Laser welding method for 3D printing state high-heat-cracking-tendency alloy

Abstract

The invention provides a laser welding method for a 3D printing state high-heat-cracking-tendency alloy, and the welding method comprises the following specific steps: 1, determining actual welding parameters: determining the welding parameters according to the fusion depth required by design; the inclination angles of the light beams are respectively 10 degrees, 20 degrees, 30 degrees, 40 degrees, 50 degrees and 60 degrees, then calculating the actual penetration depth value of inclined incidence, and further obtaining the actual penetration depth value and penetration depth deviation during welding at different inclination angles of the light beams; welding parameters corresponding to the fusion depth deviation are inquired in the fusion depth-parameter through a database, so that actual welding parameters are determined; 2, determining a minimum inclination angle: obtaining thermal cycle curves under different light beam inclination angles, and determining the minimum inclination angle according to the thermal cycle curves; and thirdly, laser welding is conducted. High-quality welding is achieved, welding deformation and welding defects are reduced, the qualified rate of products is increased, and the effect of improving production efficiency is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser welding defect control, and particularly relates to a laser welding method for a 3D printed high-temperature alloy with a strong hot cracking tendency. Background Art

[0002] Due to the poor welding stability of 3D printed high-temperature alloys and the sensitivity of the hot cracking tendency after welding, the original welding method to solve this problem was to open a groove and fill the wire by manual argon arc welding.

[0003] The overall structure of the welding position of a certain product is cylindrical, with nearly a hundred welds. The stiffness of the product itself is limited. When performing groove opening and manual argon arc wire filling welding, due to the dense and numerous welds, the overall heat input is too large, resulting in large deformation and poor consistency of the product after welding. In severe cases, it will directly lead to product scrapping. In addition, manual argon arc wire filling welding has low efficiency and a long production cycle. Therefore, the suppression of post-weld cracks and the control of welding deformation of this product are the main difficulties in production and the key technologies that need to be broken through. Summary of the Invention

[0004] The purpose of the present invention is to provide a laser welding method for a 3D printed high-temperature alloy with a strong hot cracking tendency, achieving high-quality welding, reducing welding deformation and welding defects, improving the qualified rate of products, and playing a role in improving production efficiency.

[0005] The technical solution of the present invention is that the specific steps of a laser welding method for a 3D printed high-temperature alloy with a strong hot cracking tendency are as follows:

[0006] The first step is to determine the actual welding parameters: According to the required penetration depth of the design, determine the welding parameters; Step 1, determine the penetration deviation: Determine the inclination angles of different beams, and the beam inclination angles are 10°, 20°, 30°, 40°, 50°, and 60° respectively. Then, according to the required penetration depth value of the design and the inclination angle, use trigonometric functions to calculate the actual penetration depth value of the inclined incidence, and further obtain the actual penetration depth value and penetration deviation when welding at different beam inclination angles.

[0007] Step 2, determine the actual welding parameters:

[0008] Query the welding parameters corresponding to the penetration deviation in the penetration - parameter database to determine the actual welding parameters;

[0009] The second step is to determine the minimum inclination angle:

[0010] Step 1, perform finite element calculations to obtain the thermal cycle curves at different beam inclination angles:

[0011] First, input the heat input parameters into the finite element heat source program. Then, establish a flat specimen model in the finite element, add material properties, and divide the mesh. Finally, carry out the finite element calculation of the welding temperature field to obtain the thermal cycle curve.

[0012] Step 2: Determine the minimum tilt angle according to the thermal cycle curve.

[0013] Determine the minimum tilt angle of the extraction position according to the thermal cycle curves at different beam tilt angles obtained and the thermal cycle curve under the vertical beam. The extraction position is the weld center. Take the time when the surface temperature of the vertical beam welding in the thermal cycle curve cools down to 1500 °C as the benchmark, and determine the beam tilt angles with a temperature greater than 1700 °C at the same moment. There will be multiple beam tilt angles with a temperature greater than 1700 °C, and take the minimum tilt angle among them.

[0014] The third step: Carry out laser welding.

[0015] Carry out laser welding according to the minimum tilt angle determined in the second step and the laser welding parameters determined in the first step.

[0016] The beneficial effect of the present invention is that the present invention effectively inhibits the generation of laser welding hot cracks in 3D printed superalloy materials, controls the welding deformation of products, reduces the welding time, improves the welding qualification rate of products, and achieves the effects of improving welding quality and production efficiency. Description of the Drawings

[0017] The accompanying drawings included are used to provide a further understanding of the embodiments of the present invention. They form a part of the specification, are used to illustrate the embodiments of the present invention, and are used to explain the principles of the present invention together with the written description. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 a is a welding schematic diagram with the laser beam vertically incident in the present invention;

[0019] Figure 1 b is a welding schematic diagram with the laser beam incident at a backward tilt in the present invention;

[0020] Figure 1 c is a welding schematic diagram with the laser beam incident at a forward tilt in the present invention;

[0021] Figure 2 is a schematic diagram of the finite element calculation result of the laser beam tilt angle welding in the present invention;

[0022] Figure 3 is a schematic diagram of the finite element calculation result of the welding thermal cycle at different beam tilt angles in the present invention;

[0023] Figure 4 Schematic metallographic diagrams of vertical laser welding and inclined laser welding seams of a high thermal cracking tendency alloy in the 3D printing state by using the method of the present invention. Specific embodiments

[0024] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings of the specification.

[0025] A laser welding method for a 3D printing state high thermal cracking tendency alloy of the present invention includes the following steps:

[0026] The first step is to determine the actual welding parameters: According to the required penetration depth of the design, determine the welding parameters.

[0027] Step 1, determine the penetration deviation: The required penetration depth of the design refers to the penetration depth value when the laser beam is vertically incident under the specified laser welding parameters. As Figure 1 shown, according to the required welding penetration depth of the design, calculate the actual penetration deviation during welding at different beam inclination angles. That is, determine different beam inclination angles, and the beam inclination angles are 10°, 20°, 30°, 40°, 50° and 60° respectively. Then, according to the required welding penetration depth value of the design and the inclination angle, use trigonometric functions to calculate the actual penetration depth value of the inclined incidence, and further obtain the actual penetration depth value and penetration deviation during welding at different beam inclination angles.

[0028] Step 2, determine the actual welding parameters:

[0029] Match the penetration deviation obtained in Step 1 in the penetration - parameter database, that is, query the welding parameters corresponding to the penetration deviation in the penetration - parameter database, so as to determine the actual welding parameters that meet the required welding penetration depth of the design. The welding parameters include laser power and laser welding speed.

[0030] The second step is to determine the minimum inclination angle:

[0031] Step 1, perform finite element calculation to obtain the thermal cycle curves at different beam inclination angles:

[0032] As Figure 2 and Figure 3 shown, take the welding parameters (heat input parameters) as the heat input boundary conditions, and carry out finite element calculation of the welding temperature field; first input the heat input parameters into the finite element heat source program, then establish a flat specimen model in the finite element, add material properties, divide the mesh, and finally carry out finite element calculation of the welding temperature field, so as to obtain the thermal cycle curves. The heat input parameters include laser power and welding speed. The thermal cycle curve is a curve of the relationship between time and temperature.

[0033] Step 2: Determine the minimum tilt angle according to the thermal cycle curve:

[0034] Determine the minimum tilt angle of the extraction position according to the thermal cycle curves at different beam tilt angles obtained and the thermal cycle curve under the vertical beam. The extraction position is the center of the weld. Take the time when the surface temperature of the vertical beam weld in the thermal cycle curve cools to 1500 °C as the reference, and determine the beam tilt angles with a temperature greater than 1700 °C at the same moment. There will be multiple beam tilt angles with a temperature greater than 1700 °C, and take the minimum tilt angle among them.

[0035] Step 3: Perform laser welding:

[0036] Perform laser welding according to the minimum tilt angle determined in the second step and the laser welding parameters determined in the first step.

[0037] As Figure 4 shown, through experiments, the above welding method not only ensures high-quality laser welding of 3D printed high hot cracking tendency alloys, but also effectively suppresses welding defects and controls welding deformation. This welding method can make the welding deformation of dense welds smaller.

Claims

1. A laser welding method for a 3D printing state alloy with a strong hot cracking tendency, characterized in that: The specific steps of this welding method are as follows: The first step is to determine the actual welding parameters: Determine the welding parameters according to the penetration depth required by the design. Step 1: Determine the penetration deviation: Determine the inclination angles of different beams, which are 10°, 20°, 30°, 40°, 50° and 60° respectively. Then, based on the penetration depth value required by the design and the inclination angle, use trigonometric functions to calculate the actual penetration depth value of the obliquely incident beam, and further obtain the actual penetration depth value and penetration deviation when welding with different beam inclination angles. Step 2: Determine the actual welding parameters: Query the welding parameters corresponding to the penetration deviation in the penetration - parameter database to determine the actual welding parameters. The second step is to determine the minimum inclination angle: Step 1: Conduct finite - element calculations to obtain the thermal cycle curves at different beam inclination angles: First, input the heat - input parameters into the finite - element heat - source program. Then, establish a flat - specimen model in the finite - element software, add material properties and divide the mesh. Finally, carry out the finite - element calculation of the welding temperature field to obtain the thermal cycle curves. Step 2: Determine the minimum inclination angle according to the thermal cycle curves: Determine the minimum inclination angle at the extraction position according to the thermal cycle curves at different beam inclination angles obtained and the thermal cycle curve under the vertical beam. The extraction position is the center of the weld. Take the time when the surface temperature of the vertical - beam welding in the thermal cycle curve cools to 1500°C as the reference, and determine the beam inclination angles with a temperature greater than 1700°C at the same moment. There may be multiple beam inclination angles with a temperature greater than 1700°C, and take the minimum inclination angle among them. The third step is to perform laser welding: Perform laser welding according to the minimum inclination angle determined in the second step and the laser - welding parameters determined in the first step.

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