WO2018228276A1

WO2018228276A1 - Built-in sieve-hole annular laser cladding nozzle

Info

Publication number: WO2018228276A1
Application number: PCT/CN2018/090355
Authority: WO
Inventors: 程延海; 王浩正; 韩正铜; 杨金勇; 崔然; 尹逊金
Original assignee: 中国矿业大学
Priority date: 2017-06-12
Filing date: 2018-06-08
Publication date: 2018-12-20
Also published as: CN107245715A; CN107245715B

Abstract

Disclosed in the present invention is a built-in sieve-hole annular laser cladding nozzle, comprising a laser head connecting part, a middle sleeve part, and a nozzle part, the laser head connecting part comprising an upper connecting sleeve connected to the laser head, the middle sleeve part comprising a sliding sleeve connected to the upper connecting sleeve, protective glass being disposed between the lower end of the sliding sleeve and an upper end of a central sleeve, a water cooling sleeve of the protective glass having a threaded connection to the sliding sleeve and the central sleeve, and protective air holes being disposed on the central sleeve, the nozzle part comprising a conical nozzle core connected to the central sleeve, a powder inlet sleeve, an air intake sleeve, and a water cooling sleeve being disposed in turn on the outer side of the conical nozzle core and the central sleeve. The present invention overcomes the defects of existing laser cladding nozzles, including the short service life, being unable to adjust the powder concentration diameter, and being unable to adapt to powder particles of different sizes.

Description

Built-in screen hole type annular laser cladding nozzle

Technical field

The invention relates to the technical field of laser processing, in particular to a ring-shaped coaxial laser cladding nozzle.

Background technique

Laser cladding technology is a new surface modification technology. It is a process that combines two or more different materials by heating to fuse them together and give full play to their excellent performance. Laser cladding has the characteristics of heating speed and fast cooling speed. The obtained cladding layer has fine microstructure, high strength and superior performance compared with other cladding methods, so it has attracted extensive attention from material workers all over the world.

Laser-fed powder feed nozzle design is a key technology in laser processing equipment. The function of the powder feeding nozzle is to convert the powder flow from the powder feeder into a different shape and enter the laser beam to control the injection angle and cross-sectional size of the powder flow. The structure and performance of the nozzle directly affect the cladding. The effect of the process and the precision and quality of the formed parts. At present, the coaxial powder feeding nozzle has been deeply studied at home and abroad, and has achieved certain results, but there are still many shortcomings, which are as follows: (1) It is easy to export the powder feeding tube without adding protective gas. The clogging, which tends to cause the powder to flow, is removed from the laser beam before reaching the surface of the substrate, forming a region where the cladding material is non-metallurgically bonded to the substrate. (2) The amount of powder fed is not uniform. During the implementation of the coaxial powder feeding laser cladding process, the flow of the cladding material in the laser beam is divergent, causing the powder to exceed the diameter of the laser spot, and the powder beyond the diameter of the laser spot is not sufficiently heated in the laser beam. The metallurgical bond between the cladding powder and the surface of the substrate may be caused, which may directly lead to deterioration of the surface of the formed part, and may even cause collapse, which may make the forming process unable to continue. (3) The powder feeding nozzle cannot achieve accurate coaxial adjustment of the powder and the laser beam, and the powder spot and the laser light class cannot achieve coaxial work. (4) The laser beam will reflect on the surface of the substrate, causing energy loss. In severe cases, the reflected laser beam may burn the nozzle. (5) The water-cooled pipeline cannot completely cool the lower end of the nozzle, causing damage to the molten pool near the molten pool. (6) The protective mirror glass cannot be completely cooled, and local overheating may cause glass cracking.

At present, the coaxial powder feeding nozzle used in laser cladding forming mainly has two forms: a three-beam coaxial powder feeding nozzle and a ring-shaped coaxial powder feeding nozzle. The three-beam coaxial powder feeding nozzle has three powder feeding channels symmetrically distributed by the laser beam. The inner diameter of the channel is 1-3 mm, and the powder is emitted after three channels to form a powder spot; suitable for high power (>2kw) Thicker, wider cladding processing, and 3D cladding with greater tilt requirements. The annular coaxial powder feeding nozzle guides the powder particles through a conical gap to form a circular powder flow centered on the laser beam, which is concentrated and then enters the molten pool. This structural design makes it possible to achieve a powder gathering spot of 0.4 mm or less, that is, an extremely high cladding efficiency can be obtained for an ultra-narrow cladding layer having a width of 1 mm or less.

In Chinese patent CN104694922A, a coaxial powder feeding nozzle is proposed, the main part of which is connected by bolts. Although a plurality of powder discharging holes are used to improve the powder concentration, the design is relatively cumbersome in processing, and the The size and quantity of the powder mouth are not easy to adjust. Moreover, it does not use a cooling device near the nozzle, which is more likely to cause the nozzle to be damaged by radiant heat and reduce the service life of the nozzle. U.S. Patent No. 5,747,026 discloses a multi-layer annular cone nozzle which adopts a modular structure, which facilitates replacement of parts, and the powder enters the powder tube, and a large space exists to stabilize the flow. The main disadvantage is that the powder flow at the nozzle outlet is less uniform, and the powder is easy to melt at the lowermost outlet to block the powder outlet, and the second nozzle cannot adjust the powder concentration diameter.

Summary of the invention

OBJECT OF THE INVENTION In order to solve the above problems, the present invention is directed to a built-in screen-type annular laser cladding nozzle which has a long service life and an adjustable powder concentration diameter and is suitable for use without size powder particles.

In order to achieve the above object, the present invention adopts the following technical solution: a built-in screen-type annular laser cladding nozzle including a laser head connecting portion, a middle sleeve portion and a nozzle portion; the laser head connecting portion includes an upper connecting sleeve The upper end of the upper connecting sleeve is connected with the laser head; the middle sleeve part comprises a sliding sleeve, a protective glass water cooling sleeve, a center sleeve and a protective glass, and the upper end of the sliding sleeve is connected with the lower end of the upper connecting sleeve, and the sliding sleeve There is a protective glass between the lower end and the upper end of the central sleeve. The lower end of the sliding sleeve and the outer end of the central sleeve are provided with a protective glass water cooling sleeve, and the protective glass water cooling sleeve is respectively screwed with the sliding sleeve and the central sleeve to protect the glass water cooling sleeve. The central water inlet and the central water outlet are arranged on the upper side, and two opposite protective gas holes are arranged at a position of the central sleeve near the protective glass, the lower end of the central sleeve is tapered; the nozzle portion comprises a tapered nozzle core, Into the powder sleeve, the air inlet sleeve, the water cooling sleeve, the annular sieve plate, the upper end of the conical nozzle core and the lower end of the central sleeve are threadedly connected, in a cone spray The outer side of the lower end of the core and the central sleeve is provided with a powder feeding sleeve, an air inlet sleeve and a water cooling sleeve. The upper half of the powder feeding sleeve, the air inlet sleeve and the water cooling sleeve are all cylindrical, and the lower half is tapered. The upper end of the powder sleeve is connected with the central sleeve by a threaded joint, the upper end of the powder feeding sleeve is provided with a powder inlet nozzle, the lower end of the powder feeding sleeve and the lower end of the central sleeve are provided with an annular sieve plate, and the annular sieve orifice plate is provided with a small powder. The upper end of the air inlet sleeve and the upper end of the powder feeding sleeve are threadedly connected, and the upper end of the air inlet sleeve is provided with an air inlet nozzle, and the upper end of the water cooling sleeve and the upper end of the air inlet sleeve are fixed by welding, and the upper end of the water cooling sleeve is provided with an upper water outlet, and the lower end of the water cooling sleeve It has a lower inlet nozzle and a curved baffle.

Further, the upper end of the sliding sleeve extends into the connecting sleeve and can slide up and down along the connecting sleeve. A plurality of screw holes are evenly distributed on the outer circumference of the connecting sleeve, and the centering screw is inserted into the screw hole to pass the centering. The screw clamps the sliding sleeve and keeps the sliding sleeve concentric with the upper connecting sleeve.

Further, a sealing ring is disposed between the outer circumference of the protective glass and the water-cooling sleeve of the protective glass.

Further, the inner surface of the upper end of the tapered nozzle core smoothly transitions with the inner surface of the lower end of the central sleeve, and an annular gap is left between the outer edge of the upper end of the tapered nozzle core and the outer edge of the lower end of the central sleeve. The inner ring edge portion of the mesh plate is caught in the annular gap.

Further, a plurality of mutually interleaved baffles are arranged between the water jacket and the air inlet sleeve from top to bottom.

Further, the powder inlet nozzle and the air inlet nozzle are disposed in plurality around the central sleeve.

Further, the number of the powder inlet nozzle and the air inlet nozzle are the same and the positions are in one-to-one correspondence.

Further, the diameter of the powder discharging aperture is greater than or equal to 0.2 mm and less than or equal to 3 mm.

Compared with the existing laser cladding nozzle device, the present invention has the following advantages:

(1) It can realize the size and quantity adjustment of the powder outlet, and can adjust the diameter of the powder gathering to achieve good powder and light matching;

(2) The nozzle core also provides easy replacement when it is protected by increasing the distance from the molten pool;

(3) Improve the existing protective glass cooling method.

(4) ensuring the concentricity of the sliding sleeve 3 and the upper connecting sleeve 1 by the centering screw 2, thereby avoiding the coaxiality error caused by processing and installation;

(5) Applicable to powder particles of any size, while improving the convergence, stability and powder utilization of the powder.

(6) Optimize the water cooling channel, reduce the water consumption and avoid too much piping to cause entanglement.

DRAWINGS

Figure 1 is a schematic view of the structure of the present invention;

Figure 2 is a schematic view showing the arrangement of the small holes in the annular sieve plate;

In the figure: 1, upper connecting sleeve; 2, centering screw; 3, sliding sleeve; 4, protective glass water cooling sleeve; 5, middle water inlet; 6, powder inlet; 7, air inlet; Upper water outlet; 9, powder feeding sleeve; 10, air inlet sleeve; 11, water cooling sleeve; 12, flow guiding baffle; 13, lower water inlet nozzle; 14, conical nozzle core; 15, annular sieve orifice plate; , center sleeve; 17, protective air hole; 18, central spout; 19, sealing ring; 20, protective glass; 21, powder hole, 22-curved baffle.

detailed description:

The invention will be further explained below in conjunction with the drawings.

As shown in FIG. 1, a built-in screen-type annular laser cladding nozzle of the present invention includes a laser head connecting portion, a middle sleeve portion and a nozzle portion.

The laser head connecting portion includes an upper connecting sleeve 1, and an upper end of the upper connecting sleeve 1 is connected to the laser head, and the laser cladding nozzle of the present invention is connected to the laser device through the upper connecting sleeve 1.

The central sleeve portion includes a sliding sleeve 3, a protective glass water jacket 4, a center sleeve 16, and a cover glass 20. The upper end of the sliding sleeve 3 is connected to the lower end of the upper connecting sleeve 1. In this embodiment, the upper end of the sliding sleeve 3 extends into the connecting sleeve 1 and can slide up and down along the connecting sleeve 1, outside the lower end of the connecting sleeve 1. A plurality of screw holes are evenly distributed in the circle, and the centering screw 2 is inserted into the screw hole, and the sliding sleeve 3 is clamped by the centering screw 2 and the sliding sleeve 3 is kept concentric with the upper connecting sleeve 1. A protective glass 20 is disposed between the lower end of the sliding sleeve 3 and the upper end of the central sleeve 16. The lower end of the sliding sleeve 3 and the upper end of the central sleeve 16 are provided with a protective glass water cooling sleeve 4, and the protective glass water cooling sleeve 4 and the sliding sleeve 3, respectively. The central sleeve 16 is screwed, and a sealing ring 19 is disposed between the outer circumference of the protective glass 20 and the protective glass water cooling sleeve 4. The protective glass water cooling sleeve 4 is provided with a central water inlet nozzle 5 and a central water outlet nozzle 18 at the center sleeve. The position of the cylinder 16 adjacent to the cover glass 20 is provided with two oppositely facing shielding air holes 17, and the lower end of the center sleeve 16 is tapered.

The nozzle portion includes a conical nozzle core 14, a powder inlet 9, an inlet sleeve 10, a water jacket 11, and an annular screen plate 15. The upper end of the conical nozzle core 14 is screw-fitted to the lower end of the center sleeve 16, and the powder sleeve 9, the air inlet sleeve 10, and the water cooling jacket 11 are sequentially disposed on the outer side of the lower end of the conical nozzle core 14 and the center sleeve 16. The upper half of the powder feeding sleeve 9, the air inlet sleeve 10 and the water cooling jacket 11 are both cylindrical and the lower half is tapered. The upper end of the powder feeding sleeve 9 is connected with the central sleeve 16 by screwing. The upper end of the powder feeding sleeve 9 is provided with a powder inlet nozzle 6, and the lower end of the powder feeding sleeve 9 and the lower end of the central sleeve 16 are provided with an annular sieve plate 15 at The annular sieve plate 15 is provided with a plurality of powder discharge holes 21, as shown in FIG. 2, the diameter of the powder discharge holes 21 is greater than or equal to 0.2 mm and less than or equal to 3 mm, and the number of powder discharge holes 21 can be fed with powder. Parameters such as volume and powder feeding speed are optimized and adjusted. The upper end of the air inlet sleeve 10 is connected with the upper end of the powder feeding sleeve 9 through a threaded joint. The upper end of the air inlet sleeve 10 is provided with a plurality of air inlet nozzles 7 around the center sleeve 16. The upper end of the water cooling sleeve 11 and the upper end of the air inlet sleeve 10 are fixed by welding. An upper water outlet 8 is provided at the upper end of the water jacket 11 around the center sleeve 16 and has the same number and position one-to-one correspondence with the air inlet nozzle 7, and a lower water inlet 13 and a curved shutter 22 are provided at the lower end of the water jacket 11, and A plurality of mutually interleaved baffles 12 are provided between the water jacket 11 and the air intake sleeve 10 from top to bottom. In this embodiment, the inner surface of the upper end of the tapered nozzle core 14 and the inner surface of the lower end of the central sleeve 16 smoothly transition, and the outer edge of the upper end of the tapered nozzle core 14 and the outer edge of the lower end of the central sleeve 16 are left. An annular notch, the inner ring edge portion of the annular mesh plate 15 is snapped into the annular notch, and the annular mesh plate 15 is clamped by the tapered nozzle core 14 and the center sleeve 16.

When the laser cladding nozzle is in operation, the coaxiality of the laser beam and the powder flow is adjusted by the centering screw 2. Since the air inlet sleeve 10 and the powder inlet sleeve 9 are connected by a threaded disk, the air inlet sleeve 10 can be adjusted up and down within a certain distance with respect to the powder feeding sleeve 9, so that the lower end of the air inlet sleeve 10 and the tapered powder feeding sleeve can be adjusted. The angle between the lower ends of 9 changes the angle of the airflow to achieve the regulation of the size of the powder. The lower end of the water cooling jacket 11 is provided with a curved baffle 22, which can re-reflect the laser beam reflected from the base, which greatly improves the utilization of the laser beam energy.

The distance between the nozzle portion and the molten pool can be adjusted by the sliding sleeve 3, and the tapered nozzle core 14 is detachably connected to the central sleeve 16 by screwing, so that the annular mesh plate 15 of different apertures can be easily replaced. Since the inner wall of the conical nozzle core 14 is a smooth curved surface, the powder sputtered inside the conical nozzle core 14 can slide off by itself, thereby avoiding blockage of the powder pores and improving the utilization of the powder.

In order to prevent the protective glass 20 from overheating, the outer edge of the protective glass 20 may be cooled by supplying cooling water to the protective glass water jacket 4, and two protective air holes 17 are opened under the protective glass 20, and the protective glass is passed through the protective gas. The center is air-cooled, and the outer edge of the protective glass 20 is wrapped with a sealing ring 19, which can ensure the air pressure in the cavity of the central sleeve 16 to prevent the powder from rising and contaminating the protective glass. In order to prevent local overheating of the nozzle portion, forced water cooling is achieved by introducing cooling water into the water jacket 11. The cooling water flows in from the central water inlet 5 of the protective glass water jacket 4, and then flows out from the central water outlet 18, and the outflowing cooling water enters the water jacket 11 through the lower water inlet nozzle 13 and finally flows out from the upper water outlet nozzle 8. Cooling water is cooled according to the above path, which not only reduces the amount of water but also avoids excessive entanglement of the piping.

The above description is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can also make several improvements and retouchings without departing from the principles of the present invention. It should be considered as the scope of protection of the present invention.

Claims

A built-in screen type annular laser cladding nozzle, comprising: a laser head connecting portion, a middle sleeve portion and a nozzle portion; the laser head connecting portion comprises an upper connecting sleeve (1) and an upper connecting sleeve ( 1) the upper end is connected to the laser head; the middle sleeve portion comprises a sliding sleeve (3), a protective glass water cooling jacket (4), a center sleeve (16), a protective glass (20), and an upper end of the sliding sleeve (3) Connected to the lower end of the upper connecting sleeve (1), a protective glass (20) is disposed between the lower end of the sliding sleeve (3) and the upper end of the central sleeve (16), and the lower end of the sliding sleeve (3) and the central sleeve (16) The outer side of the upper end is provided with a protective glass water cooling sleeve (4), and the protective glass water cooling sleeve (4) is respectively screwed with the sliding sleeve (3) and the central sleeve (16), and the protective glass water cooling jacket (4) is provided with a central water inlet. The mouth (5) and the central spout (18) are provided with two oppositely facing protective air holes (17) at a position of the central sleeve (16) adjacent to the protective glass (20), and the lower end of the central sleeve (16) is tapered The nozzle portion includes a conical nozzle core (14), a powder inlet sleeve (9), an air inlet sleeve (10), a water cooling jacket (11), an annular sieve plate (15), and a conical nozzle core (14). Upper and middle The lower end of the core sleeve (16) is connected by a threaded fit, and a powder feeding sleeve (9), an air inlet sleeve (10), and a water cooling sleeve are sequentially arranged on the outer side of the lower end of the cone nozzle core (14) and the center sleeve (16). ), the upper half of the powder feeding sleeve (9), the air inlet sleeve (10) and the water cooling sleeve (11) are both cylindrical, the lower half is tapered, and the upper end of the powder sleeve (9) and the center sleeve (16) through the threaded connection, the powder feeding sleeve (9) is provided with a powder inlet nozzle (6) at the upper end, and an annular sieve plate (15) between the lower end of the powder feeding sleeve (9) and the lower end of the central sleeve (16). The annular sieve plate (15) is provided with a small powder hole (21), and the upper end of the air inlet sleeve (10) and the upper end of the powder feeding sleeve (9) are screwed and connected, and the upper end of the air inlet sleeve (10) is provided with air inlet. The mouth (7), the upper end of the water cooling sleeve (11) and the upper end of the air inlet sleeve (10) are fixed by welding, the upper end of the water cooling sleeve (11) is provided with an upper water outlet nozzle (8), and the lower end of the water cooling sleeve (11) is provided with a lower water inlet nozzle. (13) and curved baffle (22).
A built-in screen-type annular laser cladding nozzle according to claim 1, characterized in that the upper end of the sliding sleeve (3) projects into the connecting sleeve (1) and can be along the connecting sleeve (1) Sliding up and down, a plurality of screw holes are arranged on the outer circumference of the lower end of the connecting sleeve (1), a centering screw (2) is inserted into the screw hole, and the sliding sleeve (3) is clamped by the centering screw (2) and slid The sleeve (3) is concentric with the upper connecting sleeve (1).
A built-in screen-type annular laser cladding nozzle according to claim 1, characterized in that a sealing ring (19) is arranged between the outer circumference of the protective glass (20) and the protective glass water-cooling sleeve (4).
A built-in screen-type annular laser cladding nozzle according to claim 1, wherein the inner surface of the upper end of the tapered nozzle core (14) smoothly transitions with the inner surface of the lower end of the center sleeve (16). An annular notch is left between the outer edge of the upper end of the tapered nozzle core (14) and the outer edge of the lower end of the central sleeve (16), and the inner ring edge portion of the annular mesh plate (15) is inserted into the annular notch.
A built-in screen-type annular laser cladding nozzle according to claim 1, wherein a plurality of mutually interlaced between the water-cooling sleeve (11) and the air inlet sleeve (10) are provided from top to bottom. Guide baffle (12).
A built-in screen-type annular laser cladding nozzle according to claim 1, characterized in that the powder inlet nozzle (6) and the air inlet nozzle (7) are disposed in plurality around the central sleeve (16).
A built-in screen-type annular laser cladding nozzle according to claim 6, characterized in that the number of the powder inlet nozzle (6) and the air inlet nozzle (7) are the same and the positions are in one-to-one correspondence.
A built-in screen-type annular laser cladding nozzle according to claim 1, wherein the diameter of the powder discharging aperture (21) is greater than or equal to 0.2 mm and less than or equal to 3 mm.