A method for detecting and judging effective thickness of a laser cladding layer of a hydraulic support stand column

Abstract

The present application relates to a kind of hydraulic support column laser cladding layer effective thickness detection determination method, it uses nondestructive component analyzer, the first element content C1 and second element content C2 of each detection point position are carried out joint detection;First element is the element in laser cladding material, content is significantly higher than base material, second element is the element in base material, content is significantly higher than laser cladding material;If C1≥T1 and C2≤T2, then eligible;If C1≥T1 and C2>T2, then need to review;If C1<T1 and C2≤T2, then for uniform thinning;If C1<T1 and C2>T2, then unqualified;T1 is the minimum content of first element required for determining effective thickness eligible;T2 is the maximum content of second element allowed for determining effective thickness eligible.The present application can solve the technical problems of insufficient accuracy of existing laser cladding layer effective thickness detection effect, easy to miss judgment, misjudgment.

Description

Technical Field

[0001] This invention relates to the field of quality inspection technology, and in particular to a method for determining the effective thickness of the laser cladding layer on a hydraulic support column. Background Technology

[0002] The underground environment in coal mines is extremely harsh. The underground water contains high levels of chloride ions (150-350 mg / L) and sulfate ions (80-200 mg / L), with a pH of 4.5-6.5, making it weakly acidic. It also contains impurities such as coal slime and suspended particulate matter (50-120 mg / L), which have a strong corrosive effect on metal surfaces. As the core support equipment in fully mechanized mining faces, hydraulic supports are constantly exposed to this corrosive environment. Key components—such as the rods and pipe parts of the vertical shaft jacks—directly bear high pressure and heavy loads. Once corrosion occurs and failure occurs, it will seriously affect the safety and efficiency of coal mining.

[0003] Components of vertical shaft jacks typically undergo surface strengthening treatment using laser cladding technology. The resulting laser cladding layer possesses advantages such as high strength, high hardness, and excellent metallurgical bonding with the substrate, significantly improving the corrosion resistance and service life of the components. The corrosion resistance of the cladding layer is a core indicator for these components, and the effective thickness of the cladding layer is a key factor determining corrosion resistance—sufficient and uniform effective thickness is a prerequisite for ensuring long-term stable operation in harsh downhole water conditions.

[0004] However, the rods and tubular components of the column jack have a slender structure, making them prone to bending or deformation during laser cladding due to uneven heat input. In subsequent machining stages, misalignment during mounting and positioning can lead to uncontrolled removal of the cladding layer in certain areas. Insufficient effective cladding thickness after machining directly reduces the corrosion resistance of the components, significantly shortens their service life, and in severe cases, may cause the column jack to fail, leading to downhole safety accidents.

[0005] Because the laser cladding layer is metallurgically bonded to the substrate, it is difficult to directly measure the actual thickness of the laser cladding layer. The mainstream method is to indirectly obtain the thickness data of the laser cladding layer by theoretical calculation of the difference between the dimensions of the component before cladding and the machined dimensions after cladding. However, this method has obvious drawbacks: it can only calculate the theoretical geometric thickness of the overall area and cannot identify problems such as excessive removal of the cladding layer due to local bending, deformation, or mounting deviations, or compositional segregation caused by laser cladding parameters. Even if the overall geometric thickness meets the standard, local areas may still have insufficient effective thickness due to the above factors. Components with local thickness defects experience a sharp decline in corrosion resistance in the harsh water environment of underground coal mines, making them prone to corrosion failure and posing serious safety hazards.

[0006] Existing detection methods also have limitations: for example, ultrasonic testing is susceptible to interference from slender structural shapes, leading to misjudgments; while cross-sectional sampling can obtain accurate and effective thickness data, it requires damaging the workpiece, making it unsuitable for finished product inspection and failing to meet the quality control requirements of mass production. Furthermore, some studies have proposed establishing a curve relating the content of a specific alloying element in the laser cladding layer to its thickness, using element content to infer the cladding layer thickness. However, this method requires pre-preparing a series of standard samples and establishing curves for each substrate material and cladding powder combination. This is time-consuming, cumbersome, and only applicable to specific material systems. Changing the substrate material or cladding powder renders the original curves invalid, necessitating a complete recalibration experiment, making it unsuitable for multi-variety, small-batch production scenarios. More importantly, when local bending deformation, machining deviations, or fluctuations in laser process parameters lead to substrate exposure or component segregation, this method still cannot effectively identify different defect situations and cannot determine whether the effective thickness is qualified. It may misjudge serious defects such as insufficient effective thickness and substrate exposure as ordinary thin layers, causing defective products to flow into the next process, or misjudge effective uniform thinning areas / segregation areas as substrate exposure, leading to the use of incorrect rework methods or scrapping of workpieces, affecting production efficiency and control costs.

[0007] In summary, existing detection methods generally suffer from insufficient accuracy and are prone to missed or misjudgments when dealing with localized insufficient thickness issues, which has become a key bottleneck restricting the improvement of the reliability of hydraulic supports used in coal mines. Therefore, there is an urgent need for a method for detecting and determining the effective thickness of the cladding layer that can accurately identify localized defects, is easy to operate, and has strong adaptability. Summary of the Invention

[0008] (a) Technical problems to be solved

[0009] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a method for detecting and determining the effective thickness of the laser cladding layer of a hydraulic support column, which solves the technical problems of insufficient accuracy, easy omission and misjudgment in the existing laser cladding layer effective thickness detection effect.

[0010] (II) Technical Solution

[0011] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0012] This invention provides a method for detecting and determining the effective thickness of the laser cladding layer on a hydraulic support column, comprising the following steps:

[0013] S1. Clean the parts to be tested after laser cladding to expose fresh metal surfaces;

[0014] S2. Set multiple detection points according to the specific structural characteristics of the component to be measured;

[0015] S3. Use a non-destructive composition analyzer to jointly detect the content C1 of the first element and the content C2 of the second element at each detection point; the first element is the characteristic alloy element with a significantly higher content in the laser cladding material than in the substrate material, and the second element is the matrix element with a significantly higher content in the substrate material than in the laser cladding material;

[0016] S4. According to the joint detection results, determine whether the effective thickness of the laser cladding layer is qualified according to the following rules:

[0017] If C1≥T1 and C2≤T2, it is determined that the effective thickness of this point is qualified;

[0018] If C1≥T1 and C2>T2, it is determined that this point is a suspicious point and needs to be rechecked;

[0019] If C1<T1 and C2≤T2, it is determined that there is uniform thinning at this point, and this point is recorded and monitored;

[0020] If C1<T1 and C2>T2, it is determined that the effective thickness of this point is insufficient and rework or scrapping is required;

[0021] Among them, T1 is the minimum content of the first element required to determine the qualified corrosion resistance of the laser cladding layer, and its value is determined according to the original content of the first element in the cladding powder, the allowable dilution rate range of the process, design indicators, statistical values of similar specimens or historical experience parameters; T2 is the maximum content of the second element allowed to determine the qualified effective thickness of the laser cladding layer, and its value is determined according to the content of the second element in the substrate material, the allowable mixing ratio of the substrate in the process, design indicators, statistical values of similar specimens or historical experience parameters.

[0022] According to a preferred embodiment of the present invention, in S1, during the cleaning treatment, an organic solvent is used to clean the detection area of the component to be measured to remove pollutants; then, a metallographic sandpaper with a particle size ≥ 800 mesh is used to polish 2-5 circles in a concentric circle manner in the detection area to remove the surface oxide film; finally, it is cleaned with an organic solvent and dried with compressed air; the organic solvent is acetone or ethanol.

[0023] According to a preferred embodiment of the present invention, in S2, the detection points are set as follows: a detection section is set every 200-300 mm along the axial direction of the component, and at least 3 detection points are evenly set along the circumferential direction of each detection section.

[0024] According to a preferred embodiment of the present invention, in S2, when the diameter of the detection section exceeds 100 mm or the circumference exceeds 400 mm, there are no less than 6 circumferential detection points for each detection section; wherein, based on the same batch or historical production data and finite element analysis data, high-risk areas and stress concentration areas that are prone to insufficient thickness are statistically analyzed; in high-risk areas and stress concentration areas, at least 2 additional detection points are added to each detection section on the basis of the above.

[0025] According to a preferred embodiment of the present invention, in S3, the base material of the hydraulic support is alloy steel, and the laser cladding material is at least one of iron-based alloy powder, nickel-based alloy powder, or cobalt-based alloy powder. The first element is a characteristic alloying element in the laser cladding material with a higher content than that in the base material, and the first element is Cr, Ni, W, Co, Mo, or Mn. The second element is a matrix element in the base material with a higher content than that in the laser cladding material, and the second element is Fe, Ni, or Co.

[0026] According to a preferred embodiment of the present invention, in S3, T1 is determined by one of the following methods:

[0027] Method 1: T1=C 粉末 ×(1-D max ), where C 粉末 D represents the content of the first element in the cladding powder. max The maximum dilution rate at which the substrate material is mixed into the laser cladding layer to ensure its corrosion resistance, resulting in dilution of the cladding layer composition;

[0028] Method 2: Grind a series of samples with different laser cladding layer thicknesses, use the same non-destructive component analyzer as S3 to detect the content of the first element, then conduct a standard salt spray corrosion test on all samples and record their corrosion rate. The content of the first element corresponding to the sample with a significantly accelerated corrosion rate is determined as T1.

[0029] Method 3: When the thickness of the laser cladding layer reaches the minimum thickness required by the product design, the content of the first element is determined as T1.

[0030] According to a preferred embodiment of the present invention, in S3, when the laser cladding material is a Cr-containing iron-based alloy powder and the base material is alloy steel, the first element is Cr, and D... max The value is determined based on design parameters, process requirements, statistical values ​​of similar samples, or historical experience parameters, and its range is 1%-10%.

[0031] According to a preferred embodiment of the present invention, in S3, T2 is determined by one of the following methods:

[0032] Method 1: T2=A 基底 ×R max +A粉末 ×(1-R max ), where A 基底 The content of the second element in the substrate material, A 粉末 R represents the content of the second element in the cladding powder. max The maximum substrate mixing ratio allowed in the laser cladding coating to ensure the effective thickness of the laser cladding layer;

[0033] Method 2: Grind a series of laser cladding layer samples with different remaining thicknesses, and use the same non-destructive component analyzer as S3 to detect them. Determine the remaining thickness corresponding to when the content of the second element begins to increase significantly as the minimum effective thickness, and determine the content of the second element corresponding to the minimum effective thickness as T2.

[0034] Method 3: The content of the second element corresponding to the minimum thickness required by the product design when the thickness of the laser cladding layer reaches the minimum thickness is determined as T2.

[0035] According to a preferred embodiment of the present invention, in S3, when the laser cladding material is iron-based alloy powder and the substrate material is alloy steel, the second element is Fe, R max The value is determined based on design specifications, process requirements, statistical values ​​of relevant samples, or historical experience parameters, and its range is 1%-10%. The maximum substrate mixing ratio range is equal to the range of the maximum dilution rate of the substrate material on the laser cladding layer that is allowed to ensure the corrosion resistance of the laser cladding layer.

[0036] According to a preferred embodiment of the present invention, in S3, the non-destructive component analyzer is a direct-reading spectrometer or an X-ray fluorescence spectrometer; each detection point is detected at least 3 times, and the average value is taken as the final data of that point.

[0037] (III) Beneficial Effects

[0038] The beneficial effects of the present invention are as follows: For a method for detecting and determining the effective thickness of a laser cladding layer (simply referred to as the cladding layer) of a hydraulic support column in the present invention, by simultaneously detecting a first element in the cladding layer and a second element in the base material, and using the content difference of the two types of elements in their respective materials for combined determination. Compared with the prior art, since the content of the first element in the cladding material is significantly higher than that in the base material, the level of its content can reflect the integrity of the main components of the cladding layer and its corrosion resistance; since the content of the second element in the base material is significantly higher than that in the cladding material, the change in its content can indicate whether the base material has mixed into the detection area. Through the combined analysis of these two parameters, the present invention can perform combined analysis and judgment on the effective thickness of the laser cladding layer from two dimensions of "the state of the cladding layer itself" and "whether the base is exposed", obtaining a more accurate analysis result, effectively distinguishing various different situations that may occur in actual production and judging whether its effective thickness is qualified, with high detection accuracy.

[0039] Specifically, when the content of the first element meets the standard and the content of the second element is normal (C1≥T1 and C2≤T2), it indicates that the main components of the cladding layer in the detection area are complete and the base material has not been significantly mixed in, that is, this area has a complete basis for corrosion resistance, and it can be directly determined that the effective thickness is qualified.

[0040] When the content of the first element meets the standard but the content of the second element increases abnormally (if C1≥T1 and C2>T2), this combination usually does not occur under normal conditions, and may be caused by factors such as surface contamination, abnormal detection instruments or serious segregation caused by operation errors. By determining it as a suspicious point and initiating a review, the possibility of misjudgment caused by problems in the detection link can be effectively reduced.

[0041] When the content of the first element is low but the content of the second element is normal (C1<T1 and C2≤T2), it indicates that there are problems such as uniform thinning or mild segregation in the cladding layer, but the base has not been exposed. Although the thickness is insufficient in this case, it may still have a certain protective ability. By determining it as uniform thinning and recording for monitoring, specific treatment methods can be selected according to the situation later, which can not only avoid excessive handling of minor defects but also provide early warning information for process adjustment.

[0042] When the content of the first element is low and the content of the second element increases abnormally (C1<T1 and C2>T2), it is a typical feature of the base material mixing into the detection area, corresponding to serious defects such as local wear-through and base exposure. At this time, the cladding layer is difficult to ensure the due protective ability. By determining that the effective thickness is insufficient and guiding rework or scrapping, major defects can be effectively identified and intercepted.

[0043] Compared to detection methods that only detect the actual thickness value or rely on a single element, the four judgment results of the present invention can effectively correspond to and distinguish different cladding layer states such as intact cladding layer, detection interference, component segregation, uniform thinning, and substrate exposure. This allows the present invention to effectively distinguish between different types of insufficient effective thickness problems, and can effectively reduce the possibility of misjudging serious defects such as substrate exposure as ordinary thin layer, or misjudging uniform thinning as substrate exposure, thereby improving the accuracy of judgment and avoiding misjudgment.

[0044] Furthermore, this invention introduces T1 and T2 for judgment. The magnitudes of these two values ​​can be calculated based on the known composition of the cladding powder and the substrate material, combined with the maximum allowable dilution rate or the maximum substrate mixing ratio. Since the composition of the cladding powder and the substrate material is determined during preparation, even if the material system is changed, its composition information can still be directly obtained without the need for extensive and lengthy calibration experiments, thus exhibiting a certain degree of adaptability to different material systems.

[0045] Furthermore, this invention cleans the parts to be tested before inspection, removing surface oil, cutting fluid residue, and oxide film, thus reducing interference from surface contaminants on component detection. Based on the slender structural characteristics of the parts, this invention uses a combination of axial segmentation and circumferential distribution to set inspection points, and adds inspection points in high-risk, easily deformable areas such as the mounting contact points and the transition arcs at both ends of the rod. This helps to cover potential defect areas caused by local bending deformation or machining deviations, reducing missed defects due to insufficient inspection points.

[0046] By comprehensively applying the above-mentioned technical means, this invention can determine the effective thickness of the laser cladding layer on the hydraulic support column, effectively identify situations such as substrate exposure and component segregation caused by local bending deformation, machining deviation, or fluctuations in laser process parameters, and distinguish between uniform thinning and severe defects. It not only has high accuracy in judgment, but also reduces the false judgment rate and missed detection rate, and provides a basis for subsequent handling, reduces management and control costs, and further ensures the safety and efficiency of downhole mining. Detailed Implementation

[0047] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below through specific embodiments.

[0048] This invention provides a method for detecting and determining the effective thickness of the laser cladding layer on a hydraulic support column, characterized by comprising the following steps:

[0049] S1. Clean the parts to be tested after laser cladding to expose fresh metal surfaces.

[0050] Among them, through cleaning treatment, possible interfering substances such as surface oil stains, cutting fluid residues, and oxide films are removed, enabling subsequent detections to truly reflect the component state of the cladding layer body and avoiding interference from surface contaminants on the detection results.

[0051] S2. According to the specific structural characteristics of the parts to be measured, set multiple detection points.

[0052] Specifically, when setting the detection points, considering the slender structural characteristics of the specific parts and the areas prone to defects, a combination of axial segmentation and circumferential uniform point distribution can be used to set the detection cross-section and detection points, and densify the points in high-risk areas such as the clamping contact part and the transition arcs at both ends of the rod body, which is conducive to comprehensively covering potential defect areas caused by local bending deformation or machining deviation, and avoiding problems such as missed detection of defects due to omission of point layout.

[0053] S3. Use a non-destructive component analyzer to jointly detect the content C1 of the first element and the content C2 of the second element at each detection point. The first element is the characteristic alloy element in the laser cladding material with a significantly higher content than the base material, and the second element is the matrix element in the base material with a significantly higher content than the laser cladding material.

[0054] Among them, the component information of the cladding layer is obtained by simultaneously detecting two types of characteristic elements. The content of the first element in the cladding material is significantly higher than that of the base material, and its content level can reflect the integrity of the main components of the cladding layer and is closely related to the corrosion resistance of the cladding layer; the content of the second element in the base material is significantly higher than that of the cladding material, and its content change can indicate the degree of mixing of the base material into the detection area, or rather, the degree of exposure of the base material.

[0055] S4. According to the joint detection results, judge whether the effective thickness of the laser cladding layer is qualified according to the following rules:

[0056] If C1≥T1 and C2≤T2, it indicates that the main components of the cladding layer in the detection area are complete and the base is not significantly mixed in, and it has a complete corrosion resistance basis, and it is judged that the effective thickness of this point is qualified.

[0057] If C1≥T1 and C2>T2, this combination usually does not occur under normal conditions and may be due to detection interference factors or operation errors. At this time, it is judged that this point is a suspicious point and needs to be rechecked.

[0058] If C1<T1 and C2≤T2, it indicates that the cladding layer has uniform thinning or mild dilution, but the base has not been exposed. Although the thickness is insufficient in this case, it may still have a certain protective ability, and it is judged that there is uniform thinning at this point, and this point is recorded and monitored.

[0059] If C1 < T1 and C2 > T2, it indicates that a large amount of the base material has mixed into the detection area, corresponding to serious defects such as partial wear-through and base exposure. It is determined that the effective thickness at this point is insufficient, and rework or scrapping is required.

[0060] Among them, T1 is the minimum content of the first element required to determine that the corrosion resistance of the laser cladding layer is qualified, and its value is determined according to the original content of the first element in the cladding powder, the allowable dilution rate range of the process, design indicators, statistical values of similar specimens, or historical experience parameters. T2 is the maximum content of the second element allowed to determine that the effective thickness of the laser cladding layer is qualified, and its value is determined according to the content of the second element in the base material, the allowable mixing ratio of the base in the process, design indicators, statistical values of similar specimens, or historical experience parameters.

[0061] In addition, it should be noted that the corrosion resistance of the laser cladding layer not only depends on its geometric thickness but also on the integrity of its chemical composition. When the alloy element content in the cladding layer decreases due to problems such as excessive dilution and segregation, even if the geometric thickness is sufficient, its corrosion resistance will be significantly reduced, and at this time, this part of the cladding layer has "failed" and the effective thickness is unqualified. On the contrary, when the cladding layer is uniformly thinned but the chemical composition remains good, even if the geometric thickness is slightly lower than the design value, its corrosion resistance may still meet the usage requirements, and at this time, it may be considered that its effective thickness is qualified. Therefore, the "effective thickness of the laser cladding layer" referred to in the present invention does not refer to the actual geometric thickness of the cladding layer, and the present invention does not aim to measure the geometric thickness of the cladding layer, but directly determines whether the cladding layer is in an "effective" state through combined composition detection.

[0062] Preferably, in S1, during the cleaning process, an organic solvent is used to clean the detection area of the component to be tested to remove contaminants. Then, a metallographic sandpaper with a particle size of ≥800 mesh is used to polish in a concentric circle pattern in the detection area for 2 - 5 circles to remove the surface oxide film and avoid causing additional damage to the cladding layer. Finally, it is cleaned with an organic solvent and dried with compressed air. The organic solvent is acetone or ethanol.

[0063] Preferably, in S2, the detection points are set as follows: a detection section is set every 200 - 300 mm along the axial direction of the component, and at least 3 detection points are evenly set along the circumferential direction of each detection section.

[0064] Preferably, in step S2, when the diameter of the inspection section exceeds 100mm or the circumference exceeds 400mm, each inspection section has no fewer than 6 circumferential inspection points. Specifically, based on batch or historical production data and finite element analysis data, high-risk areas prone to insufficient thickness and stress concentration zones are statistically analyzed. In high-risk areas and stress concentration zones, at least 2 additional inspection points are added to each inspection section beyond the above. This approach balances the uniformity of inspection with targeted coverage of high-risk areas, improving the defect detection rate and reducing the possibility of missed defects.

[0065] Preferably, in S3, the base material of the hydraulic support is alloy steel, and the laser cladding material is at least one of iron-based alloy powder, nickel-based alloy powder, or cobalt-based alloy powder. The first element is a characteristic alloying element in the laser cladding material with a higher content than that in the base material. The first element is Cr, Ni, W, Co, Mo, or Mn. The second element is a matrix element in the base material with a higher content than that in the laser cladding material. The second element is Fe, Ni, or Co.

[0066] Preferably, when selecting the first element and the second element, the difference between the mass percentage of the first element in the laser cladding material and its mass percentage in the substrate material is not less than 10%; the difference between the mass percentage of the second element in the substrate material and its mass percentage in the laser cladding material is not less than 10%. To ensure the sensitivity and accuracy of the joint detection, the contents of the first element and the second element in the two materials should have a significant difference. If the difference is too small, the compositional change caused by substrate contamination will not be obvious enough, making it susceptible to detection errors and affecting the reliability of the judgment.

[0067] More preferably, when the mass percentage of the first element in both the laser cladding material and the substrate material exceeds 50%, or when it is the element with the highest content in both, the difference in content between the two should be no less than 20%, preferably no less than 30%. When the mass percentage of the second element in both the substrate material and the laser cladding material exceeds 50%, or when it is the element with the highest content in both, the difference in content between the two should be no less than 20%, preferably no less than 30%. Wherein, when the selected element has a high proportion in both materials (e.g., both exceeding 50%) or is a major component, the requirement for content difference should be more stringent, and the difference should be no less than 30%. For example, in the combination of iron-based cladding material and steel substrate, if Fe is selected as the second element, and its content in the substrate is about 97% and its content in the cladding material is 60%-75%, the difference between the two is about 22%-37%, which meets the requirements. However, if the Fe content in the cladding material is too high (e.g., above 80%), the difference will be too small, and the detection sensitivity will decrease. In this case, other elements with more significant differences (such as Cr, Ni, etc.) should be selected as the second element.

[0068] Preferably, an element present in the laser cladding material but completely absent (or present in negligible amounts) in the substrate material can be selected as the first element, and / or an element present in the substrate material but completely absent (or present in negligible amounts) in the laser cladding material can be selected as the second element. For example, when the substrate material is alloy steel and the cladding material is cobalt-based alloy powder, Co can be selected as the first element (the cladding material contains Co while the substrate does not), and Fe can be selected as the second element (the substrate contains Fe while the cladding material has extremely low Fe content). This selection makes the source difference between the two types of elements clearer, and the change in the detection signal more directly reflects the substrate mixing situation, which is conducive to further improving the accuracy of the judgment.

[0069] Preferably, in S3, T1 is determined by one of the following methods:

[0070] Method 1: T1=C 粉末 ×(1-D max ), where C 粉末 D represents the content of the first element in the cladding powder. max This method defines the maximum dilution rate at which the substrate material can be incorporated into the laser cladding layer to ensure its corrosion resistance, thus minimizing the dilution of the cladding layer composition. It is suitable for scenarios where the cladding powder composition is known and there are design dilution rate parameters or historical experience values. The T1 value can be directly obtained through theoretical calculation, making it simple and quick to operate, and suitable for rapidly determining the threshold on the production site. Furthermore, when changing the substrate or laser cladding material, if the composition adjustment is minor (e.g., changing only one auxiliary component), and it does not significantly affect the physical properties of the laser cladding layer or substrate, and the dilution rate parameters do not change significantly, the original D1 value can be directly used. max The value is calculated.

[0071] Method 2: Prepare a series of samples with different laser cladding layer thicknesses (i.e., similar samples with the same material composition and preparation process as the laser cladding layer to be tested, or similar test blocks). Use the same non-destructive component analyzer as S3 to detect the content of the first element. Then, conduct standard salt spray corrosion tests on all samples and record their corrosion rates. The content of the first element corresponding to the sample with a significantly accelerated corrosion rate is determined as T1. In practice, the corrosion rates of samples with different laser cladding layer thicknesses can be recorded and a component content-corrosion rate curve can be fitted. The component content corresponding to the inflection point where the dilution rate significantly increases can be selected as the T1 value. This method is suitable for scenarios where dilution rate design parameters are lacking or where the reliability of theoretical calculation values ​​needs to be verified. By establishing the correspondence between component content and corrosion resistance through experimental means, the T1 value can be directly determined. If the material system to be tested is similar to existing experimental conditions, historical experimental data can be referenced to determine the T1 value, reducing the workload of repeated experiments.

[0072] Method 3: Determine the content of the first element corresponding to the minimum thickness required by the product design when the thickness of the laser cladding layer reaches the minimum thickness required by the product design as T1. In practice, the thickness of the laser cladding layer can be manually adjusted to reach the minimum thickness required by the product design, and the content of the first element at this point can be detected and confirmed as T1. This method is suitable for scenarios with clearly defined design thickness requirements, directly converting the design index into a judgment threshold.

[0073] Preferably, in S3, T2 is determined by one of the following methods:

[0074] Method 1: T2=A 基底 ×R max +A 粉末 ×(1-R max ), where A 基底 The content of the second element in the substrate material, A 粉末 R represents the content of the second element in the cladding powder. max This method defines the maximum substrate incorporation ratio in the laser cladding coating to ensure the effective thickness of the laser cladding layer. It is suitable for scenarios where the substrate material and cladding powder compositions are known, and the maximum substrate incorporation ratio can be determined based on design requirements or empirical data. The T2 value is obtained directly through theoretical calculation. When the substrate material or cladding powder composition is slightly adjusted (e.g., only one non-main material component is changed), if R... max Since the parameters have not changed significantly, the original R can be used directly. max The value is calculated to simplify the operation process.

[0075] Method 2: A series of laser cladding sample blocks with varying remaining thicknesses are prepared. These are then analyzed using the same non-destructive component analyzer as in S3. The remaining thickness at which the content of the second element begins to significantly increase is determined as the minimum effective thickness, and the corresponding second element content is defined as T2. This method is suitable for scenarios lacking mixing ratio design parameters or requiring verification of the reliability of theoretical calculations. It directly establishes the correspondence between remaining thickness and second element content through experimentation, thus determining the T2 value. When the material composition is similar to existing experimental conditions, historical experimental data can be referenced to determine the T2 value, reducing redundant calibration work.

[0076] Method 3: Determine the content of the second element corresponding to the minimum thickness required by the product design when the thickness of the laser cladding layer reaches the minimum thickness required by the product design as T2. In practice, the thickness of the laser cladding layer can be manually increased to the minimum thickness required by the product design, and the content of the second element at this point can be detected and confirmed as T2. This method is suitable for scenarios with clearly defined design thickness requirements, directly converting the design indicators into a component determination threshold.

[0077] Preferably, the standard salt spray corrosion test is performed in accordance with GB / T 10125 standard. The temperature is controlled at 35℃±2℃, the pH value at 6.5-7.2, and the salt spray deposition rate at 1-2 ml / 80cm. 2 The standard parameters for neutral salt spray testing were selected for all parameters. During the test, cladding samples of different thicknesses were placed in a salt spray chamber and continuously sprayed. The corrosion on the sample surface was observed periodically, and the time of corrosion onset and corrosion rate were recorded. The salt spray test time was determined based on the specific corrosion onset time, and the inflection point at which the corrosion rate significantly increased was obtained. In addition, in actual operation, multiple methods can be combined. For example, after calculating the preliminary threshold using method one or method three, the results of method two can be used for verification or correction, thereby obtaining more reliable T1 and T2 values ​​that are more in line with actual working conditions.

[0078] Preferred, D max It ranges from 1% to 10%. R max It is 1%-10%, of which, the above D max and R max The selection of the value range is based on the characteristics of the laser cladding process and the requirements for corrosion resistance. Specific parameters can be determined according to design specifications, process requirements, statistical values ​​of relevant samples, or historical experience parameters. During laser cladding, a certain degree of dilution is inevitable to ensure the metallurgical bond between the cladding layer and the substrate. However, excessive dilution will lead to over-dilution of alloying elements, significantly reducing the corrosion resistance of the cladding layer. Typically, when the dilution rate exceeds 10%, the content of corrosion-resistant elements such as Cr in the cladding layer decreases significantly, and the corrosion resistance begins to show a marked decline. Conversely, when the dilution rate is below 1%, the bonding strength between the cladding layer and the substrate may be insufficient, and the requirements for process control become too stringent, increasing costs. The specific maximum dilution rate can be adjusted according to the acceptable range of the actual process.

[0079] The maximum substrate mixing ratio is defined as the range of values ​​for the maximum dilution rate of the substrate material to the laser cladding layer, permissible to ensure its corrosion resistance. It should be noted that the maximum dilution rate D in T1 determination... max The maximum substrate mixing ratio R determined by T2 max In essence, R and R are the same parameter, both referring to the maximum allowable proportion of substrate material to be incorporated to ensure the effective thickness of the cladding layer is acceptable. They are results of the same physical process observed from different perspectives. max Desirable to D max Same numerical range.

[0080] Preferably, in step S3, if the sample block is to be polished, metallographic sandpaper or a grinding machine can be used to polish the surface of the cladding layer of the sample block in stages: first, use coarse sandpaper (e.g., 240-400 grit) to quickly remove excess material to near the target thickness, then use fine sandpaper (e.g., 800-1200 grit) for fine polishing, and finally use a polishing cloth for mechanical polishing to obtain a test surface with a surface finish Ra≤0.2μm. During the polishing process, the feed speed and pressure should be controlled to avoid oxidation or changes in composition of the cladding layer surface due to overheating during grinding.

[0081] After each grinding to the target thickness, ultrasonic cleaning with anhydrous ethanol for 5-10 minutes is performed to remove surface debris and contaminants. Then, the sample is analyzed using the same non-destructive component analyzer as S3. The sample prepared in this manner has a surface condition similar to that of the tested component after S1 cleaning, ensuring consistency between calibration and actual testing conditions, which improves the accuracy of T1 and T2 calibrations.

[0082] Preferably, in S3, when the laser cladding material is a Cr-containing iron-based alloy powder and the base material is alloy steel, the first element is Cr and the second element is Fe.

[0083] When the laser cladding material is an iron-based alloy powder, Cr generally serves as the main alloying element and also provides corrosion protection. Selecting the corrosion-resistant element as the primary element in the laser cladding material allows for a direct reflection of changes in the corrosion resistance of the laser cladding coating through variations in its content. In iron-based alloy powders, the Cr content is typically 15%-25%, far exceeding the Cr content in alloy steel substrates (approximately 0.1%-0.3%), making it a characteristic element that distinguishes the cladding layer from the substrate.

[0084] Preferably, in S3, the non-destructive component analyzer is a direct-reading spectrometer or an X-ray fluorescence spectrometer, preferably an X-ray fluorescence spectrometer, to ensure that the detection process is non-destructive. Handheld, benchtop, or other types can be selected according to the actual situation. Each detection point should be repeated at least 3 times, and the average value should be taken as the final data for that point. Taking the average value through multiple detections helps to reduce the random error of a single detection and improve the stability of the data.

[0085] It should be noted that although non-destructive component analyzers (such as X-ray fluorescence spectrometers) have a certain signal penetration depth, the detection results reflect the weighted average composition of the material within that penetration depth range, rather than the composition of the outermost single atomic layer. Different types of instruments may have different penetration depths, and even the same instrument may have different penetration depths for different elements or different substrates. However, this does not affect the normal detection capabilities of this invention. In actual testing, as long as the same model of instrument is used and the testing is conducted under the same conditions, the detection results at different locations are comparable. Furthermore, the T1 and T2 thresholds themselves are threshold parameters reflecting the mixing ratio of the cladding layer and the substrate. When the thickness of the laser cladding layer is within the normal design range, the detection area always includes the main body of the cladding layer. Even if some substrate signals are mixed in due to the penetration depth, the impact is systematic and predictable. Of course, for the sake of accuracy and portability, in actual operation, especially for large-scale testing, those skilled in the art can select appropriate testing equipment or perform necessary calibrations on the detection results based on the specific model of the instrument used and its penetration depth characteristics, combined with the designed thickness range of the cladding layer, etc., but this does not require changing the judgment logic of this invention.

[0086] Preferably, in S4, for points determined to have uniform thinning, if multiple consecutive points, such as 3-4 consecutive points or more than 10% of the points on the same workpiece, show this situation, a process warning is triggered, indicating that there is an abnormality in the laser cladding process or machining.

[0087] It should be noted that while a single uniform thinning point may be caused by localized, accidental factors, the appearance of consecutive or multiple points indicates a systemic problem, likely stemming from fluctuations in laser cladding process parameters or machining deviations. This invention, by setting early warning rules, can promptly prompt process adjustments when the problem is still in its minor stages, preventing it from developing into serious defects such as substrate exposure. After the warning is triggered, operators can check whether parameters such as laser power, scanning speed, and powder feed are normal, or inspect for deviations in machining fixture positioning, reducing defects at their source.

[0088] For locations deemed suspicious, a different non-destructive component analyzer was used for verification testing to confirm the presence of defects. The criteria for suspicious locations (C1≥T1 and C2>T2) are physically an abnormal combination. While the first element content meeting the standard indicates the main body of the tested area should be the cladding layer, the abnormally high second element content indicates the presence of substrate components. This contradictory state is usually difficult to explain directly by a single component test. It may stem from interference factors in the testing process, such as surface contamination, instrument channel drift, or operational deviations, or from severe imaging deviations during the cladding process, such as uneven raw material distribution or segregation. Directly relying on this result for judgment may lead to misjudgment. Therefore, cross-validation of this location using independent testing methods is necessary to confirm its true condition.

[0089] Preferably, for locations deemed suspicious, active laser thermal imaging (ALTI) is used for verification. The presence of defects is confirmed by analyzing the thermal response characteristics of the detected locations. ATI applies a short-duration laser pulse to the detected location, using an infrared thermal imager to record the change in the surface temperature field over time. The presence of internal material defects is determined by analyzing thermal response characteristics (such as heating rate, cooling curve, and thermal wave phase). This method differs significantly from component analysis, and the results are independent, effectively avoiding misjudgments caused by interference from component analysis. Furthermore, ATI is sensitive to the interface between the cladding layer and the substrate. When structural defects such as substrate exposure, cladding layer peeling, or severe thinning exist, the thermal response characteristics change significantly, showing a marked difference from normal areas, facilitating rapid defect identification. In addition, this method is non-contact, does not damage the workpiece, and is fast, making it suitable as a verification method for suspicious locations.

[0090] If thermal imaging confirms a structural defect, it should be treated as insufficient effective thickness. If no abnormality is found during the review, it may be due to detection interference. The sample should be cleaned again and the composition should be tested again for confirmation. If it is still detected as a suspicious point, it indicates a problem in the laser cladding process. The abnormal point can be re-examined as needed, or it can be ignored.

[0091] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the invention to those skilled in the art.

[0092] Example 1

[0093] This embodiment provides a method for detecting and determining the effective thickness of the laser cladding layer on a hydraulic support column. The specific steps are as follows:

[0094] Raw material preparation: A piston rod of a certain type of hydraulic support column was selected as the component to be tested. The base material was 27SiMn steel, with a chromium content of approximately 0.15% and an iron content of approximately 97%. The piston rod underwent laser cladding treatment. The cladding powder was an iron-based stainless steel alloy powder, with a chromium content ≥18% and an iron content of 60%. The laser cladding process parameters were: laser power 3kW, scanning speed 10mm / s, and powder feed rate 20g / min. After cladding, the component was machined according to the design dimensions. The designed thickness of the laser cladding coating was 0.07±0.02mm.

[0095] S1. Cleaning treatment:

[0096] First, wipe the piston rod machining area with acetone-soaked degreased cotton to remove surface oil and cutting fluid residue. After the acetone evaporates, use 800-grit metallographic sandpaper to polish the inspection area in concentric circles for 3 circles. Finally, clean with anhydrous ethanol and dry with compressed air.

[0097] S2. Set the detection points:

[0098] The piston rod is 2.5m long and 120mm in diameter. A detection section is set every 250mm along the axial direction, for a total of 9 sections; each section has 4 detection points evenly distributed circumferentially, for a total of 36 points. In addition, based on historical production data, 2 extra detection points are added at each end of the mounting contact area (200mm from the end), for a total of 40 detection points.

[0099] S3, Combined component analysis:

[0100] A portable direct-reading spectrometer was used to simultaneously detect the chromium content (C1) and iron content (C2) at each detection point. Each point was detected three times, and the arithmetic mean was taken as the final data for that point, resulting in the detection results for 40 points (not listed in full here to save space).

[0101] S4. Determine the effective thickness of the cladding layer:

[0102] Set T1 = 17.5% (the minimum chromium content required for a passing grade) and T2 = 62.0% (the maximum allowable iron content for a passing grade). Judge each of the 40 points individually according to the following rules:

[0103] If C1 ≥ 17.5% and C2 ≤ 62.0%, the effective thickness at this point is deemed acceptable.

[0104] If C1 ≥ 17.5% and C2 > 62.0%, it is considered a suspicious point and needs to be reviewed.

[0105] If C1 < 17.5% and C2 ≤ 62.0%, uniform thinning is determined to exist; record and monitor.

[0106] If C1 < 17.5% and C2 > 62.0%, the effective thickness is deemed insufficient, and rework or scrapping is required.

[0107] The judgment result is:

[0108] 35 points satisfy C1≥17.5% and C2≤62.0%, and are therefore deemed qualified;

[0109] Two points satisfy C1 < 17.5% and C2 ≤ 62.0% (C1 is 17.2% and 17.3% respectively, and C2 is 61.2% and 61.5% respectively), and are judged to be uniformly thinned;

[0110] Two points satisfy C1 < 17.5% and C2 > 62.0% (C1 is 17.1% and 17.0% respectively, and C2 is 64.5% and 65.8% respectively), indicating insufficient effective thickness;

[0111] If a suspicious case is found where C1≥17.5% and C2>62.0% (C1=17.8%, C2=63.2%), a review will be conducted.

[0112] For each of the 40 points mentioned above, wire cutting samples were taken, and the actual remaining thickness of the cladding layer at each point was measured using a metallographic microscope. The results are as follows:

[0113] The measured thickness at the 35 qualified points ranged from 0.052 to 0.085 mm, all of which met the minimum design requirement of 0.05 mm.

[0114] The measured thicknesses at the two uniformly thinned points were 0.048 mm and 0.047 mm, respectively, slightly less than 0.05 mm but without penetrating the substrate;

[0115] Of the two locations with insufficient effective thickness, one was a localized wear-through (measured thickness 0.028 mm, substrate exposed), and the other was thinned and had structural defects (measured thickness 0.042 mm, loose structure, possibly caused by segregation or fluctuations in process parameters, etc.). The effective thickness of both locations was unqualified.

[0116] The measured thickness of one suspicious point was 0.062 mm, which is within the acceptable geometric thickness. However, metallographic observation revealed obvious microcracks in the area and uneven distribution of alloying elements in the cladding layer, which may be due to compositional segregation. This may reduce the corrosion resistance and result in insufficient effective thickness.

[0117] Based on the above test results, it can be found that the judgment results of this method at 40 points are completely consistent with the metallographic measurement results: the measured thickness of qualified points all meet the standard; the measured thickness of uniformly thinned points is slightly lower than the standard but not worn through; the measured thickness of insufficient points is seriously excessive, the substrate is exposed, and there may be process problems. The judgment accuracy is high, and it can accurately distinguish between uniform thinning, local wear-through, and other types of insufficient effective thickness problems.

[0118] Example 2

[0119] This embodiment provides a method for detecting and determining the effective thickness of the laser cladding layer on a hydraulic support column. The difference from Embodiment 1 is that in S1, degreased cotton is soaked in a 5% dilute hydrochloric acid solution and wiped on the detection area for 15 seconds to dissolve the surface oxide film; then it is immediately rinsed with plenty of water, dehydrated with anhydrous ethanol, and finally dried with compressed air. The remaining steps are the same as in Embodiment 1.

[0120] Following the same method as in Example 1, destructive testing was performed on 40 points on the same piston rod, and the results are as follows:

[0121] Of the 36 sampling points, C1 was between 17.5% and 18.2%, and C2 was between 60.5% and 61.5%, which was deemed acceptable; the actual measured thickness was 0.051-0.084 mm, all meeting the standards.

[0122] At two measurement points, C1 = 17.2% and 17.3%, and C2 = 61.8% and 62.0%, indicating uniform thinning; the actual measured thicknesses were 0.047mm and 0.048mm, slightly below the standard.

[0123] At two points, C1 = 17.0% and 17.1%, and C2 = 64.0% and 65.2%, the effective thickness was determined to be insufficient; the actual measured thicknesses were 0.031 mm and 0.028 mm, indicating that the substrate was exposed.

[0124] Example 3

[0125] This embodiment provides a method for detecting and determining the effective thickness of the laser cladding layer on a hydraulic support column. The difference from Embodiment 1 is that in S2, there is a cross section every 250mm along the axial direction, with 4 points evenly distributed around the circumference of each cross section, for a total of 36 points, without adding any additional high-risk area points.

[0126] Destructive testing was performed at 36 points on the same piston rod, and the results are as follows:

[0127] Of the 34 sampling points, C1 was between 17.5% and 18.3%, and C2 was between 60.2% and 61.5%, which was deemed acceptable; the actual measured thickness was 0.051-0.085 mm, all meeting the standards.

[0128] At one point, C1 = 17.3% and C2 = 61.8%, judged as uniform thinning; the measured thickness is 0.048 mm;

[0129] At one point, C1 = 17.2% and C2 = 62.0%, judged as uniform thinning; the measured thickness is 0.047 mm.

[0130] Afterwards, the clamping contact areas at both ends (not within the 36 - point range) were retested, and 2 defect points were found: C1 = 17.0%, 65.0% and C1 = 17.1%, C2 = 64.2%. The measured thicknesses are only 0.029 mm and 0.031 mm, and the substrate is exposed. Since no detection points were set, these two thickness - insufficient defects were not detected.

[0131] Comparative Example 1

[0132] This comparative example provides a method for detecting and judging the effective thickness of the laser cladding layer of a hydraulic support column. The difference from Example 1 is that the original diameter of the piston rod before laser cladding is measured, the final diameter after machining and cladding is recorded, and the difference between the two is calculated as the thickness of the cladding layer. According to the conventional method, only 3 cross - sections at both ends and in the middle are measured, and the average value is taken as the thickness of the whole rod. The calculated average thickness is 0.08 mm, and it is judged that the whole piston rod is qualified.

[0133] Metallographic tests were carried out on all 40 points of this piston rod (the same as in Example 1). The results show that there are 2 points with thicknesses of only 0.032 mm and 0.028 mm, 2 points with thicknesses of 0.047 mm and 0.048 mm (slightly lower than the standard), and the remaining 36 points meet the standard. The traditional method judges the workpiece with serious local defects as qualified as a whole, resulting in serious missed detections (for 2 worn - through defects) and misjudgments (judging unqualified products with serious defects as qualified products).

[0134] Comparative Example 2

[0135] This comparative example provides a method for detecting and judging the effective thickness of the laser cladding layer of a hydraulic support column. The difference from Example 1 is that in S3, only the chromium content at each point is detected, and the iron content is not detected. In S4, if C1≥17.5%, it is judged as qualified, otherwise it is judged as unqualified.

[0136] Destructive verification was carried out on 40 points of the same piston rod, and the results are as follows:

[0137] For 36 points, C1≥17.5%, judged as qualified; among them, the measured thicknesses of 34 points are 0.051 - 0.085 mm, qualified. The measured thicknesses of 2 points are 0.047 mm and 0.048 mm, showing uniform thinning and slightly lower than the standard.

[0138] Four locations had a C1 value less than 17.5%, which was deemed unqualified. Among them, two locations with measured thicknesses of 0.030 mm and 0.027 mm were also deemed unqualified. Two locations with measured thicknesses of 0.047 mm and 0.048 mm, which indicated uniform thinning, were also deemed unqualified.

[0139] Comparative Example 3

[0140] This comparative example provides a method for detecting and determining the effective thickness of the laser cladding layer on a hydraulic support column. The difference from Example 1 is that the same substrate (27SiMn), cladding powder, and process parameters as in Example 1 are used to perform cladding on a single substrate sample. The sample is cut into 17 blocks by wire cutting, and the cladding layer is ground to obtain standard samples with thicknesses of 0mm, 0.01mm, 0.02mm, 0.03mm, 0.04mm, 0.05mm, 0.055mm, 0.06mm, 0.065mm, 0.07mm, 0.075mm, 0.08mm, 0.085mm, 0.09mm, 0.1mm, 0.11mm, and 0.12mm, respectively. The thickness is measured using a metallographic microscope to ensure accuracy. Then, a portable spectrometer is used to detect the chromium content on the surface of each standard sample, and a "chromium content-thickness" relationship curve is fitted. The chromium content of the 40 points detected in S3 of Example 1 was compared with the "chromium content-thickness" relationship curve. The predicted thickness of each point was obtained through the "chromium content-thickness" relationship curve: 36 points ≥ 0.05 mm, which was qualified; 4 points < 0.05 mm (corresponding to the 4 points with lower C1).

[0141] However, among the 36 qualified points: 35 were normal points with actual thickness of 0.052-0.085mm, but there was one suspicious point (C1=17.8%) with actual component segregation and microcracks, and the effective thickness was not qualified. This hidden defect was missed. Among the unqualified points, there were two points with uniform thinning, one point with wear through, and one point with structural defects and severe component segregation, which could not be effectively distinguished.

[0142] Through the test results and destructive testing results of the above embodiments and comparative examples, it can be found that Example 1, by adopting the complete technical solution of the present invention and through the joint detection and rules of Cr+Fe, shows excellent detection accuracy in the full inspection and testing of 40 detection points. Compared with the metallographic measurement results, its judgment results are highly consistent with the actual situation. It can accurately distinguish between two different types of insufficient thickness problems, namely uniform thinning and local wear-through, which is significantly better than the existing detection methods.

[0143] In Example 2, dilute hydrochloric acid chemical cleaning was used instead of acetone + sandpaper polishing in the S1 cleaning process, while the remaining steps were exactly the same as in Example 1. The test results showed that the judgment results at 40 points still maintained good agreement with the metallographic measurement results, indicating that the method of the present invention has a certain degree of adaptability, and different cleaning treatment methods do not significantly affect the core judgment logic.

[0144] In Example 3, only a uniform distribution of detection points was used in S2, without adding additional detection points in high-risk areas. The detection results showed that the 36 points within the uniform distribution range were accurately identified. However, due to the omission of two defect points in the mounting contact area, the overall defect detection rate decreased, indicating that denser distribution of detection points in high-risk areas is more effective in identifying local defects.

[0145] Comparative Example 1 uses the traditional dimensional difference method, which calculates the average thickness solely based on the dimensional difference before and after cladding. This method is completely unable to identify local wear-through defects, resulting in workpieces with serious defects being judged as qualified as a whole, leading to an extremely high risk of missed inspections.

[0146] Comparative Example 2 uses a single Cr element detection method. Although it can detect locations with low Cr content, it cannot distinguish between uniform thinning and local wear-through, resulting in two types of errors: some uniformly thinned locations are misjudged as unqualified, and some wear-through locations are judged as unqualified but the nature of the problem cannot be diagnosed, affecting subsequent handling decisions. If rework is carried out according to its plan, it will cause a lot of waste.

[0147] Comparative Example 3 also used a single Cr element for testing. Although the curve fitting method improved the accuracy of the test results to some extent, the "Cr content-thickness" curve established based on the uniformly thinned sample block could not identify points with normal Cr content but hidden defects such as microcracks and segregation. Furthermore, for unqualified points with low Cr content, it could not distinguish between defects of different natures such as uniform thinning, wear-through, and severe component failure, and categorized all unqualified points as "insufficient thickness", which affected subsequent disposal decisions.

[0148] In summary, this invention can effectively identify local wear-through defects caused by substrate exposure, and distinguish between different situations such as uniform thinning. It also has good universality and reliability, and can solve the technical problems of poor detection accuracy and the easy failure to detect local defects in existing laser cladding nondestructive testing technologies.

[0149] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for detecting and determining the effective thickness of the laser cladding layer on a hydraulic support column, characterized in that, It includes the following steps: S1. Clean the parts to be tested after laser cladding to expose the fresh metal surface; S2. Set multiple detection points according to the specific structural characteristics of the parts to be tested; S3. Use a non-destructive composition analyzer to jointly detect the content C1 of the first element and the content C2 of the second element at each of the detection points; the first element is the characteristic alloy element in the laser cladding material with a significantly higher content than the substrate material, and the second element is the matrix element in the substrate material with a significantly higher content than the laser cladding material; S4. According to the results of the joint detection, judge whether the effective thickness of the laser cladding layer is qualified according to the following rules: If C1≥T1 and C2≤T2, it is determined that the effective thickness of this point is qualified; If C1≥T1 and C2>T2, it is determined that this point is a suspicious point and needs to be rechecked; If C1<T1 and C2≤T2, it is determined that there is uniform thinning at this point, record and monitor this point; If C1<T1 and C2>T2, it is determined that the effective thickness of this point is insufficient and rework or scrapping is required; Among them, T1 is the minimum content of the first element required to judge the corrosion resistance of the laser cladding layer to be qualified, and its value is determined according to the original content of the first element in the cladding powder, the process-allowed dilution rate range, design indicators, statistical values of similar specimens or historical experience parameters; T2 is the maximum content of the second element allowed to judge the effective thickness of the laser cladding layer to be qualified, and its value is determined according to the content of the second element in the substrate material, the process-allowed substrate mixing ratio, design indicators, statistical values of similar specimens or historical experience parameters.

2. The detection and determination method as described in claim 1, characterized in that, In S1, during the cleaning process, use an organic solvent to clean the area to be tested of the parts to be tested to remove pollutants; then use metallographic sandpaper with a particle size of ≥800 mesh to polish in a concentric circle for 2-5 circles in the detection area to remove the surface oxide film; finally, clean with an organic solvent and blow dry with compressed air; the organic solvent is acetone or ethanol.

3. The detection and determination method as described in claim 1, characterized in that, In S2, set the detection points according to the following method: set a detection section every 200-300 mm along the axial direction of the part, and evenly set at least 3 detection points along the circumferential direction of each detection section.

4. The detection and determination method as described in claim 1, characterized in that, In S2, when the diameter of the detection section exceeds 100 mm or the circumference exceeds 400 mm, the number of circumferential detection points for each detection section is not less than 6; among them, according to the data of the same batch or historical production and the finite element analysis data, statistically analyze the high-risk areas and stress concentration areas where the thickness is likely to be insufficient; add at least 2 detection points to each detection section in the high-risk areas and stress concentration areas on the above basis.

5. The detection and judgment method as described in claim 1, characterized in that, In S3, the substrate material of the hydraulic support is alloy steel, the laser cladding material is at least one of iron-based alloy powder, nickel-based alloy powder or cobalt-based alloy powder, the first element is the characteristic alloy element in the laser cladding material with a higher content than the substrate material, and the first element is Cr, Ni, W, Co, Mo or Mn; the second element is the matrix element in the substrate material with a higher content than the laser cladding material, and the second element is Fe, Ni or Co.

6. The detection and determination method as described in claim 1, characterized in that, In S3, T1 is determined by one of the following methods: Method 1: T1=C 粉末 ×(1-D max ), where C 粉末 D represents the content of the first element in the cladding powder. max The maximum dilution rate at which the substrate material is mixed into the laser cladding layer to ensure its corrosion resistance, resulting in dilution of the cladding layer composition; Method 2: Grind a series of samples with different laser cladding layer thicknesses, use the same non-destructive component analyzer as S3 to detect the content of the first element, then conduct a standard salt spray corrosion test on all samples and record their corrosion rate. The content of the first element corresponding to the sample with a significantly accelerated corrosion rate is determined as T1. Method 3: When the thickness of the laser cladding layer reaches the minimum thickness required by the product design, the content of the first element is determined as T1.

7. The detection and determination method as described in claim 6, characterized in that, In S3, when the laser cladding material is a Cr-containing iron-based alloy powder and the base material is alloy steel, the first element is Cr, and the D... max The value is determined based on design parameters, process requirements, statistical values ​​of similar samples, or historical experience parameters, and its range is 1%-10%.

8. The detection and judgment method as described in claim 1, characterized in that, In S3, T2 is determined by one of the following methods: Method 1: T2=A 基底 ×R max +A 粉末 ×(1-R max ), where A 基底 The content of the second element in the substrate material, A 粉末 R represents the content of the second element in the cladding powder. max The maximum substrate mixing ratio allowed in the laser cladding coating to ensure the effective thickness of the laser cladding layer; Method 2: Grind a series of laser cladding layer samples with different remaining thicknesses, and use the same non-destructive component analyzer as S3 to detect them. Determine the remaining thickness corresponding to when the content of the second element begins to increase significantly as the minimum effective thickness, and determine the content of the second element corresponding to the minimum effective thickness as T2. Method 3: The content of the second element corresponding to the minimum thickness required by the product design when the thickness of the laser cladding layer reaches the minimum thickness is determined as T2.

9. The detection and determination method as described in claim 8, characterized in that, In S3, when the laser cladding material is iron-based alloy powder and the substrate material is alloy steel, the second element is Fe, and the R... max The value is determined based on design specifications, process requirements, statistical values ​​of relevant samples, or historical experience parameters, and its range is 1%-10%. The maximum substrate mixing ratio range is equal to the range of the maximum dilution rate of the substrate material to the laser cladding layer that is allowed to ensure the corrosion resistance of the laser cladding layer.

10. The detection and determination method as described in claim 1, characterized in that, In S3, the non-destructive component analyzer is a direct-reading spectrometer or an X-ray fluorescence spectrometer; each detection point is repeated at least 3 times, and the average value is taken as the final data for that point; In S4, if multiple points are identified as having uniform thinning, or if this occurs in more than 10% of the points on the same workpiece, a process warning is triggered, indicating an abnormality in the laser cladding process or machining. For points identified as suspicious, a non-destructive component analyzer is replaced or other detection methods are used to re-test them to confirm whether there are any defects.