Method for surfacing wear-resistant layer of low-pressure turbine rotor blade through argon arc welding

Abstract

The invention discloses a method for argon arc welding surfacing of a wear-resistant layer of a low-pressure turbine rotor blade, and relates to the field of engine part manufacturing. The cobalt-based wear-resistant alloy welding wire is adopted as a welding material, key parameters in the welding process are accurately adjusted, and the quality and reliability of the wear-resistant layer of the low-pressure turbine rotor blade are improved; meanwhile, the distance between the wear-resistant layer and the concave R region-straight line section is optimized, and point and linear fluorescence defects generated in the concave R region in the preparation process of the wear-resistant layer are reduced. Experimental results show that the wear-resistant layer surfaced by the method provided by the invention has relatively high hardness, and meanwhile, the defects of cracks, recrystallization and the like do not exist.

Description

Technical Field

[0001] The invention belongs to the field of engine parts manufacturing, and in particular relates to a method for argon arc welding of a wear-resistant layer on a low-pressure turbine rotor blade. Background Art

[0002] The low-pressure turbine rotor blades of aircraft engines generally adopt a structure with a serrated crown. The above design not only enhances the mechanical strength of the blades, but also improves their aerodynamic efficiency, thereby ensuring the efficient and stable operation of the engine. However, the operating environment of the low-pressure turbine blades is extremely harsh, and they need to withstand complex torques and bending moments, facing serious consequences such as blade deformation and failure, shortened fatigue life, reduced engine performance, and potential safety hazards. Therefore, technicians usually prepare a wear-resistant layer on the blade serrated crown to ensure the wear resistance of the serrated crown stress surface.

[0003] The existing low-pressure turbine rotor blade serrated crown wear-resistant layer is mainly prepared by tungsten inert gas arc welding. However, on the one hand, due to the quality problems of the wear-resistant material itself, such as excessive impurity content and uneven composition, the wear-resistant layer will have defects during manufacturing or use, key performance indicators such as hardness will not meet the standards, performance will be reduced, and even early failure will occur; on the other hand, defects in the production process will also seriously affect the quality of the wear-resistant layer. If the welding parameters in the production process are not properly controlled, the wear-resistant layer will have internal defects, uneven structure and other problems, which will directly affect the reliability of the wear-resistant layer. Summary of the invention

[0004] In view of this, the present invention provides a method for argon arc welding of a wear-resistant layer on a low-pressure turbine rotor blade. The method provided by the present invention can improve the quality and reliability of the wear-resistant layer, reduce its thickness while ensuring the hardness of the wear-resistant layer, and make the obtained wear-resistant layer have excellent overall performance.

[0005] Specifically, the method for argon arc welding of a wear-resistant layer on a low-pressure turbine rotor blade provided by the present invention comprises:

[0006] a) Use cobalt-based wear-resistant alloy welding wire to perform argon arc welding on the welded surface of the low-pressure turbine rotor blade, and introduce inert gas protection at the end of the cladding;

[0007] The cobalt-based wear-resistant alloy welding wire contains the following components in mass fraction: C 0.08%, Si 2.5% to 4%, Cr 15% to 20%, Mo 26% to 32%, and the balance is Co;

[0008] The welding current of the surfacing welding is 12-48A, and the welding speed is 6-15cm / min;

[0009] b) cooling the surfacing-welded low-pressure turbine rotor blade obtained in step a) to form a wear-resistant layer.

[0010] In some specific implementations, in step a), the minimum distance between the to-be-welded surface of the low-pressure turbine rotor blade and the intersection of the concave R zone and the straight line segment is 0.3-1.7 mm.

[0011] In some specific implementations, the cobalt-based wear-resistant alloy welding wire contains the following components by mass fraction: C 0.08%, Si 2.8%-4%, Cr 15.5%-19%, Mo 27%-31%, and the balance is Co. In some specific implementations, the cobalt-based wear-resistant alloy welding wire is PMet980 welding wire.

[0012] In some specific implementations, during the argon arc welding process, the nozzle diameter of the welding gun is 8-15 mm, the diameter of the welding wire is 0.8-1.8 mm, the welding voltage is 10-18 V, the tungsten electrode diameter is 1.4-2.0 mm, and the argon gas flow rate is 5-12 L / min.

[0013] In some specific implementations, the time for introducing the inert gas protection in step a) is 8 to 17 seconds.

[0014] In some specific implementations, the low-pressure turbine rotor blades are made of nickel-based single crystal high-temperature alloy DD6.

[0015] In some specific implementations, the time interval between step a) and step b) is ≤ 1 min.

[0016] In some specific implementations, the cooling in step b) refers to cooling to 13-27° C. in no less than 10 minutes. In some specific implementations, the average thickness of the wear-resistant layer in step b) is 0.6-1.4 mm.

[0017] The present invention selects a cobalt-based wear-resistant alloy welding wire that is better matched with a blade substrate as the welding material, thereby ensuring the fusibility and permeability during the welding process, forming a uniform and dense bond between the weld and the base material, and improving the hardness of the wear-resistant layer; optimizing various parameters during the welding process, significantly reducing the incidence of welding defects, improving the quality and reliability of the wear-resistant layer, and making the obtained wear-resistant layer thinner and having a higher hardness; at the same time, the present invention optimizes the distance between the wear-resistant layer and the intersection of the concave R zone-straight line segment of the low-pressure turbine rotor blade during the welding process, improving the bonding between the wear-resistant layer and the base material, improving the bonding strength and quality stability, and thus improving the overall reliability and service life of the blade. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the low-pressure turbine rotor blade crown;

[0019] Figure 2This is a metallographic test image of the wear-resistant layer prepared in Example 1;

[0020] Figure 3 This is a metallographic test image of the wear-resistant layer prepared in Example 2;

[0021] Figure 4 This is a metallographic test image of the wear-resistant layer prepared in Example 3;

[0022] Figure 5 This is a metallographic test image of the wear-resistant layer prepared in Example 4;

[0023] Figure 6 This is a photo of the wear-resistant layer prepared in Comparative Example 1;

[0024] Figure 7 This is a photo of the wear-resistant layer prepared in Comparative Example 2;

[0025] Figure 8 This is a photo of the wear-resistant layer prepared in Comparative Example 3;

[0026] Fig. 9 This is a photograph of the wear-resistant layer prepared in Comparative Example 4. DETAILED DESCRIPTION

[0027] It should be understood that the expression "one or more of..." includes each of the items recited after the expression individually and in various different combinations of two or more of the recited items, unless otherwise understood from the context and usage. The expression "and / or" in combination with three or more recited items should be understood to have the same meaning, unless otherwise understood from the context.

[0028] The use of the terms "comprising", "having" or "containing", including their grammatical synonyms, should generally be understood as open and non-restrictive, for example not excluding other unrecited elements or steps, unless otherwise specifically stated or otherwise understood from the context.

[0029] It should be understood that the order of steps or the order in which certain actions are performed is not important as long as the present invention remains operable. In addition, two or more steps or actions may be performed simultaneously.

[0030] The use of any and all examples or exemplary language, such as "for example" or "including", herein is intended only to better illustrate the invention and does not limit the scope of the invention unless otherwise claimed. No language in this specification should be construed as indicating that any non-claimed element is essential to the practice of the invention.

[0031] In addition, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as accurately as possible. However, any numerical value inherently inevitably contains standard deviations due to individual test methods. Therefore, unless otherwise expressly stated, it should be understood that all ranges, quantities, values ​​and percentages used in this disclosure are modified by "about". Here, "about" generally means that the actual value is within plus or minus 10%, 5%, 1% or 0.5% of a specific value or range.

[0032] The present invention provides a method for argon arc welding of a wear-resistant layer on a low-pressure turbine rotor blade. Specifically, the present invention selects a low-pressure turbine rotor blade made of a nickel-based high-temperature alloy DD6 for surfacing the wear-resistant layer. First, it is preferred to perform a pretreatment on the blade. The pretreatment can reduce the generation of pores during welding and improve the welding quality. In some specific implementations, the pretreatment includes the following steps: grinding and rounding the blade crown surface to be welded of the low-pressure turbine rotor blade, removing surface oxides, oil stains and other foreign matter until the metallic luster is exposed; wiping the blade crown surface to be welded with acetone. The present invention has no special requirements for the method and parameters of the pretreatment, and a solution familiar to those skilled in the art can be used.

[0033] After the pretreatment is completed, the low-pressure turbine rotor blade is fixed on the workbench to ensure that the low-pressure turbine rotor blade is in good contact with the positive electrode of the argon arc welding equipment to prevent local discharge from burning the blade. Then, a cobalt-based wear-resistant alloy welding wire is used to argon arc weld the wear-resistant layer of the low-pressure turbine rotor blade, and the cobalt-based wear-resistant alloy welding wire contains the following components by mass fraction: C 0.08%, Si 2.5% to 4%, Cr 15% to 20%, Mo 26% to 32%, and the balance Co; preferably C 0.08%, Si 2.8% to 4%, Cr 15.5% to 19%, Mo 27% to 31%, and the balance Co; more preferably C 0.08%, Si 3% to 3.8%, Cr 16.5% to 18.5%, Mo 27.5% to 30%, and the balance Co.

[0034] The present invention selects cobalt-based wear-resistant alloy welding wire as the wear-resistant layer material, which has better matching with the low-pressure turbine rotor blade substrate, effectively ensuring the fusion and permeability during the welding process, forming a uniform and dense bond between the weld and the base material, and improving the hardness of the wear-resistant layer. It helps to improve the overall quality of welding, avoid recrystallization, and effectively prevent the occurrence of cracks; at the same time, it reduces the sensitivity to welding parameters during the welding process, making the welding process more stable and easy to control.

[0035] The welding current during the welding process is 12 to 48 A, preferably 14 to 46 A, and more preferably 15 to 45 A; the welding speed is 6 to 15 cm / min, preferably 7 to 14 cm / min, and more preferably 8 to 12 cm / min.

[0036] In some specific implementations, the nozzle diameter of the welding gun during the argon arc welding process is 8-15 mm, preferably 9-13 mm, and more preferably 10-12 mm; the welding wire diameter is 0.8-1.8 mm, preferably 0.9-1.6 mm, and more preferably 1-1.5 mm; the welding voltage is 10-18 V, preferably 11-17 V, and more preferably 12-16 V; the tungsten electrode diameter is 1.4-2.0 mm, preferably 1.5-1.9 mm, and more preferably 1.6-1.8 mm; the argon gas flow rate is 5-12 L / min, preferably 6-11 L / min, and more preferably 7-10 L / min.

[0037] At the end of the surfacing, an inert gas is used for protection for 8 to 17 seconds, preferably 9 to 16 seconds, and more preferably 10 to 15 seconds. In some specific implementations, the inert gas is preferably argon or helium, and more preferably argon.

[0038] The applicant of the present invention has found that the welding process parameters have a great influence on the quality and life of the wear-resistant layer. Too high welding current can easily lead to overheating, increase the formation of pores and inclusions; too low current will lead to poor weld fusion, resulting in defects such as unfused or incomplete welds; too fast welding speed will cause the weld to cool too quickly, which is easy to cause cracks; too slow welding speed will easily lead to overheating, increasing the risk of pores and inclusions. Therefore, the present invention significantly reduces the incidence of welding defects by accurately adjusting key parameters such as welding current, voltage, and speed, improves the quality and reliability of the wear-resistant layer, and makes the obtained wear-resistant layer thinner and higher in hardness, which not only helps to improve the overall performance and service life of the low-pressure turbine rotor blades, but also reduces production costs and maintenance costs, and has good economic benefits.

[0039] Figure 1 The figure shows a schematic diagram of the blade crown of a low-pressure turbine rotor blade according to the present invention, wherein a is the surface to be welded, b is the concave R area of ​​the blade, c is the intersection of the concave R area and the straight line segment, and d is the minimum distance between the surface to be welded of the blade and the intersection of the concave R area and the straight line segment. In the present invention, the minimum distance between the surface to be welded of the blade and the intersection of the concave R area and the straight line segment is 0.3 to 1.7 mm, preferably 0.4 to 1.6 mm, and more preferably 0.5 to 1.5 mm.

[0040] The present invention helps to improve the bonding between the wear-resistant layer and the substrate by optimizing the minimum distance between the surface to be welded and the intersection of the concave R zone and the straight line segment, thereby improving the bonding strength of the wear-resistant layer and reducing the failure of the wear-resistant layer due to peeling or cracking during use; at the same time, it can significantly reduce the point and linear fluorescent defects generated in the concave R zone during the preparation of the wear-resistant layer, reduce the stress concentration in the concave R zone, improve the qualified rate and quality stability of the wear-resistant layer preparation, thereby improving the overall reliability and service life of the blade.

[0041] After obtaining the low-pressure turbine rotor blade after surfacing welding, place it in a sand box filled with quartz sand to cool within 1 minute to form a wear-resistant layer, the cooling temperature is 13-27°C, preferably 14-26°C, more preferably 15-25°C; the cooling time is not less than 10 minutes, preferably not less than 20 minutes, more preferably not less than 30 minutes. In some specific implementations, the average thickness of the wear-resistant layer is 0.6-1.4 mm, preferably 0.7-1.4 mm, more preferably 0.8-1.4 mm.

[0042] The present invention is further described below in conjunction with the following examples. The protection scope of the present invention is not limited by the following examples.

[0043] Example 1

[0044] This embodiment provides a method for argon arc welding of a wear-resistant layer on a low-pressure turbine rotor blade, comprising the following steps:

[0045] (1) The blade crown to be welded surface of the nickel-based single crystal high-temperature alloy DD6 low-pressure turbine rotor blade is ground and rounded. The minimum distance between the blade crown to be welded surface and the intersection of the concave R zone and the straight line segment is 0.5 mm. The surface oxides, oil stains and other foreign matter within a range of not less than 3 mm are removed until the metallic luster is exposed; then the blade crown to be welded surface is wiped with a non-woven cloth dipped in acetone;

[0046] (2) Fix the low-pressure turbine rotor blades on the workbench to ensure that the low-pressure turbine rotor blades are in good contact with the positive electrode of the argon arc welding equipment to prevent local discharge from burning the blades;

[0047] (3) PMet980 welding wire was selected, and its composition was C 0.08%, Si 3%, Cr 18.5%, Mo 28%, and the balance was Co. After the arc was started, the welding current was gradually increased. When the base material was slightly melted, the welding wire was added to form a weld and quickly fill the root. The welding parameters were: nozzle diameter 10 mm, welding wire diameter 1 mm, welding voltage 15 V, welding current 25 A, welding speed 10 cm / min, tungsten electrode diameter 1.6 mm, and argon gas flow rate 10 L / min. At the end of the weld, the current was gradually attenuated to fill the arc crater. After the arc was extinguished, the welding gun should stay at the end for 10 s and continue to pass argon protection.

[0048] (4) Within 1 minute after the argon arc welding is completed, the low-pressure turbine rotor blades are placed in a sand box filled with quartz sand and cooled to a temperature of 25°C. The cooling time is 30 minutes, and a low-pressure turbine rotor blade with an average wear-resistant layer thickness of 1.2 mm is obtained.

[0049] Example 2

[0050] This embodiment provides a method for argon arc welding of a wear-resistant layer on a low-pressure turbine rotor blade, comprising the following steps:

[0051] (1) The blade crown to be welded surface of the nickel-based single crystal high-temperature alloy DD6 low-pressure turbine rotor blade is ground and rounded. The minimum distance between the blade crown to be welded surface and the intersection of the concave R zone and the straight line segment is 1 mm. The surface oxides, oil stains and other foreign matter within a range of not less than 3 mm are removed until the metallic luster is exposed; then the blade crown to be welded surface is wiped with a non-woven cloth dipped in acetone;

[0052] (2) Fix the low-pressure turbine rotor blades on the workbench to ensure that the low-pressure turbine rotor blades are in good contact with the positive electrode of the argon arc welding equipment to prevent local discharge from burning the blades;

[0053] (3) PMet980 welding wire was selected, whose composition was C 0.08%, Si 3.8%, Cr 17.5%, Mo 27.5%, and the balance Co. After arcing, the welding current was gradually increased. When the base material was slightly melted, welding wire was added to form a weld and quickly fill the root. The welding parameters were: nozzle diameter 12 mm, welding wire diameter 1.5 mm, welding voltage 13 V, welding current 30 A, welding speed 8 cm / min, tungsten electrode diameter 1.6 mm, argon gas flow 8 L / min; at the end of the weld, the current was gradually attenuated to fill the arc crater. After the arc was extinguished, the welding gun should stay at the end for 15 s and continue to pass argon protection;

[0054] (4) Within 1 minute after the argon arc welding is completed, the low-pressure turbine rotor blades are placed in a sand box filled with quartz sand and cooled to a temperature of 25°C. The cooling time is 40 minutes, and a low-pressure turbine rotor blade with an average wear-resistant layer thickness of 0.8 mm is obtained.

[0055] Example 3

[0056] This embodiment provides a method for argon arc welding of a wear-resistant layer on a low-pressure turbine rotor blade, comprising the following steps:

[0057] (1) The blade crown to be welded surface of the nickel-based single crystal high-temperature alloy DD6 low-pressure turbine rotor blade is ground and rounded. The minimum distance between the blade crown to be welded surface and the intersection of the concave R zone and the straight line segment is 1.5 mm. The surface oxides, oil stains and other foreign matter within a range of not less than 3 mm are removed until the metallic luster is exposed; then the blade crown to be welded surface is wiped with a non-woven cloth dipped in acetone;

[0058] (2) Fix the low-pressure turbine rotor blades on the workbench to ensure that the low-pressure turbine rotor blades are in good contact with the positive electrode of the argon arc welding equipment to prevent local discharge from burning the blades;

[0059] (3) PMet980 welding wire was selected, whose composition was C 0.08%, Si 3.2%, Cr 16.5%, Mo 30%, and the balance Co. After arcing, the welding current was gradually increased. When the base material was slightly melted, welding wire was added to form a weld and quickly fill the root. The welding parameters were: nozzle diameter 10 mm, welding wire diameter 1.2 mm, welding voltage 12 V, welding current 15 A, welding speed 12 cm / min, tungsten electrode diameter 1.8 mm, and argon gas flow rate 7 L / min. At the end of the weld, the current was gradually attenuated to fill the arc crater. After the arc was extinguished, the welding gun should stay at the end for 10 s and continue to pass argon gas protection.

[0060] (4) Within 1 minute after the argon arc welding is completed, the low-pressure turbine rotor blades are placed in a sand box filled with quartz sand and cooled to a temperature of 15°C. The cooling time is 25 minutes to obtain low-pressure turbine rotor blades with an average wear-resistant layer thickness of 1 mm.

[0061] Example 4

[0062] This embodiment provides a method for argon arc welding of a wear-resistant layer on a low-pressure turbine rotor blade, comprising the following steps:

[0063] (1) The blade crown to be welded surface of the nickel-based single crystal high-temperature alloy DD6 low-pressure turbine rotor blade is ground and rounded. The minimum distance between the blade crown to be welded surface and the intersection of the concave R zone and the straight line segment is 1.2 mm. The surface oxides, oil stains and other foreign matter within a range of not less than 3 mm are removed until the metallic luster is exposed; then the blade crown to be welded surface is wiped with a non-woven cloth dipped in acetone;

[0064] (2) Fix the low-pressure turbine rotor blades on the workbench to ensure that the low-pressure turbine rotor blades are in good contact with the positive electrode of the argon arc welding equipment to prevent local discharge from burning the blades;

[0065] (3) PMet980 welding wire was selected, whose composition was C 0.08%, Si 3.4%, Cr 17%, Mo 29%, and the balance Co. After arcing, the welding current was gradually increased. When the base material was slightly melted, welding wire was added to form a weld and quickly fill the root. The welding parameters were: nozzle diameter 10 mm, welding wire diameter 1.2 mm, welding voltage 16 V, welding current 40 A, welding speed 9 cm / min, tungsten electrode diameter 1.6 mm, argon gas flow rate 10 L / min; at the end of the weld, the current was gradually attenuated to fill the arc crater. After the arc was extinguished, the welding gun should stay at the end for 15 s and continue to pass argon protection;

[0066] (4) Within 1 minute after the argon arc welding is completed, the low-pressure turbine rotor blades are placed in a sand box filled with quartz sand and cooled to a temperature of 20°C. The cooling time is 30 minutes, and a low-pressure turbine rotor blade with an average wear-resistant layer thickness of 1.4 mm is obtained.

[0067] Comparative Example 1

[0068] This comparative example provides a method for argon arc welding of a wear-resistant layer on a low-pressure turbine rotor blade, comprising the following steps:

[0069] (1) Same as Example 4;

[0070] (2) Same as Example 4;

[0071] (3) Select RE1 welding wire, whose composition is Cr 29%, Ni 3%, W 12.5%, Fe 3%, Mo1%, C 2.5%, Mn 1%, Si 2%, Co balance, and conduct welding. After arc starting, gradually increase the welding current. When the base material is slightly melted, add welding wire to form a weld and quickly fill the root. The welding parameters are: nozzle diameter 10mm, welding wire diameter 1.2mm, welding voltage 16V, welding current 40A, welding speed 9cm / min, tungsten electrode diameter 1.6mm, argon gas flow rate 10L / min; at the end of the weld, gradually reduce the current to fill the arc crater. After the arc is extinguished, the welding gun should stay at the end for 15s and continue to pass argon protection;

[0072] (4) Same as Example 4; the average thickness of the wear-resistant layer obtained in this comparative example is 2.1 mm.

[0073] Comparative Example 2

[0074] This comparative example provides a method for argon arc welding of a wear-resistant layer on a low-pressure turbine rotor blade, comprising the following steps:

[0075] (1) Same as Example 4;

[0076] (2) Same as Example 4;

[0077] (3) PMet980 welding wire was selected, whose composition was C 0.08%, Si 3.4%, Cr 17%, Mo 29%, and the balance Co. After arcing, the welding current was gradually increased. When the base material was slightly melted, welding wire was added to form a weld and quickly fill the root. The welding parameters were: nozzle diameter 10 mm, welding wire diameter 1.2 mm, welding voltage 16 V, welding current 10 A, welding speed 5 cm / min, tungsten electrode diameter 1.6 mm, argon gas flow rate 10 L / min; at the end of the weld, the current was gradually attenuated to fill the arc crater. After the arc was extinguished, the welding gun should stay at the end for 15 s and continue to pass argon protection;

[0078] (4) Same as Example 4; the average thickness of the wear-resistant layer obtained in this comparative example is 1.9 mm.

[0079] Comparative Example 3

[0080] This comparative example provides a method for argon arc welding of a wear-resistant layer on a low-pressure turbine rotor blade, comprising the following steps:

[0081] (1) Same as Example 4;

[0082] (2) Same as Example 4;

[0083] (3) PMet980 welding wire was selected, whose composition was C 0.08%, Si 3.4%, Cr 17%, Mo 29%, and the balance Co. After arcing, the welding current was gradually increased. When the base material was slightly melted, welding wire was added to form a weld and quickly fill the root. The welding parameters were: nozzle diameter 10 mm, welding wire diameter 1.2 mm, welding voltage 16 V, welding current 60 A, welding speed 20 cm / min, tungsten electrode diameter 1.6 mm, argon gas flow rate 10 L / min; at the end of the weld, the current was gradually attenuated to fill the arc crater. After the arc was extinguished, the welding gun should stay at the end for 15 s and continue to pass argon protection;

[0084] (4) Same as Example 4; the average thickness of the wear-resistant layer obtained in this comparative example is 2.2 mm.

[0085] Comparative Example 4

[0086] This comparative example provides a method for argon arc welding of a wear-resistant layer on a low-pressure turbine rotor blade, comprising the following steps:

[0087] (1) The blade crown to be welded surface of the nickel-based single crystal high-temperature alloy DD6 low-pressure turbine rotor blade is ground and rounded. The minimum distance between the blade crown to be welded surface and the intersection of the concave R zone and the straight line segment is 0.1 mm. The surface oxides, oil stains and other foreign matter within a range of not less than 3 mm are removed until the metallic luster is exposed; then the blade crown to be welded surface is wiped with a non-woven cloth dipped in acetone;

[0088] (2) Same as Example 4;

[0089] (3) Same as Example 4;

[0090] (4) Same as Example 4; the average thickness of the wear-resistant layer obtained in this comparative example is 1.8 mm.

[0091] Test Example 1

[0092] Metallographic samples were cut from the blades prepared in Examples 1 to 4 at the position parallel to the blade crown wear-resistant layer, and the metallographic structure was analyzed after grinding and polishing to remove corrosion. Figures 2 to 5They are metallographic test images of Examples 1 to 4 respectively. Figures 2 to 5 It can be seen that there are no problems such as cracks and recrystallization in the welding heat affected zones of the four blade specimens. Figures 6 to 9 These are photos of leaves prepared in Comparative Examples 1 to 4, from which it can be seen intuitively that Figure 6 The wear-resistant layer prepared in Comparative Example 1 has cracks at the edge area; Figure 7 The wear-resistant layer prepared in Comparative Example 2 has an unfused cavity with a length of 0.677 mm and a distance of 0.690 mm from the edge of the wear-resistant layer due to the mismatch between the welding speed and the welding current; Figure 8 The wear-resistant layer prepared in Comparative Example 3 also has a crack with a length of 0.641 mm due to the mismatch between welding speed and welding current; Fig. 9 The wear-resistant layer prepared in Comparative Example 4 has cracks in the concave R region. The above test results show that the wear-resistant layer prepared by the surfacing process of the present invention has excellent overall quality.

[0093] Test Example 2

[0094] Four different points were taken from the surfacing area, heat-affected zone and substrate of the low-pressure turbine rotor blades containing the wear-resistant layer obtained in Examples 1 to 4 and Comparative Examples 1 to 4, with one point taken every 0.5 mm, and the hardness of each point was tested. The data on the thickness of the obtained wear-resistant layer are summarized in Table 1.

[0095] Table 1. Test results of Examples 1 to 4 and Comparative Examples 1 to 4

[0096]

[0097]

[0098] It can be seen from Table 1 that the wear-resistant layers obtained in Examples 1 to 4 have high hardness and low average thickness. When the welding wire is replaced, the surfacing parameters are changed, or the distance to the concave R zone is shortened, the hardness of the surfacing zone and the heat-affected zone decreases to varying degrees, and the thickness of the wear-resistant layer also increases significantly. In addition, due to the lack of fusion in Comparative Example 2 and the presence of pores in Comparative Example 3, there is a large difference in the hardness values ​​of the two points, which is not conducive to application in fields with high wear resistance requirements and narrows the application range of low-pressure turbine rotor blades.

[0099] Test Example 3

[0100] The wear-resistant properties of the wear-resistant layers prepared in Examples 1 to 4 and Comparative Examples 1 to 4 were tested under the conditions of a load of 20 N, a stroke of 5 mm, a frequency of 5 Hz and a time of 30 minutes. The obtained experimental data are summarized in Table 2.

[0101] Table 2. Wear resistance test results of Examples 1 to 4 and Comparative Examples 1 to 4

[0102] Example <![CDATA[Wear rate (mm 3 ·N -1 ·m -1 )]]> Example 1 <![CDATA[3.67×10 -6 ]]> Example 2 <![CDATA[2.98×10 -6 ]]> Example 3 <![CDATA[3.52×10 -6 ]]> Example 4 <![CDATA[3.07×10 -6 ]]> Comparative Example 1 <![CDATA[4.63×10 -6 ]]> Comparative Example 2 <![CDATA[5.25×10 -6 ]]> Comparative Example 3 <![CDATA[4.93×10 -6 ]]> Comparative Example 4 <![CDATA[6.78×10 -6 ]]>

[0103] It can be seen from Table 2 that under the same conditions, the wear rates of the wear-resistant layers prepared in Examples 1 to 4 are significantly lower than those in Comparative Examples 1 to 4, which indicates that the wear resistance of Examples 1 to 4 is more excellent.

[0104] In summary, the wear-resistant layer prepared by the method of surfacing wear-resistant layer provided by the present invention has a lower average thickness and higher hardness, and there are no defects such as cracks and recrystallization in the heat-affected zone. The overall quality is higher and the wear resistance is better, which can effectively improve the reliability and service life of the low-pressure turbine rotor blades.

[0105] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for argon arc welding of wear-resistant layers on low-pressure turbine rotor blades, characterized in that: include: a) Use cobalt-based wear-resistant alloy welding wire to perform argon arc welding on the welded surface of the low-pressure turbine rotor blade, and introduce inert gas protection at the end of the cladding; The cobalt-based wear-resistant alloy welding wire contains the following components in mass fraction: C 0.08%, Si 2.5% to 4%, Cr 15% to 20%, Mo 26% to 32%, and the balance is Co; The welding current of the surfacing welding is 12-48A, and the welding speed is 6-15cm / min; b) cooling the surfacing-welded low-pressure turbine rotor blade obtained in step a) to form a wear-resistant layer.

2. The method according to claim 1, characterized in that: In the step a), the minimum distance between the surface to be welded of the low-pressure turbine rotor blade and the intersection of the concave R zone and the straight line segment is 0.3-1.7 mm.

3. The method according to claim 1, characterized in that The cobalt-based wear-resistant alloy welding wire comprises the following components in mass fractions: C 0.08%, Si 2.8%-4%, Cr 15.5%-19%, Mo 27%-31%, and the balance is Co.

4. The method according to claim 3, characterized in that The cobalt-based wear-resistant alloy welding wire is PMet980 welding wire.

5. The method according to claim 1, characterized in that In the argon arc welding process, the nozzle diameter of the welding gun is 8-15 mm, the diameter of the welding wire is 0.8-1.8 mm, the welding voltage is 10-18 V, the diameter of the tungsten electrode is 1.4-2.0 mm, and the argon gas flow rate is 5-12 L / min.

6. The method according to claim 1, characterized in that The time for introducing the inert gas protection in the step a) is 8 to 17 seconds.

7. The method according to claim 1, characterized in that The low-pressure turbine rotor blades are made of nickel-based single crystal high-temperature alloy DD6.

8. The method according to claim 1, characterized in that The time interval between step a) and step b) is ≤1 min.

9. The method according to claim 1, characterized in that: The cooling in step b) is to cool the low-pressure turbine rotor blades to 13-27° C. in a time of not less than 10 minutes.

10. The method according to claim 1, characterized in that The average thickness of the wear-resistant layer in step b) is 0.6-1.4 mm.

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