CN113102862B - Ultrasonic-assisted arc additive manufacturing method - Google Patents

Abstract

The invention discloses an ultrasonic-assisted arc additive manufacturing method which is characterized in that a stirring needle with a reciprocating ultrasonic vibration characteristic is inserted into an additive manufacturing molten pool and synchronously moves along with the molten pool when arc additive manufacturing is carried out, ultrasonic vibration and stirring are carried out on the solidification process of molten pool metal, and solidification structure and mechanical property of the molten pool metal are improved. The invention has the advantages of better introducing ultrasonic assistance in the arc additive manufacturing process, improving the ultrasonic effect and improving the tissue and mechanical properties of the arc additive manufacturing material or part.

Description

An ultrasonic-assisted arc additive manufacturing method

technical field

The invention relates to the field of additive manufacturing, in particular to an ultrasonic-assisted arc additive manufacturing method.

Background technique

In recent years, under the background of resource saving and high-efficiency manufacturing, the additive manufacturing technology based on the "additive" processing mode has shown broad application prospects in the manufacture of thin-walled parts with complex shapes. With the increasingly stringent requirements for the performance, precision, manufacturing cost and cycle time of dense metal parts in key technical fields such as aerospace, national defense and military industry, and rail transportation, it is urgent to carry out relevant research to break through and master the direct forming technology of metal parts. Arc additive manufacturing mostly uses arcs such as melting inert gas welding (MIG), tungsten inert gas welding (TIG) and plasma welding (PA) as heat sources, adding wire, and under program control, according to the three-dimensional digital model Metal parts are gradually formed from line-surface-body. The main features are high deposition efficiency and wire utilization, short overall manufacturing cycle (deposition rate can reach 1kg/h), low cost, and in-situ composite manufacturing and large-scale forming. Capability of dimensional parts (workpieces as large as lm3 can be manufactured). However, the accumulation layer of arc additive manufacturing is essentially the solidified structure after the welding wire is melted. Similar to the arc surfacing structure, the structure often appears uneven, and the solidified structure near the fusion line tends to grow into thick columnar crystals; Defects such as pores may occur, resulting in poor performance of the additive manufacturing build-up layer, making it difficult to obtain high-performance additive manufacturing materials or parts.

In response to the above problems, two patents of CN106363173A and CN111215843A respectively announced a device and method of using ultrasonic-assisted laser welding additive manufacturing and a manufacturing method and device of arc additive manufacturing hot rolling, although to a certain extent, the Pore defects are eliminated, and the quality of the weld seam is improved. However, there are still some problems: the structure of laser welding equipment is relatively complex, the process flow, operation steps are cumbersome, and the cost is high; hot rolling equipment uses multiple rolling after welding, and the process is complicated, which affects production efficiency.

In addition, the two patents of CN102794542A and CN101239415A both disclose a welding method that uses an external source of vibration to vibrate the welding wire to reduce welding pores during the welding process. The vibration wire can improve the generation of welding pores, but there are some problems: 1) The melting position of the welding wire is above the molten pool, and the stirring effect on the molten pool is limited; 2) The vibrating welding wire makes the welding arc vibrate accordingly, which is easy to cause poor arc stability of the welding wire, or even arc extinction, thus affecting the forming quality of the weld.

Contents of the invention

Aiming at the deficiencies of the above-mentioned existing technologies, the technical problem to be solved by the present invention is: how to provide a method that can better introduce ultrasonic assistance in the arc additive manufacturing process, improve the ultrasonic effect, and improve the arc additive manufacturing materials or parts. Microstructure and Mechanical Properties of Ultrasound-Assisted Arc Additive Manufacturing.

In order to solve the problems of the technologies described above, the present invention adopts the following technical solutions:

An ultrasonic-assisted arc additive manufacturing method is characterized in that, when performing arc additive manufacturing, a stirring needle with reciprocating ultrasonic vibration characteristics is inserted into the additive manufacturing molten pool, and moves synchronously with the molten pool to The solidification process of the pool metal implements ultrasonic vibration and stirring to improve its solidification structure and mechanical properties.

In this way, during arc additive manufacturing in this method, a stirring needle in a vibrating state is directly inserted into the molten pool, and ultrasonic vibration is introduced into the molten pool through stirring, so that the cavitation effect and vibration effect of ultrasonic vibration can be better utilized, and welding pores can be reduced. , refine the grains, increase the bonding strength between the edge of the molten pool in the welded area and the non-welded area during the crystallization process, and improve the solidification structure and mechanical properties of the molten pool metal. Compared with other ultrasonic vibration methods, such as loading on the base material or through arc loading, the ultrasonic vibration loading method of the present invention is more direct to the ultrasonic vibration of the molten pool, and also has a good mechanical stirring effect, which is beneficial to the molten pool metal The improvement effect of coagulation structure and mechanical properties is better.

As an optimization, the stirring needle is made of metal tungsten or tungsten alloy.

In this way, it can be better ensured that the stirring needle will not react with the molten pool metal.

As an optimization, the vibration direction of the stirring needle is along its own axis.

In this way, the stirring needle acting on the molten pool will only drive the liquid metal in the molten pool to perform high-frequency reciprocating vibrations within a certain area. Stirring) to reduce welding porosity and increase the bonding density of welding materials at the molecular level, thereby improving the mechanical properties of the welding area and improving the welding effect.

As an optimization, the vibration frequency of the stirring needle is 20-100KHZ, and the amplitude is 0.2-1mm. The vibration in this range can better ensure that the vibration has a benign effect on the metal crystallization, and avoid excessive vibration that will affect the crystallization and reduce the welding quality.

As an option, the arc additive manufacturing welding torch is arranged along the direction perpendicular to the product plane where the molten pool is located, and the stirring pin is inserted obliquely downward from the front or rear of the arc additive manufacturing welding gun to the middle of the molten pool to achieve ultrasonic vibration.

This is because the welding torch is arranged perpendicular to the product plane during conventional arc additive manufacturing, so this method can be implemented by directly adding a stirring needle to introduce ultrasonic vibration on the basis of the conventional arc additive manufacturing process control process, and there is no need to adjust the arc augmentation. The control program of the material manufacturing welding torch is convenient for implementation and application.

As another option, the arc additive manufacturing welding torch is arranged so that the upper end of the arc additive manufacturing welding torch is arranged obliquely in front of the traveling direction of the arc additive manufacturing welding torch, and the stirring pin is arranged behind the arc additive manufacturing welding torch and inserted vertically downward into the additive manufacturing molten pool Ultrasonic vibration is achieved in the middle.

In this way, the upper end of the arc additive manufacturing welding torch is inclined along the direction of travel, which can better preheat the area to be processed in front of the molten pool, and at the same time make room for the vertical arrangement of the stirring needle along the middle of the molten pool, and the vertical arrangement of the stirring needle After being located in the middle of the molten pool, the ultrasonic vibration can be transmitted to the entire molten pool very uniformly, avoiding the influence of the uneven transmission of ultrasonic vibration in the molten pool on the fusion effect of metal crystals, and greatly improving the forming quality of the product.

Further, the method is realized by means of the following arc additive manufacturing equipment, the arc additive manufacturing equipment includes an arc additive manufacturing welding torch, the arc additive manufacturing welding torch is installed on a horizontally arranged cage as a whole and the welding head One end is downward, and a vibrating stirring device is installed on the cage. The vibrating stirring device includes an ultrasonic vibrator. A stirring needle is arranged downward at the lower end of the ultrasonic vibrator. The ultrasonic vibrator can provide axial vibration for the stirring needle.

In this way, the welding gun and the vibration stirring device are installed on the same cage, which can better ensure that the stirring needle follows the welding gun synchronously to realize vibration stirring.

Further, the arc additive manufacturing welding torch is installed on a welding torch mounting sleeve, and the welding torch mounting sleeve is vertically rotatably mounted on the holder through a welding torch mounting sleeve rotation adjustment handle.

Unscrew the welding torch mounting sleeve and turn the adjusting handle so that the angle of inclination of the welding torch mounting sleeve in the vertical direction can be rotated, and then the angle of the welding torch can be adjusted as required. The structure involving the adjustment handle in the scheme to realize the adjustment and fastening is a mature existing technology. It can be realized by setting a bolt on the adjustment handle through the welding torch mounting sleeve and cooperating with the corresponding screw hole on the cage. The specific structure will not be detailed here. stated.

Further, the arc additive manufacturing welding torch can be slidably installed on the welding gun mounting sleeve in the axial direction, and the welding gun mounting sleeve is also screwed with a welding gun fastening bolt to fix the arc additive manufacturing welding gun.

In this way, it is convenient to adjust the height position of the welding torch after the inclination adjustment, so that it can maintain sufficient molten pool depth and adjust the relative position matched with the stirring needle.

Further, the ultrasonic vibrator is installed vertically on a vibrator mounting sleeve, and the vibrator mounting sleeve is vertically rotatably mounted on a sliding sleeve through a vibration adjustment handle of the vibrator mounting sleeve, and the sliding sleeve can slide horizontally Installed on the cage.

In this way, it is convenient to adjust the inclination angle of the stirring needle according to the needs, so that it is arranged perpendicular to the direction of the molten pool, or arranged obliquely, and it is also convenient to adjust the front and rear distance of the stirring needle relative to the welding torch, so that the lower end can be better located in the molten pool middle position. The adjustment structure of the vibration adjustment handle of the vibrator installation sleeve can be consistent with the rotation adjustment handle of the welding torch installation sleeve, and will not be described in detail here.

Further, the cage is in the shape of a long strip with the same width from top to bottom, and the sliding sleeve can be horizontally slidably sleeved and installed on the cage, and the sliding sleeve is also threaded through and provided with fastening bolts for the sliding sleeve to fix the sliding sleeve. .

In this way, it is more convenient to adjust and fix the front and rear positions of the stirring needle.

Further, the ultrasonic vibrator is mounted on the vibrator mounting sleeve through a vibration damping spring.

In this way, the vibration-absorbing spring acts between the ultrasonic vibrator and the vibrator mounting sleeve, which can prevent the ultrasonic vibration from being transmitted to the holder through the vibrator mounting sleeve, thereby causing vibration of the welding torch. It can better keep the working stability of the welding torch.

Further, the ultrasonic vibrator is a pneumatic ultrasonic vibrator.

This has the advantages of stable effect, favorable control, convenient implementation and little effect of ultrasonic vibration on the reaction effect of the cage. Moreover, the pneumatic ultrasonic vibration source has a much higher tolerance to heat and high temperature, and is more suitable for high-temperature conditions such as arc additive manufacturing.

Further, the cage is fixedly installed on the mechanical arm of the special robot for arc additive manufacturing.

In this way, it is convenient to realize automatic arc additive manufacturing of products through robot computer control.

Further, the lower end of the stirring needle has a circle of horizontally convex protrusions.

In this way, when the stirring needle vibrates up and down along the axial direction, the protrusion can greatly amplify the vibration of the molten pool and improve the effect of ultrasonic vibration. During specific implementation, the protrusion distance should not be too large, and generally can be controlled within three times the diameter of the stirring needle, and the specific size can be obtained according to experimental verification.

Furthermore, a plurality of protrusions are evenly arranged in the circumferential direction, and the upper surface and the lower surface of each protrusion are respectively set as reverse symmetrical inclined surfaces or helical blade surfaces.

In this way, with the reciprocating vibration of the stirring needle in the axial direction, the upper and lower surfaces of the protrusion will form the effect of pushing the molten metal outward in a reciprocating manner in the circumferential direction during the reciprocating motion, and then vibrate the molten metal in the axial direction At the same time, a reciprocating vibration along the circumferential direction is generated, wherein the vibration in the axial direction can better act on the bottom of the molten pool, and the vibration in the circumferential direction can better act on the surrounding wall of the molten pool. A composite high-frequency vibration effect greatly improves the bonding of the molten pool to the surrounding wall metal, which can better refine the metal crystal structure, improve the influence of vibration on the metal crystal fusion effect, and improve the forming quality of the product.

Therefore, the scheme of the present invention introduces ultrasonic vibration stirring in the arc additive manufacturing, on the one hand, it can break the growing columnar crystals, so that the grains can be refined and homogenized, and on the other hand, it can promote the gas overflow in the molten pool and reduce the Porosity, the combined effect of the two greatly improves the mechanical properties of arc additive manufacturing materials or parts.

To sum up, the present invention has the advantages of being able to better introduce ultrasonic assistance in the arc additive manufacturing process, improve the effect of ultrasonic action, and improve the structure and mechanical properties of arc additive manufacturing materials or parts.

Description of drawings

Fig. 1 is a structural schematic diagram of arc additive manufacturing equipment used in the implementation of the present invention.

Fig. 2 is a schematic diagram of the direction of the welding torch and the stirring needle in Fig. 1 adjusted.

Fig. 3 is a schematic structural view of the protrusion at the lower end of the individual stirring needle in Fig. 1 .

Detailed ways

The present invention will be further described in detail below in combination with specific embodiments.

In the specific implementation: an ultrasonic-assisted arc additive manufacturing method, the improvement point is that when performing arc additive manufacturing, a stirring needle with reciprocating ultrasonic vibration characteristics is inserted into the additive manufacturing molten pool, and along with the molten pool Synchronous movement, ultrasonic vibration and stirring are performed on the solidification process of molten pool metal to improve its solidification structure and mechanical properties.

In this way, during arc additive manufacturing in this method, a stirring needle in a vibrating state is directly inserted into the molten pool, and ultrasonic vibration is introduced into the molten pool through stirring, so that the cavitation effect and vibration effect of ultrasonic vibration can be better utilized, and welding pores can be reduced. , refine the grains, increase the bonding strength between the edge of the molten pool in the welded area and the non-welded area during the crystallization process, and improve the solidification structure and mechanical properties of the molten pool metal. Compared with other ultrasonic vibration methods, such as loading on the base material or through arc loading, the ultrasonic vibration loading method of the present invention is more direct to the ultrasonic vibration of the molten pool, and also has a good mechanical stirring effect, which is beneficial to the molten pool metal The improvement effect of coagulation structure and mechanical properties is better.

During implementation, the stirring needle is made of metal tungsten or tungsten alloy. Its size parameters can be 1.0-2.0mm in diameter and 80-150mm in length.

In this way, it can be better ensured that the stirring needle will not react with the molten pool metal.

During implementation, the vibration direction of the stirring needle is along its own axis.

In this way, the stirring needle acting on the molten pool will only drive the liquid metal in the molten pool to perform high-frequency reciprocating vibrations within a certain area. Stirring) to reduce welding porosity and increase the bonding density of welding materials at the molecular level, thereby improving the mechanical properties of the welding area and improving the welding effect.

During implementation, the vibration frequency of the stirring needle is 20-100KHZ, and the amplitude is 0.2-1mm. The vibration in this range can better ensure that the vibration has a benign effect on the metal crystallization, and avoid excessive vibration that will affect the crystallization and reduce the welding quality.

Referring to Fig. 1, as an implementation option, the arc additive manufacturing torch 1 is arranged along the direction perpendicular to the product plane where the molten pool is located during welding, and the stirring pin 2 is inserted obliquely downward into the molten pool from the front or rear of the arc additive manufacturing welding torch's traveling direction. Ultrasonic vibration is realized below the middle of the pool.

This is because the welding torch is arranged perpendicular to the product plane during conventional arc additive manufacturing, so this method can be implemented by directly adding a stirring needle to introduce ultrasonic vibration on the basis of the conventional arc additive manufacturing process control process, and there is no need to adjust the arc augmentation. The control program of the material manufacturing welding torch is convenient for implementation and application.

Referring to Fig. 2, as another implementation option, during welding, the arc additive manufacturing welding torch 1 is arranged so that the upper end is arranged obliquely in front of the arc additive manufacturing welding torch, and the stirring needle 2 is arranged behind the arc additive manufacturing welding torch and vertically downward Inserted into the middle of the additive manufacturing molten pool to achieve ultrasonic vibration.

In this way, the upper end of the arc additive manufacturing welding torch is inclined along the direction of travel, which can better preheat the area to be processed in front of the molten pool, and at the same time make room for the vertical arrangement of the stirring needle along the middle of the molten pool, and the vertical arrangement of the stirring needle After being located in the middle of the molten pool, the ultrasonic vibration can be transmitted to the entire molten pool very uniformly, avoiding the influence of the uneven transmission of ultrasonic vibration in the molten pool on the fusion effect of metal crystals, and greatly improving the forming quality of the product.

Specifically, when this method is implemented, it is realized by relying on the arc additive manufacturing equipment shown in Figures 1-3. The arc additive manufacturing equipment includes an arc additive manufacturing welding gun 1, and the arc additive manufacturing welding gun is installed in a whole On the cage 4 arranged horizontally and one end of the welding head is downward, a vibrating stirring device is also installed on the cage 4, the vibrating stirring device includes an ultrasonic vibrator 3, and a stirring needle 2 is arranged at the lower end of the ultrasonic vibrator 3 downwards , the ultrasonic vibrator 3 can provide the stirring needle 2 with vibration along the axial direction.

In this way, the welding gun and the vibration stirring device are installed on the same cage, which can better ensure that the stirring needle follows the welding gun synchronously to realize vibration stirring.

Wherein, the arc additive manufacturing welding torch is installed on a welding torch mounting sleeve 5 , and the welding torch mounting sleeve 5 is vertically rotatably mounted on the holder 4 through a welding torch mounting sleeve rotation adjustment handle 6 .

Unscrew the welding torch mounting sleeve and turn the adjusting handle so that the angle of inclination of the welding torch mounting sleeve in the vertical direction can be rotated, and then the angle of the welding torch can be adjusted as required. The structure involving the adjustment handle in the scheme to realize the adjustment and fastening is a mature existing technology. It can be realized by setting a bolt on the adjustment handle through the welding torch mounting sleeve and cooperating with the corresponding screw hole on the cage. The specific structure will not be detailed here. stated.

Wherein, the arc additive manufacturing welding torch can be slidably installed on the welding gun mounting sleeve 5 in the axial direction, and a welding gun fastening bolt 10 is screwed through the welding gun mounting sleeve to realize the fixing of the arc additive manufacturing welding gun.

In this way, it is convenient to adjust the height position of the welding torch after the inclination adjustment, so that it can maintain sufficient molten pool depth and adjust the relative position matched with the stirring needle.

Wherein, the ultrasonic vibrator 3 is vertically installed on a vibrator installation sleeve 7, and the vibrator installation sleeve 7 is vertically rotatably installed on a sliding sleeve 8 through a vibrator installation sleeve vibration adjustment handle 9, and the sliding sleeve Mounted horizontally on the cage.

In this way, it is convenient to adjust the inclination angle of the stirring needle according to the needs, so that it is arranged perpendicular to the direction of the molten pool, or arranged obliquely, and it is also convenient to adjust the front and rear distance of the stirring needle relative to the welding torch, so that the lower end can be better located in the molten pool middle position. The adjustment structure of the vibration adjustment handle of the vibrator installation sleeve can be consistent with the rotation adjustment handle of the welding torch installation sleeve, and will not be described in detail here.

Among them, the cage 4 is in the shape of a long strip with the same width from top to bottom, and the sliding sleeve 8 can be horizontally slidably sleeved and installed on the cage, and the sliding sleeve is also screwed through to be provided with a bolt 11 for fastening the sliding sleeve to realize the fastening of the sliding sleeve. 8 fixed.

In this way, it is more convenient to adjust and fix the front and rear positions of the stirring needle.

Wherein, the ultrasonic vibrator 3 is installed on the vibrator mounting sleeve through a damping spring.

In this way, the vibration-absorbing spring acts between the ultrasonic vibrator and the vibrator mounting sleeve, which can prevent the ultrasonic vibration from being transmitted to the holder through the vibrator mounting sleeve, thereby causing vibration of the welding torch. It can better keep the working stability of the welding torch.

Wherein, the ultrasonic vibrator 3 is a pneumatic ultrasonic vibrator.

This has the advantages of stable effect, favorable control, convenient implementation and little effect of ultrasonic vibration on the reaction effect of the cage. Moreover, the pneumatic ultrasonic vibration source has a much higher tolerance to heat and high temperature, and is more suitable for high-temperature conditions such as arc additive manufacturing.

Among them, the cage 4 is fixedly installed on the mechanical arm of the special robot for arc additive manufacturing (the special robot for arc additive manufacturing is a mature existing product, which can control the walking path of the welding torch by computer programming to realize additive welding manufacturing, so it is not shown in the figure. show).

In this way, it is convenient to realize automatic arc additive manufacturing of products through robot computer control.

Wherein, the lower end of the stirring needle 2 has a circle of horizontally convex protrusions 12 .

In this way, when the stirring needle vibrates up and down along the axial direction, the protrusion can greatly amplify the vibration of the molten pool and improve the effect of ultrasonic vibration. During specific implementation, the protrusion distance should not be too large, and generally can be controlled within three times the diameter of the stirring needle, and the specific size can be obtained according to experimental verification.

Wherein, the plurality of protrusions are evenly arranged in the circumferential direction, and the upper surface and the lower surface of each protrusion are respectively set as reverse symmetrical inclined surfaces or helical blade surfaces.

In this way, with the reciprocating vibration of the stirring needle in the axial direction, the upper and lower surfaces of the protrusion will form the effect of pushing the molten metal outward in a reciprocating manner in the circumferential direction during the reciprocating motion, and then vibrate the molten metal in the axial direction At the same time, a reciprocating vibration along the circumferential direction is generated, wherein the vibration in the axial direction can better act on the bottom of the molten pool, and the vibration in the circumferential direction can better act on the surrounding wall of the molten pool. A composite high-frequency vibration effect greatly improves the bonding of the molten pool to the surrounding wall metal, which can better refine the metal crystal structure, improve the influence of vibration on the metal crystal fusion effect, and improve the forming quality of the product.

On the basis of the above-mentioned specific implementation methods, the applicant further conducted the following tests for comparison and verification. The following materials and parameters were selected during the test: the substrate of arc additive manufacturing is aluminum alloy, the geometric size is 100×50×10mm, and a MIG welding machine is used. The process parameters are: welding current 80A, voltage 19.8V, welding wire diameter 1.6 mm, the wire feeding speed is 120cm/min, the welding speed is 200mm/min, the shielding gas is 99.99% argon, and the gas flow rate is 15L/min. Arc additive manufacturing 4 build-up layers, each pass at intervals of two minutes, welding 3 samples for each example, each sample was tested at three positions in the front, middle and back, and the average value was taken after the performance test.

Comparative example:

Directly use MIG welding machine and ER5356 aluminum alloy welding wire for arc additive manufacturing without ultrasonic assistance.

Experimental results: The average tensile strength of the arc additive manufacturing build-up layer is 248.7MPa.

Test example 1:

Use MIG welding machine and ER5356 welding wire to carry out arc additive manufacturing. At the same time, adopt the method shown in Figure 1 of this method to implement ultrasonic vibration and stirring for the solidification process of arc additive manufacturing molten pool metal. The reciprocating ultrasonic vibration direction is the axial direction of the tungsten needle. , The size of the tungsten needle is 1.5mm in diameter x 100mm in length, the vibration frequency is 20KHZ, and the amplitude is 0.8mm.

Experimental results: The average tensile strength of the arc additive manufacturing stacked layer is 259.2MPa, and compared with the control example, the grains of the additively manufactured stacked layer are finer, and there are no columnar grains and pores.

Example 2:

Use MIG welding machine and ER5356 aluminum alloy welding wire to carry out arc additive manufacturing. At the same time, adopt the method shown in Figure 2 of this method to implement ultrasonic vibration and stirring for the solidification process of arc additive manufacturing molten pool metal. The reciprocating ultrasonic vibration direction is the direction of the tungsten needle. Axially, the size of the tungsten needle is 1.2mm in diameter x 90mm in length, the vibration frequency is 25KHZ, and the amplitude is 0.6mm.

Experimental results: The average tensile strength of the arc additive manufacturing stacked layer is 264.5MPa, and compared with the control example, the grains of the additively manufactured stacked layer are finer, and there are no columnar grains and pores.

Example 3:

Use MIG welding machine and ER5356 aluminum alloy welding wire to carry out arc additive manufacturing. At the same time, adopt the method shown in Figure 2 of this method to implement ultrasonic vibration and stirring for the solidification process of arc additive manufacturing molten pool metal. The reciprocating ultrasonic vibration direction is the direction of the tungsten needle. Axially, the size of the tungsten needle is 1.0mm in diameter x 80mm in length, the vibration frequency is 28KHZ, and the amplitude is 0.5mm.

Experimental results: The average tensile strength of the arc additive manufacturing stacked layer is 261.7MPa, and compared with the control example, the grains of the additively manufactured stacked layer are finer, and there are no columnar grains and pores.

In summary, it can be seen from the results of the examples that, after adopting the technical solution of the present invention, the structure and mechanical properties of the stacked layer obtained by arc additive manufacturing are better.

Claims (7)

1. An ultrasonic-assisted arc additive manufacturing method is characterized in that, when performing arc additive manufacturing, a stirring pin with reciprocating ultrasonic vibration characteristics is inserted into the additive manufacturing molten pool, and moves synchronously with the molten pool, Ultrasonic vibration and stirring are performed on the solidification process of molten pool metal to improve its solidification structure and mechanical properties; The vibration direction of the stirring needle is along its own axis; This method relies on the following arc additive manufacturing equipment to achieve, the arc additive manufacturing equipment includes an arc additive manufacturing welding torch, the arc additive manufacturing welding torch is installed on a cage that is integrally arranged horizontally and one end of the welding head is downward , a vibrating stirring device is also installed on the cage, the vibrating stirring device includes an ultrasonic vibrator, a stirring needle is arranged downward at the lower end of the ultrasonic vibrator, and the ultrasonic vibrator can provide axial vibration for the stirring needle; the lower end of the stirring needle There is a circle of horizontally convex protrusions, and the distance of the protrusions is within three times the diameter of the stirring needle; the protrusions are evenly arranged in multiples in the circumferential direction, and the upper surface and the lower surface of each protrusion are respectively set to be reversed. Symmetrically inclined or spiral blades. 2. The ultrasonic-assisted arc additive manufacturing method according to claim 1, wherein the stirring needle is made of metal tungsten or tungsten alloy. 3. The ultrasonic-assisted arc additive manufacturing method according to claim 1, wherein the vibration frequency of the stirring needle is 20-100KHZ, and the amplitude is 0.2-1mm. 4. The ultrasonic-assisted arc additive manufacturing method according to claim 1, wherein the arc additive manufacturing torch is arranged along a direction perpendicular to the plane of the product where the molten pool is located during welding, and the stirring pin travels from the arc additive manufacturing welding gun. The front or rear of the machine is inserted obliquely downwards under the middle of the molten pool to achieve ultrasonic vibration. 5. The ultrasonic-assisted arc additive manufacturing method according to claim 1, characterized in that, during welding, the arc additive manufacturing welding torch is arranged such that the upper end is inclined along the front of the arc additive manufacturing welding gun, and the stirring needle is arranged on the arc. The additive manufacturing welding torch is inserted vertically downwards into the middle of the additive manufacturing molten pool to realize ultrasonic vibration. 6. The ultrasonic-assisted arc additive manufacturing method according to claim 1, wherein the arc additive manufacturing welding gun is mounted on a welding gun mounting sleeve, and the welding gun mounting sleeve can be rotated vertically by rotating the adjustment handle of a welding gun mounting sleeve ground mounted on the cage; The arc additive manufacturing welding torch can be slidably installed on the welding gun mounting sleeve in the axial direction, and the welding gun mounting sleeve is also screwed with bolts for fastening the welding gun to realize the fixing of the arc additive manufacturing welding gun. 7. The ultrasonic-assisted arc additive manufacturing method according to claim 1, wherein the ultrasonic vibrator is vertically installed on a vibrator mounting sleeve, and the vibrator mounting sleeve is adjusted by vibration of a vibrator mounting sleeve The handle can be rotated vertically on a sliding sleeve, and the sliding sleeve can be horizontally slidably installed on the cage; The cage is in the shape of a long strip with the same width from top to bottom, and the sliding sleeve can be horizontally slidably socketed and installed on the cage, and the sliding sleeve is also threaded through and provided with fastening bolts for the sliding sleeve to fix the sliding sleeve; The ultrasonic vibrator is installed on the vibrator mounting sleeve through a damping spring.

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