9 of the turbine. Powder 13 in this case is a powder containing a γ'-phase supersplash Nickel-based, for example, IN 738LC, IN 939, Rene 80, IN 6203DS, PWA 1483, Alloy 247, etc.

Tr is ictoria P1, which are zone 11 heat supply, as well as the hit area for the powder 13 when overlaying the first layer on intended for welding region 7, schematically depicted in figure 5. This figure shows the blade 9 turbines designed for welding region 7 and the direction S1 welding when the welding of the first layer 19. Area 11 of heat, which simultaneously represents the area into powder 13, moves, however, is not linear in the direction S1 welding, and while moving in the direction of welding simultaneously oscillates in the direction perpendicular to the direction of welding. Due to this area 11 heat and scope popadanija powder 13 follow landroversnow path P1 on intended for welding region 7.

For deposition of the second layer 21 (figure 4) laser 3 and the device 5 powder supply is slightly shifted in the z-direction scanning device 15. In addition, in the present embodiment, the direction S2 welding is rotated relative to the direction S1 welding of the first layer by 90°. Path P2 zone 11 heat and the hit area of the powder 13 when overlaying the second layer 21 is depicted in Fig.6. When overlaying the second layer zone 21 11 heat also oscillates together with the region into powder 13 in the direction perpendicular to S2 welding. So you get mangroomer the Naya path P2 zone 11 heat and the hit area of the powder 13 is designed for welding region 7.

Described in this embodiment, the trajectory represent only one of various possible options. In principle there are several possibilities welding: 1) unidirectional or 2) bidirectional (e.g., landroverusa) surfacing. Each of these options cushions (trajectory) of the 2nd layer can be parallel displaced or to be welded perpendicular to the rollers (trajectories) of the first layer. All these options can be used in the framework proposed by the invention method.

When moving the laser and feeder powder oscillation can be chosen so that a single trajectory in the direction of welding covered all designed for welding region 7, as shown in figure 5, or so that were covered only part intended for welding region 7, and overlaying all of this area was carried out in several passes next to each other trajectories P2 in the direction S2, as shown in Fig.6.

Moving zone 11 heat and the hit area of the powder 13 to path P1 or P2 is performed in the present embodiment, with the process speed equal to at least 500 mm/min

Mass feed rate is ≤350 mg/min, preferably ≤330 mg/min (as it comes to surfacing, the value of zero, and is enabled, that is, at least 50 mg/min, in particular at least 100 mg/min). This gives the advantage that the supplied fuse material very well melted, becomes a high temperature and, thus, the stronger is cooled by cooling.

The laser power, beam diameter and the flow of the powder is thus selected so that the cooling rate of the covered area during crystallization of more than 8000 K/C. When applying the second layer 21 process parameters related to the laser power and beam diameter, in addition, chosen so that the depth of re-melting, which is re-melted the first layer 19 is less than 50% of the height of the roller of the first layer 19. The depth of the re-melting in figure 4 is indicated by the dashed line. In principle, it is also possible other than indicated in this example, the process speed, and then you must have the appropriate approval and other parameters of the laser power, beam diameter and flow of the powder.

Due to the high cooling rate and high speed of crystallization of the distribution coefficient increases so that microlocal largely prevented. Happens dendritic crystallization of the melt obtained through zone 11 of heat, while the adopted structure of the re-crystallization of the molten region. P and this direction of growth of dendrites vary along the trajectory P1, P2 welding. The reason for this is that the orientation of the possible directions of growth of dendrites varies relative to the temperature gradient, and the predominant direction of growth with the least direction to the temperature gradient or, respectively, with the lowest growth rate. In addition, the crystallization nuclei, which are formed prior to crystallization front and which during crystallization captured by the crystallization front, initiate statistically distributed direction of growth of dendrites. These unevenly distributed orientation of the dendrites are mostly in the upper half of the layer 19. Therefore, when a shallow depth of re-melting is provided by the imposition of the solidification front in the region with non-uniformly distributed orientation of dendrites that when the multilayer welding leads formed polycrystal grains, the diameter of which is on average very small. Thanks weldable area of the vanes 9 of the turbine becomes insensitive to the formation of cracks.

Once there is a drawing of the required number of layers 19, 21, the blade 9 of the turbine may be subjected to heat treatment, in which you specify the desired morphology of the γ'-phase. This serves to further improve the strength of the area to be welded blades 9 of the s.

Using the invention method, the welding welding can be carried out at room temperature and without prior perestiani designed for welding region, and the occurrence of crystallization cracks and fissures caused by repeated melting, is prevented. In turn, this leads to the welding quality, which is acceptable for structural welding, in particular high-load regions of gas turbine blades and other structural elements. At the same time is only a very small effect on the core material, because a small area of heat (pre-heating does not occur) and to prevent cracking caused by repeated melting, in the area exposed to heat, is only a very small supply of the body in the substrate.

1. Method of laser welding of the workpieces (9) of highly temperature-resistant superalloys,
when you are applying welding filler material (13) on the surface (10) of the workpiece in the zone (11) of heat in the zone of welding filler material in the zone (11) of heat,
when this zone (11) of heat supply and the feed area, on the one hand, and the surface (10) of the workpiece, on the other hand, move relative to each other,
the welding filler is of the material is performed with a mass velocity of ≤350 mg/min, and establish, at least one of the following parameters of laser welding:
the laser power of 100 W to 300 W,
the diameter of the laser beam from 500 μm to 800 μm,
welding speed of at least 250 mm/min

2. The method according to claim 1, characterized in that the mass feed rate is ≤330 mg/min, in particular ≤300 mg/min

3. The method according to claim 1, characterized in that at least the welding parameters, such as applied power, welding speed, the diameter of the beam welding, choose from a condition of providing the cooling rate during crystallization of the material of at least 8000 degrees Kelvin per second (K/s).

4. The method according to claim 1, characterized in that the welding parameters relating to the supplied power, the diameter of the zone of heat, set of conditions ensuring the cooling rate during crystallization of the material of at least 8000 degrees Kelvin per second (K/s).

5. The method according to claim 1, characterized in that the welding speed is 400-600 mm/min, in particular of 500 mm/min

6. The method according to claim 1, wherein the welded seam is formed by layering a welding filler material (13).

7. The method according to claim 6, in which the melt of the previous layer (19).

8. The method according to claim 7, characterized in that the previously applied layer (19) re-melted less than half its thickness.

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

10. The method according to claim 1, characterized in that the zone (11) of heat supply and the input area is moved by the oscillating around the direction (S1, S2) welding path (P1, P2) relative to the surface (10) of the workpiece.

11. The method according to claim 1, wherein the workpiece includes containing a γ'-phase superslow Nickel-based, in particular, consists of him, and welding filler material (13) is forming a γ'-phase material supersplash Nickel-based.

12. The method according to claim 1, characterized in that during the application of welding filler material (13) perform heat treatment.

13. The method according to claim 1, in which the applied laser at 300 watts.

14. The method according to item 12, which used the Nd-Yag laser, in particular with λ=1.06 µm.

15. The method according to item 13, wherein the laser power ranges from 100 W to 200 W, in particular from 100 watts to 150 watts.

16. The method according to claim 1, wherein the diameter of the laser beam is 600 microns.

17. The method according to claim 1, wherein receiving polycrystalline weld (19, 21).

18. The method according to claim 1, wherein the mass feed rate is at least 50 mg/min, in particular at least 100 mg/min