Powder-cored wire for welding turbine disc of aero-engine and preparation method and application of powder-cored wire

Abstract

The invention discloses a powder-cored wire for welding a turbine disc of an aero-engine, which comprises a flux core and an outer skin, the powder core comprises a powder core and a welding skin, and the powder core comprises the following components by mass percent: 7% < = Cr < = 14%; 4.0% < = Si < = 4.5%; 3.0% < = B < = 3.5%; 2.5% < = Fe < = 4.5%; 0% < = Co < = 1.0%; the welding skin is a nickel strip; the invention further discloses a preparation method and application of the powder-cored wire for welding the turbine disc of the aero-engine, the powder-cored wire is utilized, the turbine disc of the aero-engine is welded through double-beam laser brazing, the performance of a nickel-based cladding layer cladded on the welding surface of the turbine disc of the aero-engine by the powder-cored wire is excellent, and the welding quality of the turbine disc of the aero-engine is improved. The prepared cladding layer can be well combined with a base material, and the surface performance is excellent.

Description

Technical Field

[0001] The invention belongs to the technical field of welding materials, and specifically relates to a powder cored welding wire for welding an aircraft engine turbine disk and a preparation method thereof, and also relates to an application method of the powder cored welding wire for welding an aircraft engine turbine disk. Background Art

[0002] The turbine disk is a core component in an aircraft engine, responsible for connecting the blades and withstanding extreme conditions of high temperature, high pressure and high-speed rotation. It is exposed to harsh environments such as centrifugal loads, thermal stress and corrosion for a long time, so the requirements for welding technology are extremely high. The introduction of laser welding technology provides a new solution for the manufacture of turbine disks, greatly improving production efficiency and material properties. However, laser welding involves powder feeding and wire feeding. Compared with coaxial powder feeding, wire feeding welding usually uses prefabricated welding wire, which can more accurately control the amount of filler material, thereby reducing material waste and improving material utilization. The scattering and splashing of powder can easily cause material waste, and the material utilization rate is relatively low.

[0003] Compared with the traditional solid welding wire, the internal metal composition of the powder cored welding wire can be freely adjusted, and its welding process performance and efficiency are much better than the traditional solid welding wire. Flux cored welding wire can easily adjust the chemical composition of the deposited metal, thereby improving the mechanical properties of the weld. The use of flux cored welding wire can obtain chemical composition and mechanical properties that match the welding parent material. In addition, due to the low matching of the existing powder cored welding wire, the strength of the welded joint may be insufficient (low yield strength), and the weld may easily have pores or cracks. These problems may affect the performance and life of the welded joint. The powder cored welding wire proposed by the present invention perfectly solves the problem of matching welding materials and welding technology, and has an important role and significance in promoting the development of modern industry. Summary of the invention The first object of the present invention is to provide a powder cored welding wire for welding aircraft engine turbine disks, which solves the problems of low yield strength of welded joints and easy weld formation that may occur in existing welding wires.

[0004] A second object of the present invention is to provide a method for preparing a powder cored welding wire for welding aero-engine turbine disks.

[0005] The third object of the present invention is to provide an application of powder cored welding wire for welding aircraft engine turbine disks, which overcomes the limitations of traditional manufacturing methods, improves material utilization and production efficiency, and at the same time ensures the high performance and reliability of the turbine disk.

[0006] The first technical solution adopted by the present invention is: a powder cored welding wire for welding aircraft engine turbine disks, comprising a powder core and a weld skin, wherein the powder core is composed of the following components in terms of mass percentage: 7% ≤ Cr ≤ 14%; 4.0% ≤ Si ≤ 4.5%; 3.0% ≤ B ≤ 3.5%; 2.5% ≤ Fe ≤ 4.5%; 0% ≤ Co ≤ 1.0%, and the rest is nickel, and the sum of the masses of the various components is 100%; the weld skin is a nickel strip, and the filling amount of the powder core powder in the welding wire is 18%-25%.

[0007] The roles of various raw materials in welding wire are as follows: (1) The Ni element has good corrosion resistance, which enables Inconel718 alloy to have excellent corrosion resistance in high temperature, high pressure and corrosive environments. By controlling the content of the Ni element and the heating treatment conditions, the grain refinement of the alloy can be effectively promoted.

[0008] (2) Cr can form strengthening phases with other elements. These strengthening phases can effectively inhibit lattice slip and grain boundary slip, and improve the high temperature strength and deformation resistance of the alloy. Cr can form stable compounds with Nb and other elements, such as Ni3 (Nb, Cr), etc. These compounds can inhibit the precipitation phase transformation of the alloy at high temperature and improve the thermal stability of the alloy.

[0009] (3) The role of Fe in welding wire is to enhance the mechanical properties and corrosion resistance of the alloy. Fe can increase the strength and hardness of the alloy. Fe forms a solid solution with elements such as Ni and Cr, giving the alloy good strength and hardness. In addition, Fe can also increase the strength of the alloy by forming precipitation phases and solid solution strengthening phases.

[0010] (4) Co can significantly improve the strength and hardness of the weld, making it more wear-resistant. It can also improve the weld's oxidation resistance, making it more stable in high temperature environments. Co can also improve the weld's toughness and reduce its brittleness.

[0011] (5) B can act as a deoxidizer to reduce the oxygen content in the weld and prevent the occurrence of oxidation reactions. Improve weld performance: Improve the strength and toughness of the weld while reducing the brittleness of the weld. Promote grain refinement: B can promote grain refinement of weld metal and improve the mechanical properties of the weld.

[0012] (6) Si is one of the most commonly used deoxidizing elements in welding wires. It can prevent iron from combining with oxygen and can reduce FeO in the molten pool. Improve weld strength: Si can improve the strength and hardness of the weld, but if used alone, it may cause slag inclusions in the weld metal. Improve weld toughness: Si can improve the toughness of the weld, making it more durable.

[0013] The second technical solution adopted by the present invention is: a method for preparing a powder cored welding wire for welding an aircraft engine turbine disk, and the specific operation steps are as follows: Step 1, weigh 7%≤Cr≤14%; 4.0%≤Si≤4.5%; 3.0%≤B≤3.5%; 2.5%≤Fe≤4.5%; 0%≤Co≤1.0% respectively according to mass percentage, and the rest is nickel; Step 2, weighing alloy powders of different proportions and placing them in a ball mill for ball milling to obtain core powders with a particle size of 15-45 µm; Step 3: The powder cores obtained by ball milling in step 2 are uniformly mixed and placed in a tube furnace for drying while continuously introducing argon gas. The dried powder cores are placed in a powder mixer for sufficient mixing. The mixing time is 1 h to 2 h. Step 4: Roll the nickel strip on a wire drawing machine, wrap the powder core prepared in step 2 in the nickel strip, close the alloy strip through a die, reduce the diameter of the thick welding wire to 1.6 mm, and remove impurities on the surface of the welding wire; thus, a powder core welding wire is obtained.

[0014] The second technical solution of the present invention is also characterized in that: The ball mill described in step 2 uses stainless steel ball milling beads, and the diameters of the ball milling beads are 5mm, 10mm, and 20mm.

[0015] In step 2, the ball milling speed is 200-300 r / min, and the ball milling time is 2-3 hours.

[0016] In step 3, the temperature of the tubular furnace is set to 150° C. to 180° C., and the drying time is 1 h to 1.5 h.

[0017] The filling amount of the powder core in the powder core welding wire in step 4 is 18%-25%.

[0018] The third technical solution adopted by the present invention is: application of powder cored welding wire for welding aero-engine turbine disks, and the specific operation steps are as follows: Using powder cored wire, dual beam laser brazing was adopted, the laser power was set to 350~400W, and the laser energy density range was 50~200 J / mm^ 3 , the scanning speed is 400~500 mm / s. During the laser brazing process, argon gas is continuously introduced to prevent oxidation during the welding process, and laser brazing is completed in an argon gas environment with a gas flow rate of 5~10L / min. The beneficial effects of the present invention are: (1) The powder cored welding wire designed in the present invention is targeted at the use environment of turbine disks. It uses nickel as the main component and can work for a long time in a high temperature environment of more than 1000 degrees Celsius without significant deformation. It has high hardness and excellent corrosion resistance. It can also provide high-quality welds with good mechanical properties and crack resistance. The welding wire has high deposition efficiency and improves the utilization rate of materials.

[0019] (2) The method of the present invention uses dual-beam laser welding to improve the toughness of the weld by controlling the cooling rate of the welding molten pool; dual-beam laser welding can change the flow pattern of liquid metal, which helps to prevent defects such as undercut and weld bead protrusion, and improve weld formation. The nickel-based cladding layer clad on the welding surface of the aircraft engine turbine disk by the powder cored welding wire of the present invention has excellent performance, and the prepared cladding layer can be well combined with the substrate and has excellent surface performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Microstructure diagram of the weld prepared in Example 1 of the present invention; Figure 2 Microstructure diagram of the weld prepared in Example 2 of the present invention; Figure 3 Microstructure diagram of the weld prepared in Example 3 of the present invention; Figure 4 Microstructure diagram of the weld obtained by welding the turbine disk of an aero-engine in Examples 1-5 of the present invention. DETAILED DESCRIPTION

[0021] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Example 1 First, a powder cored welding wire for welding an aircraft engine turbine disk is prepared, and then the welding wire is used to weld the aircraft engine turbine disk, specifically: Step 1: Weigh the following core powders according to mass percentage: Cr 20%, Si 4.5%, B 15%, Fe 4.5%, Co 1.0%, and the rest Ni, and the sum of the mass percentages of the above components is 100%.

[0023] Step 2: Weigh alloy powders of different proportions and place them in a ball mill. Select stainless steel ball mill beads with diameters of 5mm, 10mm, and 20mm. The ball mill speed reaches 300r / min and the ball mill time is 2~3 hours. The obtained powder particle size is 15~45µm.

[0024] Step 3: The powder cores obtained by ball milling in step 2 are evenly mixed and placed in a tube furnace and argon gas is continuously introduced. The furnace temperature is set to 150° C. and the drying time is 1 h. The dried powder cores are placed in a powder mixer for sufficient mixing, and the mixing time is 2 h. Step 4: Roll the nickel strip on a wire drawing machine, wrap the powder core prepared in step 2 in the nickel strip, close the alloy strip through a mold, reduce the diameter of the thick welding wire to 1.6 mm, and remove impurities on the surface of the welding wire; the filling amount of the powder core powder in the powder core welding wire is 18.%.

[0025] Step 5: Use dual-beam laser brazing, set the laser power to 350W, and the laser energy density range is 50 J / mm^ 3 , the scanning speed is 400mm / s.

[0026] Step 6: Continuously introduce argon gas during the laser brazing process to prevent oxidation during welding, and complete the laser brazing in an argon environment with a gas flow rate of 5~10L / min.

[0027] The weld test results show that the mechanical properties test and microstructure observation (such as Figure 1 ) after, the average microhardness can reach 634.80HV 0.5 The shear strength reaches 371.58MPa and the tensile strength is 401.34MPa.

[0028] Example 2 First, a powder cored welding wire for welding an aircraft engine turbine disk is prepared, and then the welding wire is used to weld the aircraft engine turbine disk, specifically: Step 1: Weigh the following core powders according to mass percentage: Cr 20%, Si 4.5%, B 10%, Fe 4.5%, Co 1.0%, and the rest Ni, and the sum of the mass percentages of the above components is 100%.

[0029] Step 2: Weigh alloy powders of different proportions and place them in a ball mill. Select stainless steel ball mill beads with diameters of 5mm, 10mm, and 20mm. The ball mill speed reaches 300r / min and the ball mill time is 2~3 hours. The obtained powder particle size is 15~45µm.

[0030] Step 3: The powder cores obtained by ball milling in step 2 are evenly mixed and placed in a tube furnace and argon gas is continuously introduced. The furnace temperature is set to 150° C. and the drying time is 1 h. The dried powder cores are placed in a powder mixer for sufficient mixing, and the mixing time is 2 h. Step 4: Roll the nickel strip on a wire drawing machine, wrap the powder core prepared in step 2 in the nickel strip, close the alloy strip through a mold, reduce the diameter of the thick welding wire to 1.6 mm, and remove impurities on the surface of the welding wire; the filling amount of the powder core powder in the powder core welding wire is 18.%.

[0031] Step 5: Use dual-beam laser brazing, set the laser power to 350W, and the laser energy density range is 50 J / mm^ 3 , the scanning speed is 400mm / s.

[0032] Step 6: Continuously introduce argon gas during the laser brazing process to prevent oxidation during welding, and complete the laser brazing in an argon environment with a gas flow rate of 5~10L / min.

[0033] The weld test results show that the mechanical properties test and microstructure (such as Figure 2 ) After observation, the average microhardness can reach 576.40HV 0.5 , the shear strength reaches 412.52MPa and the tensile strength is 457.82MPa.

[0034] Example 3 First, a powder cored welding wire for welding an aircraft engine turbine disk is prepared, and then the welding wire is used to weld the aircraft engine turbine disk, specifically: Step 1: Weigh the following core powders according to mass percentage: Cr 14%, Si 4.5%, B 5%, Fe 4.5%, Co 1.0%, and the rest Ni, and the sum of the mass percentages of the above components is 100%.

[0035] Step 2: Weigh alloy powders of different proportions and place them in a ball mill. Select stainless steel ball mill beads with diameters of 5mm, 10mm, and 20mm. The ball mill speed reaches 300r / min and the ball mill time is 2~3 hours. The obtained powder particle size is 15~45µm.

[0036] Step 3: The powder cores ball-milled in step 2 are evenly mixed and placed in a tube furnace and argon is continuously introduced, the furnace temperature is set to 150°C, and the drying time is 1hh; the dried powder cores are placed in a powder mixer for sufficient mixing, and the mixing time is 2h; Step 4: Roll the nickel strip on a wire drawing machine, wrap the powder core prepared in step 2 in the nickel strip, close the alloy strip through a mold, reduce the diameter of the thick welding wire to 1.6 mm, and remove impurities on the surface of the welding wire; the filling amount of the powder core powder in the powder core welding wire is 18.%.

[0037] Step 5: Use dual-beam laser brazing, set the laser power to 370W, and the laser energy density range is 50 J / mm^ 3, the scanning speed is 400mm / s.

[0038] Step 6: Continuously introduce argon gas during the laser brazing process to prevent oxidation during welding, and complete the laser brazing in an argon environment with a gas flow rate of 5~10L / min.

[0039] The weld test results show that the mechanical properties test and microstructure (such as Figure 3 ) After observation, the average microhardness can reach 415.00HV 0.5 The shear strength reaches 571.20MPa and the tensile strength is 559.30MPa.

[0040] Example 4 First, a powder cored welding wire for welding an aircraft engine turbine disk is prepared, and then the welding wire is used to weld the aircraft engine turbine disk, specifically: Step 1: Weigh the following core powders according to mass percentage: Cr 15%, Si 4.2%, B 3.5%, Fe 3.0%, Co 0.5%, and the rest Ni, and the sum of the mass percentages of the above components is 100%.

[0041] Step 2: Weigh alloy powders of different proportions and place them in a ball mill. Select stainless steel ball mill beads with diameters of 5mm, 10mm, and 20mm. The ball mill speed reaches 250r / min and the ball mill time is 2~3 hours. The obtained powder particle size is 15~45µm.

[0042] Step 3: The powder cores obtained by ball milling in step 2 are evenly mixed and placed in a tube furnace and argon gas is continuously introduced. The furnace temperature is set to 160° C. and the drying time is 1 h. The dried powder cores are placed in a powder mixer for sufficient mixing, and the mixing time is 2 h. Step 4: Roll the nickel strip on a wire drawing machine, wrap the powder core prepared in step 2 in the nickel strip, close the alloy strip through a mold, reduce the diameter of the thick welding wire to 1.6 mm, and remove impurities on the surface of the welding wire; the filling amount of the powder core powder in the powder core welding wire is 20.%.

[0043] Step 5: Use dual-beam laser brazing, set the laser power to 370W, and the laser energy density range is 100J / mm^ 3 , the scanning speed is 450mm / s.

[0044] Step 6: Continuously introduce argon gas during the laser brazing process to prevent oxidation during welding, and complete the laser brazing in an argon environment with a gas flow rate of 5~10L / min.

[0045] The weld test results show that after mechanical properties testing and microstructure observation, the average microhardness can reach 375.90HV 0.5The shear strength reaches 603.52MPa and the tensile strength is 589.20MPa.

[0046] Example 5 First, a powder cored welding wire for welding an aircraft engine turbine disk is prepared, and then the welding wire is used to weld the aircraft engine turbine disk, specifically: Step 1: Weigh the following core powders according to mass percentage: Cr 10%, Si 4.2%, B 2.5%, Fe 3.0%, Co 0.5%, and the rest Ni, and the sum of the mass percentages of the above components is 100%.

[0047] Step 2: Weigh alloy powders of different proportions and place them in a ball mill. Select stainless steel ball mill beads with diameters of 5mm, 10mm, and 20mm. The ball mill speed reaches 300r / min and the ball mill time is 2~3 hours. The obtained powder particle size is 15~45µm.

[0048] Step 3: The powder cores obtained by ball milling in step 2 are evenly mixed and placed in a tube furnace and argon gas is continuously introduced. The furnace temperature is set to 160° C. and the drying time is 1 h. The dried powder cores are placed in a powder mixer for sufficient mixing, and the mixing time is 2 h. Step 4: Roll the nickel strip on a wire drawing machine, wrap the powder core prepared in step 2 in the nickel strip, close the alloy strip through a mold, reduce the diameter of the thick welding wire to 1.6 mm, and remove impurities on the surface of the welding wire; the filling amount of the powder core powder in the powder core welding wire is 25.%.

[0049] Step 5: Use dual-beam laser brazing, set the laser power to 400W, and the laser energy density range to 200J / mm^ 3 , the scanning speed is 500mm / s.

[0050] Step 6: Continuously introduce argon gas during the laser brazing process to prevent oxidation during welding, and complete the laser brazing in an argon environment with a gas flow rate of 5~10L / min.

[0051] The weld test results show that after mechanical properties testing and microstructure observation, the average microhardness can reach 345.80HV 0.5 , shear strength reaches 408.23Mpa, tensile strength 375.10MPa The performance results obtained by laser brazing the welding wires of Examples 1-5 are as follows: Figure 4 As shown, with the change of B and Cr content, the weld performance changes accordingly. When B and Cr account for a high proportion, the weld hardness is high, but the tensile and shear properties are reduced. When B and Cr account for a low proportion, the overall performance is poor. The optimal result is the ratio of Example 3, which takes into account the hardness while improving the tensile and shear strength.

[0052] In summary, the high temperature resistance of ordinary welding wire meets the requirements, but the wear resistance, tensile and shearing performance of the turbine disk working for a long time under high temperature conditions is insufficient, and it cannot meet the long-term use in the application environment of the aircraft engine turbine disk. The nickel-based alloy material meets the requirements. Since the welding of the aircraft engine turbine disk is difficult, double-beam laser welding is used. The method of the present invention can improve the hardness, wear resistance and corrosion resistance of the aircraft engine turbine disk welding.

[0053] Example 6 The powder core welding wire for welding aero-engine turbine disks of the present invention comprises a powder core and a welding skin, wherein the powder core consists of the following components by mass percentage: 7%≤Cr≤14%; 4.0%≤Si≤4.5%; 3.0%≤B≤3.5%; 2.5%≤Fe≤4.5%; 0%≤Co≤1.0%, and the rest is nickel; the welding skin is a nickel strip, and the filling amount of the powder core in the powder core welding wire is 18%-25%.

[0054] The powder cored welding wire designed in the present invention is targeted at the use environment of turbine disks. It uses nickel as the main component and can work for a long time in a high temperature environment of over 1000 degrees Celsius without significant deformation. It has high hardness and excellent corrosion resistance. It can also provide high-quality welds with good mechanical properties and crack resistance. The welding wire has high deposition efficiency and improves material utilization.

Claims

1. A powder cored welding wire for welding aero-engine turbine disks, characterized in that: The welding wire comprises a powder core and a welding skin, wherein the powder core comprises the following components by mass percentage: 7%≤Cr≤14%; 4.0%≤Si≤4.5%; 3.0%≤B≤3.5%; 2.5%≤Fe≤4.5%; 0%≤Co≤1.0%, and the rest is nickel; the welding skin is a nickel strip, and the filling amount of the powder core in the powder core welding wire is 18%-25%.

2. A method for preparing a powder cored welding wire for welding an aircraft engine turbine disk, characterized in that: The specific steps are as follows: Step 1, weigh 7%≤Cr≤14%; 4.0%≤Si≤4.5%; 3.0%≤B≤3.5%; 2.5%≤Fe≤4.5%; 0%≤Co≤1.0% respectively according to mass percentage, and the rest is nickel; Step 2, weighing alloy powders of different proportions and placing them in a ball mill for ball milling to obtain core powders with a particle size of 15µm to 45µm; Step 3: The powder cores obtained by ball milling in step 2 are uniformly mixed and placed in a tube furnace for drying while continuously introducing argon gas. The dried powder cores are placed in a powder mixer for sufficient mixing. The mixing time is 1 h to 2 h. Step 4: Roll the nickel strip on a wire drawing machine, wrap the powder core prepared in step 2 in the nickel strip, close the alloy strip through a die, reduce the diameter of the thick welding wire to 1.6 mm, and remove impurities on the surface of the welding wire; thus, a powder core welding wire is obtained.

3. The method for preparing a powder cored welding wire for welding an aircraft engine turbine disk according to claim 2, characterized in that: The ball mill described in step 2 uses stainless steel ball milling beads, and the diameters of the ball milling beads are 5mm, 10mm, and 20mm.

4. The method for preparing a powder cored welding wire for welding an aircraft engine turbine disk according to claim 2, characterized in that: In step 2, the ball milling speed is 200-300 r / min, and the ball milling time is 2-3 hours.

5. The method for preparing a powder cored welding wire for welding an aircraft engine turbine disk according to claim 2, characterized in that: In step 3, the temperature of the tubular furnace is set to 150° C. to 180° C., and the drying time is 1 h to 1.5 h.

6. The method for preparing a powder cored welding wire for welding an aircraft engine turbine disk according to claim 2, characterized in that: The filling amount of the powder core in the powder core welding wire in step 4 is 18%-25%.

7. Application of powder cored welding wire for welding turbine disks of aircraft engines, characterized in that: The specific steps are as follows: Using powder cored wire, dual beam laser brazing is adopted, the laser power is set to 350W~400W, and the laser energy density range is 50~200J / mm^ 3 , the scanning speed is 400~500mm / s; argon gas is continuously introduced during the laser brazing process to complete the laser brazing.

8. The use of the powder cored welding wire for welding aero-engine turbine disks according to claim 7, characterized in that: The argon gas continuously flows at a flow rate of 5-10 L / min.

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