Submerged arc welding boron content control method based on boron transition response and ferrite structure constraint

Abstract

The application provides a submerged-arc welding boron content control method based on boron transition response and ferrite structure constraint, belongs to the technical field of low-alloy steel submerged-arc welding, and under the conditions of fixed base material, welding wire, basic flux and welding parameters, at least three different boron supply levels are used for calibration welding, the boron content of each calibration weld and the area fraction of acicular ferrite, grain boundary ferrite and side plate ferrite are determined, and the segmented boron transition response between the boron component addition amount and the weld boron content is established; the boron supply amount is inversely calculated within the calibration interval meeting the target boron content and the ferrite structure window, and the component and structure results of the verification welding are fed back and corrected. The boron supply deviation caused by boron high-temperature burning loss, slag-metal reaction and weld dilution can be reduced, the boron supply deficiency and excess caused by the control according to the fixed flux formula or the theoretical boron amount can be avoided, and the low-alloy steel submerged-arc welding weld with the boron content and the ferrite structure meeting the requirements can be obtained.

Description

Technical Field

[0001] This application belongs to the field of submerged arc welding technology for low alloy steel, and specifically relates to a method for controlling boron content in submerged arc welding based on boron transition response and ferrite microstructure constraints. Background Technology

[0002] The weld metal of low-carbon low-alloy steel typically consists of grain boundary ferrite, lamellar ferrite, acicular ferrite, and intragranular ferrite of various morphologies. The fine, interwoven acicular ferrite can increase the tortuosity of crack propagation paths; while continuous or coarse grain boundary ferrite and lamellar ferrite may form more direct crack propagation paths. Therefore, synergistic control of these ferrite transformation products during submerged arc welding is a crucial technical step in improving the low-temperature toughness and microstructure stability of the weld.

[0003] Boron exhibits a strong sensitivity to the ferrite transformation behavior of low-alloy steel welds. An appropriate amount of boron can weaken the preferential nucleation tendency of ferrite at the original austenite grain boundaries, reducing grain boundary ferrite and lamellar ferrite, and reserving transformation space for the formation of intragranular acicular ferrite. However, insufficient boron content makes it difficult to achieve effective microstructure control, while excessive boron content may lead to an increase in coarse intragranular ferrite, decreased microstructure uniformity, or other adverse effects. Therefore, the effective boron content in the weld is not necessarily better the higher it is, but rather needs to be limited within a suitable window in conjunction with the ferrite microstructure.

[0004] Current submerged arc welding (SAW) boron supply technologies typically achieve this by selecting boron-containing welding wire or pre-setting a fixed content of boron-containing components such as B2O3 in the flux. However, for flux-supply boron processes, the theoretical amount of boron-containing components added to the flux does not directly equate to the actual boron content in the weld metal. During the welding arc and droplet transfer processes, boron undergoes high-temperature volatilization, redox reactions, slag-metal interface distribution, and molten pool dilution. Furthermore, different welding wires, base metals, welding heat inputs, slag-metal ratios, and basic flux systems all alter the actual boron transfer outcome. Therefore, the same amount of boron-containing component added may result in different weld boron contents under different welding systems.

[0005] Furthermore, existing methods often rely on a single indicator, such as flux formulation, theoretical boron addition, or final weld boron content, as the basis for control. There is a lack of methods for determining the boron supply that simultaneously incorporates the actual boron transition behavior and the weld ferrite microstructure. When controlling solely based on a fixed formulation, it is difficult to eliminate boron content deviations caused by raw material fluctuations and changes in welding conditions. Conversely, when controlling solely based on the total weld boron content, the combined effects of different boron states and other welding metallurgical factors on the microstructure may be overlooked. This can result in the weld achieving the preset boron content, but the acicular ferrite, grain boundary ferrite, or coarse intragranular ferrite still failing to meet manufacturing requirements. Summary of the Invention

[0006] In view of this, the purpose of this application is to provide a method for controlling the amount of boron in submerged arc welding based on boron transition response and ferrite microstructure constraints, which can solve the problems that it is difficult to accurately correspond the fixed flux boron supply amount to the actual weld boron content, the inability to avoid microstructure runaway based solely on the weld boron content, and the lack of verification feedback and correction path for the boron supply amount.

[0007] This application provides a method for controlling boron content in submerged arc welding based on boron transition response and ferrite microstructure constraints. The method includes the following steps: Under the condition that the base material, welding wire, basic flux and welding parameters are kept the same, at least three different amounts of boron-supplying components are set and submerged arc welding is performed respectively to obtain the calibration weld. The boron content in each of the calibration welds was determined, and the ferrite structure in each of the calibration welds was quantitatively characterized. The ferrite structure includes at least acicular ferrite and grain boundary ferrite. Based on the addition amount of adjacent boron-supplying components and their corresponding weld boron content, the segmented boron transition response of each addition amount range is determined, and candidate boron-supply ranges are determined from each addition amount range based on the preset target boron content range and the preset ferrite structure window. The initial amount of boron-supplying component to be added is determined based on the target boron content, the segmented boron transition response within the candidate boron-supply interval, and the endpoint data of the candidate boron-supply interval. Verification welding is performed using the initial boron supply component addition amount. The boron content of the verification weld is measured and its ferrite structure is quantitatively characterized. When both the boron content and ferrite structure of the verification weld meet the target boron content range and the ferrite structure window, the initial boron supply component addition amount is determined as the target boron supply amount. When at least one of them is not met, the boron supply component addition amount is corrected according to the boron content deviation and / or ferrite structure deviation of the verification weld, and verification welding is performed again until the verification weld simultaneously meets the target boron content range and the ferrite structure window.

[0008] In some embodiments, the at least three different boron-donating component addition amounts include a baseline level with no boron-donating component added and at least two non-zero addition levels, with the difference in the mass fraction of the boron-donating component between each addition level being 0.2% to 1.5%. The boron-supplying component includes boron trioxide (B2O3), and the mass fraction of B2O3 in the flux is 0.1% to 3.0%. The flux components other than B2O3 and the preparation process of each flux component remain the same in each calibration level and verification welding.

[0009] In some embodiments, the formula for calculating the segmented boron transition response is:

[0010] in, For the first Interval segmented boron transition response; , This refers to the amount added to two adjacent boron-donating components; , These represent the boron content in the corresponding calibrated weld seam.

[0011] In some embodiments, the ferrite microstructure window includes a lower limit for the area fraction of acicular ferrite and an upper limit for the area fraction of grain boundary ferrite; wherein the area fraction of acicular ferrite is not less than 55% and the area fraction of grain boundary ferrite is not more than 35%.

[0012] In some embodiments, the initial amount of boron-donating component added is calculated using the following formula:

[0013] in, This represents the initial amount of boron-donating component added. For the target boron content, , These refer to the amount of boron-supplying component added at the low-addition endpoint of the candidate boron-supply range and the boron content in the weld, respectively. The segmented boron transition response of the candidate boron supply interval.

[0014] In some embodiments, when the boron content of the verified weld is lower than the lower limit of the target boron content range and the area fraction of acicular ferrite is lower than the lower limit and / or the area fraction of grain boundary ferrite is higher than the upper limit, the amount of boron-supplying component added is increased; when the boron content of the verified weld is higher than the upper limit of the target boron content range and / or the area fraction of coarse grain ferrite is higher than the upper limit, the amount of boron-supplying component added is decreased. Among them, the The amount of boron-donating component added in the second verification weld. according to Correction; For the first The amount of boron-donating component added in the second verification weld was determined. For the first The boron content of the weld was verified in the second verification. For the first The segmented boron transition response within the calibration interval of the second verification result. The correction factor is between 0.3 and 1.0.

[0015] In some embodiments, the preset target boron content range is 20~100ppm, and the additional constraint is that the increase in the oxygen content of the weld before and after the addition of the boron component is no more than 50ppm. The quantitative characterization of the ferrite structure was performed using area fraction statistics based on optical microscopy images and / or scanning electron microscopy images.

[0016] In some embodiments, a submerged arc welding boron quantity control device based on boron transition response and ferrite microstructure constraint is also provided, the device comprising: The calibration module is used to set at least three different amounts of boron-supplying components and perform submerged arc welding respectively, under the condition that the base material, welding wire, basic flux and welding parameters are kept the same, to obtain the calibration weld. The detection module is used to determine the boron content in each of the calibration welds and to quantitatively characterize the ferrite structure in each of the calibration welds, wherein the ferrite structure includes at least acicular ferrite and grain boundary ferrite. The screening module is used to determine the segmented boron transition response of each addition range based on the addition amount of adjacent boron-supplying components and their corresponding weld boron content, and to determine the candidate boron-supply range from each addition range based on the preset target boron content range and the preset ferrite structure window. The calculation module is used to determine the initial amount of boron-supplying component to be added based on the target boron content, the segmented boron transition response within the candidate boron-supply interval, and the endpoint data of the candidate boron-supply interval. The correction module is used to perform verification welding using the initial boron supply component addition amount, determine the boron content of the verification weld, and quantitatively characterize its ferrite structure; when the boron content and ferrite structure of the verification weld both meet the target boron content range and the ferrite structure window, the initial boron supply component addition amount is determined as the target boron supply amount; when at least one of them is not met, the boron supply component addition amount is corrected according to the boron content deviation and / or ferrite structure deviation of the verification weld, and verification welding is performed again until the verification weld simultaneously meets the target boron content range and the ferrite structure window.

[0017] In some embodiments, an electronic device is also provided, including: a processor, a memory, and a bus, wherein the memory stores machine-readable instructions executable by the processor, and when the electronic device is running, the processor communicates with the memory via the bus, and when the machine-readable instructions are executed by the processor, the steps of the submerged arc welding boron quantity control method based on boron transition response and ferrite microstructure constraint described in any of the preceding embodiments are executed.

[0018] In some embodiments, a computer-readable storage medium is also provided, on which a computer program is stored, which, when executed by a processor, performs the steps of the submerged arc welding boron quantity control method based on boron transition response and ferrite microstructure constraint as described in any one of the preceding embodiments.

[0019] This application describes a method for controlling boron content in submerged arc welding based on boron transition response and ferrite microstructure constraints. Under fixed base material, welding wire, basic flux, and welding parameters, calibration welding is performed using at least three different boron supply levels. The boron content and the area fractions of acicular ferrite, grain boundary ferrite, and side strip ferrite in each calibration weld are measured to establish a segmented boron transition response between the amount of boron supplied and the weld boron content. The boron supply is then calculated back-calculated within the calibration range that meets the target boron content and ferrite microstructure window, and feedback correction is performed by verifying the composition and microstructure results of the weld. This method can reduce boron supply deviations caused by high-temperature burn-off, slag-metal reaction, and weld dilution, and avoid insufficient or excessive boron supply due to controlling only the flux formula or theoretical boron content. This results in submerged arc welds of low-alloy steel that meet both boron content and ferrite microstructure requirements. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A flowchart of the submerged arc welding boron quantity control method based on boron transition response and ferrite microstructure constraint described in the embodiments of this application is shown; Figure 2 This paper shows a schematic diagram of the submerged arc welding boron quantity control device based on boron transition response and ferrite microstructure constraint as described in an embodiment of this application. Figure 3 A schematic diagram of the structure of the electronic device described in an embodiment of this application is shown. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the accompanying drawings in this application are for illustrative and descriptive purposes only and are not intended to limit the scope of protection of this application. Furthermore, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this application illustrate operations implemented according to some embodiments of this application. It should be understood that the operations in the flowcharts may not be implemented in sequence, and steps without logical contextual relationships may be reversed or implemented simultaneously. In addition, those skilled in the art, guided by the content of this application, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts.

[0023] Furthermore, the described embodiments are merely some, not all, of the embodiments of this application. The components of the embodiments of this application described and illustrated herein can typically be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0024] It should be noted that the term "comprising" will be used in the embodiments of this application to indicate the presence of the features declared thereafter, but does not exclude the addition of other features.

[0025] This application provides a method, apparatus, equipment, and storage medium for controlling boron content in submerged arc welding based on boron transition response and ferrite microstructure constraints. It can solve the problems that it is difficult to accurately correspond the fixed flux boron supply to the actual weld boron content, that relying solely on the weld boron content cannot avoid microstructure runaway, and that the boron supply lacks verification feedback and correction paths.

[0026] See the instruction manual appendix Figure 1 This application provides a method for controlling boron content in submerged arc welding based on boron transition response and ferrite microstructure constraints. The method includes the following steps: S1. Under the condition that the base material, welding wire, basic flux and welding parameters are kept the same, set at least three different amounts of boron supply component and perform submerged arc welding respectively to obtain the calibration weld. S2. Determine the boron content in each of the calibration welds and quantitatively characterize the ferrite structure in each of the calibration welds, wherein the ferrite structure includes at least acicular ferrite and grain boundary ferrite. S3. Based on the addition amount of adjacent boron-supplying components and their corresponding weld boron content, determine the segmented boron transition response of each addition amount range, and determine the candidate boron-supply range from each addition amount range based on the preset target boron content range and the preset ferrite structure window. S4. Determine the initial amount of boron-supplying component to be added based on the target boron content, the segmented boron transition response within the candidate boron-supply interval, and the endpoint data of the candidate boron-supply interval; S5. Perform verification welding using the initial boron supply component addition amount, determine the boron content of the verification weld and quantitatively characterize its ferrite structure; when the boron content and ferrite structure of the verification weld both meet the target boron content range and the ferrite structure window, determine the initial boron supply component addition amount as the target boron supply amount; when at least one is not met, correct the boron supply component addition amount according to the boron content deviation and / or ferrite structure deviation of the verification weld, and perform verification welding again until the verification weld simultaneously meets the target boron content range and the ferrite structure window.

[0027] Step S1 mainly involves determining the welding system to be controlled and preparing the calibration weld.

[0028] First, establish a calibration matrix specific to this working condition, locking all welding-related conditions throughout the process. Only the amount of boron supplied is added as a single variable. The resulting segmented boron transition response is only applicable to the current base metal-welding wire-flux-heat input system, eliminating the need to borrow empirical coefficients from other steel grades, fluxes, and heat inputs, thus avoiding boron content deviations caused by cross-system conversions. Specific fixed conditions include: base metal grade and thickness, welding wire grade and diameter, basic flux components, complete flux preparation process (mixing, granulation, melting / sintering, crushing and screening, drying), welding current, arc voltage, welding speed, wire pitch, contact tip extension, and all process parameters that alter the slag-metal interface reaction and weld dilution rate. At least three different boron supplied component addition levels should be set, including one baseline zero-addition level (no boron supplied component) and at least two non-zero addition levels. The total number of calibration levels is preferably 3-7; too few levels will fail to identify the nonlinear variation of boron transfer, while too many will significantly increase experimental costs. For conventional low-alloy steel submerged arc welding systems with an effective B2O3 addition range of 0–2.0%, five gradients can be directly set: 0, 0.5%, 1.0%, 1.5%, and 2.0%. In the initial rapid screening stage, only three basic gradients (0, 1.0%, and 2.0%) can be set. Subsequently, based on the boron content and microstructure detection results, intermediate gradients can be added to refine the calibration within the selected candidate range.

[0029] The preferred boron component is B2O3, compatible with three mainstream submerged arc welding fluxes: smelting flux, sintering flux, and bonding flux. The mass fraction of B2O3 in the flux is controlled within the range of 0.1% to 3.0%. All calibration groups only adjust the B2O3 content by replacing the inert component in the base flux by the same mass; all other raw material ratios and processing procedures remain completely consistent, ensuring that B2O3 is the only variable. Submerged arc welding is performed on all gradients separately, producing multiple sets of calibration welds. The applicable welding methods are single-wire submerged arc welding or tandem double-wire submerged arc welding, with welding heat input controlled between 20 and 80 kJ / cm. Suitable base materials are AH36, DH36, EH36, and low-carbon low-alloy structural steels with a yield strength ≥355 MPa.

[0030] Step S2 mainly involves obtaining calibration data.

[0031] For all calibrated welds, samples are taken uniformly at a fixed distance from the fusion line in the center area of ​​the weld metal. When the microstructure of a single weld with high heat input is unevenly layered, it is statistically analyzed in three zones (upper, middle, and lower) along the weld thickness. Finally, the overall microstructure score is obtained by equal weighted average or area-weighted average.

[0032] Inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) were used to detect the total boron content in the weld. The sampling location, digestion process, and instrument calibration curves of each group of samples were completely consistent. Each group of samples underwent at least two parallel tests and the average value was taken. If the background boron content of the base material and welding wire was extremely low and negligible, the boron content of the zero-addition reference weld was used as the boron background value to calculate the boron increment of each group of welds and to help verify the accuracy of the boron transition response model.

[0033] Microscopic images were acquired using optical microscopes and scanning electron microscopes to complete the statistical analysis of the area fraction of various ferrites. At least three non-overlapping observation areas were selected for each weld, and no less than five field-of-view images were randomly collected for each area. After unifying the corrosion regime, microscope magnification, and microstructure image segmentation rules, acicular ferrite, grain boundary ferrite, and side strip ferrite were manually verified and classified, and the average value of multiple fields of view was used as the microstructure index of the weld.

[0034] The mandatory parameters for analysis are the area fraction of acicular ferrite and the area fraction of grain boundary ferrite. It is preferable to simultaneously analyze the area fraction of side strip ferrite and the area fraction of coarse-grained ferrite. Additionally, one or more parameters can be collected, including average ferrite size, high-angle grain boundary ratio, grain aspect ratio, and geometrically necessary dislocation density. For welds with unclear boundaries between acicular ferrite and coarse-grained ferrite, auxiliary discrimination can be made by combining grain size, aspect ratio, high-angle grain boundary ratio, and geometrically necessary dislocation density obtained from electron backscatter diffraction.

[0035] Step S3 mainly involves establishing a segmented boron transition response and screening qualified candidate boron supply intervals.

[0036] All calibration levels are sorted from low to high according to the B2O3 addition mass fraction. Adjacent gradients form independent calculation intervals. The piecewise boron transition response of each interval is solved by the following formula. Unlike the traditional global single linear conversion coefficient, this method can accurately reflect the nonlinear transmission law caused by the increased high-temperature burn-off of boron and the change in slag-gold distribution after the increase in boron supply:

[0037] in, For the first Interval segmented boron transition response; , This refers to the amount added to two adjacent boron-donating components; , These represent the boron content in the corresponding calibrated weld seam.

[0038] Simultaneously set up a dual-constraint window, and filter candidate boron supply intervals based on window requirements: The target boron content in the weld is in the basic range of 20-100 ppm, and preferably 35-70 ppm under high heat input conditions. An additional constraint is added on the increase of oxygen content in the weld, with an upper limit of preferably 50 ppm and a better control standard of 40 ppm. If the increase of oxygen in the weld exceeds the limit after adding B2O3 in a certain range, the range is directly discarded.

[0039] The basic ferrite window requires an area fraction of acicular ferrite ≥ 55%, an area fraction of grain boundary ferrite ≤ 35%, and an area fraction of side strip ferrite ≤ 10%. A more preferred implementation window is 60%–75% acicular ferrite and 20%–35% grain boundary ferrite. This range can simultaneously avoid two types of defects: excessive boundary ferrite caused by boron deficiency and coarsening of the intragranular ferrite structure caused by excessive boron.

[0040] Among them, only the range of boron content that completely covers the target boron content and whose ferrite change trend within the range meets all microstructure limits is retained; if the range can cover the target boron, but the area fraction of coarse intragranular ferrite at the high addition point exceeds the limit, it is directly rejected; if the acicular ferrite within the range continuously increases with the increase of B2O3, while the grain boundary and side lamellar ferrite continuously decreases, and the highest addition level in the range still meets the upper limit of coarse intragranular ferrite, it is determined to be a valid range. When there are multiple qualified ranges, the range with lower B2O3 addition and smaller increase in weld oxygen content is selected as the sole candidate boron supply range.

[0041] Step S4 mainly involves calculating the initial amount of boron-supplying component to be added. The calculation formula is as follows:

[0042] in, This represents the initial amount of boron-donating component added. For the target boron content, , These refer to the amount of boron-supplying component added at the low-addition endpoint of the candidate boron-supply range and the boron content in the weld, respectively. This represents the segmented boron transition response for the candidate boron supply range. This interpolation calculation outputs non-integer addition amounts between calibration gradients, significantly reducing the number of subsequent welding verification tests.

[0043] Step S5 mainly involves verifying the welding and providing feedback for correction.

[0044] The calculated initial boron supply was used to prepare the verification flux. The entire welding process was replicated, with all fixed conditions from step S1 (calibration stage) remaining unchanged: flux raw material batches, preparation processes, all welding parameters, and sample processing dimensions were all maintained. The methods and criteria for weld sampling, boron content detection, and ferrite microstructure quantification were completely consistent with those for the calibration weld. Only when the boron content of the verification weld falls within the preset target range, the oxygen increment in the weld does not exceed the limit, and all ferrite microstructure indicators meet the microstructure window requirements, can the current B2O3 addition amount be determined as the target boron supply for mass production under this condition.

[0045] If any component or tissue indicator fails to meet the standard, the amount of B2O3 added shall be adjusted according to the deviation of boron content and the type of tissue defect. The iterative correction formula is as follows:

[0046] in, For the first The amount of boron-donating component added in the second verification weld was determined. For the first The boron content of the weld was verified in the second verification. For the first The segmented boron transition response within the calibration interval of the second verification result. The correction factor is between 0.3 and 1.0.

[0047] If the boron content of the weld is below the target lower limit, and the area fraction of acicular ferrite is insufficient or the grain boundary ferrite exceeds the limit, increase the amount of B2O3 added. If the boron content of the weld is above the target upper limit, or the area fraction of coarse grain ferrite exceeds the limit, decrease the amount of B2O3 added. If the boron content of the weld is low, but the coarse grain ferrite has reached the upper limit, the boron supply should not be increased further. It is necessary to change the basic flux system, adjust the titanium-nitrogen element balance of the weld, or optimize the welding heat input before recalibrating.

[0048] The implementation scheme of the method of this application will be described in detail below with reference to specific embodiments.

[0049] Example 1 This embodiment uses tandem twin-wire single-pass submerged arc welding of 30mm thick EH36 low-alloy ship plate steel as an example to establish a segmented boron transition response between B2O3 addition and weld boron content. No boron source that could be accounted for in the boron supply was found in the base metal and welding wire; therefore, the change in weld boron content is mainly attributed to boron supply from B2O3 in the flux.

[0050] The base flux contains 15% SiO2 and 20% TiO2 by mass percentage, with the balance being CaF2. Three calibration levels, B0, B1, and B2, are set, with B2O3 mass fractions of 0%, 1.0%, and 2.0%, respectively. Additional B2O3 is replaced by CaF2 by mass, while other components and the mixing, melting, cooling, crushing, sieving, and drying conditions remain consistent.

[0051] Welding was performed using tandem twin-wire submerged arc welding. The first wire used DC welding with a welding current of 850A and an arc voltage of 32V; the second wire used AC welding with a welding current of 625A and an arc voltage of 36V. The welding speed was 500mm / min, the wire pitch was 25mm, the contact tip distance from the plate surface was 25mm, and the nominal heat input was approximately 60kJ / cm. All calibration groups used the same base material, welding wire, bevel condition, and flux deposition conditions.

[0052] After welding, samples were taken from the central area of ​​each weld metal, and the boron content was determined using the same method. The results are shown in Table 1.

[0053] Table 1 Test results for each weld

[0054] Table 1 shows that when B2O3 increases from 0 to 1.0%, the boron content in the weld increases from 3 ppm to 59 ppm, with a segmented boron transition response of 56.0 ppm / (wt%) in this range. When B2O3 increases from 1.0% to 2.0%, the boron content in the weld increases to 110 ppm, with a segmented boron transition response of 51.0 ppm / (wt%) in this range. The response in the second range is lower than that in the first range, indicating that the relationship between the amount of B2O3 added and the boron content in the weld is not strictly proportional. Using the segmented response is more consistent with the actual boron supply process than using a single theoretical conversion factor.

[0055] Within the 0~2.0%B2O3 calibration range of this embodiment, the total increase in weld oxygen content is approximately 34ppm, which is lower than the additional constraint upper limit of 50ppm, indicating that the candidate range can control the change in weld oxygen content while supplying effective boron.

[0056] Example 2 This embodiment quantifies the ferrite microstructure of the B0 and B1 calibrated welds in Example 1 and establishes a ferrite microstructure window applicable to this welding system. The same corrosion regime is used to display the microstructure of the weld metal. Multiple random fields of view are selected in the central region of the weld to classify and statistically analyze acicular ferrite (AF), grain boundary ferrite (GBF), and side strip ferrite (FSP). The results are shown in Table 2.

[0057] Table 2 Test results for each weld

[0058] In this embodiment, the ferrite microstructure window is set to have an area fraction of acicular ferrite of no less than 60%, an area fraction of grain boundary ferrite of no more than 35%, and an area fraction of side lath ferrite of no more than 10%. In weld B0, acicular ferrite accounts for only 44.84%, while grain boundary ferrite and side lath ferrite account for 42.28% and 12.88% respectively, which do not enter the microstructure window. In weld B1, acicular ferrite increases to 63.40%, while grain boundary ferrite and side lath ferrite decrease to 29.96% and 6.64% respectively, thus satisfying all three microstructure constraints.

[0059] The above results demonstrate that, under the base material-welding wire-base flux-heat input combination of this embodiment, the actual weld boron content corresponding to approximately 1.0% B2O3 can suppress the nucleation of grain boundary ferrite and side-plate ferrite, and increase the proportion of fine, interlocking acicular ferrite. Therefore, the determination of the boron supply amount should not only be based on the weld boron content, but also on whether the ferrite structure enters the preset window as an acceptance condition.

[0060] Example 3 This embodiment uses the calibration results of Embodiment 1 and Embodiment 2 to determine the B2O3 supply amount when the target weld boron content range is 55~65ppm, the area fraction of acicular ferrite is not less than 60%, the area fraction of grain boundary ferrite is not more than 35%, and the area fraction of side strip ferrite is not more than 10%.

[0061] Since the target boron content of 59 ppm falls within the range of 3-59 ppm for the B0 and B1 calibrated weld boron contents, and the B1 endpoint meets the preset ferrite microstructure window, the 0-1.0% B2O3 range is selected as the candidate boron supply range. The segmented boron transition response R0 in this range is 56.0 ppm / (wt%). The initial B2O3 addition amount is calculated according to the following formula: C0 = 0 + (59 - 3) / 56.0 = 1.000 wt% Based on the calculation results, the initial B2O3 addition amount was determined to be 1.0%. After verification welding using 1.0% B2O3, the boron content in the weld was 59 ppm, which is within the target boron content range of 55-65 ppm. The area fractions of acicular ferrite, grain boundary ferrite, and side lamellar ferrite were 63.40%, 29.96%, and 6.64%, respectively, all meeting the preset ferrite microstructure window. Therefore, 1.0% B2O3 was determined as the boron supply amount for this welding system under the above target conditions.

[0062] This embodiment demonstrates that the 1.000% B2O3 obtained through back-calculation of the actual boron transition response is consistent with the verified 1.0% B2O3, and the weld simultaneously meets the boron content and microstructure requirements. This control result does not directly convert the theoretical B2O3 boron content into the weld boron content, but rather incorporates the comprehensive losses and distribution effects during the actual welding process.

[0063] Example 4 This embodiment illustrates the method for calculating the boron supply when the target boron content changes. When the target boron content is set to 65 ppm, this target value falls between 59 and 110 ppm for the boron content of the B1 and B2 calibrated welds, and the corresponding segmented boron transition response is 51.0 ppm / (wt%). Initial The amount to be added is calculated as follows: C0 = 1.0 + (65 - 59) / 51.0 = 1.118 wt% Therefore, 1.12% B2O3 can be used as the initial addition amount for verifying the weld. After verifying the weld, if the weld boron content and ferrite structure both meet the preset window, then 1.12% is determined as the target boron supply amount; if the weld boron content is lower than the target lower limit and acicular ferrite is insufficient, then the B2O3 addition amount is increased according to the corresponding segmented response; if the weld boron content is higher than the target upper limit or coarse intragranular ferrite exceeds the limit, then the B2O3 addition amount is reduced. This embodiment is used to illustrate that this method can calculate non-integer addition amounts within an established calibration range and achieve feedback correction through subsequent verification.

[0064] Comparative Example 1 This comparative example used the same base material, welding wire, basic flux, and welding parameters as Example 1, but without adding B2O3, and without determining the boron supply based on the boron transition response and ferrite microstructure window. The resulting B0 weld had a boron content of 3 ppm, with acicular ferrite, grain boundary ferrite, and side lamellar ferrite area fractions of 44.84%, 42.28%, and 12.88%, respectively. This weld did not meet the target boron content and microstructure window set in Example 3.

[0065] Experimental Example To compare the results of different control methods, Example 3, Comparative Example 1, and Comparative Example 2, which only uses theoretical boron amount conversion, are summarized, and the results are shown in Table 3.

[0066] Table 3 Comparison of different methods for determining boron supply

[0067] As shown in Table 3, Example 3 obtained the actual boron transition response through calibration, and the calculation results were verified using a ferrite microstructure window. With a B2O3 addition of 1.0%, a weld boron content of 59 ppm was obtained, while simultaneously achieving a acicular ferrite area fraction of 63.40%, and reducing grain boundary ferrite and side lath ferrite to 29.96% and 6.64%, respectively. Comparative Example 1, without boron supply, did not meet the target for weld boron content and microstructure. Although Comparative Example 2 could calculate the theoretical boron content in the flux raw material, it could not directly obtain the actual weld boron content, nor could it determine whether the weld microstructure met the requirements.

[0068] This application presents a method for controlling boron content in submerged arc welding based on boron transition response and ferrite microstructure constraints. Compared with existing technologies, the advantages are as follows: (1) This application does not directly replace the actual boron content in the weld with the theoretical boron content in the flux. Instead, under the specified combination of base material, welding wire, basic flux and welding parameters, the actual segmented boron transition response is obtained by calibrating the welding. This can incorporate the comprehensive effects of high-temperature boron burn-off, slag-metal reaction, droplet transfer and weld dilution into the process of determining the boron supply.

[0069] (2) This application sets both the boron content constraint and the ferrite structure constraint of the weld, which not only eliminates the excessive grain boundary ferrite and side strip ferrite caused by insufficient boron supply, but also avoids the increase of coarse intragranular ferrite caused by pursuing high boron content, thus achieving the unity of composition control and structure control.

[0070] (3) This application uses segmented boron transition response for interpolation, which can adapt to the nonlinear relationship between the boron supply and the boron content of the weld; through verification welding and feedback correction, it can reduce the target deviation caused by fluctuations in raw material batches, flux consumption or welding conditions.

[0071] (4) This application protects the boron supply determination and control process for specific welding systems. It does not rely on a fixed complete flux formula, can be applied to different low alloy steels, different welding wires and different basic flux systems, and can be used as a method for determining boron supply parameters before welding process qualification and mass production.

[0072] Based on the same inventive concept, this application also provides a submerged arc welding boron quantity control device based on boron transition response and ferrite structure constraint. Since the principle of the device in this application is similar to the submerged arc welding boron quantity control method based on boron transition response and ferrite structure constraint described above in this application, the implementation of the device can refer to the implementation of the method, and the repeated parts will not be described again.

[0073] As per the instruction manual Figure 2 As shown in the embodiments of this application, a submerged arc welding boron quantity control device based on boron transition response and ferrite microstructure constraint is also provided. The device includes: The calibration module 201 is used to set at least three different amounts of boron supply component addition and perform submerged arc welding respectively under the condition that the base material, welding wire, basic flux and welding parameters are kept the same, so as to obtain a calibration weld. The detection module 202 is used to determine the boron content in each of the calibration welds and to quantitatively characterize the ferrite structure in each of the calibration welds, wherein the ferrite structure includes at least acicular ferrite and grain boundary ferrite. The screening module 203 is used to determine the segmented boron transition response of each addition range based on the addition amount of adjacent boron-supplying components and their corresponding weld boron content, and to determine the candidate boron-supply range from each addition range based on the preset target boron content range and the preset ferrite structure window. Calculation module 204 is used to determine the initial amount of boron-supplying component to be added based on the target boron content, the segmented boron transition response within the candidate boron-supply interval, and the endpoint data of the candidate boron-supply interval. The correction module 205 is used to perform verification welding using the initial boron supply component addition amount, determine the boron content of the verification weld and quantitatively characterize its ferrite structure; when the boron content and ferrite structure of the verification weld both meet the target boron content range and the ferrite structure window, the initial boron supply component addition amount is determined as the target boron supply amount; when at least one is not met, the boron supply component addition amount is corrected according to the boron content deviation and / or ferrite structure deviation of the verification weld, and verification welding is performed again until the verification weld simultaneously meets the target boron content range and the ferrite structure window.

[0074] The submerged arc welding boron quantity control device based on boron transition response and ferrite microstructure constraint described in this application can solve the problems that it is difficult to accurately correspond the fixed flux boron supply to the actual weld boron content, that relying solely on the weld boron content cannot avoid microstructure loss of control, and that the boron supply lacks verification feedback and correction paths.

[0075] Based on the same concept of the present invention, as shown in the appendix to the specification. Figure 3 As shown in the figure, an embodiment of this application provides the structure of an electronic device 300, which includes: at least one processor 301, at least one network interface 304 or other user interface 303, memory 305, and at least one communication bus 302. The communication bus 302 is used to realize the connection and communication between these components. The electronic device 300 may optionally include a user interface 303, including a display (e.g., touch screen, LCD, CRT, holographic imaging, or projector, etc.), a keyboard, or a clicking device (e.g., mouse, trackball, touchpad, or touch screen, etc.).

[0076] Memory 305 may include read-only memory and random access memory, and provides instructions and data to processor 301. A portion of memory 305 may also include non-volatile random access memory (NVRAM).

[0077] In some implementations, memory 305 stores executable modules or data structures, or subsets thereof, or extended sets thereof: The 3051 operating system contains various system programs used to implement various basic business functions and handle hardware-based tasks. Application module 3052 contains various applications, such as desktop (launcher), media player (MediaPlayer), browser (Browser), etc., to implement various application services.

[0078] In this embodiment, by calling the program or instructions stored in the memory 305, the processor 301 is used to execute steps such as a method for controlling boron quantity in submerged arc welding based on boron transition response and ferrite microstructure constraints.

[0079] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, performs steps such as those in a method for controlling boron quantity in submerged arc welding based on boron transition response and ferrite microstructure constraints.

[0080] Specifically, the storage medium can be a general-purpose storage medium, such as a portable disk or hard disk. When the computer program on the storage medium is run, it can solve the problems that the fixed flux boron supply is difficult to accurately correspond to the actual weld boron content, that relying solely on the weld boron content cannot avoid microstructure loss, and that the boron supply lacks verification feedback and correction paths.

[0081] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and there may be other division methods in actual implementation. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the mutual coupling or direct coupling or communication connection shown or discussed may be through some communication interface, and the indirect coupling or communication connection of the apparatus or units may be electrical, mechanical, or other forms.

[0082] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0083] In addition, the functional units in the embodiments provided in this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0084] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0085] Finally, it should be noted that the above embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The protection scope of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this application; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application. All should be covered within the protection scope of this application. Therefore, the protection scope of this application should be determined by the protection scope of the claims.

Claims

1. A method for controlling boron content in submerged arc welding based on boron transition response and ferrite microstructure constraints, characterized in that, The method includes the following steps: Under the condition that the base material, welding wire, basic flux and welding parameters are kept the same, at least three different amounts of boron-supplying components are added and submerged arc welding is performed separately to obtain the calibration weld. The boron content in each of the calibration welds was determined, and the ferrite structure in each of the calibration welds was quantitatively characterized. The ferrite structure includes at least acicular ferrite and grain boundary ferrite. Based on the addition amount of adjacent boron-supplying components and their corresponding weld boron content, the segmented boron transition response of each addition amount range is determined, and candidate boron-supply ranges are determined from each addition amount range based on the preset target boron content range and the preset ferrite structure window. The initial amount of boron-supplying component to be added is determined based on the target boron content, the segmented boron transition response within the candidate boron-supply interval, and the endpoint data of the candidate boron-supply interval. Verification welding is performed using the initial boron supply component addition amount. The boron content of the verification weld is measured and its ferrite structure is quantitatively characterized. When both the boron content and ferrite structure of the verification weld meet the target boron content range and the ferrite structure window, the initial boron supply component addition amount is determined as the target boron supply amount. When at least one of them is not met, the boron supply component addition amount is corrected according to the boron content deviation and / or ferrite structure deviation of the verification weld, and verification welding is performed again until the verification weld simultaneously meets the target boron content range and the ferrite structure window.

2. The method for controlling boron content in submerged arc welding based on boron transition response and ferrite microstructure constraint according to claim 1, characterized in that, The at least three different boron-donating component addition levels include a baseline level with no boron-donating component added and at least two non-zero addition levels, with the mass fraction difference of the boron-donating component between each addition level being 0.2% to 1.5%. The boron-supplying component includes boron trioxide (B2O3), and the mass fraction of B2O3 in the flux is 0.1% to 3.0%. The flux components other than B2O3 and the preparation process of each flux component remain the same in each calibration level and verification welding.

3. The method for controlling boron content in submerged arc welding based on boron transition response and ferrite microstructure constraint according to claim 1, characterized in that, The formula for calculating the segmented boron transition response is: in, For the first Interval segmented boron transition response; , This refers to the amount added to two adjacent boron-donating components; , These represent the boron content in the corresponding calibrated weld seam.

4. The method for controlling boron content in submerged arc welding based on boron transition response and ferrite microstructure constraint according to claim 1, characterized in that, The ferrite microstructure window includes a lower limit for the area fraction of acicular ferrite and an upper limit for the area fraction of grain boundary ferrite; wherein the area fraction of acicular ferrite is not less than 55% and the area fraction of grain boundary ferrite is not more than 35%.

5. The method for controlling boron content in submerged arc welding based on boron transition response and ferrite microstructure constraint according to claim 1, characterized in that, The formula for calculating the initial amount of boron-donating component added is: in, This represents the initial amount of boron-donating component added. For the target boron content, , These refer to the amount of boron-supplying component added at the low-addition endpoint of the candidate boron-supply range and the boron content in the weld, respectively. The segmented boron transition response of the candidate boron supply interval.

6. The method for controlling boron content in submerged arc welding based on boron transition response and ferrite microstructure constraint according to claim 1, characterized in that, When the boron content of the verified weld is lower than the lower limit of the target boron content range and the area fraction of acicular ferrite is lower than the lower limit and / or the area fraction of grain boundary ferrite is higher than the upper limit, the amount of boron-supplying component added is increased; when the boron content of the verified weld is higher than the upper limit of the target boron content range and / or the area fraction of coarse grain ferrite is higher than the upper limit, the amount of boron-supplying component added is decreased. Among them, the The amount of boron-donating component added in the second verification weld. according to Correction; For the first The amount of boron-donating component added in the second verification weld was determined. For the first The boron content of the weld was verified in the second verification. For the first The segmented boron transition response within the calibration interval of the second verification result. The correction factor is between 0.3 and 1.

0.

7. The method for controlling boron content in submerged arc welding based on boron transition response and ferrite microstructure constraint according to claim 1, characterized in that, The preset target boron content range is 20~100ppm, with an additional constraint that the increase in weld oxygen content before and after the addition of boron component is no more than 50ppm. The quantitative characterization of the ferrite structure was performed using area fraction statistics based on optical microscopy images and / or scanning electron microscopy images.

8. A submerged arc welding boron quantity control device based on boron transition response and ferrite microstructure constraint, characterized in that, The device includes: The calibration module is used to set at least three different amounts of boron-supplying components and perform submerged arc welding respectively, under the condition that the base material, welding wire, basic flux and welding parameters are kept the same, to obtain the calibration weld. The detection module is used to determine the boron content in each of the calibration welds and to quantitatively characterize the ferrite structure in each of the calibration welds, wherein the ferrite structure includes at least acicular ferrite and grain boundary ferrite. The screening module is used to determine the segmented boron transition response of each addition range based on the addition amount of adjacent boron-supplying components and their corresponding weld boron content, and to determine the candidate boron-supply range from each addition range based on the preset target boron content range and the preset ferrite structure window. The calculation module is used to determine the initial amount of boron-supplying component to be added based on the target boron content, the segmented boron transition response within the candidate boron-supply interval, and the endpoint data of the candidate boron-supply interval. The correction module is used to perform verification welding using the initial boron supply component addition amount, determine the boron content of the verification weld, and quantitatively characterize its ferrite structure; when the boron content and ferrite structure of the verification weld both meet the target boron content range and the ferrite structure window, the initial boron supply component addition amount is determined as the target boron supply amount; when at least one of them is not met, the boron supply component addition amount is corrected according to the boron content deviation and / or ferrite structure deviation of the verification weld, and verification welding is performed again until the verification weld simultaneously meets the target boron content range and the ferrite structure window.

9. An electronic device, characterized in that, include: The device includes a processor, a memory, and a bus. The memory stores machine-readable instructions executable by the processor. When the electronic device is running, the processor communicates with the memory via the bus. When the machine-readable instructions are executed by the processor, they perform the steps of the submerged arc welding boron quantity control method based on boron transition response and ferrite microstructure constraint as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, performs the steps of the submerged arc welding boron quantity control method based on boron transition response and ferrite microstructure constraint as described in any one of claims 1 to 7.

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