Auxiliary cooling device for friction welding of solid bars and working method of auxiliary cooling device

Abstract

The invention provides an auxiliary cooling device for friction welding of solid bars and a working method of the auxiliary cooling device, and belongs to the technical field of friction welding. The problem that after welding of existing friction welding equipment is finished, due to the fact that the residual temperature of a welding seam is too high, a welded workpiece needs to be transferred to a heat treatment procedure for quenching treatment, and the strength of the welding seam cannot be improved in time is solved. The device comprises a main shaft side box body, a movable sliding table box body, a machine tool body, a tailstock fixing seat, a tailstock side to-be-welded part and a gas spraying mechanism, the main shaft side box body is installed on one side of the machine tool body, the movable sliding table box body is installed on the other side of the machine tool body in a sliding mode through a movable sliding table rail, and a main shaft side clamp is installed in the main shaft side box body through a main shaft fixing seat. The tailstock side clamp is installed in the movable sliding table box body through the tailstock fixing base, a to-be-welded workpiece on the tailstock side is clamped and fixed through the tailstock side clamp, and the gas spraying mechanism is arranged on the outer side of a welding area of the to-be-welded workpiece on the tailstock side. The device is mainly used for protecting a welding area during welding.

Description

Technical Field

[0001] The invention belongs to the technical field of friction welding, and in particular relates to an auxiliary cooling device for friction welding of solid bars and a working method thereof. Background Art

[0002] In recent years, inertia friction welding has the advantages of fewer process parameters, high stability, less heat input, narrow weld zone, and high joint mechanical properties. It has great potential in the industrial field. Many products are used in the aerospace field, etc. The existing inertia friction welding process is: the workpieces to be welded are fixed at the rotating end and the sliding end respectively. When the speed of the rotating end reaches the set value, the spindle drive motor is separated from the rotating end, and the sliding end is driven by the hydraulic servo to move toward the rotating end, generating friction heat at the contact interface. Due to the action of friction, the material undergoes plastic deformation at the welding interface, and the material The temperature gradually increases. When the rotation speed of the rotating end drops to a certain value, the workpiece to be welded begins to be forged. After a certain period of time, the sliding end withdraws. After welding, the welded workpiece is quenched to improve the strength of the workpiece. For example, carbon steel materials have excellent performance characteristics such as high strength and hardness based on this process, and are widely used in transmission shaft parts in the fields of automobiles, ships, petrochemicals, wind power, etc. In addition, some shaft components in aircraft engines use nickel-based high-temperature alloy materials. After inertia friction welding, the weld also needs to be quenched to improve the strength.

[0003] However, after welding, due to the excessively high residual temperature at the weld, the welded workpiece needs to be transferred to the heat treatment process for quenching, resulting in the failure to improve the weld strength in time. During the quenching process, the weld is equivalent to secondary heating, which leads to coarse structure at the weld, thereby reducing the strength of the weld joint. Based on the above problems, an auxiliary cooling device for friction welding of solid bars and a working method thereof are proposed. Summary of the invention

[0004] In view of this, the present invention aims to propose an auxiliary cooling device for solid bar friction welding and a working method thereof, so as to solve the problem that after the existing friction welding equipment is completed, due to the excessively high residual temperature at the weld, the welded workpiece needs to be transferred to a heat treatment process for quenching treatment, resulting in the failure to improve the weld strength in time. During the quenching process, the weld is heated again, resulting in a coarse structure at the weld, thereby reducing the strength of the weld joint.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical scheme: a friction welding auxiliary processing device, comprising a spindle side box, a spindle side fixture, an external blowing assembly, a spindle side workpiece to be welded, a movable slide box, a bed, a tailstock fixed seat, a tailstock side workpiece to be welded and a gas ejection mechanism, wherein the spindle side box is installed on one side of the bed, the movable slide box is slidably installed on the other side of the bed through a movable slide track, the spindle side fixture is installed in the spindle side box through the spindle fixed seat, the spindle side workpiece to be welded is clamped and fixed by the spindle side fixture, the external blowing assembly is arranged on the outside of the welding area of ​​the spindle side workpiece to be welded, the tailstock side fixture is installed in the movable slide box through the tailstock fixed seat, the tailstock side workpiece to be welded is clamped and fixed by the tailstock side fixture, and the gas ejection mechanism is arranged on the outside of the welding area of ​​the tailstock side workpiece to be welded.

[0006] Furthermore, the external blowing assembly includes a driving mechanism, a blowing support, a guide rail, a cylinder, a connecting rod, a semi-ring bracket and a blowing head. The blowing support is connected to the driving mechanism, the fixed end of the cylinder is installed on the blowing support, and the telescopic end is connected to the semi-ring bracket. Guide rails are provided on both sides of the cylinder, and a support plate is installed on the top of the guide rail. Both sides of the semi-ring bracket are connected to the support plate through connecting rods, and a number of blowing heads are evenly distributed in a ring on the inner side of the semi-ring bracket, and the several blowing heads are connected to the semi-ring bracket through the blowing head support.

[0007] Furthermore, the driving mechanism includes a motor and a lead screw, the blowing support is threadedly connected to the lead screw, and the lead screw is connected to the output shaft of the motor and is installed on the bed.

[0008] Furthermore, a direction-adjusting connecting rod is connected to the middle of the blowing head, and the direction-adjusting connecting rod is connected to the inner side of the semi-ring bracket through a locking nut.

[0009] Furthermore, the gas ejection mechanism includes an external atomizing nozzle and an external gas nozzle, the external atomizing nozzle is sleeved on the outside of the external gas nozzle, and the external atomizing nozzle is arranged on the outside of the welding area of ​​the workpiece to be welded on the tailstock side.

[0010] Furthermore, the external gas nozzle is connected to the external gas connecting pipe, the external atomizing nozzle is connected to the liquid inlet pipe connecting pipe, and the liquid inlet pipe connecting pipe is sleeved on the outside of the external gas connecting pipe.

[0011] Furthermore, the liquid inlet pipe connecting pipe is installed on the water-gas nozzle bracket, and the water-gas nozzle bracket is installed on the movable slide box.

[0012] Furthermore, the liquid inlet pipe connecting pipe is connected to the liquid storage tank, the external gas connecting pipe is connected to the gas storage tank, and electromagnetic control valves are installed on the connecting pipelines between the external gas connecting pipe and the gas storage tank and the liquid inlet pipe connecting pipe and the liquid storage tank, and both electromagnetic control valves are connected to the control system.

[0013] Furthermore, the workpiece to be welded on the spindle side and the workpiece to be welded on the tailstock side are both solid structures.

[0014] A method for operating the friction welding auxiliary processing device according to any one of claims 1 to 9, comprising the following steps:

[0015] Step 1: Before welding, clamp and fix the workpiece on the spindle side with the spindle side fixture, and clamp and fix the workpiece on the tailstock side with the tailstock side fixture;

[0016] Step 2: Move the external blowing assembly and the gas ejection mechanism to the welding area of ​​the workpiece to be welded on the spindle side and the workpiece to be welded on the tailstock side;

[0017] Step 3: During welding, inert gas is sprayed through the external blowing assembly to protect the welding process;

[0018] Step 4: After welding, the amount of cooling medium and gas entering the external atomizing nozzle and the external gas nozzle is controlled by the control system, and then atomized and sprayed out through the external atomizing nozzle to cool the weld joint.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. After welding, the present invention sprays aerosol through an external atomizing nozzle to quickly cool the weld joint to achieve a quenching effect, so that the welding environment is quickly cooled to below room temperature to form a martensitic structure, which can greatly enhance the strength of the weld and solve the problem of excessive residual temperature after welding, which causes the joint to soften and affects the performance of the weld joint.

[0021] 2. After welding, the present invention sprays aerosol through an external atomizing nozzle to rapidly cool the weld joint, which can quickly cool the weld joint, reduce the diffusion range of the heat-affected zone, ensure that other positions of the welded workpiece are not affected, and improve the quality of the weld.

[0022] 3. The invention adopts aerosol to rapidly cool the welding joint after welding, which can quickly complete the subsequent steps of the welding process, shorten the entire production cycle, improve production efficiency, and improve the grain structure and mechanical properties of the welding joint, thereby increasing hardness and strength.

[0023] 4. During the friction welding process, the weld joint may soften or deform due to high temperature. According to the welding requirements, the external spray mist is used to achieve rapid cooling, which can quickly fix the shape of the weld joint and ensure that the geometric size and shape of the weld joint meet the requirements. In addition, during the welding process, the weld joint and the surrounding area are exposed to the air and are prone to oxidation reactions. The spraying of protective gas can effectively isolate the work period, prevent the occurrence of oxidation reactions, and ensure the surface cleanliness of the weld joint.

[0024] 5. The present invention can quickly cool the weld in time after welding to achieve the quenching effect, which can reduce the final heat treatment process in the friction welding process, reduce the process steps, improve work efficiency, and reduce the secondary heating process of the weld, so that the weld structure can be formed in one time, further improving efficiency.

[0025] 6. The present invention provides an external blowing assembly outside the welding area. The external spraying of shielding gas can form a protective layer during the welding process to prevent the metal at the weld from oxidizing with the oxygen in the surrounding air, thereby maintaining the purity of the metal at the weld and reducing the formation of an oxide layer, thereby improving the welding quality.

[0026] 7. The external spraying of protective gas in the present invention can prevent the welding area from being polluted by the external environment, help reduce the pollution of the welding joint surface, keep the welding area clean, and improve the welding quality.

[0027] 8. The present invention can reduce the spark splashing generated during the welding process by spraying a protective gas externally. The inert gas barrier formed around the welding joint can effectively suppress the generation of sparks, improve the safety of the working environment, and provide a good welding environment, reduce the impact of external environmental factors on the welding joint, reduce the factors that may occur during the welding process, and improve the quality and reliability of the welding joint.

[0028] 9. The present invention can adjust the position of the external gas mist spray group at any time. Since the weld position changes during the welding process, the position of the external gas mist spray assembly can be controlled by the telescopic cylinder to keep the external gas mist spray assembly consistent with the weld position, thereby ensuring the stability of the cooling rate at the weld. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0030] Figure 1 The structure of the auxiliary cooling device for friction welding of solid bars according to the present invention is shown in FIG. Figure 1 ;

[0031] Figure 2 The structure of the auxiliary cooling device for friction welding of solid bars according to the present invention is shown in FIG. Figure 2 ;

[0032] Figure 3 is an enlarged schematic diagram of the gas ejection mechanism of the present invention;

[0033] Figure 4 It is a schematic structural diagram of the external blowing assembly of the present invention;

[0034] Figure 5 It is a partially enlarged schematic diagram of the external blowing assembly described in the present invention.

[0035] 1-spindle side box, 2-spindle fixed seat, 3-spindle side fixture, 4-external blowing assembly, 5-spindle side parts to be welded, 6-movable slide box, 7-bed, 8-movable slide rail, 9-external atomizing nozzle, 10-external gas nozzle, 11-water gas nozzle bracket, 13-tail stock side fixture, 14-tail stock fixed seat, 15-tail stock side parts to be welded, 401-motor, 402-screw, 403-blowing support, 404-guide rail, 405-cylinder, 406-connecting rod, 407-semi-ring bracket, 408-blowing head, 409-blowing head support, 410-direction adjustment connecting rod, 411-locking nut. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely explain the technical solutions in the embodiments of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict, and the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0037] See also Figure 1-5 The present embodiment is described as follows: an auxiliary cooling device for friction welding of solid bars comprises a spindle side box 1, a spindle side fixture 3, an external blowing assembly 4, a spindle side workpiece to be welded 5, a movable slide box 6, a bed 7, a tailstock fixed seat 14, a tailstock side workpiece to be welded 15 and a gas ejection mechanism, wherein the spindle side box 1 is mounted on one side of the bed 7, the movable slide box 6 is slidably mounted on the other side of the bed 7 via a movable slide rail 8, and the spindle side fixture 3 is mounted on the spindle side through a spindle fixed seat 2. In the spindle side box 1, the spindle side workpiece 5 to be welded is clamped and fixed by the spindle side clamp 3, the external blowing assembly 4 is arranged on the outside of the welding area of ​​the spindle side workpiece 5 to be welded, the tailstock side clamp 13 is installed in the movable slide box 6 through the tailstock fixing seat 14, the tailstock side workpiece 15 to be welded is clamped and fixed by the tailstock side clamp 13, and the gas ejection mechanism is arranged on the outside of the welding area of ​​the tailstock side workpiece 15 to be welded, and the spindle side workpiece 5 to be welded and the tailstock side workpiece 15 to be welded are both solid structures.

[0038] Before welding, the spindle side workpiece 5 to be welded is clamped and fixed by the spindle side clamp 3, and the tailstock side workpiece 15 to be welded is clamped and fixed by the tailstock side clamp 13, and the external blowing assembly 4 and the gas ejection mechanism are moved to the welding area of ​​the spindle side workpiece 5 to be welded and the tailstock side workpiece 15 to be welded. During welding, the external blowing assembly 4 ejects inert gas to protect the welding process. After welding, the control system controls the amount of cooling medium and gas entering the external atomizing nozzle 9 and the external gas nozzle 10, and then the external atomizing nozzle 9 is used to perform atomization ejection to cool the weld joint. The external spraying of protective gas can form a protective layer during the welding process to prevent the metal at the weld from oxidizing with the oxygen in the surrounding air, thereby maintaining the purity of the metal at the weld and reducing the oxidation layer. Generation, thereby improving welding quality, can prevent the welding area from being contaminated by the external environment, help reduce contamination on the surface of the weld joint, keep the welding area clean, improve welding quality, can help control the temperature distribution in the welding area, slow down the temperature rise rate on the surface of the weld joint, reduce the temperature gradient during welding, reduce the impact of thermal stress, reduce the risk of deformation and cracks in the weld joint, can reduce the spark splashing generated during welding, and through the inert gas barrier formed around the weld joint, can effectively suppress the generation of sparks, improve the safety of the working environment, and can provide a good welding environment, reduce the impact of external environmental factors on the weld joint, reduce the factors that may occur during welding, and improve the quality and reliability of the weld joint.

[0039] After welding, the control system controls the amount of cooling medium and gas entering the external atomizing nozzle 9 and the external gas nozzle 10, and then the external atomizing nozzle 9 is used to spray out the cooling treatment of the welding joint, which can quickly cool the welding joint, reduce the diffusion range of the heat-affected zone, and reduce the deformation of the material. The rapid cooling can prevent the welding joint from cracking or deforming during the cooling process, maintain the shape and quality of the weld, ensure the strength and sealing of the welding joint, and quickly complete the subsequent steps of the welding process, shorten the entire production cycle, and improve production efficiency. The grain structure and mechanical properties of the welding joint can be improved, the hardness and strength can be improved, and the welding joint can be more wear-resistant, corrosion-resistant and fatigue-resistant. During the friction welding process, the welding joint may soften or deform due to high temperature. The external spraying of aerosol can achieve rapid cooling, which can quickly fix the shape of the welding joint and ensure that the geometric size and shape of the welding joint meet the requirements. In the welding process, the welding joint and the surrounding area are exposed to the air and are prone to oxidation reactions. Spraying aerosol cooling can effectively isolate the construction period, prevent the occurrence of oxidation reactions, and ensure the surface cleanliness of the welding joint and the properties of the metal.

[0040] The external blowing assembly 4 includes a driving mechanism, a blowing support 403, a guide rail 404, a cylinder 405, a connecting rod 406, a semi-ring bracket 407 and a blowing head 408. The blowing support 403 is connected to the driving mechanism. The fixed end of the cylinder 405 is installed on the blowing support 403, and the telescopic end is connected to the semi-ring bracket 407. Guide rails 404 are provided on both sides of the cylinder 405, and a support plate is installed on the top of the guide rail 404. Both sides of the semi-ring bracket 407 are connected to the support plate through connecting rods 406. Several blowing heads 408 are evenly distributed in a ring shape on the inner side of the semi-ring bracket 407, and several blowing heads 408 are connected to the semi-ring bracket 407 through a blowing head support 409. The position of the semi-ring bracket 407 is moved by the driving mechanism, and the position of the semi-ring bracket 407 is adjusted according to the welding position. Then, during the welding process, the protective gas is sprayed by the blowing head 408 to protect the welding area during the welding process.

[0041] The driving mechanism includes a motor 401 and a screw 402. The blowing support 403 is threadedly connected to the screw 402. The screw 402 is connected to the output shaft of the motor 401 and is installed on the bed 7. The motor 401 is started to drive the screw 402 to rotate. Since the blowing support 403 is threadedly connected to the screw 402, the blowing support 403 can drive the blowing head 408 to move back and forth.

[0042] A direction-adjusting connecting rod 410 is connected to the middle of the blowing head 408 , and the direction-adjusting connecting rod 410 is connected to the inner side of the semi-ring bracket 407 through a locking nut 411 .

[0043] The gas ejection mechanism includes an external atomizing nozzle 9 and an external gas nozzle 10, wherein the external atomizing nozzle 9 is sleeved on the outside of the external gas nozzle 10, and the external atomizing nozzle 9 is arranged on the outside of the welding area of ​​the workpiece 15 to be welded on the tailstock side, and the external gas nozzle 10 is connected to the external gas connecting pipe, and the external atomizing nozzle 9 is connected to the liquid inlet pipe connecting pipe, and the liquid inlet pipe connecting pipe is sleeved on the outside of the external gas connecting pipe, and the liquid inlet pipe connecting pipe is installed on the water gas nozzle bracket 11, and the water gas nozzle bracket 11 is installed on the movable slide box 6, the liquid inlet pipe connecting pipe is connected to the liquid storage tank, and the external gas connecting pipe is connected to the gas storage tank, and the connecting pipelines between the external gas connecting pipe and the gas storage tank and the liquid inlet pipe connecting pipe and the liquid storage tank are both equipped with electromagnetic control valves, and both electromagnetic control valves are connected to the control system.

[0044] The amount of gas and liquid entering the external gas nozzle 10 and the external atomizing nozzle 9 is controlled by a control system, and then the gas and liquid are mixed in the gap between the external gas nozzle 10 and the external atomizing nozzle 9, and then the gas mist is sprayed out through the atomizing nozzle on the external gas nozzle 10, and the weld joint is rapidly cooled by the sprayed gas mist.

[0045] A working method for a solid bar friction welding auxiliary cooling device, comprising the following steps:

[0046] Step 1: Before welding, the workpiece 5 on the spindle side is clamped and fixed by the spindle side fixture 3, and the workpiece 15 on the tailstock side is clamped and fixed by the tailstock side fixture 13;

[0047] Step 2: Move the external blowing assembly 4 and the gas ejection mechanism to the welding area of ​​the workpiece 5 on the spindle side and the workpiece 15 on the tailstock side;

[0048] Step 3: During welding, inert gas is sprayed out through the external spray assembly 4 to protect the welding process;

[0049] Step 4: After welding, the amount of cooling medium and gas entering the external atomizing nozzle 9 and the external gas nozzle 10 is controlled by the control system, and then atomized and sprayed out through the external atomizing nozzle 9 to cool the weld joint.

[0050] The embodiments of the present invention disclosed above are only used to help illustrate the present invention. The embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. According to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well.

Claims

1. An auxiliary cooling device for friction welding of solid bars, characterized in that: The invention comprises a spindle side box (1), a spindle side fixture (3), an external blowing assembly (4), a spindle side workpiece to be welded (5), a movable slide box (6), a bed (7), a tailstock fixing seat (14), a tailstock side workpiece to be welded (15) and a gas ejection mechanism, wherein the spindle side box (1) is mounted on one side of the bed (7), the movable slide box (6) is slidably mounted on the other side of the bed (7) via a movable slide rail (8), and the spindle side fixture (3) is mounted via a spindle fixing seat (2 ) is installed in the spindle side box (1), the spindle side workpiece (5) to be welded is clamped and fixed by the spindle side clamp (3), the external blowing assembly (4) is arranged on the outside of the welding area of ​​the spindle side workpiece (5), the tailstock side clamp (13) is installed in the movable slide box (6) through the tailstock fixing seat (14), the tailstock side workpiece (15) to be welded is clamped and fixed by the tailstock side clamp (13), and the gas ejection mechanism is arranged on the outside of the welding area of ​​the tailstock side workpiece (15).

2. The auxiliary cooling device for friction welding of solid bars according to claim 1, characterized in that: The external blowing assembly (4) comprises a driving mechanism, a blowing support (403), a guide rail (404), a cylinder (405), a connecting rod (406), a semi-ring bracket (407) and a blowing head (408). The blowing support (403) is connected to the driving mechanism. The fixed end of the cylinder (405) is mounted on the blowing support (403), and the telescopic end is connected to the semi-ring bracket (407). Guide rails (404) are arranged on both sides of the cylinder (405). A support plate is installed on the top of the guide rail (404). Both sides of the semi-ring bracket (407) are connected to the support plate via a connecting rod (406). A plurality of blowing heads (408) are evenly distributed in a ring shape on the inner side of the semi-ring bracket (407). The plurality of blowing heads (408) are connected to the semi-ring bracket (407) via a blowing head support (409).

3. The auxiliary cooling device for friction welding of solid bars according to claim 2, characterized in that: The driving mechanism comprises a motor (401) and a lead screw (402); the blowing support (403) is threadedly connected to the lead screw (402); the lead screw (402) is connected to the output shaft of the motor (401) and is mounted on the bed (7).

4. The auxiliary cooling device for friction welding of solid bars according to claim 2, characterized in that: A direction-adjusting connecting rod (410) is connected to the middle of the blowing head (408), and the direction-adjusting connecting rod (410) is connected to the inner side of the semi-ring bracket (407) via a locking nut (411).

5. The auxiliary cooling device for friction welding of solid bars according to claim 1, characterized in that: The gas ejection mechanism comprises an external atomizing nozzle (9) and an external gas nozzle (10), wherein the external atomizing nozzle (9) is sleeved on the outside of the external gas nozzle (10), and the external atomizing nozzle (9) is arranged on the outside of the welding area of ​​the workpiece (15) to be welded on the tailstock side.

6. The auxiliary cooling device for friction welding of solid bars according to claim 5, characterized in that: The external gas nozzle (10) is connected to the external gas connecting pipe, the external atomizing nozzle (9) is connected to the liquid inlet connecting pipe, and the liquid inlet connecting pipe is sleeved on the outside of the external gas connecting pipe.

7. The auxiliary cooling device for friction welding of solid bars according to claim 6, characterized in that: The liquid inlet pipe connecting pipe is mounted on a water-gas nozzle bracket (11), and the water-gas nozzle bracket (11) is mounted on a movable slide box (6).

8. The auxiliary cooling device for friction welding of solid bars according to claim 6, characterized in that: The liquid inlet pipe connecting pipe is connected to the liquid storage tank, the external gas connecting pipe is connected to the gas storage tank, and electromagnetic control valves are installed on the connecting pipelines between the external gas connecting pipe and the gas storage tank and the liquid inlet pipe connecting pipe and the liquid storage tank, and both electromagnetic control valves are connected to the control system.

9. The auxiliary cooling device for friction welding of solid bars according to claim 1, characterized in that: The spindle-side welded component (5) and the tailstock-side welded component (15) are both solid structures.

10. A method for operating the auxiliary cooling device for solid bar friction welding according to any one of claims 1 to 9, characterized in that: It includes the following steps: Step 1: Before welding, the workpiece to be welded (5) on the spindle side is clamped and fixed by the spindle side clamp (3), and the workpiece to be welded (15) on the tailstock side is clamped and fixed by the tailstock side clamp (13); Step 2: Move the external blowing assembly (4) and the gas ejection mechanism to the welding area of ​​the workpiece to be welded (5) on the main spindle side and the workpiece to be welded (15) on the tailstock side; Step 3: During welding, an inert gas is sprayed through the external spray assembly (4) to protect the welding process; Step 4: After welding, the amount of cooling medium and gas entering the external atomizing nozzle (9) and the external gas nozzle (10) is controlled by the control system, and then atomized and sprayed out through the external atomizing nozzle (9) to cool the weld joint.

Images