Sulfur-corrosion-resistant cladding material for boiler tube bank and preparation method of sulfur-corrosion-resistant cladding material

Abstract

The invention relates to the technical field of surface protection, in particular to a boiler tube bank sulfur-corrosion-resistant cladding material and a preparation method thereof.The preparation method comprises the steps that a metal sheath is filled with alloy powder and sealed, and a blank is obtained; when it is judged that preparation of the blank does not reach the standard according to the structural uniformity characterization value, the preset vibration frequency is increased or an alloy powder supply abnormal alarm is given out; the blank reaching the standard is drawn, and a powder core wire is obtained; when the drawing heat characterization value is larger than or equal to a first preset drawing heat characterization value and smaller than a second preset drawing heat characterization value, whether preparation of the powder core wire reaches the standard or not is judged secondarily according to the diameter fluctuation range; when the drawing thermal characterization value is larger than or equal to a second preset drawing thermal characterization value, the reason for substandard preparation of the cored wire is determined and judged according to the thermal anomaly aggregation degree; and winding and packaging the powder core wire which reaches the standard to obtain the sulfur corrosion resistant cladding material for the boiler tube bank. The preparation efficiency of the cladding material is improved.

Description

Technical Field

[0001] This invention relates to the field of surface protection technology, and in particular to a boiler tube bank anti-sulfur corrosion cladding material and its preparation method. Background Technology

[0002] The "four tubes" (water-cooled walls, superheaters, reheaters, and economizers) of coal-fired power plant boilers, biomass furnaces, and waste incinerators are constantly exposed to high-temperature, sulfur- and vanadium-containing corrosive flue gas, facing severe high-temperature sulfur corrosion problems. In particular, sulfides in the flue gas react with the tube wall metal to form low-melting-point complex sulfates, which severely corrode the tube wall material, greatly shorten the service life of the boiler tube bank, and pose a serious threat to the safe and stable operation of the power plant.

[0003] Currently, cladding technology is one of the effective solutions for preparing anti-sulfur corrosion protective coatings on boiler tube bank surfaces. Among these, powder-cored wire, as a cladding material, has attracted widespread attention due to its flexible composition design and low manufacturing cost. In existing technologies, nickel-based alloy systems are typically used as the powder-cored material. The powder-cored wire is produced through processes such as filling and drawing, and then a protective coating is formed through processes such as thermal spraying or arc cladding.

[0004] Chinese Patent Application Publication No. CN113369639A discloses a method for preparing an ultra-thin, ultra-low dilution rate high-temperature alloy cladding layer for waste incinerators. This method focuses on the protective process of preparing a high-temperature alloy cladding layer on the heated surfaces of waste incinerators to prevent high-temperature corrosion from molten salts such as chlorine, sulfur, and their compounds. It belongs to the field of new material surface protection technology. This cladding layer provides excellent corrosion protection for the heated surfaces of waste incinerators, effectively extending their service life. Therefore, it is of great significance for ensuring the safe and efficient operation of waste incineration power plant boilers, environmental protection, and promoting harmonious social development.

[0005] It can be seen that the above technical solution does not consider the impact of powder filling voids and the synergistic deformation failure of the outer skin on the preparation of cladding materials, thus resulting in poor preparation efficiency of cladding materials. Summary of the Invention

[0006] Therefore, the present invention provides a boiler tube bank anti-sulfur corrosion cladding material and its preparation method, in order to overcome the problem that the prior art does not consider the influence of powder filling voids and the synergistic deformation failure of the outer skin on the preparation of cladding materials, thus resulting in poor preparation efficiency of cladding materials.

[0007] To achieve the above objectives, in one aspect, the present invention provides a sulfur corrosion cladding material for boiler tubes and a method for preparing it, comprising: Alloy powder is filled into a metal outer shell at a preset vibration frequency and then sealed to obtain a billet; several diameters of the billet are obtained, and the structural uniformity characterization value of the billet is calculated; determine whether the preparation of the blank conforms to the preset standard according to the structural uniformity value of the blank, and increase the preset vibration frequency of the preparation of the next batch of blank or issue the alloy powder supply abnormality alarm when the preparation of the blank is determined not to conform to the preset standard; drawing the blank at a preset drawing speed to obtain a powder core wire, and collecting a thermal image of the powder core wire to obtain a drawing thermal value of the powder core wire; when the drawing thermal value is greater than or equal to the first preset drawing thermal value and less than the second preset drawing thermal value, determining whether the preparation of the powder core wire conforms to the preset standard according to the diameter fluctuation range of the powder core wire; when the drawing thermal value is greater than or equal to the second preset drawing thermal value, determining the reason why the preparation of the powder core wire does not conform to the preset standard according to the thermal abnormality aggregation degree of the powder core wire, wherein the reason is that the internal friction of the alloy powder is too large or the plasticity of the metal skin is insufficient; winding the powder core wire that conforms to the preset standard to obtain a boiler tube row anti-sulfur corrosion cladding material.

[0008] Further, the process of determining whether the preparation of the blank conforms to the preset standard according to the structural uniformity value of the blank comprises: comparing the structural uniformity value with a first preset structural uniformity threshold value and a second preset structural uniformity threshold value respectively; if the structural uniformity value is less than the first preset structural uniformity threshold value, it is determined that the preparation of the blank conforms to the preset standard; if the structural uniformity value is greater than or equal to the first preset structural uniformity threshold value and less than the second preset structural uniformity threshold value, it is determined that the preparation of the blank does not conform to the preset standard, and the preset vibration frequency of the preparation of the next batch of blank is increased according to the difference between the structural uniformity value and the first preset structural uniformity threshold value; if the structural uniformity value is greater than or equal to the second preset structural uniformity threshold value, it is determined that the preparation of the blank does not conform to the preset standard, and the alloy powder supply abnormality alarm is issued; the structural uniformity value is the ratio of the standard deviation to the average value of the diameter of the blank.

[0009] Further, the increase of the preset vibration frequency for the preparation of the next batch of blank is provided with several frequency adjustment modes, and the increase amplitude of each frequency adjustment mode is different.

[0010] Further, the process of determining whether the preparation of the powder core wire conforms to the preset standard according to the drawing thermal value of the powder core wire comprises: comparing the drawing thermal value with a first preset drawing thermal value and a second preset drawing thermal value respectively; If the drawing heat characteristic value is less than a first preset drawing heat characteristic value, it is determined that the preparation of the powder core wire meets the preset standard; If the drawing heat characteristic value is greater than or equal to the first preset drawing heat characteristic value and less than a second preset drawing heat characteristic value, it is determined that the preparation of the powder core wire is at risk of not meeting the preset standard, and whether the preparation of the powder core wire meets the preset standard is determined again according to the diameter fluctuation range of the powder core wire; If the drawing heat characteristic value is greater than or equal to the second preset drawing heat characteristic value, it is determined that the preparation of the powder core wire does not meet the preset standard, and the reason why the preparation of the powder core wire does not meet the preset standard is determined according to the thermal abnormality aggregation degree of the powder core wire.

[0011] Further, the process of obtaining the drawing heat characteristic value comprises: Taking a thermal image of the powder core wire of a preset length; Based on the thermal image, obtaining a plurality of surface temperatures of the powder core wire; Calculating the standard deviation of the plurality of surface temperatures, denoted as the drawing heat characteristic value.

[0012] Further, when it is determined again that the preparation of the powder core wire does not meet the preset standard according to the comparison result that the diameter fluctuation range of the powder core wire is greater than or equal to a preset diameter fluctuation range, the preset drawing speed of the preparation of the next batch of blank is reduced according to the difference between the diameter fluctuation range and the preset diameter fluctuation range. The diameter fluctuation range is the difference between the maximum diameter of the powder core wire and the minimum diameter of the powder core wire.

[0013] Further, the reduction range of the preset drawing speed of the preparation of the next batch of blank is positively correlated with the diameter fluctuation deviation value, wherein the diameter fluctuation deviation value is the difference between the diameter fluctuation range and the preset diameter fluctuation range.

[0014] Further, the process of determining the reason why the preparation of the powder core wire does not meet the preset standard according to the thermal abnormality aggregation degree of the powder core wire comprises: If the thermal abnormality aggregation degree is less than a preset thermal abnormality aggregation degree, it is determined that the plasticity of the metal sheath is insufficient; If the thermal abnormality aggregation degree is greater than or equal to the preset thermal abnormality aggregation degree, it is determined that the internal friction of the alloy powder is too large.

[0015] Further, the process of obtaining the thermal abnormality aggregation degree comprises: Sorting the temperature values of all pixel points in the thermal image from high to low, determining the highest temperature value in the thermal image, taking the highest temperature value as the upper limit and a preset temperature value as the lower limit, and recording the pixel points in the temperature interval as relative hot spots; The number of independent connected regions formed by the relative hot spots adjacent in the statistical spatial position is recorded as a hot anomaly aggregation degree. The preset temperature value is a temperature value corresponding to a front preset percentage in a sequence of temperature values of all pixel points in the thermal image from high to low.

[0016] In one aspect, the application provides a boiler tube row anti-sulfur corrosion cladding material prepared by the above preparation method, comprising an alloy powder and a metal skin, wherein the material of the metal skin is stainless steel; the alloy powder comprises the following components in mass fraction: C: ≤0.10wt.%; Mn: ≤0.50wt.%; Si: ≤0.50wt.%; P: ≤0.015wt.%; S: ≤0.015wt.%; Cr: 20.0-23.0wt.%; (Nb+Ta): 3.15-4.15wt.%; Co: ≤1.0wt.%; Mo: 8.0-10.0wt.%; Fe: <5.0wt.%; Al: ≤0.40wt.%; Ti: ≤0.40wt.%; and Ni: the balance.

[0017] Compared with the prior art, the application has the beneficial effects that by introducing the quantitative indexes of the structural uniformity characterization value, the drawing thermal characterization value, and the hot anomaly aggregation degree, the full-chain closed-loop control system of the blank uniformity feedback regulation, the real-time monitoring of the drawing process, the hierarchical judgment, and the precise traceability is constructed, the controllability and the intelligentization of the preparation process are realized, and the product qualification rate and the preparation stability are improved; meanwhile, the targeted parameter adjustment strategy is designed, the optimization of the vibration frequency and the drawing rate is associated with the quality deviation degree, and the efficiency waste or the unstable process caused by blind adjustment is avoided; in terms of material performance, by scientifically proportioning the alloy powder components and selecting the adaptive stainless steel skin, the cladding material has excellent sulfur corrosion resistance, high-temperature stability, and forming performance, and can perfectly adapt to the complex service conditions of the boiler tube row, thereby improving the preparation efficiency of the cladding material.

[0018] Further, the application sets the structural uniformity characterization value to reflect the filling uniformity of the internal alloy powder, when the powder is aggregated or locally voided, the discrete degree of the diameter will be intuitively reflected, and the three-level judgment logic is established layer by layer, for the case of slight deviation from the preset standard, the subsequent filling effect is optimized by increasing the vibration frequency to avoid the accumulation of small defects into serious quality problems; for the case of serious deviation, an alloy powder supply abnormality alarm is directly issued to timely block the continuous output of unqualified blanks, thereby realizing precise detection.

[0019] Further, the application sets multiple frequency adjustment modes and different increasing amplitudes for each mode, thereby realizing precise control of the increasing amplitude of the vibration frequency.

[0020] Further, the present application realizes accurate identification and classified management of the quality risk of the drawing process by establishing a three-level response mechanism of the drawing thermal characterization value, and the system divides the thermal anomaly into two levels of potential risk and determined unqualified, and designs a differentiated processing flow for each level: the secondary determination is started for the potential risk to further confirm, and the cause diagnosis is directly performed for the determined unqualified; the hierarchical processing strategy avoids misjudgment and ensures that serious quality problems can be processed in time; by associating the thermal anomaly with different subsequent processing flows, the targeted quality control path is formed, so that the intelligent monitoring of the drawing process is realized.

[0021] Further, the present application takes the diameter fluctuation range as the index of the secondary determination, reflects the uniformity of the powder densification in the drawing process by quantifying the fluctuation range of the diameter of the powder core wire, and when the diameter fluctuation anomaly is detected, the system can automatically adjust the drawing speed of the next batch according to the deviation size, so that the local bulging phenomenon caused by too fast compression is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 A flowchart of the preparation method of the anti-sulfur corrosion cladding material of the boiler tube bank of the embodiment of the present application; Figure 2 A flowchart of the preparation of the embodiment of the present application for determining whether the prepared blank meets the preset standard; Figure 3 A flowchart of the preparation of the embodiment of the present application for determining whether the prepared powder core wire meets the preset standard according to the drawing thermal characterization value of the powder core wire; Figure 4 A flowchart of the preparation of the embodiment of the present application for determining the reason why the prepared powder core wire does not meet the preset standard. DETAILED DESCRIPTION

[0023] In order to make the purpose and advantages of the present application clearer and more apparent, the present application is further described below in combination with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present application, and do not limit the present application.

[0024] The preferred embodiments of the present application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application, and are not intended to limit the protection scope of the present application.

[0025] It should be pointed out that the data in the embodiment are comprehensive analysis and evaluation results of historical detection data and corresponding historical detection results of the application in the three months before the detection. Those skilled in the art can understand that the determination method of the application for a single parameter can be to select the value with the highest proportion as the preset standard parameter according to the data distribution, to use weighted summation to obtain the value as the preset standard parameter, to substitute each historical data into a specific formula and to obtain the value by using the formula as the preset standard parameter, or other selection methods, as long as the application can clearly define different specific situations in the single determination process through the obtained value.

[0026] Please refer to Figure 1 , Figure 2 , Figure 3 and Figure 4 , which are respectively a flowchart of a preparation method of a boiler tube row anti-sulfur corrosion cladding material according to the embodiment of the application; a flowchart of determining whether the preparation of a blank conforms to a preset standard according to the embodiment of the application; a flowchart of determining whether the preparation of a powder core wire conforms to a preset standard according to the drawing thermal characteristic value of the powder core wire according to the embodiment of the application; and a flowchart of determining the reason why the preparation of the powder core wire does not conform to the preset standard according to the embodiment of the application.

[0027] In one aspect, the embodiment of the application provides a preparation method of a boiler tube row anti-sulfur corrosion cladding material, comprising: Step S1, using a 304 stainless steel strip as a metal outer skin, the thickness of the metal outer skin is 0.3 mm, the width of the metal outer skin is 8 mm, rolling the stainless steel strip into a U-shaped groove, filling alloy powder into the U-shaped groove at a preset vibration frequency of 50 Hz, sealing by argon arc welding after filling is completed, to obtain a blank, wherein the particle size of the alloy powder is 45-75 μm; using a laser diameter gauge to continuously scan and detect along the length direction of the blank at an interval of 10 mm, a total of 100 diameter data of the blank are collected, and a structure uniformity characteristic value of the blank is obtained; Step S2, when it is determined that the preparation of the blank does not conform to the preset standard according to the structure uniformity characteristic value of the blank, increasing the preset vibration frequency of the preparation of the next batch of blank or issuing an alloy powder supply abnormal alarm; Step S3, putting the blank conforming to the preset standard into a wire drawing machine to draw at a preset drawing rate of 2.5 m / min, to obtain a powder core wire, collecting a thermal image of the powder core wire, and obtaining a drawing thermal characteristic value of the powder core wire; Step S4, when the drawing thermal characteristic value is greater than or equal to a first preset drawing thermal characteristic value and less than a second preset drawing thermal characteristic value, determining whether the preparation of the powder core wire conforms to the preset standard according to the diameter fluctuation range of the powder core wire; Step S5, when the drawing hot characteristic value is greater than or equal to a second preset drawing hot characteristic value, determining the reason for the preparation of the powder core wire not meeting the preset standard according to the thermal abnormal aggregation degree of the powder core wire, wherein the reason is that the internal friction of the alloy powder is too large or the plasticity of the metal skin is insufficient; Step S6, winding the powder core wire meeting the preset standard through an automatic take-up device to obtain a boiler tube row anti-sulfur corrosion cladding material.

[0028] It should be pointed out that the data in the embodiment are results obtained through preliminary experiments before the detection by the method of the application, and each preset value can be adjusted according to the specific use, as long as the method of the application can determine different specific conditions in the single determination process through the obtained numerical value. The preset values set in the embodiment are obtained according to the preliminary experiments, and each correction coefficient is also selected through experimental verification.

[0029] Specifically, the process of determining whether the preparation of the blank meets the preset standard according to the structure uniformity characteristic value of the blank includes: The structure uniformity characteristic value is compared with a first preset structure uniformity threshold value 0.025 and a second preset structure uniformity threshold value 0.046, respectively. If the structure uniformity characteristic value is less than the first preset structure uniformity threshold value, it is determined that the preparation of the blank meets the preset standard. If the structure uniformity characteristic value is greater than or equal to the first preset structure uniformity threshold value and less than the second preset structure uniformity threshold value, it is determined that the preparation of the blank does not meet the preset standard, and the preset vibration frequency of the next batch of blank preparation is increased according to the difference between the structure uniformity characteristic value and the first preset structure uniformity threshold value. If the structure uniformity characteristic value is greater than or equal to the second preset structure uniformity threshold value, it is determined that the preparation of the blank does not meet the preset standard, and an alloy powder supply abnormality alarm is issued. The structure uniformity characteristic value is the ratio of the standard deviation to the average value of the diameter of the blank.

[0030] Specifically, the first preset structure uniformity threshold value has a value range of [0.015, 0.030], and the second preset structure uniformity threshold value has a value range of [0.045, 0.060]. In the embodiment, the first preset structure uniformity threshold value has a value of 0.025, and the second preset structure uniformity threshold value has a value of 0.046.

[0031] Specifically, by adopting the ratio of the standard deviation of the blank diameter to the average value as the structural uniformity characteristic value, when the structural uniformity characteristic value is less than the first preset structural uniformity threshold value, it indicates that the relative fluctuation of the diameters of each cross section of the blank is extremely small, the metal skin and the powder are balanced in stress and cooperatively deformed during the drawing process, and stress concentration leading to bulging or cracking does not occur, and the thickness of the cladding layer can also be ensured to be uniform during subsequent cladding, forming a continuous and dense sulfur corrosion resistant protective film, so it is determined that the blank meets the preset standard; when the characteristic value is greater than or equal to the first preset structural uniformity threshold value and less than the second preset structural uniformity threshold value, the internal powder is slightly agglomerated but not irreversible agglomerated, by increasing the preset vibration frequency of the next batch of blank preparation, the slightly agglomerated powder can be dispersed by mechanical vibration impact force, so that the filling density deviation is adjusted to the qualified range, therefore it is determined that the blank does not meet the preset standard and is repaired by adjusting the vibration frequency, when the characteristic value is greater than or equal to the second preset structural uniformity threshold value, it means that the internal powder is seriously agglomerated, agglomerated or locally voided, and simply increasing the vibration frequency cannot eliminate the serious unevenness caused by powder moisture absorption, agglomeration or supply pipeline blockage, and the skin will inevitably crack due to local stress concentration during drawing, therefore it is determined that the blank does not meet the preset standard and an alloy powder supply abnormal alarm is issued, thereby establishing a one-to-one correspondence between the characteristic value and the defect severity and the processing method, screening qualified blanks from the source, repairing slight defects, and blocking serious abnormalities, avoiding misjudgment, thereby improving production efficiency.

[0032] Specifically, the increase of the preset vibration frequency for the next batch of blank preparation has several frequency adjustment modes, wherein, If the structural uniformity characteristic difference value is less than the first preset structural uniformity characteristic difference value 0.005, the preset vibration frequency for the next batch of blank preparation is increased to the corresponding value by using the first adjustment coefficient 1.04; If the structural uniformity characteristic difference value is greater than or equal to the first preset structural uniformity characteristic difference value and less than the second preset structural uniformity characteristic difference value 0.019, the preset vibration frequency for the next batch of blank preparation is increased to the corresponding value by using the second adjustment coefficient 1.06; If the structural uniformity characteristic difference value is greater than or equal to the second preset structural uniformity characteristic difference value, the preset vibration frequency for the next batch of blank preparation is increased to the corresponding value by using the third adjustment coefficient 1.08; The structural uniformity characteristic difference value is the difference between the structural uniformity characteristic value and the first preset structural uniformity threshold value.

[0033] Specifically, the process of determining whether the preparation of the powder core wire meets the preset standard according to the drawing thermal characteristic value of the powder core wire includes: The drawing thermal characteristic value is compared with the first preset drawing thermal characteristic value 1.6 DEG C and the second preset drawing thermal characteristic value 3.4 DEG C, respectively; If the drawing heat characteristic value is less than a first preset drawing heat characteristic value, it is determined that the preparation of the powder core wire meets the preset standard; If the drawing heat characteristic value is greater than or equal to the first preset drawing heat characteristic value and less than a second preset drawing heat characteristic value, it is determined that the preparation of the powder core wire is at risk of not meeting the preset standard, and whether the preparation of the powder core wire meets the preset standard is determined again according to the diameter fluctuation range of the powder core wire. If the drawing heat characteristic value is greater than or equal to the second preset drawing heat characteristic value, it is determined that the preparation of the powder core wire does not meet the preset standard, and the reason why the preparation of the powder core wire does not meet the preset standard is determined according to the thermal abnormal aggregation degree of the powder core wire.

[0034] Specifically, the first preset drawing heat characteristic value is in the range of [1.2℃, 2.1℃], and the second preset drawing heat characteristic value is in the range of [2.9℃, 3.8℃]. In this embodiment, the first preset drawing heat characteristic value is 1.6℃, and the second preset drawing heat characteristic value is 3.4℃.

[0035] The drawing heat characteristic value is the standard deviation of the surface temperature of the powder core wire during the drawing process, which characterizes the uniformity of the surface temperature distribution of the wire during drawing, and further reflects the deformation coordination state of the internal alloy powder and the metal skin and the degree of internal friction of the powder. The smaller the drawing heat characteristic value, the more uniform the heat production of each part of the wire, the smoother the process of powder particle rearrangement and compaction, and the better the deformation coordination of the metal skin and the powder without local stress concentration or abnormal friction. The larger the drawing heat characteristic value, the more local heat production increases during the drawing process, which corresponds to the deformation imbalance caused by excessive internal friction of the powder or insufficient plasticity of the skin, and the risk of defects such as bulging and cracking of the wire increases.

[0036] Specifically, the drawing heat characteristic value is obtained by the following process: An infrared thermal imager is used to take a thermal image of the powder core wire with a preset length of 1m at the exit side of the drawing die of the wire drawing machine; Based on the thermal image, 30 sampling points are uniformly selected along the length direction of the wire using FLIRResearchStudio analysis software, and the surface temperature of each sampling point is extracted; The standard deviation of the surface temperature of the 30 sampling points is calculated using MATLAB, which is recorded as the drawing heat characteristic value.

[0037] In this embodiment, the preset length is 1m, but the above value is not limited thereto, and those skilled in the art can adjust the above value according to actual needs.

[0038] Specifically, whether the preparation of the powder core wire meets the preset standard is determined again according to the diameter fluctuation range of the powder core wire, wherein, If the diameter fluctuation range is less than the preset diameter fluctuation range 0.03 mm, it is determined that the preparation of the powder core wire meets the preset standard; If the diameter fluctuation range is greater than or equal to the preset diameter fluctuation range, it is determined that the preparation of the powder core wire does not meet the preset standard, and the preset drawing speed of the next batch of blank preparation is reduced according to the difference between the diameter fluctuation range and the preset diameter fluctuation range. The diameter fluctuation range is the difference between the maximum diameter of the powder core wire and the minimum diameter of the powder core wire, wherein the diameter of the powder core wire is obtained by a laser scanning diameter gauge.

[0039] Specifically, the diameter fluctuation range represents the radial dimensional stability and internal powder densification uniformity of the powder core wire, and the diameter fluctuation range directly reflects the uniformity of the wire shape during drawing. The smaller the range is, the better the size consistency is. A stable drawing process should produce a wire with a very small diameter fluctuation. An increase in the range indicates that the process system is disturbed.

[0040] In this embodiment, the diameter data of 100 batches of powder core wires under normal production state are statistically analyzed to determine that the diameter fluctuation range conforms to a normal distribution with a mean value of 0.018 mm and a standard deviation of 0.005 mm. Accordingly, the preset diameter fluctuation range is set to 0.03 mm, but the above values are not limited thereto. Those skilled in the art can adjust the above values according to actual needs.

[0041] Specifically, the reduction amplitude of the preset drawing speed of the next batch of blank preparation is positively correlated with the diameter fluctuation deviation value, wherein the positive correlation is, for example, linear positive correlation or nonlinear positive correlation. The linear slope of the linear positive correlation is not specifically limited. It can be understood that the larger the diameter fluctuation deviation value is, the larger the reduction amplitude of the preset drawing speed of the next batch of blank preparation is. The diameter fluctuation deviation value is the difference between the diameter fluctuation range and the preset diameter fluctuation range.

[0042] Specifically, the process of determining the reason why the preparation of the powder core wire does not meet the preset standard according to the thermal abnormal aggregation degree of the powder core wire includes: If the thermal abnormal aggregation degree is less than the preset thermal abnormal aggregation degree 8, it is determined that the plasticity of the metal sheath is insufficient. If the thermal abnormal aggregation degree is greater than or equal to the preset thermal abnormal aggregation degree, it is determined that the internal friction of the alloy powder is too large.

[0043] Specifically, the thermal abnormality aggregation degree characterizes the spatial distribution of the surface high-temperature area in the core-in-wire drawing process. When the metal sheath is not plastic enough, the sheath cannot uniformly bear the tension during the drawing process, and the heat generated by the local stretching resistance will be dispersed along the length direction of the wire. Such high-temperature areas are mostly scattered and independent, and have no obvious aggregation characteristics, so the corresponding thermal abnormality aggregation degree value is small. When the internal friction of the alloy powder is too large, the agglomerated powder will form local friction, and the violent friction between the agglomerates and the metal sheath and the internal particles of the agglomerates will generate concentrated heat. The high-temperature area is mostly in the form of a block, and there may be multiple independent aggregation high-temperature areas, so the corresponding thermal abnormality aggregation degree value is large.

[0044] Specifically, the preset thermal abnormality aggregation degree is 8, but the above value is not limited thereto, and those skilled in the art can adjust the above value according to actual needs.

[0045] Specifically, the process of obtaining the thermal abnormality aggregation degree includes: The thermal imaging image of the core-in-wire taken by the infrared thermal imager is imported into the FLIRResearchStudio software, the temperature values of all pixel points in the thermal imaging image are extracted, and a data set containing pixel coordinates-temperature values is generated. All pixel temperature values are sorted from high to low using the FLIRResearchStudio software, and the highest temperature value, for example, 93℃, is recorded. Based on the sorted temperature sequence, the temperature value corresponding to the top 10% percentile is selected as the preset temperature value, for example, the lowest temperature value of the top 10% (30720) pixels in 307200 pixels is 78℃, and the temperature interval is [78℃, 93℃]. All pixel points in this interval are recorded as relative hot spots.

[0046] All relative hot spots are marked in the thermal imaging image using the Image software, the spatial adjacent determination standard is set as the upper, lower, left, right and four corner adjacent pixels, the number of independent connected regions formed by the relative hot spots is automatically counted, and the number is the thermal abnormality aggregation degree, wherein the independent connected region is formed by the relative hot spots adjacent in spatial position.

[0047] In another aspect, the embodiment of the present application provides a boiler tube bank sulfur corrosion resistant cladding material prepared by the above preparation method, comprising an alloy powder and a metal skin, wherein the material of the metal skin is stainless steel; the alloy powder comprises the following components in mass fraction: C: ≤0.10wt.%; Mn: ≤0.50wt.%; Si: ≤0.50wt.%; P: ≤0.015wt.%; S: ≤0.015wt.%; Cr: 20.0-23.0wt.%; (Nb+Ta): 3.15-4.15wt.%; Co: ≤1.0wt.%; Mo: 8.0-10.0wt.%; Fe: <5.0wt.%; Al: ≤0.40wt.%; Ti: ≤0.40wt.%; and Ni: balance.

[0048] In the embodiment, C: 0.05wt.%; Mn: 0.30wt.%; Si: 0.25wt.%; P: 0.010wt.%; S: 0.008wt.%; Cr: 21.5wt.%; (Nb+Ta): 3.65wt.%; Co: 0.5wt.%; Mo: 9.0wt.%; Fe: 3.2wt.%; Al: 0.20wt.%; Ti: 0.25wt.%; and Ni: balance.

[0049] Up to now, the technical solution of the present application has been described in combination with the preferred embodiments shown in the drawings, but it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the present application, and the technical solutions after the changes or replacements will all fall within the protection scope of the present application.

Claims

1. A method of producing a cladding material for boiler tube banks resistant to sulphur corrosion, characterized in that The method comprises the following steps: filling the alloy powder into the metal shell at a preset vibration frequency, and sealing to obtain a blank; obtaining the diameters of the blank, and obtaining a structure uniformity representation value of the blank; when it is determined according to the structure uniformity representation value of the blank that the preparation of the blank does not meet the preset standard, increasing the preset vibration frequency for the preparation of the next batch of blank or issuing an abnormal alarm for the alloy powder supply; drawing the blank meeting the preset standard at a preset drawing rate to obtain a powder core wire, collecting a thermal image of the powder core wire, and obtaining a drawing thermal representation value of the powder core wire; when the drawing thermal representation value is greater than or equal to a first preset drawing thermal representation value and less than a second preset drawing thermal representation value, determining whether the preparation of the powder core wire meets the preset standard according to the diameter fluctuation range of the powder core wire; when the drawing thermal representation value is greater than or equal to the second preset drawing thermal representation value, determining the reason why the preparation of the powder core wire does not meet the preset standard according to the thermal abnormal aggregation degree of the powder core wire, wherein the reason is that the internal friction of the alloy powder is too large or the plasticity of the metal shell is insufficient; winding the powder core wire meeting the preset standard to obtain a boiler tube row anti-sulfur corrosion cladding material.

2. The method of claim 1, wherein the method further comprises: The process of determining whether the preparation of the blank meets the preset standard according to the structure uniformity representation value of the blank comprises: comparing the structure uniformity representation value with a first preset structure uniformity threshold value and a second preset structure uniformity threshold value respectively; if the structure uniformity representation value is less than the first preset structure uniformity threshold value, it is determined that the preparation of the blank meets the preset standard; if the structure uniformity representation value is greater than or equal to the first preset structure uniformity threshold value and less than the second preset structure uniformity threshold value, it is determined that the preparation of the blank does not meet the preset standard, and the preset vibration frequency for the preparation of the next batch of blank is increased according to the difference between the structure uniformity representation value and the first preset structure uniformity threshold value; if the structure uniformity representation value is greater than or equal to the second preset structure uniformity threshold value, it is determined that the preparation of the blank does not meet the preset standard, and an abnormal alarm for the alloy powder supply is issued; the structure uniformity representation value is the ratio of the standard deviation to the average value of the diameter of the blank.

3. The method of claim 2, wherein the method further comprises: The increase of the preset vibration frequency for the preparation of the next batch of blank is provided with a plurality of frequency adjustment modes, and the increase amplitude of each frequency adjustment mode is different.

4. The method of claim 3, wherein the method further comprises the step of: The process of determining whether the preparation of the powder core wire meets the preset standard according to the drawing thermal representation value of the powder core wire comprises: comparing the drawing thermal representation value with a first preset drawing thermal representation value and a second preset drawing thermal representation value respectively; if the drawing thermal representation value is less than the first preset drawing thermal representation value, it is determined that the preparation of the powder core wire meets the preset standard; if the drawing thermal representation value is greater than or equal to the first preset drawing thermal representation value and less than the second preset drawing thermal representation value, it is determined that the preparation of the powder core wire has a risk of not meeting the preset standard, and whether the preparation of the powder core wire meets the preset standard is determined according to the diameter fluctuation range of the powder core wire; If the drawing heat characteristic value is greater than or equal to a second preset drawing heat characteristic value, it is determined that the preparation of the powder core wire does not meet the preset standard, and the reason for the preparation of the powder core wire not meeting the preset standard is determined according to the thermal abnormal aggregation degree of the powder core wire.

5. The method of claim 4, wherein the method further comprises: The drawing heat characteristic value is obtained by: Taking a thermal image of the powder core wire of a preset length; Based on the thermal image, obtaining a plurality of surface temperatures of the powder core wire; Calculating the standard deviation of the plurality of surface temperatures, denoted as the drawing heat characteristic value.

6. The method of claim 5, wherein the method further comprises the step of: When the second determination of the preparation of the powder core wire not meeting the preset standard is made according to the comparison result that the diameter fluctuation range of the powder core wire is greater than or equal to a preset diameter fluctuation range, the preset drawing speed of the next batch of blank preparation is reduced according to the difference between the diameter fluctuation range and the preset diameter fluctuation range. The diameter fluctuation range is the difference between the maximum diameter of the powder core wire and the minimum diameter of the powder core wire.

7. The method of claim 6, wherein the method further comprises the step of: The reduction range of the preset drawing speed of the next batch of blank preparation is positively correlated with the diameter fluctuation deviation value, wherein the diameter fluctuation deviation value is the difference between the diameter fluctuation range and the preset diameter fluctuation range.

8. The method of claim 7, wherein the method further comprises: The process of determining the reason for the preparation of the powder core wire not meeting the preset standard according to the thermal abnormal aggregation degree of the powder core wire includes: If the thermal abnormal aggregation degree is less than a preset thermal abnormal aggregation degree, it is determined that the plasticity of the metal sheath is insufficient; If the thermal abnormal aggregation degree is greater than or equal to the preset thermal abnormal aggregation degree, it is determined that the internal friction of the alloy powder is too large.

9. The method of claim 8, wherein the method further comprises the step of: The process of obtaining the thermal abnormal aggregation degree includes: Sorting the temperature values of all pixel points in the thermal image from high to low, determining the highest temperature value in the thermal image, taking the highest temperature value as the upper limit, taking a preset temperature value as the lower limit, and recording the pixel points in the temperature interval as relative hot spots; Counting the number of independent connected regions formed by the relative hot spots adjacent in space position, denoted as the thermal abnormal aggregation degree; Wherein, the preset temperature value is the temperature value corresponding to the front preset percentage in the sequence of the temperature values of all pixel points in the thermal image sorted from high to low.

10. A boiler tube bank sulphidation corrosion resistant cladding material produced according to the method of any one of claims 1 to 9, characterised in that, The alloy powder includes the following components by mass fraction: C: ≤0.10wt.%; Mn: ≤0.50wt.%; Si: ≤0.50wt.%; P: ≤0.015wt.%; S: ≤0.015wt.%; Cr: 20.0-23.0wt.%; (Nb+Ta): 3.15-4.15wt.%; Co: ≤1.0wt.%; Mo: 8.0-10.0wt.%; Fe: <5.0wt.%; Al: ≤0.40wt.%; Ti: ≤0.40wt.%; Ni: balance. The metal sheath is made of stainless steel.

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