Real-time observation method for simulating melting and solidification of welding material for high-strength steel in welding process

Abstract

The invention belongs to the technical field of high-strength steel welding, and particularly relates to a real-time observation method for simulating melting and solidification of a welding material for high-strength steel in the welding process and application of the real-time observation method. The real-time observation method comprises the following steps: 1) preparing a cylindrical sample; (2) the sample is placed in ultra-high-temperature laser confocal equipment, and simulated welding working parameters of the ultra-high-temperature laser confocal equipment and image acquisition frequencies of different temperature stages are set according to the simulated welding process; and (3) starting the ultrahigh-temperature laser confocal equipment to test according to the simulated welding working parameters in the step (2), acquiring image data in the whole test process according to the acquisition frequency in the step (2), storing the data, and analyzing an image. According to the method, real-time change condition information of welding material metal along with temperature and time under different welding processes of the high-strength steel sleeve welding material can be obtained in situ.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-strength steel welding, and in particular relates to a real-time observation method for simulating the melting and solidification of high-strength steel welding materials during welding, and an application thereof. Background Art

[0002] High-strength steel, due to its excellent strength and toughness, is widely used in various fields of the national economy. Welding is a key forming process for high-strength steel, from materials to equipment applications, so the microstructure and performance of the weld have a significant impact on the application of high-strength steel. To accelerate the development of high-strength steel supporting welding materials and save R&D funds, in-situ observation of the microstructure of supporting welding materials during solidification is used to directly observe the microstructure of supporting welding materials. This can deepen the understanding of the effect of alloying elements in the welding materials on the evolution of microstructure during solidification, thereby providing technical support for the alloy composition system, welding process, and post-weld heat treatment methods of supporting welding materials.

[0003] During the welding process, welding consumables undergo melting, solidification, and cooling, with changes in grain size and solid-state phase transformations. Changes in the welding process significantly impact the consumables' solidification and microstructure. By understanding the real-time microstructural changes of the consumables from liquid to solid and then to room temperature, and based on these test results, we can optimize the consumables' alloy composition, welding process, and post-weld heat treatment. This allows us to determine the optimal application for specific welding consumables. Summary of the Invention

[0004] To enable real-time observation of the microstructural evolution of high-strength steel welding consumables under different welding processes, the present invention provides a method and application for simulating the real-time observation of the melting and solidification of high-strength steel welding consumables during welding. This method enables in-situ acquisition of real-time information on the changes in weld metal metal with temperature and time under different welding processes. Furthermore, this method records the entire process, greatly facilitating understanding of the microstructural evolution of high-strength steel welding consumables under different welding processes, thereby helping to determine the appropriate welding method for the tested consumables.

[0005] The technical solutions provided by the present invention are as follows:

[0006] A method for real-time observation of melting and solidification of a high-strength steel welding material during welding is provided, comprising the following steps:

[0007] 1) Prepare cylindrical samples;

[0008] 2) Place the sample in an ultrahigh temperature laser confocal instrument and set the simulated welding parameters of the ultrahigh temperature laser confocal instrument and the image acquisition frequency at different temperature stages according to the simulated welding process;

[0009] 3) Starting the ultrahigh temperature laser confocal device to conduct a test according to the simulated welding working parameters described in step 2), and obtaining image data throughout the entire test process according to the acquisition frequency of step 2), saving the data, and analyzing the image.

[0010] Based on the above technical solution:

[0011] It can observe the changes of high-strength steel welding materials with temperature and time under different welding processes in real time, thus realizing real-time in-situ observation;

[0012] Based on the analysis of the acquired test images, it can be further used to determine whether the alloy composition of the tested welding material meets the requirements and whether the tested welding method meets the requirements, thereby determining the appropriate welding material and the welding method that matches it.

[0013] Specifically, the step 1) includes the following steps:

[0014] S1. Prepare a sample on a wire rod of high-strength steel welding material by wire cutting. The sample is cylindrical and has parallel upper and lower end surfaces.

[0015] S2. Clean the sample, then grind and polish the test surface of the sample;

[0016] S3. Ultrasonic clean the polished sample and blow dry it, then place it in a vacuum drying oven for later use.

[0017] Specifically, in step S1, 3 to 6 mm, thickness 2 to 3 mm;

[0018] Specifically, in step S2, the cleaning solvent is acetone, and an ultrasonic cleaning method is used. Then, the sample is polished with 240#, 600#, 1000#, 1200#, 1500#, and 2000# sandpaper in sequence, and the sample surface is polished with a 1-2 μm diamond polishing liquid;

[0019] Specifically, in step S3, the alcohol is ultrasonically cleaned and then dried with hot air.

[0020] Based on the above technical solution, the cleanliness of the test samples can be ensured to avoid being affected by the test.

[0021] Specifically, the step 2) includes the following steps:

[0022] S4. Place the sample in the heating furnace of the ultra-high temperature laser confocal instrument with the test surface facing upward, and evacuate the heating furnace using a vacuum pump;

[0023] S5. Adjust the lens position and focal length of the ultra-high temperature laser confocal device to ensure a clear field of view;

[0024] S6. According to the simulated welding process, the heating rate, peak temperature, holding time, and cooling rate are set in the control module of the ultra-high temperature laser confocal device, and the image acquisition frequency parameters at different temperature stages are also set.

[0025] Specifically, in step S6, the heating rate is the maximum heating rate of the equipment.

[0026] Based on the above technical solution, the temperature change of the welding process can be effectively simulated using ultra-high temperature laser confocal equipment.

[0027] Specifically, in step S6, the peak temperature is not lower than the melting temperature of the welding material.

[0028] Specifically, in step S6, the holding time is not less than the complete melting time of the sample.

[0029] Based on the above technical solution, it can be ensured that the ultra-high temperature laser confocal equipment can accurately obtain image information of the molten state of the welding material and the process of transformation from the molten state to the solid state.

[0030] Specifically, in step S6, the cooling rate matches the size and thermal conductivity of the welding material.

[0031] The cooling rate of the welding material is affected by the size of the welded parts and the heat conduction system. Based on the above technical solution, the cooling rate of the welding material during the welding process can be effectively simulated.

[0032] Specifically, in step S6, the image acquisition frequency is not less than 1 picture every 3°C, and at the same time, it is ensured that not less than 1 picture is acquired per second.

[0033] Based on the above technical approach, the problem of failure to record key information during the solidification process due to too low an acquisition frequency can be avoided.

[0034] Specifically, the step 3) includes the following steps:

[0035] S7. Starting the test based on the parameters set in step 2), dynamically adjusting the observation field of view during the test so that the observation field of view is located at the same position;

[0036] S8. After the test is completed, the image data of the entire test process is saved and data processing and analysis are performed.

[0037] Specifically, in step S8: analyzing the image includes determining whether proeutectoid ferrite or acicular ferrite is observed in the image data.

[0038] In the above technical solution, the size and distribution of microstructures such as acicular ferrite, proeutectoid ferrite, and lath bainite observed in the imaging data are analyzed to determine whether the test welding material and the test welding method are compatible. Generally, when the aspect ratio of the acicular ferrite is ≥4 and the acicular ferrite is interlaced, resembling a woven structure, the requirements are considered met.

[0039] The present invention also provides an application of the above-mentioned real-time observation method, which is used to determine the applicable conditions of welding materials based on the results of image analysis.

[0040] Specifically, the applicable conditions include:

[0041] Alloy composition of welding consumables;

[0042] Welding method.

[0043] Beneficial effects of the present invention:

[0044] The present invention can help study the microstructural evolution of welding materials with different alloy systems under different welding processes. By analyzing the test results, it can quickly screen the alloy composition and welding process that meet the service conditions. This can avoid the time and financial costs of conducting cladding metal testing after large-scale production of welding materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is an image collected in Example 1 of the present invention.

[0046] Figure 2 This is an image collected in Example 2 of the present invention.

[0047] Figure 3 This is an image collected in Example 3 of the present invention. DETAILED DESCRIPTION

[0048] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0049] Example 1

[0050] Taking X80 pipeline steel submerged arc welding wire as an example, an in-situ observation method of the weld material microstructure under the simulated submerged arc welding process is carried out. A real-time observation method of the melting and solidification process of the high-strength steel welding material is simulated, including the following steps:

[0051] S1. Prepare samples by wire cutting on wire rod of submerged arc welding wire for X80 pipeline steel. The samples are cylindrical with a diameter of 6.5 mm and a thickness of 3 mm, with the upper and lower surfaces kept parallel.

[0052] S2. Place the sample in acetone and ultrasonically clean the sample for 10 minutes. Then, polish the sample test surface with 240#, 600#, 1000#, 1200#, 1500# and 2000# sandpaper in sequence. Then, polish the sample surface with 1.5μm diamond polishing liquid.

[0053] S3. Place the polished sample in alcohol, clean it with ultrasonic waves for 10 minutes, blow it dry with hot air, and then place it in a vacuum drying oven for later use.

[0054] S4. Place the sample in the heating furnace of the ultra-high temperature laser confocal equipment with the test surface facing upward, and use a vacuum pump to evacuate the heating furnace.

[0055] S5. Adjust the lens position and focal length of the ultra-high temperature laser confocal device to make the observation field clear.

[0056] S6. According to the submerged arc welding process, the heating control module of the ultra-high temperature laser confocal equipment is set to a heating rate of 1000℃ / min, a peak temperature of 1600℃, and a peak temperature holding time of 30s to homogenize the liquid. The cooling rate is 300℃ / min, and the image acquisition frequency of the heating section is 15 frames / s, the image acquisition frequency of the holding section is 3 frames / s, and the image acquisition frequency of the cooling section is 4 frames / s.

[0057] S7. Open the control program and start the test according to the program set in S6. During the test, the observation field of view is dynamically adjusted so that the observation field of view is located at the same position.

[0058] S8. After the test is completed, the image data of the entire test process is saved and data processing and analysis are performed.

[0059] The composition of the X80 pipeline steel submerged arc welding wire used in this embodiment is: 0.04wt% C, 0.36wt% Si, 1.72wt% Mn, 0.012wt% P, 0.005wt% S, 0.31wt% Mo, 0.025wt% Ti, 0.5wt% Ni, and the remainder is Fe. A typical image during the test is shown in FIG. Figure 1 As shown in the figure, the material is undergoing a solid-liquid phase transition. Based on the above scheme, the solidification process of the submerged arc welding wire can be clearly observed. Furthermore, the growth direction of the dendrites during solidification can be seen in the figure, and the image quality is good. Furthermore, it can be determined that the welding process suitable for this X80 pipeline steel wire is a submerged arc welding process with a heat input of 4.0 to 5.5 kJ / mm.

[0060] Example 2

[0061] Taking X80 pipeline steel welding wire as an example, an in-situ observation method of the weld material microstructure under the simulated metal arc welding process is carried out. A real-time observation method of the melting and solidification process of the high-strength steel welding material is simulated, including the following steps:

[0062] S1. Prepare samples by wire cutting on X80 pipeline steel wire rod. The samples are cylindrical with a diameter of 5 mm and a thickness of 2 mm, with the upper and lower surfaces kept parallel.

[0063] S2. Place the sample in acetone and ultrasonically clean the sample for 10 minutes. Then, polish the sample test surface with 240#, 600#, 1000#, 1200#, 1500# and 2000# sandpaper in sequence. Then, polish the sample surface with 1.5μm diamond polishing liquid.

[0064] S3. Place the polished sample in alcohol, clean it with ultrasonic waves for 10 minutes, blow it dry with hot air, and then place it in a vacuum drying oven for later use.

[0065] S4. Place the sample in the heating furnace of the ultra-high temperature laser confocal equipment with the test surface facing upward, and use a vacuum pump to evacuate the heating furnace.

[0066] S5. Adjust the lens position and focal length of the ultra-high temperature laser confocal device to make the observation field clear.

[0067] S6. According to the metal-metal gas shielded welding process, the heating control module of the ultra-high temperature laser confocal equipment is set to a heating rate of 1000°C / min, a peak temperature of 1600°C, and a peak temperature holding time of 30s to homogenize the liquid. The cooling rate is 6000°C / min, and the image acquisition frequency of the heating section is 15 frames / s, the image acquisition frequency of the holding section is 3 frames / s, and the image acquisition frequency of the cooling section is 30 frames / s.

[0068] S7. Open the control program and start the test according to the program set in S6. During the test, the observation field of view is dynamically adjusted so that the observation field of view is located at the same position.

[0069] S8. After the test is completed, the image data of the entire test process is saved and data processing and analysis are performed.

[0070] The composition of the X80 pipeline steel welding wire used in this embodiment is: 0.035wt% C, 0.51wt% Si, 1.21wt% Mn, 0.006wt% P, 0.005wt% S, 0.25wt% Mo, 0.018wt% Ti, 0.81wt% Ni, and the remainder is Fe. A typical image during the test is shown in FIG. Figure 2As shown in the figure, the material is in the process of solid-liquid phase transformation. Based on the above scheme, the image of the welding wire material during melting can be clearly observed. Furthermore, the coexistence of the solid and liquid phases can be clearly seen in the figure. Statistical analysis of the proportion and size of acicular ferrite during the subsequent solidification process determined that the welding process suitable for this X80 pipeline steel wire is a gas shielded automatic welding process with a heat input of less than 1.2 kJ / mm.

[0071] Example 3

[0072] Taking X70 pipeline steel manual arc welding electrodes as an example, an in-situ observation method of the weld material microstructure under the simulated manual arc welding process is carried out. A real-time observation method of the melting and solidification process of the high-strength steel welding material is simulated, including the following steps:

[0073] S1. Prepare samples by wire cutting on X70 pipeline steel welding consumable wire rod. The samples are cylindrical with a diameter of 6 mm and a thickness of 2 mm, and the upper and lower surfaces are kept parallel.

[0074] S2. Place the sample in acetone and ultrasonically clean the sample for 10 minutes. Then, polish the sample test surface with 240#, 600#, 1000#, 1200#, 1500# and 2000# sandpaper in sequence. Then, polish the sample surface with 1.5μm diamond polishing liquid.

[0075] S3. Place the polished sample in alcohol, clean it with ultrasonic waves for 10 minutes, blow it dry with hot air, and then place it in a vacuum drying oven for later use.

[0076] S4. Place the sample in the heating furnace of the ultra-high temperature laser confocal equipment with the test surface facing upward, and use a vacuum pump to evacuate the heating furnace.

[0077] S5. Adjust the lens position and focal length of the ultra-high temperature laser confocal device to make the observation field clear.

[0078] S6. According to the manual arc welding process, the heating control module of the ultra-high temperature laser confocal equipment is set to a heating rate of 1000℃ / min, a peak temperature of 1600℃, and a peak temperature holding time of 30s to homogenize the liquid. The cooling rate is 2400℃ / min, and the image acquisition frequency of the heating section is 15 frames / s, the image acquisition frequency of the holding section is 3 frames / s, and the image acquisition frequency of the cooling section is 15 frames / s.

[0079] S7. Open the control program and start the test according to the program set in S6. During the test, the observation field of view is dynamically adjusted so that the observation field of view is located at the same position.

[0080] S8. After the test is completed, the image data of the entire test process is saved and data processing and analysis are performed.

[0081] The composition of the X70 pipeline steel manual arc welding consumables used in this embodiment is as follows: 0.05wt% C, 0.35wt% Si, 1.64wt% Mn, 0.012wt% P, 0.008wt% S, 0.01wt% Mo, 0.016wt% Cr, 0.89wt% Ni, 0.015wt% V, and the remainder is Fe. A typical image during the test is shown in FIG. Figure 3 As shown in the figure, the material is undergoing a solid-liquid phase transition. Based on the above scheme, the melting process of the submerged arc welding wire can be clearly observed. Furthermore, the nucleation point during solidification can be seen in the figure, with clear image quality. Statistical analysis of the proportion and size of acicular ferrite during the subsequent solidification process indicates that the welding process suitable for this X70 pipeline steel wire is a gas shielded automatic welding process with a heat input of approximately 1.5 to 2.5 kJ / mm.

[0082] Example 4

[0083] Taking Q690 steel welding consumables as an example, an in-situ observation method of the welding consumable microstructure under the simulated metal arc welding process is carried out. A real-time observation method of the melting and solidification process of the welding consumables for high-strength steel is simulated, including the following steps:

[0084] S1. Prepare samples by wire cutting on 690 steel welding consumable wire rod. The samples are cylindrical with a diameter of 5 mm and a thickness of 3 mm, and the upper and lower surfaces are kept parallel.

[0085] S2. Place the sample in acetone and ultrasonically clean the sample for 10 minutes. Then, polish the sample test surface with 240#, 600#, 1000#, 1200#, 1500# and 2000# sandpaper in sequence. Then, polish the sample surface with 1.5μm diamond polishing liquid.

[0086] S3. Place the polished sample in alcohol, clean it with ultrasonic waves for 10 minutes, blow it dry with hot air, and then place it in a vacuum drying oven for later use.

[0087] S4. Place the sample in the heating furnace of the ultra-high temperature laser confocal equipment with the test surface facing upward, and use a vacuum pump to evacuate the heating furnace.

[0088] S5. Adjust the lens position and focal length of the ultra-high temperature laser confocal device to make the observation field clear.

[0089] S6. According to the metal-metal gas shielded welding process, the heating control module of the ultra-high temperature laser confocal equipment is set to a heating rate of 1000°C / min, a peak temperature of 1600°C, and a peak temperature holding time of 30s to homogenize the liquid. The cooling rate is 6000°C / min, and the image acquisition frequency of the heating section is 15 frames / s, the image acquisition frequency of the holding section is 3 frames / s, and the image acquisition frequency of the cooling section is 30 frames / s.

[0090] S7. Open the control program and start the test according to the program set in S6. During the test, the observation field of view is dynamically adjusted so that the observation field of view is located at the same position.

[0091] S8. After the test is completed, the image data of the entire test process is saved and data processing and analysis are performed.

[0092] Comparative Example 1

[0093] The experimental process is the same as that of Example 2, except that the acquisition frequency during the cooling process is 5 frames / s. Due to the excessively fast cooling rate during the cooling process, the solidification nucleation point cannot be captured during the solidification process, and the phase transition starting point cannot be obtained during the subsequent phase transition process.

[0094] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for real-time observation of melting and solidification during the welding process of high-strength steel welding materials, characterized in that: The following steps are involved: 1) Prepare cylindrical samples; 2) Place the sample in an ultrahigh temperature laser confocal instrument and set the simulated welding parameters of the ultrahigh temperature laser confocal instrument and the image acquisition frequency at different temperature stages according to the simulated welding process; 3) Starting the ultrahigh temperature laser confocal device to conduct a test according to the simulated welding working parameters described in step 2), and obtaining image data throughout the entire test process according to the acquisition frequency of step 2), saving the data, and analyzing the image.

2. The method for real-time observation of melting and solidification of a welding material for simulating high-strength steel during welding according to claim 1, characterized in that: The step 1) specifically includes the following steps: S1. Prepare a sample on a wire rod of high-strength steel welding material by wire cutting. The sample is cylindrical and has parallel upper and lower end surfaces. S2. Clean the sample, then grind and polish the test surface of the sample; S3. Ultrasonic clean the polished sample and blow dry it, then place it in a vacuum drying oven for later use.

3. The method for real-time observation of melting and solidification of a high-strength steel welding material during welding according to claim 2, characterized in that: In step S1, 3 to 6 mm, thickness 2 to 3 mm; In step S2, the cleaning solvent is acetone, and an ultrasonic cleaning method is used. Then, the sample is polished with 240#, 600#, 1000#, 1200#, 1500#, and 2000# sandpaper in sequence, and the sample surface is polished with a 1-2 μm diamond polishing liquid; In step S3, the alcohol is ultrasonically cleaned and then dried with hot air.

4. The method for real-time observation of melting and solidification of a welding material for simulating high-strength steel during welding according to claim 1, characterized in that: The step 2) specifically includes the following steps: S4. Place the sample in the heating furnace of the ultra-high temperature laser confocal instrument with the test surface facing upward, and evacuate the heating furnace using a vacuum pump; S5. Adjust the lens position and focal length of the ultra-high temperature laser confocal device to ensure a clear field of view; S6. According to the simulated welding process, the heating rate, peak temperature, holding time, and cooling rate are set in the control module of the ultra-high temperature laser confocal device, and the image acquisition frequency parameters at different temperature stages are also set.

5. The method for real-time observation of melting and solidification of a welding material for simulating high-strength steel during welding according to claim 4, characterized in that: In step S6, the heating rate is the maximum heating rate of the equipment; In step S6, the peak temperature is not lower than the melting temperature of the welding material; In step S6, the holding time is not less than the complete melting time of the sample; In step S6, the cooling rate is matched to the size and thermal conductivity of the welding material.

6. The method for real-time observation of melting and solidification of a welding material for simulating high-strength steel during welding according to claim 4, characterized in that: In step S6, the image acquisition frequency is not less than 1 picture every 3°C, and at the same time, it is ensured that not less than 1 picture is acquired per second.

7. The method for real-time observation of melting and solidification of a high-strength steel welding material during welding according to any one of claims 1 to 6, characterized in that: The step 3) specifically includes the following steps: S7. Starting the test based on the parameters set in step 2), dynamically adjusting the observation field of view during the test so that the observation field of view is located at the same position; S8. After the test is completed, the image data of the entire test process is saved and data processing and analysis are performed.

8. The method for real-time observation of melting and solidification of a welding material for simulating high-strength steel during welding according to claim 7, characterized in that: In step S8 , the image is analyzed to determine whether proeutectoid ferrite or acicular ferrite is observed in the image data.

9. An application of the real-time observation method according to any one of claims 1 to 8, characterized in that: Used to determine the applicable conditions of welding materials based on the results of image analysis.

10. The use according to claim 9, characterized in that The applicable conditions include: Alloy composition of welding consumables; Welding method.

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