CN105714284B - The method and apparatus of ultrasonic vibration-electromagnetic agitation recombination energy field auxiliary laser cladding - Google Patents

Abstract

A method and device for ultrasonic vibration-electromagnetic stirring composite energy field assisted laser cladding, characterized in that the device mainly includes a laser, ultrasonic vibration equipment, and an AC excitation device. The device applies ultrasonic field and electromagnetic field at the same time during the laser cladding process, so that the laser melting area is subjected to the synergistic effect of ultrasonic vibration-electromagnetic stirring, thereby regulating the microstructure in the molten pool, controlling the grain size, and improving the macroscopic surface morphology. To improve, and then to obtain excellent cladding layer performance. The device effectively solves the shortcomings of the small range of ultrasonic treatment in a single application of an ultrasonic field and the inconspicuous tissue refinement effect in a single application of an electromagnetic field. The invention realizes the control of the microstructure and properties of the laser cladding layer by the ultrasonic vibration-electromagnetic stirring composite energy field, and can obtain a cladding layer with no crack holes, fine structure and excellent performance, and has the advantages of simple structure, convenient operation, low cost and applicable Features such as wide range.

Description

Ultrasonic vibration-electromagnetic stirring composite energy field assisted laser cladding method and device

technical field

The present invention relates to laser cladding technology, especially a method and device for laser cladding treatment on the surface of materials by using laser cladding technology, specifically a laser cladding assisted laser cladding by using ultrasonic vibration and electromagnetic stirring composite energy field Methods and Apparatus.

Background technique

Laser cladding technology is widely used in aerospace, chemical industry, mold, machinery, steel and other industries due to its controllable heat source and rapid solidification, as well as its high bonding strength and fine structure. However, there are still some problems in the laser cladding process. The main problems include defects such as pores, cracks, and coarse columnar grains in the cladding layer, as well as large residual stress due to rapid heating and quenching during the laser cladding process. At present, the solutions to these defects mainly include reducing these problems by adding some special alloy elements or rare earth oxides, or by optimizing the laser cladding process and preheating and postheating. , porosity and residual stress have no breakthrough.

In response to the above problems, scholars at home and abroad have improved the solidification structure of the metal, reduced internal defects, and reduced residual stress to improve the mechanical properties of the cladding layer by adding physical fields. The main methods include ultrasonic vibration and electromagnetic stirring. Wang Wei (see Wang Wei, Guo Pengfei, Zhang Jianzhong, etc. China Laser, 2013, 40 (8): 0803004) performed laser cladding experiments by adding ultrasonic vibration with a frequency of 19.56kHz on the titanium alloy substrate. The results show that the ultrasonic vibration of the power makes the surface of the cladding layer smooth, the porosity of the internal structure is reduced to 0.75%, the grain size of the cladding layer is reduced by about 42%, and the length of the sheet is reduced by 23.9%. The stacking efficiency decreased by 36.7% in the growth direction. Wu Dongjiang (Dongjiang Wu , Minhai Guo, Guangyi Ma et al. Materials Letters, 2015(141):207–209) used ultrasonic-assisted laser cladding of YSZ thermal barrier coating and studied its microstructure and dilution rate, and found that The application of ultrasonic vibration in laser cladding can change the cross-sectional morphology of the coating and refine the structure. At the same time, due to the influence of ultrasonic nonlinearity, the matrix and powder are completely mixed so that the dilution rate can be controlled. However, since the ultrasonic sound pressure amplitude is mainly concentrated near the ultrasonic probe, and with the increase of the distance, the ultrasonic intensity will also decrease significantly; on the other hand, the acoustic flow effect generated by ultrasonic can produce convection in the melt, but the effect Weak, unable to fully stir the melt. Therefore, applying a single ultrasonic field in the laser cladding process cannot achieve a very ideal tissue regulation effect. Electromagnetic stirring is to use electromagnetic force to promote the movement of the metal melt to change the flow of the melt in the molten pool, heat conduction, break the dendrites, and then refine the grains and improve the microstructure. Yu Xiaobin (Yu Xiaobin, Liu Fencheng, Lin Xin, et. The base superalloy still has the characteristics of epitaxial continuous growth of coarse columnar grains, but has a dense structure and no metallurgical defects. Since the electromagnetic stirring only stirs the liquid molten pool in the laser cladding process, and the existence time of the liquid molten pool in the cladding process is very short, that is, the stirring time for the molten pool is very short, so the structure of the cladding layer is fine The effect is not very significant. Therefore, applying electromagnetic stirring while performing ultrasonic vibration can effectively improve the shortcomings of the small range of action of ultrasonic treatment, promote the uniform distribution of added reinforcing particles into the cladding layer, and improve the phenomenon of segregation of the cladding layer. At the same time, in the process of electromagnetic stirring The introduction of ultrasonic vibration can make up for the inconspicuous effect of electromagnetic stirring.

Therefore, the present invention proposes a method and device for ultrasonic vibration-electromagnetic stirring composite energy field assisted laser cladding. Ultrasonic vibration and electromagnetic stirring are applied during the laser cladding process, and the synergistic effect of the composite energy field is used to refine and uniform the structure of the laser cladding layer, improve component segregation and relax residual stress, and improve defects such as cracks and pores in the cladding layer. The purpose of improving the performance of laser cladding layer.

By searching domestic and foreign literature, more researchers are currently focusing on the influence of a single electromagnetic stirring or ultrasonic vibration on the cladding layer structure and properties, and the application of combining the two in laser cladding is seldom. The present invention It is the first time to propose the method and device.

Contents of the invention

The purpose of the present invention is to solve the problem that the existing laser cladding auxiliary technology has single function and unsatisfactory effect, and invents a method that combines ultrasonic vibration and electromagnetic stirring composite energy field to assist laser cladding, and at the same time provides a corresponding The device effectively regulates the microstructure of the cladding layer through the synergistic effect of ultrasonic vibration and electromagnetic stirring, thereby improving the defects of the cladding layer and improving the comprehensive performance of the cladding layer.

One of technical solutions of the present invention is:

A method for ultrasonic vibration-electromagnetic stirring composite energy field assisted laser cladding, characterized in that it comprises the following steps:

(1) Pre-spread the required powder on the cladding substrate by the preset method, and dry it in a vacuum drying oven;

(2) Connect the dried cladding matrix with pre-set powder to the ultrasonic vibration device through a threaded rod, and place it horizontally at the center of the coaxial lines of the two excitation coils;

(3) Adjust the frequency and power of the ultrasonic power supply so that the cladding substrate with the pre-set powder generates high-frequency vibrations, and at the same time automatically adjust the voltage of the electronic voltage regulator so that the AC current in the circuit can be adjusted so that in the cladding area An alternating magnetic field is generated inside;

(4) Turn on the laser, complete the cladding process through the control of the industrial computer, turn on the argon gas cylinder at the same time during the process, and protect the molten pool through the gas supply nozzle;

(5) Laser cladding parameters are: laser power 1000-1800W, scanning speed 400-1200mm/min, spot diameter 1-4mm, flow rate of protective gas argon 10-25L/h.

The ultrasonic power supply makes the cladding substrate with the pre-prepared powder produce a maximum amplitude of 50 μm and a vibration frequency of 20-80 kHz.

The maximum current applied by the electronic voltage regulator is 20A, and a large alternating magnetic field of 65.7mT is generated in the cladding area.

The pre-powder method used includes adding binder, pre-powder compression and supersonic spraying.

The powder used for presetting must first be dried in a vacuum drying oven at 100°C for 20 minutes, and the cladding substrate with the pre-set powder should be dried in a vacuum drying oven at 100°C for 2 hours.

The second technical scheme of the present invention is:

An ultrasonic vibration-electromagnetic stirring compound energy field assisted laser cladding device is characterized in that it mainly includes a laser 1, an excitation coil 4, an ultrasonic vibration device 6, an argon gas cylinder 14 and an air supply nozzle 17, and the laser 1 and The argon gas cylinders 14 are all controlled by the industrial computer 2; the ultrasonic vibration device 6 that causes the cladding sample 3 to vibrate at high frequency during the laser cladding process is connected to the adjustable ultrasonic power supply 10, and the ultrasonic power supply 10 can adjust the ultrasonic vibration device 6 the amplitude and vibration frequency of the front end vibrator, the cladding sample 3 is installed on the threaded rod 18, and the threaded rod 18 is installed on the ultrasonic vibration device 6; the excitation coil 4 is installed on both sides of the cladding sample 3 so as to During the laser cladding process, an alternating magnetic field is generated on the cladding sample 3; the argon gas cylinder 14 is connected to the gas supply nozzle 17, and the gas supply nozzle 17 is used for gas supply protection during the laser cladding process.

The excitation coil 4 is connected with the electronic voltage regulator 11, and the electronic voltage regulator 11 performs automatic stepless voltage regulation through the servo motor 13, and the voltage regulation range is 0~250v; the electronic voltage regulator 11 and the ultrasonic power supply 10 are controlled by the single chip microcomputer 8 , the single chip microcomputer 8 is controlled by the industrial computer 2 .

The electronic voltage regulator 11 regulates its voltage through the servo motor 13 through the reducer 12 , and the electronic voltage regulator 11 and the excitation coil 4 form a closed loop.

The electronic voltage regulator 11 is connected with an adjustable resistor 9 that can expand its voltage regulation range.

The cladding sample 3 is placed horizontally at the center of the coaxial lines of the two excitation coils 4 .

The beneficial effects of the present invention are:

(1) In view of the shortcomings of the small range of action of a single external ultrasonic field on the molten pool and the ineffective effect of a single applied electromagnetic field on the molten pool, the two physical fields are combined, and various parameters of the composite energy field are adjusted to achieve It is an effect of synergistic regulation on the structure of cladding layer, and exerts the advantages of respective energy fields, so that the performance of cladding layer is further improved compared with that under the action of a single external energy field.

(2) The installation position of the ultrasonic vibration device and the electromagnetic stirring device in this device can make the molten pool be stirred from left to right and up and down, so that the molten pool can be stirred more fully, and the obtained crystal grains are finer and the structure is more compact.

(3) Compared with a single magnetic field, this device requires a larger magnetic field strength and a single ultrasonic field requires a higher amplitude. The composite energy field can achieve coordinated regulation at a lower magnetic field strength and smaller amplitude energy Function, so that the quality of the cladding layer can be greatly improved under the condition of low energy input, it is a high-efficiency energy-saving environmental protection device.

(4) The present invention is a simple in structure, flexible in regulation, economical and versatile method for refining and improving the microstructure and performance of molten pool during the thermal effect of laser and material, and has strong engineering application value.

Description of drawings

Fig. 1 is a schematic diagram of an ultrasonic vibration-electromagnetic stirring compound energy field assisted laser cladding device of the present invention.

Fig. 2 is a connection diagram of the threaded rod and the sample of the present invention.

Fig. 3 is a metallographic diagram of cladding layer cross-section under the application of ultrasonic vibration-electromagnetic stirring composite energy field in the embodiment of the present invention.

Fig. 4 is a metallographic diagram of the section structure of the cladding layer applied with the ultrasonic vibration field in the embodiment of the present invention.

Fig. 5 is a metallographic diagram of the cross-sectional structure of the cladding layer applied with an electromagnetic field in the embodiment of the present invention.

Fig. 6 is a metallographic diagram of cladding layer section without applying ultrasonic vibration-electromagnetic stirring composite energy field in the embodiment of the present invention.

In the figure: 1. Laser (Nd:YAG); 2. Industrial computer; 3. Sample; 4. Excitation coil; 5. Support frame; 6. Ultrasonic vibration device; 7. Working platform; Resistor adjustment; 10. Ultrasonic power supply; 11. Electronic voltage regulator; 12. Reducer; 13. Servo motor; 14. Argon cylinder; 15. Mirror; 16. Focusing lens; 17. Air supply nozzle; 18. threaded rod.

Detailed ways

The present invention will be further described below in conjunction with drawings and embodiments.

As shown in Figure 1-2.

A device for ultrasonic vibration-electromagnetic stirring composite energy field assisted laser cladding, mainly including Nd:YAG laser 1, industrial computer 2, excitation coil 4, ultrasonic vibration device 6, adjustable resistor 9, single-chip microcomputer 8, electronic voltage regulator Device 11, ultrasonic power supply 10, argon gas cylinder 14 and gas delivery nozzle 17, as shown in Figure 1; Described Nd:YAG laser device 1, single-chip microcomputer 8 and argon gas cylinder 14 all link to each other with described industrial computer 2; Described The single-chip microcomputer 8 controls the electronic voltage regulator 11 and the ultrasonic power supply 10 respectively; the electronic voltage regulator 11 carries out automatic stepless voltage regulation through the reducer 12 through the servo motor 13, and the electronic voltage regulator 11 and the excitation coil 4 and can The adjustable resistor 9 is connected in series to form a closed loop, and the adjustable resistor 9 is used to expand the voltage regulation range of the electronic voltage regulator 11; the ultrasonic power supply 10 is connected to the ultrasonic vibration device 6, and the ultrasonic power supply 10 is used to adjust the ultrasonic vibration device 6 the amplitude and vibration frequency of the front vibrator; the cladding sample 3 is connected to the ultrasonic vibration device 6 through a threaded rod 18 (Fig. 2); the cladding sample 3 is placed horizontally on the coaxial line of the two excitation coils 4 At the center position; the argon gas cylinder 14 is connected to the air supply nozzle 17, and when the laser is turned on to start the cladding process, the ultrasonic vibration device causes the cladding sample 3 to generate high-frequency vibrations with an amplitude of 0.1-50 μm, adjustable, vibrating The frequency is 20-80kHz, which is adjustable. At the same time, the excitation coil 4 is energized to generate an alternating magnetic field to the cladding sample 3. The maximum current applied by the electronic voltage regulator 11 is 20A, and a large alternating current is generated in the cladding area. The variable magnetic field is 65.7mT. The air supply nozzle 17 is used for air supply protection during the laser cladding process.

Embodiment two.

A kind of ultrasonic vibration-electromagnetic stirring composite energy field assisted laser cladding method, it comprises the following steps:

(1) Use the preset method to pre-spread the required powder on the cladding substrate by means of binder or powder tableting, and place it in a vacuum drying oven to dry;

(2) Connect the dried cladding matrix with pre-set powder to the ultrasonic vibration device through a threaded rod, and place it horizontally at the center of the coaxial lines of the two excitation coils;

(3) Adjust the frequency and power of the ultrasonic power supply so that the cladding substrate with pre-set powder produces an amplitude of 0.1-50μm and a vibration frequency of 20-80kHz. At the same time, the electronic voltage regulator is automatically adjusted to make the current in the circuit in the 3-20A is adjustable, and an alternating magnetic field of 9.7-65.7mT is generated in the cladding area;

(4) Turn on the laser, complete the cladding process through the control of the industrial computer, turn on the argon gas cylinder at the same time during the process, and protect the molten pool through the gas supply nozzle;

(5) Laser cladding parameters are: laser power 1000-1800w, scanning speed 400-1200mm/min, spot diameter 1-4mm, flow rate of protective gas argon 10-25L/h.

Application example one.

First, the AZ91D magnesium alloy substrate with a size of 50mm×50mm×10mm was polished with sandpaper, ultrasonically cleaned with absolute ethanol for 5 minutes, and dried at a temperature of 100°C for 20 minutes. The laser cladding powder is Ni60 alloy powder with a particle size of 75-135 μm. Mix the powder with absolute ethanol to make a paste and coat it on the magnesium alloy substrate, and place it in a vacuum drying oven at 100°C for 2 hours. The sample is placed on the threaded rod used to connect the sample at the front end of the ultrasonic vibration device, the electronic voltage regulator and the ultrasonic power supply are turned on through the industrial computer to generate 32.7mT, 20kHz and 3μm vibrations on the sample, and the laser is turned on at the same time. Argon gas was injected to protect the molten pool, and a single laser scan was performed to obtain the laser cladding layer. The laser cladding process parameters are: laser power 1500w, scanning speed 400mm/min, spot diameter 2.5mm, flow rate of protective gas argon 15L/h. The microstructure of the cladding layer obtained in this embodiment is shown in Fig. 3 . When the laser cladding process parameters used in this example remain the same, only one ultrasonic field and electromagnetic field is added, and the obtained coating microstructures are shown in Figures 4 and 5, respectively. In this embodiment, when all the laser cladding process parameters are consistent, the additional ultrasonic field and electromagnetic field are removed, and the microstructure of the Ni60 alloy coating is laser clad on the AZ91D magnesium alloy, as shown in FIG. 6 .

Combining Figure 3 and Figure 6, it can be found that ultrasonic vibration-electromagnetic stirring composite energy field assisted laser cladding can effectively break up dendrites and fine-tune the microstructure. Comparing Figure 3, Figure 4 and Figure 5, it can be found that the ultrasonic vibration-electromagnetic stirring composite energy field has a more obvious effect of grain refinement and uniform organization than the single ultrasonic field and electromagnetic field.

Application example two.

The difference between this application example and application example 1 is that the electronic voltage regulator and ultrasonic power supply make it vibrate at 65.7mT, 80kHz and 50μm on the sample, and the laser is turned on and argon gas is introduced to protect the molten pool at the same time, and a single-channel laser is performed. Scan to obtain the laser cladding layer. The laser cladding process parameters are: laser power 1800W, scanning speed 1000mm/min, spot diameter 1mm, flow rate of protective gas argon 25L/h.

Application example three.

The difference between this application example and application example 1 is that the electronic voltage regulator and ultrasonic power supply make it vibrate at 9.7mT, 20kHz and 10μm on the sample, turn on the laser and feed in argon gas to protect the molten pool at the same time, and perform single-channel laser Scan to obtain the laser cladding layer. The laser cladding process parameters are: laser power 1000W, scanning speed 1200mm/min, spot diameter 4mm, flow rate of protective gas argon 10L/h.

The metallographic structure of the actual cladding layer is similar to that shown in Figure 3-6.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Relevant improvements made without departing from the principle of the present invention should also be regarded as the scope of protection of the present invention.

The parts not involved in the present invention are the same as the prior art or can be realized by adopting the prior art.

Claims (6)

1. a kind of method of ultrasonic vibration-electromagnetic agitation recombination energy field auxiliary laser cladding, it is characterized in that it includes the following steps：

（1）Required powder is layered in advance on cladding matrix, and place it in vacuum drying chamber and dry using preset method；

（2）The dried cladding matrix with fore-put powder is connected by threaded rod with ultrasonic vibration apparatus, and It is placed horizontally at the center of two magnet exciting coil coaxial lines；

（3）The frequency and power of ultrasonic power are adjusted, the cladding matrix with fore-put powder is made to generate high-frequency vibration, it is maximum Amplitude is 50 μm, vibration frequency 20-80kHz；Make the alternating current in circuit to electronic pressure controller progress automatic Regulation simultaneously It is adjustable, to generate alternating magnetic field in cladding area；The maximum current that the electronic pressure controller applies is 20A, in cladding area Interior generation is big alternating magnetic field 65.7mT；

（4）Laser is opened, cladding is completed by the control of industrial personal computer and is processed, opens argon gas gas cylinder simultaneously in process, Molten bath is protected by feed nozzle；

（5）Laser melting coating parameter is：Laser power 1000-1800W, sweep speed 400-1200mm/min, spot diameter 1- 4mm, the flow velocity 10-25L/h of protective gas argon gas.

2. according to the method described in claim 1, it is characterized in that the preset method includes addition binding agent, fore-put powder tabletting And supersonic spray coating.

3. according to the method described in claim 1, it is characterized in that the fore-put powder must be 100 DEG C first in vacuum drying chamber Dry 20min, and the cladding matrix of powder 100 DEG C of dry 2h in vacuum drying chamber again will be preset.

4. a kind of device of ultrasonic vibration-electromagnetic agitation recombination energy field auxiliary laser cladding, it is characterized in that it mainly includes laser Device（1）, magnet exciting coil（4）, ultrasonic vibration apparatus（6）, argon gas gas cylinder（14）And feed nozzle（17）, the laser（1） With argon gas gas cylinder（14）It is controlled by industrial personal computer（2）；Make cladding sample in laser cladding process（3）Generate the super of high-frequency vibration Acoustic vibration device（6）With adjustable ultrasonic power（10）It is connected, ultrasonic power（10）Ultrasonic vibration apparatus can be adjusted（6） The amplitude and vibration frequency of front-end vibration, the cladding sample（3）Mounted on threaded rod（18）On, threaded rod（18）It is mounted on Ultrasonic vibration apparatus（6）On；Magnet exciting coil（4）Mounted on cladding sample（3）Both sides so as to right in laser cladding process Cladding sample（3）Generate alternating magnetic field；The argon gas gas cylinder（14）With feed nozzle（17）It is connected, feed nozzle（17）For Protection of supplying gas is carried out in laser cladding process；Electronic pressure controller（11）Pass through servo motor（13）Automatic stepless pressure regulation is carried out, is adjusted Press 0 ~ 250V of range；Electronic pressure controller（11）And ultrasonic power（10）It is controlled by microcontroller（8）, microcontroller（8）It is controlled by work Control machine（2）；The magnet exciting coil（4）With electronic pressure controller（11）It is connected, electronic pressure controller（11）Pass through servo motor（13） By retarder（12）Pressure regulation, electronic pressure controller are carried out to it（11）With magnet exciting coil（4）Form closed circuit.

5. device according to claim 4, it is characterized in that the electronic pressure controller（11）Its pressure regulation can be expanded by being connected with The adjustable resistor of range（9）.

6. device according to claim 4, it is characterized in that the cladding sample（3）It is placed horizontally at two magnet exciting coils （4）Coaxial line center position.