Online detection method and system for components of molten steel in RH refining furnace based on LIBS (Laser-induced Breakdown Spectroscopy)

Abstract

The invention provides an LIBS-based online detection method and system for components of molten steel in an RH refining furnace, and belongs to the field of ferrous metallurgy. The slag breaking gun, the purging gun and the detection gun are integrated in the three guns respectively, and the three guns are controlled to ascend and descend integrally in a servo motor and lead screw transmission mode. The slag breaking gun adopts high-pressure pulse injection type propane gas non-contact slag breaking, the purging gun adopts high-pressure nitrogen gas purging, and the detection gun is used for LIBS element composition detection; a gun self-protection linkage mechanism is detected, when the gas pressure and flow are too low, the temperature is too high or equipment communication faults occur, fault signals are fed back to an industrial personal computer, and a servo motor immediately responds and lifts the three guns to a safe distance; the molten steel liquid level continuously fluctuates, the laser range finder and a servo motor encoder are jointly controlled through an RS422 serial port communication protocol, laser is emitted to collect data, and meanwhile automatic focusing and distance adjusting are conducted; according to the invention, the accuracy, the real-time performance and the precision of online detection of the molten steel components are improved.

Description

Technical field:

[0001] The present invention belongs to the field of iron and steel metallurgy, and in particular relates to a LIBS-based online detection method and system for the composition of molten steel in an RH refining furnace. Background technology:

[0002] With the emergence of energy and environmental issues, the steel smelting industry has also attached increasing importance to energy conservation and emission reduction. Precise, automated and intelligent control of the smelting process is one of the important ways to improve product quality and save energy and reduce consumption. The refining process of the steelmaking refining furnace is an important process in the steel smelting process. Refining plays the role of deoxidation, decarbonization, desulfurization, removal of impurities, modification of inclusions, and adjustment of the composition of molten steel. It is an important link in improving the quality of steel products, smelting high-end steel grades, optimizing production process flow, and improving production efficiency. The endpoint control of the refining process composition is a key control process related to the quality of steel products, which also provides new demands and challenges for intelligent equipment and real-time online detection of molten steel composition.

[0003] In the existing technology, the composition detection of molten steel in the refining furnace is usually carried out by offline and intermittent detection, which requires manual sampling and removal of the oxide layer on the sample surface. The sample's component content is then detected using a spark direct reading spectrometer, a carbon and sulfur meter, or an ICP chemical dissolution method. The above detection methods cannot achieve real-time and synchronous detection, resulting in a lack of real-time and accuracy in process control, and there are problems such as low control precision, low endpoint hit rate, low degree of intelligence, and great control difficulty. Summary of the invention:

[0004] To address the above-mentioned issues, the present invention provides a method and system for online detection of the composition of molten steel in an RH refining furnace based on laser induced breakdown spectroscopy (LIBS). The method and system utilize pulsed lasers, an ICCD spectrometer, a laser rangefinder, and a digital delayed pulse generator. The method excites the sample surface to generate plasma through a pulsed laser, which is then collected by an optical system and transmitted through an optical fiber to the ICCD spectrometer for spectral separation. Spectral data analysis and algorithm modeling are then performed to ultimately achieve online, rapid, and accurate detection of the composition of molten steel in the RH refining furnace, thereby improving the real-time, accuracy, and precision of composition detection.

[0005] In order to achieve the above objectives, the technical solutions adopted in the embodiments of the present invention are as follows:

[0006] In a first aspect, an embodiment of the present invention provides a method for online detection of the composition of molten steel in a RH refining furnace based on LIBS, comprising:

[0007] Step S1: First, start the industrial computer self-test module to check whether the air pressure flow, temperature and communication signal are normal. After the self-test is normal, start all devices and enter the system linkage working mode;

[0008] Step S2: The laser rangefinder measures the distance between the inspection gun and the molten steel and feeds it back to the industrial computer. The industrial computer sends a distance adjustment instruction to the servo motor based on the preset constant value and the feedback distance, and drives the slag breaking gun, the purge gun, and the inspection gun to move up and down as a whole through the screw drive to complete the distance adjustment;

[0009] Step S3: When the parameters measured by the first pressure and flow sensors are normal, the slag breaking gun starts to work, spraying high-pressure propane gas toward the molten steel liquid surface at the focus point to break the slag layer on the surface of the molten steel liquid;

[0010] Step S4: After the slag breaking is completed and the parameters measured by the third pressure and flow sensors are normal, the purge gun starts to work and blows high-pressure nitrogen gas toward the molten steel liquid surface at the focus point to purge the residue on the surface of the molten steel liquid;

[0011] Step S5: After the purge is completed and the measurement parameters of the second pressure and flow sensors are normal, the detection gun starts working. Since the molten steel liquid level fluctuates continuously, it is easy to cause inaccurate distance measurement and unstable spectral data. The laser rangefinder is controlled by the RS422 serial port communication protocol and the servo motor encoder. It automatically focuses and adjusts the distance while collecting spectral data.

[0012] Step S6, the self-protection linkage mechanism of the detection gun. When any of the first pressure and flow sensor, the second pressure and flow sensor, the third pressure and flow sensor, the communication and temperature sensor fails in any of the steps S3-S5, a fault signal is fed back to the industrial computer, and the servo motor is controlled to immediately raise the detection gun to a safe distance.

[0013] In step S7, the LIBS detection system completes data collection when no abnormal faults occur, and the software algorithm integration module of the industrial computer displays the LIBS molten steel composition detection results in real time.

[0014] As a preferred embodiment of the present invention, the distance between the surface of the molten steel liquid and the detection gun is constant at 1550 mm. When the laser rangefinder measures 1550 mm, the focal points of the detection gun, the purge gun and the slag breaking gun are located on the surface of the molten steel liquid.

[0015] As a preferred embodiment of the present invention, in step S3, the slag breaking gun uses a high-pressure pulse jet method to emit propane gas to perform non-contact slag breaking on the surface of the molten steel.

[0016] As a preferred embodiment of the present invention, in step S5, the laser rangefinder transmits a detection distance instruction to the servo motor through the RS422 serial communication protocol. The servo motor controls the real-time distance from the surface of the molten steel liquid to the outlet end face of the detection gun to maintain a constant value through the instruction and the screw transmission method, and synchronously controls the pulse laser to collect spectral data while controlling the overall up and down movement of the slag breaking gun, the detection gun and the purge gun and automatically adjusting the distance between the molten steel liquid and the detection gun.

[0017] As a preferred embodiment of the present invention, in step S6, after the industrial computer feeds back a fault signal, the servo motor encoder feedback control drives the traction point to move and controls the detection gun, purge gun and slag breaking gun to rise to a safe distance, and the equipment stops suddenly; after the fault problem is solved, go to step S2; if there is no abnormal fault, go directly to step S7.

[0018] In a second aspect, an embodiment of the present invention further provides an online detection system for the composition of molten steel in an RH refining furnace based on LIBS, the system comprising a detection gun 1, a first positioning and fixing plate 2, a purge gun 3, a second positioning and fixing plate 4, a servo motor 5, a pulse laser 6, an industrial computer 7, a reflector 8, a digital delayed pulse machine 9, a nitrogen bottle 10, a propane bottle 11, a cooling circulation integrated box 12, an ICCD spectrometer 13, a temperature sensor 14, a flame arrester 15, a slag breaking gun 16, a first pressure and flow sensor 17, a second pressure and flow sensor 18, a laser rangefinder 19, a third pressure and flow sensor 20, a vacuum induction furnace 21, and molten steel 22;

[0019] The outer surfaces of the detection gun 1, the purge gun 3 and the slag breaking gun 16 are respectively provided with a first fixed point and a second fixed point; the first fixed points of the detection gun 1, the purge gun 3 and the slag breaking gun 16 are simultaneously fixed on the first positioning fixing plate 2, and the second fixed points are simultaneously fixed on the second positioning fixing plate 4, and the central axes of the detection gun 1, the purge gun 3 and the slag breaking gun 16 converge at the same focusing point, so that the focusing point is located on the surface of the molten steel liquid 22 during operation; the vacuum induction furnace 21 smelts the molten steel liquid 22 at a temperature of 1500-1600°C; the detection gun 1, the purge gun 3, the slag breaking gun 16, the first positioning fixing plate 2 and the second positioning fixing plate 4 are as a whole, and a traction point is provided at any position, and the traction point is connected to the screw traction end of the servo motor 5; the overall rise and fall of the detection gun 1, the purge gun 3 and the slag breaking gun 16 are controlled by the servo motor 5 and the screw transmission mode, and the servo motor 5 is communicatively connected to the industrial computer 7;

[0020] The slag lance 16 is provided with a flame arrester 15 for isolating the backflow of propane combustible gas. A first pressure and flow sensor 17 is provided near the end of the molten steel. The internal gas path is connected to the propane bottle 11.

[0021] A second pressure and flow sensor 18 is provided at the end of the detection gun 1 near the molten steel, and a cooling circulation gas path is provided inside and connected to the nitrogen cylinder 10. At the same time, a laser rangefinder 19 is provided at a preset position. The detection gun 1 has a long-distance LIBS optical path system, which can realize the convergence and collection of light paths, focusing on the surface of the molten steel 22. The collected light is transmitted to the ICCD spectrometer 13 via an optical fiber line.

[0022] A third pressure and flow sensor 20 is provided at the end of the purging gun 3 near the molten steel, and the internal gas path is connected to the nitrogen cylinder 10;

[0023] The cooling cycle integrated box 12 is located on the top platform of the slag breaking gun 16, the detection gun 1 and the purge gun 3. The interior of the cooling cycle integrated box 12 mainly includes a servo motor 5, a pulse laser 6, an industrial computer 7, a reflector 8, a digital delayed pulse generator 9, a nitrogen bottle 10, a propane bottle 11 and an ICCD spectrometer 13. A nitrogen cooling cycle is used to cool the equipment. A temperature sensor 14 is installed on the outside of the cooling cycle integrated box 12 to detect the temperature of the box;

[0024] The industrial computer 7 integrates software and hardware equipment and algorithms to realize the timing control of the detection gun 1, the slag breaking gun 16 and the purge gun 3, the servo motor 5 through encoder feedback control and the linkage control response of the laser rangefinder 6 and the traction point, and the real-time online analysis of the composition of the molten steel liquid 22.

[0025] As a preferred embodiment of the present invention, the laser rangefinder 19 forms an angle of less than 15° with the vertical downward axis of the detection gun 1 when in operation; the laser rangefinder 19 communicates data with the servo motor 5 via the RS422 serial communication protocol.

[0026] As a preferred embodiment of the present invention, all communication lines and gas pipeline channels of the detection gun 1, slag breaking gun 16, purge gun 3 and equipment inside the cooling circulation integrated box 12 should be made into separate pipeline channels and protected, and the optical lenses and equipment should work under the conditions of cooling nitrogen circulation. Since all equipment is located in a closed state in the cooling circulation integrated box 12 at the top of the vacuum induction furnace 21, remote visual linkage protection control should be guaranteed to ensure that the equipment, optical lenses and cooling circulation system are working normally.

[0027] The solution of the embodiment of the present invention has the following beneficial effects:

[0028] The embodiment of the present invention provides an online detection method and system for the composition of molten steel in an RH refining furnace based on LIBS. The system integrates software and hardware equipment and algorithms in an industrial computer, including the timing control of a detection gun, a slag-breaking gun and a purge gun, a nitrogen cooling circulation system, a linkage control response between a servo motor and a detection device, and a real-time online prediction function of the LIBS composition of the molten steel. The system eliminates the need for offline pneumatic sampling, and does not require sample preparation and manual detection links, thus saving labor costs, improving smelting detection efficiency, and having a high level of system integration and intelligence. The slag-breaking gun, purge gun and detection gun are respectively integrated into the three guns, and the central axes of the slag-breaking gun, the detection gun and the purge gun are focused on the same point, and the focusing point is located on the surface of the molten steel, ensuring that the slag-breaking and purge components are detected in the same area. The slag-breaking gun, the purge gun and the detection gun are connected by two positioning fixing plates to form an integrated structure of three guns, which can be controlled by a servo. The motor and screw drive mode realizes the overall rising and falling of the three guns. Compared with chain drive or gear drive, the screw drive mode has higher precision and is more conducive to the ranging work of the laser rangefinder; the slag breaking gun uses propane high-pressure gas for non-contact slag breaking. Compared with physical contact slag breaking, the non-contact slag breaking gun head is not easy to stick to molten steel residue, and the residue on the gun head is easy to clean; in addition, propane has high calorific value and good controllability. The propane combustion temperature is about 2000-2500℃, which is higher than methane and ethane, and is more conducive to slag breaking on the surface of molten steel; the self-protection linkage mechanism of the detection gun is automatically controlled by the industrial computer. When the gas pressure and flow are too low, the temperature is too high or the equipment communication fails, the detection gun is immediately raised, and the servo motor encoder is used to timely feedback and control the detection gun to rise to prevent the molten steel temperature from being too high and radiating to damage the detection equipment. This equipment linkage control self-protection mechanism avoids the risk of equipment damage.

[0029] Of course, it is not necessary to achieve all of the advantages described above simultaneously in order to implement any product or method of the present invention. Description of the drawings:

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 This is a schematic structural diagram of an online detection system for molten steel composition in an RH refining furnace based on LIBS according to an embodiment of the present invention;

[0032] Figure 2 In the embodiment of the present invention Figure 1 The control logic diagram of the slag breaking gun, purge gun and detection gun in the system shown;

[0033] Figure 3 This is a complete flow chart of the LIBS online composition detection method for molten steel in an RH refining furnace of the present invention.

[0034] Description of reference numerals:

[0035] 1. Detection gun; 2. First positioning fixing plate; 3. Purge gun; 4. Second positioning fixing plate; 5. Servo motor; 6. Pulse laser; 7. Industrial computer; 8. Reflector; 9. Digital delayed pulse generator; 10. Nitrogen cylinder; 11. Propane cylinder; 12. Cooling circulation integrated box; 13. ICCD spectrometer; 14. Temperature sensor; 15. Flame arrester; 16. Slag breaking gun; 17. First pressure and flow sensor; 18. Second pressure and flow sensor; 19. Laser rangefinder; 20. Third pressure and flow sensor; 21. Vacuum induction furnace; 22. Molten steel. Specific implementation method:

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; the components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. It should be noted that the embodiments of the present invention and the features in the embodiments can also be combined with each other without conflict.

[0037] It should be noted that similar numbers and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In the description of the present invention, the terms "first", "second", "third", "fourth", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0038] Based on the problem of detecting the composition of molten steel in an RH refining furnace, an embodiment of the present invention provides a method and system for online detection of the composition of molten steel in an RH refining furnace based on LIBS. In the system, a slag breaking gun, a purge gun and a detection gun are respectively integrated into three guns, and the overall rise and fall of the three guns are controlled by a servo motor and a screw drive; high-pressure pulse jet propane gas is used in the slag breaking gun to perform non-contact slag breaking on the surface of the molten steel, high-pressure nitrogen in the purge gun is used to purge residual slag on the surface of the molten steel, and the detection gun performs LIBS elemental composition detection on the molten steel; the detection gun has a self-protection linkage mechanism, and when the gas pressure and flow are too low, the temperature is too high, or the equipment communication fails, the servo motor encoder is used to provide timely feedback to control the detection gun to be immediately raised; the industrial control computer integrates software and hardware algorithm functions to complete the timing control of the detection gun, slag breaking gun and purge gun, the nitrogen cooling circulation system, and the linkage control response of the servo motor and the detection equipment, so as to realize real-time online composition detection of the molten steel in the RH refining furnace.

[0039] like Figure 1 As shown, the LIBS-based online detection system for the composition of molten steel in an RH refining furnace includes a detection gun 1, a first positioning fixing plate 2, a purge gun 3, a second positioning fixing plate 4, a servo motor 5, a pulse laser 6, an industrial computer 7, a reflector 8, a digital delayed pulse machine 9, a nitrogen bottle 10, a propane bottle 11, a cooling circulation integrated box 12, an ICCD spectrometer 13, a temperature sensor 14, a flame arrester 15, a slag breaking gun 16, a first pressure and flow sensor 17, a second pressure and flow sensor 18, a laser rangefinder 19, a third pressure and flow sensor 20 and a vacuum induction furnace 21.

[0040] Among them, the outer surfaces of the detection gun 1, the purge gun 3 and the slag breaking gun 16 are respectively provided with a first fixed point and a second fixed point; the first fixed points of the detection gun 1, the purge gun 3 and the slag breaking gun 16 are simultaneously fixed on the first positioning fixing plate 2, and the second fixed points are simultaneously fixed on the second positioning fixing plate 4, and the central axes of the detection gun 1, the purge gun 3 and the slag breaking gun 16 converge at the same focal point, so that the focal point is located on the surface of the molten steel liquid 22 during operation, and the temperature of the molten steel liquid 22 smelted by the vacuum induction furnace 21 is 1500-1600°C; a flame arrester 15 is provided in the slag breaking gun 16 to block the backflow of propane combustible gas A first pressure and flow sensor 17 is provided near the end of the molten steel, and the internal gas circuit is connected to the propane bottle 11; a second pressure and flow sensor 18 is provided near the end of the detection gun 1 near the molten steel, and a cooling circulation gas circuit is provided inside and is connected to the nitrogen bottle 10, and a laser rangefinder 19 is provided at a preset position; there is a long-distance LIBS optical path system in the detection gun 1, which can realize the gathering and light collection of the light path, focusing on the surface of the molten steel liquid 22, and the light collection is transmitted to the ICCD spectrometer 13 through the optical fiber line; a third pressure and flow sensor 20 is provided at the end of the purge gun 3 near the molten steel, and the internal gas circuit is connected to the nitrogen bottle 10.

[0041] The detection gun 1, the purge gun 3, the slag breaking gun 16, the first positioning fixing plate 2 and the second positioning fixing plate 4 are regarded as a whole, and a traction point is set at any position. The traction point is connected to the screw traction end of the servo motor 5, and the overall rise and fall of the detection gun 1, the purge gun 3 and the slag breaking gun 16 are controlled by the servo motor 5 and the screw transmission method.

[0042] The cooling cycle integrated box 12 is located on the top platform of the slag breaking gun 16, the detection gun 1 and the purge gun 3. The cooling cycle integrated box 12 is provided with a servo motor 5, a pulse laser 6, an industrial computer 7, a reflector 8, a digital time-delay pulse machine 9, a nitrogen bottle 10, a propane bottle 11, a cooling cycle system, and an ICCD spectrometer 13. The cooling cycle integrated box 12 is provided with a temperature sensor 14 outside. Among them, the software integration module of the industrial computer 7 is connected with the servo motor 5, the pulse laser 6, the digital time-delay pulse machine 9, the nitrogen bottle 10, the propane bottle 11, the ICCD spectrometer 13, and the temperature sensor 14. , flame arrester 15, first pressure and flow sensor 17, second pressure and flow sensor 18, laser rangefinder 19 and third pressure and flow sensor 20 control association; cooling circulation system is connected to the cooling circulation gas path inside the detection gun 1, and is cooled by nitrogen; the temperature sensor 14 is used to detect the box temperature; preferably, the energy of the pulse laser 6 is 200mJ, the operating voltage is 220V, the repetition frequency is 10Hz, the actual working frequency is 2.5Hz, the inherent delay time of the pulse laser is 110μs, and the Q of the receiving digital delayed pulse machine 9 is 200mJ. in and Clk in Two signals thereby trigger the laser; the digital delayed pulse machine 9 is set with two channels, which are set to 100μs and 110μs respectively, and the voltage is set to 5V, which are used to control the timing signals of the pulse laser 6 and the ICCD spectrometer 13; the resolution of the ICCD spectrometer 13 is λ / 6000nm, the integration time is 1ms, the band range of the ICCD spectrometer is 199-936nm, and the resolution of each channel is different.

[0043] The industrial computer 7 integrates software and hardware equipment and algorithms to realize the timing control of the detection gun 1, slag breaking gun 16 and purge gun 3, the servo motor 5 through encoder feedback control and the linkage control response of the laser rangefinder 6 and the traction point, and the real-time online analysis of the composition of the molten steel liquid.

[0044] The laser rangefinder 19 is used to detect the distance between the surface of the molten steel liquid 22 in the vacuum induction furnace 21 and the outlet end face of the detection gun head, and send a distance instruction to the servo motor 5; preferably, the laser rangefinder 19 communicates data with the servo motor 5 through the RS422 serial communication protocol; the servo motor 5 calculates and controls the distance according to the received distance to generate a control instruction, controls the screw transmission mechanism through the instruction, and the screw transmission mechanism then controls the traction point through the screw nut transmission, thereby controlling the real-time distance from the surface of the molten steel liquid 22 to the detection gun 1; the screw transmission adopts a screw nut transmission mode. Compared with the chain drive or gear drive, the screw transmission mode has higher precision and is more conducive to the operation of the laser rangefinder 19, and can more accurately measure the distance between the surface of the molten steel liquid 22 and the outlet end face of the detection gun head 1; preferably, the laser rangefinder 19 adopts a single wavelength of 650nm red light with an accuracy of 0.1mm. When the laser rangefinder 19 is working, the angle between it and the vertical downward axis of the detection gun 1 is less than 15°.

[0045] The slag breaking gun 16 works after the real-time distance from the surface of the molten steel 22 to the detection gun 1 is stabilized at 1550mm, and then emits high-pressure propane gas to break the slag layer on the surface of the molten steel 22; preferably, the slag breaking gun 16 uses a high-pressure pulse jet method to emit propane gas to perform non-contact slag breaking on the surface of the molten steel; the flame arrester 15 provided in the slag breaking gun 16 is used to prevent the backflow of flammable propane gas; a first pressure and flow sensor installed at the slag breaking gun 16 near the molten steel end is used to provide real-time feedback of the pressure and flow of the propane gas. Propane has a high calorific value and good controllability. The propane combustion temperature is about 2000-2500°C, which is higher than that of methane and ethane, making it more conducive to slag breaking on the surface of the molten steel; the propane high-pressure gas is non-contact slag breaking. Compared with physical contact slag breaking, the contact slag breaking gun tip is prone to adhesion to molten steel residue, and the residue on the gun tip is difficult to clean. However, the non-contact slag breaking in this embodiment does not have the above problems, does not adhere to molten steel residue, and the gun tip is easy to clean.

[0046] The purge gun 3 is used to blow high-pressure nitrogen into the slag breaking area after the slag breaking is completed, so as to purge the residue on the surface of the molten steel liquid 22 and ensure that there is no residue on the surface of the molten steel liquid 22; the third pressure and flow sensor installed at the end of the purge gun 3 near the steel liquid is used to provide real-time feedback on the pressure and flow of the purge gas (nitrogen is used in this embodiment).

[0047] After the detection gun 1 is used for purging, when the distance between the surface of the molten steel liquid 22 and the outlet end face of the detection gun measured in real time by the laser rangefinder 19 remains constant, the laser emitted by the pulsed laser 6 is received to perform laser processing on the surface of the molten steel liquid 22, and a spectral signal is collected; the distance constant is a predetermined value, preferably 1550 mm; since the surface of the molten steel liquid 22 is constantly fluctuating, it is easy to cause instability in the measured spectral data. The laser rangefinder 19 transmits a detection distance instruction to the servo motor 5 through the RS422 serial port communication protocol. The servo motor 5 controls the real-time distance from the surface of the molten steel liquid 22 to the outlet end face of the detection gun to remain constant through the instruction and the screw transmission mode, and synchronously controls the laser to automatically adjust the distance between the molten steel liquid and the detection gun while firing the laser to collect spectral data, so as to maintain a constant distance, thereby improving the stability of the data; a second pressure and flow sensor installed at the steel liquid end near the detection gun 1 is used to provide real-time feedback on the pressure and flow of the cooling gas (nitrogen is used in this embodiment).

[0048] The industrial computer 7 automatically controls the self-protection linkage mechanism of the detection gun 1; when the industrial computer 7 receives information that the gas pressure and flow are too low, the temperature is too high, or there is a device communication failure, the device linkage protection mechanism is activated, a fault instruction is sent to the industrial computer 7, the fault is fed back through the servo motor 5 encoder, and the detection gun 1 is controlled to rise immediately to prevent the molten steel liquid 22 from being damaged by radiation due to excessive temperature; after the fault problem is found and solved, the integrated device of the industrial computer 7 is restarted; the temperature of the molten steel liquid 22 smelted in the vacuum induction furnace 21 is usually 1500-1600℃.

[0049] In addition, from the perspective of the equipment itself, all communication lines and gas pipeline channels of the detection gun 1, slag breaking gun 16, purge gun 3 and internal equipment of the cooling circulation integrated box 12 are made into separate pipeline channels and protected. The optical lenses and equipment work under the conditions of the cooling circulation gas circuit and are maintained within a safe temperature range; since all equipment is located in a closed state of the cooling circulation integrated box 12 at the top of the vacuum induction furnace 21, remote visual linkage protection control must also be guaranteed to ensure that the equipment, optical lenses and cooling circulation system are all working normally.

[0050] like Figure 2 As shown in the figure, after the system self-check is normal, the industrial computer starts all the equipment in the system, and the laser rangefinder controls the overall rise and fall of the slag breaking gun, purge gun and detection gun through the RS422 serial communication protocol and servo motor encoder, and the screw transmission method; when the first pressure and flow sensor, the second pressure and flow sensor, the third pressure and flow sensor, the communication and temperature sensor have abnormal faults, the fault signal is fed back to the industrial computer, and the slag breaking gun, purge gun and detection gun will immediately rise to a safe distance as a whole; the industrial computer determines whether the system equipment should be stopped suddenly. If the operation is an emergency stop, the slag breaking gun, purge gun and detection gun will also immediately rise to a safe distance as a whole.

[0051] Based on the same idea, the embodiment of the present invention also provides an online detection method for the composition of molten steel in a RH refining furnace based on LIBS, which is implemented by the above-mentioned detection system. Figure 3 As shown, the method includes the following steps:

[0052] Step S1: First, start the industrial computer self-test module to check whether the air pressure flow, temperature and communication signal are normal. After the self-test is normal, start all devices and enter the system linkage working mode;

[0053] Step S2: The laser rangefinder measures the distance between the inspection gun and the molten steel and feeds it back to the industrial computer. The industrial computer sends a distance adjustment instruction to the servo motor based on the preset constant value and the feedback distance, and drives the slag breaking gun, the purge gun, and the inspection gun to move up and down as a whole through the screw drive to complete the distance adjustment;

[0054] Step S3: When the parameters measured by the first pressure and flow sensors are normal, the slag breaking gun starts to work, spraying high-pressure propane gas toward the molten steel liquid surface at the focus point to break the slag layer on the surface of the molten steel liquid;

[0055] Step S4: After the slag breaking is completed and the parameters measured by the third pressure and flow sensors are normal, the purge gun starts to work and blows high-pressure nitrogen gas toward the molten steel liquid surface at the focus point to purge the residue on the surface of the molten steel liquid;

[0056] Step S5: After the purge is completed and the measurement parameters of the second pressure and flow sensors are normal, the detection gun starts working. Since the molten steel liquid level fluctuates continuously, it is easy to cause inaccurate distance measurement and unstable spectral data. The laser rangefinder is controlled by the RS422 serial port communication protocol and the servo motor encoder. It automatically focuses and adjusts the distance while collecting spectral data.

[0057] Step S6, the self-protection linkage mechanism of the detection gun. When any of the first pressure and flow sensor, the second pressure and flow sensor, the third pressure and flow sensor, the communication and temperature sensor fails in any of the steps S3-S5, a fault signal is fed back to the industrial computer, and the servo motor is controlled to immediately raise the detection gun to a safe distance.

[0058] In step S7, the LIBS detection system completes data collection when no abnormal faults occur, and the software algorithm integration module of the industrial computer displays the LIBS molten steel composition detection results in real time.

[0059] It should be noted that the above-mentioned LIBS-based online detection method for the composition of molten steel in the RH refining furnace corresponds to the LIBS-based online detection system for the composition of molten steel in the RH refining furnace. The description of the system is also applicable to the description of the method, and will not be repeated here.

[0060] It can be seen that the present embodiment provides an online detection method and system for the composition of molten steel in an RH refining furnace based on LIBS, which integrates software and hardware equipment and algorithms in an industrial computer, including the timing control of the detection gun, slag-breaking gun and purge gun, a nitrogen cooling circulation system, the linkage control response of the servo motor and the detection equipment, and the real-time online prediction function of the LIBS composition of the molten steel. It eliminates the need for the original offline pneumatic sample delivery, the need for sample preparation and manual detection links, saves labor costs, improves the efficiency of smelting detection, and has a high level of system integration and intelligence; the slag-breaking gun, purge gun and detection gun are respectively integrated into the three guns, and the central axes of the slag-breaking gun, detection gun and purge gun are focused on the same point, and the focus point is located on the surface of the molten steel, ensuring The slag breaking and purging component detection is carried out in the same area; the slag breaking gun, purge gun and detection gun are connected by two positioning fixing plates to form an integrated structure of three guns, which can realize the overall rising and falling of the three guns; the propane high-pressure gas of the slag breaking gun is non-contact slag breaking. Compared with physical contact slag breaking, the non-contact slag breaking gun head is not easy to stick to the molten steel residue, and the residue on the gun head is easy to clean; the self-protection linkage mechanism of the detection gun is automatically controlled by the industrial computer. When the gas pressure and flow are too low, the temperature is too high or the equipment communication fails, the detection gun is immediately lifted up, and the servo motor encoder is used to timely feedback and control the detection gun to rise to prevent the molten steel temperature from being too high and radiating to damage the detection equipment. This equipment linkage control self-protection mechanism avoids the risk of equipment damage.

[0061] The above description is only a preferred embodiment of the present invention and an explanation of the technical principles used. It is not intended to limit the scope of the invention claimed for protection, but merely represents the preferred embodiment of the present invention. Those skilled in the art should understand that the scope of the invention involved in the present invention is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but should also cover other technical solutions formed by any combination of the above-mentioned technical features or their equivalent features without departing from the inventive concept. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative work shall fall within the scope of protection of the present invention.

Claims

1. A LIBS-based online detection method for the composition of molten steel in a RH refining furnace, characterized in that: include: Step S1: First, start the industrial computer self-test module to check whether the air pressure flow, temperature and communication signal are normal. After the self-test is normal, start all devices and enter the system linkage working mode; Step S2: The laser rangefinder measures the distance between the inspection gun and the molten steel and feeds it back to the industrial computer. The industrial computer sends a distance adjustment instruction to the servo motor based on the preset constant value and the feedback distance, and drives the slag breaking gun, the purge gun, and the inspection gun to move up and down as a whole through the screw drive to complete the distance adjustment; Step S3: When the parameters measured by the first pressure and flow sensors are normal, the slag breaking gun starts to work, spraying high-pressure propane gas toward the molten steel liquid surface at the focus point to break the slag layer on the surface of the molten steel liquid; Step S4: After the slag breaking is completed and the parameters measured by the third pressure and flow sensors are normal, the purge gun starts to work and blows high-pressure nitrogen gas toward the molten steel liquid surface at the focus point to purge the residue on the surface of the molten steel liquid; Step S5: After the purge is completed and the measurement parameters of the second pressure and flow sensors are normal, the detection gun starts working. Since the molten steel liquid level fluctuates continuously, it is easy to cause inaccurate distance measurement and unstable spectral data. The laser rangefinder is controlled by the RS422 serial port communication protocol and the servo motor encoder. It automatically focuses and adjusts the distance while collecting spectral data. Step S6, the self-protection linkage mechanism of the detection gun. When any of the first pressure and flow sensor, the second pressure and flow sensor, the third pressure and flow sensor, the communication and temperature sensor fails in any of the steps S3-S5, a fault signal is fed back to the industrial computer, and the servo motor is controlled to immediately raise the detection gun to a safe distance. In step S7, the LIBS detection system completes data collection when no abnormal faults occur, and the software algorithm integration module of the industrial computer displays the LIBS molten steel composition detection results in real time.

2. The method for online detection of RH refining furnace molten steel composition based on LIBS according to claim 1, characterized in that: The distance between the surface of the molten steel and the detection gun is constant at 1550 mm. When the laser rangefinder measures 1550 mm, the focal points of the detection gun, the purge gun and the slag breaking gun are located on the surface of the molten steel.

3. The method for online detection of RH refining furnace molten steel composition based on LIBS according to claim 1, characterized in that: In step S3, the slag breaking gun uses high-pressure pulse jet to emit propane gas to perform non-contact slag breaking on the surface of the molten steel liquid.

4. The method for online detection of RH refining furnace molten steel composition based on LIBS according to claim 1, characterized in that: In step S5, the laser rangefinder transmits a detection distance instruction to the servo motor through the RS422 serial communication protocol. The servo motor controls the real-time distance from the surface of the molten steel liquid to the outlet end face of the detection gun to maintain a constant value through the instruction and the screw transmission method, and synchronously controls the pulse laser to collect spectral data while controlling the overall up and down movement of the slag breaking gun, the detection gun and the purge gun and automatically adjusting the distance between the molten steel liquid and the detection gun.

5. The method for online detection of RH refining furnace molten steel composition based on LIBS according to claim 1, characterized in that: In step S6, after the industrial computer feeds back the fault signal, the servo motor encoder feedback control drives the traction point to move and controls the detection gun, purge gun and slag breaking gun to rise to a safe distance, and the equipment stops suddenly; after the fault problem is solved, go to step S2; if there is no abnormal fault, go directly to step S7.

6. An online detection system for RH refining furnace molten steel composition based on LIBS, characterized in that: The system comprises a detection gun (1), a first positioning fixing plate (2), a purge gun (3), a second positioning fixing plate (4), a servo motor (5), a pulse laser (6), an industrial computer (7), a reflector (8), a digital time-delay pulse machine (9), a nitrogen bottle (10), a propane bottle (11), a cooling circulation integrated box (12), an ICCD spectrometer (13), a temperature sensor (14), a flame arrester (15), a slag breaking gun (16), a first pressure and flow sensor (17), a second pressure and flow sensor (18), a laser rangefinder (19), a third pressure and flow sensor (20), a vacuum induction furnace (21) and molten steel (22); The outer surfaces of the detection gun (1), the purge gun (3) and the slag breaking gun (16) are respectively provided with a first fixed point and a second fixed point; the first fixed points of the detection gun (1), the purge gun (3) and the slag breaking gun (16) are simultaneously fixed on the first positioning fixing plate (2), and the second fixed points are simultaneously fixed on the second positioning fixing plate (4), and the central axes of the detection gun (1), the purge gun (3) and the slag breaking gun (16) converge at the same focal point, so that the focal point is located on the surface of the molten steel liquid (22) during operation; the vacuum induction furnace (2 1) The temperature of the molten steel liquid (22) is 1500-1600° C.; the detection gun (1), the purge gun (3), the slag breaking gun (16), the first positioning fixing plate (2) and the second positioning fixing plate (4) are integrated as a whole, and a traction point is provided at any position, and the traction point is connected to the lead screw traction end of the servo motor (5); the overall rise and fall of the detection gun (1), the purge gun (3) and the slag breaking gun (16) are controlled by the servo motor (5) and the lead screw transmission mode, and the servo motor (5) is connected to the industrial control computer (7); A flame arrester (15) is provided in the slag breaking gun (16) for isolating the backflow of propane combustible gas. A first pressure and flow sensor (17) is provided near the end of the molten steel, and the internal gas path is connected to the propane bottle (11); The detection gun (1) is provided with a second pressure and flow sensor (18) at the end near the molten steel, a cooling circulation gas path is provided inside and is connected to the nitrogen bottle (10), and a laser rangefinder (19) is provided at a preset position; the detection gun (1) has a long-distance LIBS optical path system, which can realize the convergence and collection of the optical path, focusing on the surface of the molten steel (22), and the light collection is to transmit the optical signal to the ICCD spectrometer (13) through the optical fiber line; A third pressure and flow sensor (20) is provided at the end of the purging gun (3) near the molten steel, and the internal gas path is communicated with the nitrogen bottle (10); The cooling cycle integrated box (12) is located on the top platform of the slag breaking gun (16), the detection gun (1) and the purge gun (3). The interior of the cooling cycle integrated box (12) mainly includes a servo motor (5), a pulse laser (6), an industrial computer (7), a reflector (8), a digital delayed pulse machine (9), a nitrogen bottle (10), a propane bottle (11) and an ICCD spectrometer (13). A nitrogen cooling cycle is used to cool the equipment. A temperature sensor (14) is installed on the outside of the cooling cycle integrated box (12) for detecting the temperature of the box body. The industrial control computer (7) integrates software and hardware equipment and algorithms to realize the timing control of the detection gun (1), the slag breaking gun (16) and the purge gun (3), the servo motor (5) controls the response of the linkage control with the laser rangefinder (6) and the traction point through encoder feedback control, and the real-time online analysis of the composition of the molten steel liquid (22).

7. The LIBS-based online detection system for RH refining furnace molten steel composition according to claim 6, characterized in that: When the laser rangefinder (19) is in operation, the included angle with the vertically downward axis of the detection gun (1) is less than 15°; the laser rangefinder (19) performs data communication with the servo motor (5) via the RS422 serial communication protocol.

8. The LIBS-based online detection system for RH refining furnace molten steel composition according to claim 6, characterized in that: All communication lines and gas pipelines of the equipment inside the detection gun (1), slag breaking gun (16), purge gun (3) and cooling circulation integrated box (12) should be made into separate pipelines and protected. The optical lenses and equipment should work under the condition of cooling nitrogen circulation. Since all equipment is located in a closed state in the cooling circulation integrated box (12) at the top of the vacuum induction furnace (21) at a high altitude, remote visual linkage protection control should be guaranteed to ensure that the equipment, optical lenses and cooling circulation system are working properly.

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