Method for quickly distinguishing and processing responsibility attribution of round steel and wire rod post-sale quality anomaly

Abstract

The present application relates to a kind of round steel and wire rod post-sale quality abnormality responsibility attribution quick discrimination and processing method, method includes: quickly identifying obvious raw material defects;Inviting customers to participate throughout, collect defect appearance, processing technology and on-site test information;Contrast the five-level logic discrimination of disclosed feature album;According to weight calculation responsibility probability, output A, B or C class conclusion, and give corresponding processing method;If customer does not recognize, start internal quick review and third-party reinspection grading solution mechanism.The present application will convert the responsibility discrimination of personal experience into regularized, repeatable method, ensure public trust through customer participation verification and grading dispute resolution, while maintaining customer relationship with service-oriented processing method, for general problem, can complete on-site discrimination or decision processing direction within 30 minutes, greatly improve the efficiency of post-sale dispute handling.

Description

Technical Field

[0001] This invention relates to the field of metallurgical product quality inspection and after-sales technical services, and in particular to a method for rapid on-site determination of responsibility for quality abnormalities such as surface cracks, scratches, processing cracks, and folds that occur in round steel and wire rod metallurgical products during customer use, as well as a method for handling and classifying dispute resolution based on the determination results. Background Technology

[0002] Round steel bars and wire rods are the two main product categories in the metallurgical industry, widely used in fastener manufacturing, cold heading, drawing, and machining of mechanical parts. During customer use, surface cracks, scratches, and quality abnormalities such as cracking and folding during processing frequently occur. When these problems arise, quality disputes often arise between customers and metallurgical companies. The core issue is whether the defects are inherent in the raw materials or generated during the customer's processing.

[0003] In existing technologies, methods for handling quality objections related to steel products mainly fall into the following categories: The first category is quality objection analysis methods based on big data platforms and knowledge graphs. For example, a method and related equipment for analyzing quality objections in steel products (application number: CN202510572302.4) acquires multi-source heterogeneous data on steel products, constructs a quality knowledge graph based on a big data platform, determines the actual values ​​of process parameters corresponding to the target quality objection type based on the quality knowledge graph, and compares them with internal design standard values. This method relies on the enterprise's internal big data platform and knowledge graph system, requiring data analysis to be completed within the enterprise. It cannot be quickly executed at the customer's site, and its analysis object is the comparison of process parameters with design standards, not directly determining responsibility for the defects themselves.

[0004] The second category is testing and analysis methods based on online inspection requests. For example, existing technologies have proposed a method and system for requesting and analyzing quality objections to steel products. After a user submits an electronic objection letter to the steel mill, the objection information is connected to the quality system through the sales system, and then an online inspection request is initiated through the quality system. This method is essentially an information-based transformation of the existing quality objection handling process. The entire process still relies on laboratory testing and analysis, which is time-consuming and cannot achieve rapid on-site identification.

[0005] The third category is traditional methods based on case analysis and failure analysis. In metallurgical industry practice, after-sales personnel typically rely on personal experience to identify defects and determine responsibility, or send samples back to the laboratory for metallographic analysis, energy dispersive spectroscopy, and other tests. Although textbooks and industry literature such as "Analysis and Countermeasures for Metallurgical Defects in Iron and Steel Products" record the characteristics and causes of various metallurgical defects, this knowledge is scattered across different chapters and examples and has not been systematically organized into a rule-based method for the binary discrimination problem of raw material causes and processing causes, nor has it provided an operational procedure that can be quickly implemented at the customer's site. Existing technologies also include research on the identification and prevention of common crack types in metal parts, summarizing and classifying the characteristic morphologies of raw material cracks, quenching cracks, etc., but these are also limited to the classification and identification of the defects themselves, without involving the determination of responsibility and subsequent handling methods.

[0006] Therefore, it is evident that the existing technology has the following shortcomings: (1) Reliance on laboratory analysis: Existing methods require samples to be sent back to the laboratory for metallographic examination, energy dispersive spectroscopy and other tests, which usually takes several days or even weeks, resulting in high costs and making it impossible to quickly determine responsibility at the customer's site.

[0007] (2) Reliance on personal experience: There is a lack of systematic judgment rules for raw material problems and processing problems in the industry. The judgment ability of after-sales personnel is highly dependent on personal experience accumulation, which is difficult to replicate and quantify. Different personnel may draw different conclusions about the same defect.

[0008] (3) Lack of customer participation verification mechanism: The existing method is to conduct testing and judgment unilaterally by the manufacturer. It is difficult for customers to participate in the verification process, and the credibility of the judgment results is insufficient, which can easily lead to disputes.

[0009] (4) Diagnosis without solutions: Existing technology only addresses what the problem or defect is and how it is caused, without providing solutions for what to do next. After-sales personnel still need to develop a separate solution after reaching a conclusion. Summary of the Invention

[0010] The technical problem this invention aims to solve is to provide a method for rapidly determining and handling responsibility for after-sales quality abnormalities in round steel and wire rod. This method can output a preliminary conclusion on the responsibility for quality abnormalities within 30 minutes at the customer's site through standardized observation, testing, and logical comparison, and output corresponding handling methods based on the conclusion. At the same time, the credibility of the results is ensured through a customer participation verification mechanism, and efficiency and authority are balanced through a tiered dispute resolution mechanism, thereby quickly resolving quality disputes and maintaining customer relationships.

[0011] The technical solution adopted by this invention to solve its technical problem is: a method for rapid determination and handling of responsibility for abnormal after-sales quality of round steel and wire rod, including the following steps: S1. Conduct on-site visual inspection of round steel or wire rod products. If any obvious raw material defect is found, such as bent steel, scratches on the surface of the raw material, or cracks on the surface of the raw material, the conclusion of A0 or A1 will be directly output. S2. Invite customer representatives to participate throughout the process, collect information on defect appearance features and customer processing technology under the customer's witness, and conduct on-site rapid testing. All test results shall be jointly recorded and signed by both parties for confirmation. S3. Compare the information collected in step S2 with the pre-constructed typical defect feature library of raw materials and typical defect feature library of processing. The feature library is publicly available at the customer site in the form of a standard atlas for both parties to review and compare. S4. Perform step-by-step judgment according to the five-level judgment logic and record the result of each level. The five-level judgment logic includes defect morphology judgment, oxidation and decarburization judgment, work hardening degree judgment, inclusion judgment, customer processing process rationality and stress correlation judgment. The judgment result of each level is divided into three types: raw material-oriented, processing-oriented, and neutral. S5. Based on the five-level discrimination results, calculate the probability of responsibility attribution according to the preset weights, and output the three-level discrimination results and corresponding processing methods according to the probability values. S6. If the customer does not accept the on-site assessment results, a tiered dispute resolution mechanism will be initiated, including a first-level internal rapid review and a second-level third-party re-inspection.

[0012] Furthermore, the weight allocation of each level in the five-level discrimination logic of the present invention is as follows: defect morphology discrimination weight 35%, oxidation and decarburization discrimination weight 20%, work hardening degree discrimination weight 15%, inclusion discrimination weight 10%, and process rationality and stress correlation discrimination weight 20%.

[0013] Furthermore, the work hardening degree determination method described in this invention specifically involves: measuring the hardness values ​​of the crack edge region and the matrix region far from the crack, and calculating the hardness increase ratio ΔH = (H... 裂纹边缘— H 基体 ) / H 基体 ×100%; if ΔH≥20%, it indicates a processing defect; if ΔH<10%, it indicates a raw material defect; if 10%≤ΔH<20%, ​​it is considered neutral.

[0014] Furthermore, the three-level determination result described in this invention is as follows: Category A: P 原材料 For ≥80%, the handling methods include explaining the basis to the customer, proactively replenishing materials or providing compensation, and informing them of the corrective measures. Category B: P 加工 For ≥70%, the handling methods include tactful explanation, free dispatch of personnel to assist in inspecting the process / mold / lubrication, and providing process optimization suggestions; Category C: Other situations. Handling methods include providing insufficient information, suggesting that both parties jointly take samples for third-party testing, guiding the customer to temporarily adjust the process, and handling it as Category A or Category B based on the analysis results.

[0015] Furthermore, the typical raw material defect feature library of the present invention includes typical features of subsurface cracks in continuously cast billets, rolling folds, internal shrinkage cavities / porosity, and non-metallic inclusions; the typical processing defect feature library includes typical features of drawing cracks, cold heading cracks, bending cracks, processing folds, and heat treatment cracks.

[0016] Furthermore, the customer processing process rationality and stress correlation judgment in the fifth level of judgment described in this invention includes three sub-items: process parameter rationality judgment, mold and lubrication status judgment, and defect location and stress direction correlation judgment, and the final direction is determined by majority voting principle.

[0017] Furthermore, the criteria for judging the rationality of the process parameters described in this invention include: a single-pass reduction rate of >25% or a total reduction rate of >80% is unreasonable; cold heading deformation > the material's recommended value is unreasonable; bending radius < the material's minimum bending radius is unreasonable; and heat treatment temperature or cooling rate deviating from the process specifications is unreasonable.

[0018] Furthermore, in the tiered dispute resolution mechanism described in this invention, the first level of internal rapid review includes: on-site data upload for remote consultation with an expert group, communication between the manufacturer's experts and the customer, and on-site retesting when necessary, with all costs borne by the manufacturer; the second level of third-party re-inspection includes: joint sampling and sealing by both parties, sending to a third-party testing institution recognized by both parties, using the third-party report as the final basis, and bearing the costs according to the attribution of responsibility.

[0019] The beneficial effect of this invention is that it solves the defects existing in the prior art. 1. This invention systematically organizes various defect knowledge scattered in metallurgical textbooks and industry literature into two opposing feature libraries: a raw material typical defect feature library and a processing typical defect feature library. Furthermore, it refines this into a five-level progressive logic and a weighted probability model. Different after-sales personnel operating according to the same set of rules can arrive at consistent conclusions, fundamentally eliminating the subjectivity of judgment caused by differences in individual experience, and providing a standardized and replicable technical foundation for determining responsibility attribution.

[0020] 2. This invention utilizes a rapid screening mechanism (directly identifying obvious raw material defects) and a rapid on-site judgment process. For common problems, on-site judgment or a decision on the handling direction can be completed within 30 minutes. Compared to traditional laboratory analysis methods (which typically require several days or even weeks), the time is reduced by more than 90%. This efficiency improvement is achieved by transforming defect analysis (such as decarburization detection, hardness measurement, and inclusion observation), which could originally only be performed in the laboratory, into rapid on-site detection using portable equipment, combined with structured judgment logic.

[0021] 3. This invention requires customer representatives to participate in the entire information collection, testing, and judgment process. All test results are jointly recorded and signed by both parties. The feature library is publicly available at the customer's site in the form of a standard catalog for both parties to compare. The five-level judgment is jointly confirmed by both parties. These mechanisms make the judgment process completely transparent and verifiable, allowing customers to witness every judgment step, greatly improving the credibility of the judgment results and customer acceptance.

[0022] 4. This invention not only outputs the conclusion of liability attribution (Class A / Class B / Class C), but also provides clear handling methods for each type of conclusion, including specific measures such as material replenishment compensation, process optimization suggestions, and free trial material verification; it helps customers solve problems and maintains customer relationships.

[0023] 5. This invention establishes a two-tiered dispute resolution mechanism: the first tier, internal rapid review, demonstrates the manufacturer's service sincerity and rapid response capability; the second tier, third-party re-inspection, serves as the final adjudication method, ensuring the impartiality of the final conclusion. This two-tiered mechanism avoids escalating minor issues into lengthy third-party testing processes, while providing an authoritative solution for complex cases where consensus cannot be reached, thus balancing efficiency and authority.

[0024] 6. This invention systematically accumulates data, photos, and re-examination results from each judgment through case recording and archiving, forming a unique knowledge base for the enterprise. By regularly calculating the judgment accuracy and revising the feature library, judgment rules, and weights, the method possesses self-improvement capabilities, and the judgment accuracy can be continuously improved with long-term use. Attached Figure Description

[0025] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a schematic diagram of the five-level discrimination logic of the present invention; Figure 3 This is a flowchart of the hierarchical dispute resolution mechanism of the present invention. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and preferred embodiments. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0027] like Figures 1-3 The method for quickly determining and handling responsibility for after-sales quality abnormalities in round steel and wire rod, as shown, includes the following steps: Step 1: Rapid Identification of Obvious Raw Material Defects Upon arrival at the customer's site, after-sales personnel will first conduct a quick visual inspection. If the following typical defects are found, the issue can be directly attributed to raw materials, eliminating the need to proceed to steps two through five. However, it is necessary to further determine the stage at which the defect occurred: Bent steel: Visual inspection or ruler measurement shows that the curvature exceeds the allowable value in the standard agreement. If the packaging is intact and the curvature is uniform, it is due to a defect in the rolling or cooling process at the factory; if the packaging is damaged or has impact marks, it is due to the transportation process.

[0028] Surface scratches on raw materials: continuous or discontinuous groove-like scratches of varying depths. If there is no iron oxide scale inside the scratch, it is a cold scratch; if it is found before uncoiling, it is a defect in the finishing process within the factory; if it is found for the first time after uncoiling, it is caused by transportation or customer storage.

[0029] Raw material surface cracks: longitudinal straight cracks along the rolling direction, without plastic deformation. After corrosion, there is a decarburized layer on both sides of the crack, which is a defect in the rolling or continuous casting process in the plant; if there is no decarburized layer but it is located at the end, it is a defect in the finishing stage in the plant.

[0030] Output conclusion: Category A0: Obvious raw material issues (factory responsibility), directly initiate the material replenishment or compensation process; Category A1: Obvious cause of raw material issues (possibly due to external factors), to be verified jointly with the customer and logistics provider.

[0031] Step Two: On-site Information Collection and Customer Testimonials

[0032] After the after-sales personnel arrive at the customer's site, a customer representative is invited to participate throughout the entire process. All operations are conducted in the presence of the customer. (1) Sample selection: The customer representative shall specify the most typical defect sample; if the customer believes that the defects are randomly distributed, the customer shall randomly select 3-5 samples.

[0033] (2) Defect appearance feature information collection: Both parties jointly observe and record the crack direction (longitudinal, transverse, network, arc), crack shape (straight, bifurcated, star-shaped, curled), crack opening shape (V-shaped, U-shaped, irregular), crack edge color (whether there is blue-black oxide color), crack depth (visual observation or simple measurement), and defect distribution pattern (whether they appear in pairs or are distributed along the entire length).

[0034] (3) Customer processing technology information collection: collected through standardized inquiry forms, including material grade, processing method (drawing, cold heading, bending, turning, heat treatment, cold upsetting, etc.), process parameters (drawing passes and reduction rate, cold heading deformation, bending radius and angle, heat treatment temperature and cooling method, etc.), mold condition (new mold, worn mold), lubrication status, and quality status of other processed parts of the same batch of materials.

[0035] (4) On-site rapid detection information collection: Portable testing equipment may be used, including one or more of the following: a portable Leeb hardness tester to measure the hardness values ​​of the defective area and the normal area; a portable metallographic microscope to observe the microstructure on both sides of the crack; and simple decarburization detection. Customers can operate or repeat the test themselves.

[0036] (5) Image recording: Use a mobile terminal to take high-definition photos or videos of the defective parts and share them with the customer on the spot.

[0037] (6) Recording and Signing: All test results shall be filled in by both parties on the standardized on-site judgment record form. Each data item shall be recorded after confirmation by both parties. The record form shall be in duplicate.

[0038] Step 3: Preset dual feature library

[0039] The following two standard feature libraries will be pre-printed as standard comparison booklets and made available at the customer's site for both parties to use for comparison: (1) Typical Defect Feature Library for Raw Materials: Subsurface cracks in continuously cast billets: longitudinal straight cracks, shallow in depth, usually less than 0.5 mm, straight and continuous, with no work hardening on both sides, and decarburization or non-metallic inclusions can be seen under metallographic examination. Rolled folded type: in the same direction as rolling, with a V-shaped or U-shaped cross section, and often with iron oxide scale at the root; Internal shrinkage cavities and porosity: After processing, these appear as irregularly shaped cracks or holes, distributed randomly, accompanied by the accumulation of non-metallic inclusions. Non-metallic inclusions: They are distributed in the form of dots or short strips, and can be elongated along the processing direction. Obvious inclusions can be seen at the crack initiation point.

[0040] (2) Typical processing defect feature library: Pulling crack type: transverse or oblique cracks appear after multiple drawing passes. The crack edges show obvious plastic deformation and work hardening. The hardness is usually more than 20% higher than that of the matrix. There is no decarburized layer near the crack and there is a fresh metallic luster. Cold heading cracks: Star-shaped or radial cracks appear at the ends or heads, the cracks extend along the grain boundaries, accompanied by obvious metal flow line cut-off, no iron oxide scale at the root of the crack, and sharp edges; Bending crack type: Located outside the bending deformation zone, it is a transverse arc-shaped crack that extends from the surface inward. The opening is relatively wide and the bottom is relatively blunt, accompanied by work hardening. Processed folding type: The surface metal is pressed in to form a curled shape, embedded in a "U" shape, without metallurgical bonding with the substrate, without iron oxide scale, and the edges have a fresh metallic luster; Heat treatment cracking: network or arc-shaped cracks that extend along grain boundaries, with decarburization or carburization nearby, coarse grains, and oxidation color.

[0041] Step 4: Five-level logical judgment

[0042] The information collected in step two is compared with the feature library disclosed in step three, and the following five-level discrimination logic is used for sequential judgment. The result of each level of discrimination is categorized into three types: raw material-oriented, processing-oriented, and neutral. These results are recorded after mutual confirmation by both parties. Level 1: Defect Morphology Identification If the defect is a longitudinal straight crack along the rolling direction, with shallow depth and continuous straightness, it points to a defect in the raw material; If the defect is a transverse or oblique crack, accompanied by obvious plastic deformation, it indicates a processing defect; If the defect is a star-shaped or radial crack, located at the end of the deformation zone, it points to a cold heading type machining defect; If the defect is a network or arc-shaped crack, it extends along the grain boundary and points to heat treatment-related processing defects; If the defect is a curled fold with a fresh metallic luster at the opening, it indicates that the fold was machined. Other forms point to neutrality.

[0043] Level 2: Determination of the degree of oxidative decarbonization

[0044] A portable metallographic microscope or a simple corrosion method was used to detect whether a decarburized layer existed on both sides of the crack. If there is a clear decarburized layer on both sides of the crack (a bright white layer after grinding and corrosion), it indicates a defect in the raw material (excluding heat treatment decarburization). If there is no decarburized layer on both sides of the crack and the crack edge is a fresh metal structure, it indicates a processing defect. If it cannot be determined, it points to neutral.

[0045] Level 3: Determination of work hardening degree

[0046] A portable Leeb hardness tester was used to measure the hardness values ​​of the crack edge region and the matrix region far from the crack, and the hardness increase ratio ΔH = (H 裂纹边缘 -H 基体 ) / H 基体 ×100%; If ΔH ≥ 20%, and there are obvious signs of plastic deformation at the crack edge, it indicates a processing defect; If ΔH < 10%, there is no plastic deformation at the crack edge, indicating a defect in the raw material; If 10%≤ΔH<20%, it indicates neutrality.

[0047] Level 4: Identification of Impurities

[0048] Use a magnifying glass or a portable metallographic microscope to observe whether there are non-metallic inclusions at the root of the crack. If there is obvious accumulation of inclusions at the root of the crack, it indicates a defect in the raw material. If there are no inclusions at the root of the crack and the crack edge shows a fresh metallic color, it indicates a processing defect. If it cannot be determined, it points to neutral.

[0049] Level 5: Judgment of the rationality of customer's processing technology and stress correlation

[0050] This level comprehensively evaluates the following three sub-items and uses a majority vote to determine the final outcome: Sub-item 1, Reasonableness of process parameters: A single-pass reduction in surface area of ​​>25% or a total reduction in surface area of ​​>80% is unreasonable, indicating machining; cold heading deformation > the material's recommended value is unreasonable, indicating machining; bending radius < the material's minimum bending radius is unreasonable, indicating machining; heat treatment temperature or cooling rate significantly deviating from the process specification is unreasonable, indicating machining; all within the recommended range are reasonable, indicating neutrality.

[0051] Sub-item 2, Mold and Lubrication Status: Severe mold wear or insufficient lubrication indicates machining; good mold and normal lubrication indicate neutrality.

[0052] Sub-item 3, Correlation between Defect Location and Stress Direction: If the defect is located in a typical processing stress area and other customers in the same batch do not have similar problems, it points to processing; if the defect distribution is unrelated to stress and is a common problem for multiple customers, it points to raw materials; otherwise, it points to neutral.

[0053] Comprehensive rule: If at least two of the three sub-items point to processing, then the fifth level is ultimately judged to point to processing; if at least two of the sub-items point to raw materials, then it is judged to point to raw materials; otherwise, it is neutral.

[0054] Step 5: Calculation of the probability of liability attribution and output of conclusions

[0055] Based on the above five-level discrimination results, the probability of liability attribution is calculated using a preset weighted rule. The weights are allocated as follows:

[0056] Sum the weights of each level pointing to the raw material to get P. 原材料 The weights of each level pointing to the processing are summed to obtain P. 加工 The weight of the neutral term is not included.原材料 + P 加工 ≤ 100%, the remainder is uncertainty.

[0057] Output the three-level judgment result based on the probability value, and provide the corresponding processing method: Category A (most likely due to raw material issues): P 原材料 ≥ 80% Handling methods: Sincerely explain the situation to the customer and show the basis for judgment; immediately initiate the replenishment or compensation process; inform the customer of the corrective measures already taken in the factory; if necessary, provide a batch of trial materials to restore customer confidence; record the case for internal quality improvement.

[0058] Category B (most likely due to processing reasons): P 加工 ≥70%

[0059] Handling methods: Explain the basis for judgment to the customer, avoiding an accusatory tone; suggest that the customer check the processing parameters, mold condition, and lubrication status; provide process optimization suggestions; if necessary, provide a batch of trial material free of charge for the customer to verify the optimized process; if the customer does not agree, initiate a tiered dispute resolution procedure.

[0060] Category C (Uncertain): Other cases (P) 原材料 <80% and P 加工 <70%

[0061] Handling method: Explain to the customer that the existing information is insufficient to determine the issue, but agree to conduct joint analysis; both parties shall jointly take samples, and the manufacturer shall conduct metallographic analysis in the laboratory free of charge; the analysis report shall be fully disclosed to the customer; the case shall be handled as either Category A or Category B based on the analysis conclusions; if the customer does not agree, a tiered dispute resolution procedure shall be initiated.

[0062] Step Six: Tiered Dispute Resolution Mechanism

[0063] If the customer does not accept the on-site assessment results, initiate the following tiered procedure: Level 1: Internal Rapid Review (within 24 hours, manufacturer bears the cost). On-site data is uploaded to the company's internal quality expert group; the expert group conducts remote consultation and issues a review opinion within 2 hours. The expert group consists of personnel from quality, technology, and production; the quality expert communicates with the customer to explain the review results; if necessary, personnel are dispatched to conduct on-site retesting with portable equipment.

[0064] Level Two: Third-Party Re-inspection. If the customer still does not accept the internal review, a third-party re-inspection will be initiated. Both parties will jointly cut and take samples from the defective area, making three copies, sealing and numbering each copy, and both parties will sign the seal. The samples will be sent to a third-party testing agency recognized by both parties. The third-party report will be the final basis, and the testing costs will be borne according to the attribution of responsibility, i.e., the manufacturer will bear the cost for reasons related to raw materials, and the customer will bear the cost for reasons related to processing.

[0065] Step Seven: Case Recording and Experience Accumulation

[0066] Regardless of whether an agreement is reached on-site, all records of this judgment will be archived. The manufacturer will periodically calculate the judgment accuracy and manually adjust the feature library, judgment rules, and weights based on the statistical results to continuously optimize the method.

[0067] Example 1: Dispute over bent steel

[0068] A customer reported that a batch of round steel bars had excessive bending and requested a return or replacement. Upon arrival, after-sales personnel visually observed significant bending, measuring 8mm / m with a ruler, exceeding the 4mm / m limit specified in GB / T 28300. The packaging was intact, with no signs of impact. Based on step one, it was directly classified as Category A0. The after-sales personnel demonstrated the standard terms to the customer, who accepted them, and the factory arranged for replacement materials. The entire process was resolved in 15 minutes, and the customer was satisfied.

[0069] Example 2: Dispute over cold heading cracking of cold heading steel wire rod

[0070] A customer used 12mm diameter SWRCH35K cold heading steel wire rod to machine bolts, and a batch of nuts cracked during the cold heading process. The customer believed it was a raw material quality issue and demanded compensation. After the after-sales personnel arrived on site, they operated according to the method of this invention: Step Two: Invite the client's quality manager to participate throughout the process. The client randomly selects 5 cracked parts. Both parties jointly observe that the cracks are located in the deformation zone of the bolt head, exhibiting radial star-shaped cracks with sharp edges, a fresh metallic luster, and no oxidation color. The client provides processing information: cold heading deformation is approximately 65%, and the mold is an old mold used after 5000 pieces. After-sales personnel use a portable hardness tester to measure the hardness of the crack edge: 235 HBW, matrix: 195 HBW, ΔH = 20.5%. The client performs a retest, and the results are consistent. A portable metallographic microscope is used to observe both sides of the crack; no decarburized layer is found. All data is recorded in a log sheet, and both parties sign it.

[0071] Step 3: Both parties compared the publicly available images, and the customer found that the crack morphology was highly similar to that of cold heading cracks.

[0072] Step 4: Step-by-step judgment: Level 1 directional machining, Level 2 directional machining, Level 3 directional machining, Level 4 directional machining, Level 5 (process rationality: deformation amount 65% within reasonable range, neutral; mold wear, directional machining; positional correlation, directional machining; majority vote directional machining).

[0073] Step 5: Calculate P 加工=85%, outputting a Class B conclusion. Solution: After explaining the basis for the judgment to the customer, we suggested they check the processing parameters, mold condition, and lubrication. We found that severe mold wear caused poor lubrication. The problem disappeared after the customer replaced the mold. We provided a free batch of trial material for verification, which the customer accepted, resulting in no claims and subsequent orders.

[0074] Example 3: Dispute over longitudinal cracks after turning round steel bars

[0075] A customer used 25mm diameter 45# steel round bars for turning. After machining, longitudinal straight cracks were found on the surface of the bars. The customer believed it was a defect in the raw materials and requested a return or exchange.

[0076] After-sales personnel and customer representatives jointly observed: the crack is longitudinally linear, straight and continuous, with a depth of approximately 0.3mm. Observation with a portable metallographic microscope revealed a decarburized layer on both sides of the crack after simple acid pickling. Hardness measurement: 185 HBW at the crack edge, 182 HBW in the matrix, ΔH=1.6%. The defect is distributed along the entire length; two other customers from the same batch also reported similar issues. Both parties compared the crack morphology to the catalog, and the crack type matched subcutaneous cracks. Step-by-step identification pointed to the raw material, P. 原材料 =100%, Output Class A conclusion. Handling method: Explain the basis to the customer, immediately replenish materials, and inform them of the corrective measures already taken within the factory. The customer approved, and subsequent cooperation was smooth.

[0077] Example 4: Uncertain Cases and Tiered Dispute Resolution

[0078] A customer encountered a small number of transverse cracks during the drawing of 20mm round steel. Information collected jointly by both parties: the cracks are short, transverse strips, 0.2mm deep, with slight plastic deformation at the edges (ΔH=12%), no decarburized layer, no iron oxide scale, and no inclusions. The defect only appears in a small batch of materials from this customer. A step-by-step assessment was conducted: Level 1: directional machining; Level 2: directional machining; Level 3: neutral; Level 4: directional machining; Level 5 (reasonable process parameters, neutral; good die, neutral; positional correlation, directional machining), P 加工 =80%, P 原材料 =0%, uncertainty 20%, output a type C conclusion.

[0079] Handling Method: The manufacturer conducted a free metallographic analysis in the laboratory. The report showed slight non-metallic inclusions at the crack initiation site, but poor lubrication during processing was the main cause of crack propagation. The analysis report was made public to the customer, and the responsibility was determined to be shared by both parties. Initially, the customer did not accept this, and an internal review was initiated: an expert team conducted a remote consultation to confirm the conclusion, and the manufacturer's quality experts communicated with the customer, who still insisted on their decision. A third-party re-inspection was initiated, and the report's conclusion was consistent with the internal one. The customer borne the testing costs. Although the customer paid the fees, they acknowledged the impartiality of the results.

[0080] The above description is merely a specific embodiment of the present invention. Various examples and illustrations do not constitute a limitation on the substantive content of the present invention. Those skilled in the art can make modifications or variations to the specific embodiments described above after reading the specification, without departing from the essence and scope of the invention.

Claims

1. A method for rapidly determining and handling responsibility for after-sales quality abnormalities in round steel and wire rod, characterized in that: Includes the following steps, S1. Conduct on-site visual inspection of round steel or wire rod products. If any obvious raw material defect is found, such as bent steel, scratches on the surface of the raw material, or cracks on the surface of the raw material, the conclusion of A0 or A1 will be directly output. S2. Invite customer representatives to participate throughout the process, collect information on defect appearance features and customer processing technology under the customer's witness, and conduct on-site rapid testing. All test results shall be jointly recorded and signed by both parties for confirmation. S3. Compare the information collected in step S2 with the pre-constructed typical defect feature library of raw materials and typical defect feature library of processing. The feature library is publicly available at the customer site in the form of a standard atlas for both parties to review and compare. S4. Perform step-by-step judgment according to the five-level judgment logic and record the result of each level. The five-level judgment logic includes defect morphology judgment, oxidation and decarburization judgment, work hardening degree judgment, inclusion judgment, customer processing process rationality and stress correlation judgment. The judgment result of each level is divided into three types: raw material-oriented, processing-oriented, and neutral. S5. Based on the five-level discrimination results, calculate the probability of responsibility attribution according to the preset weights, and output the three-level discrimination results and corresponding processing methods according to the probability values. S6. If the customer does not accept the on-site assessment results, a tiered dispute resolution mechanism will be initiated, including a first-level internal rapid review and a second-level third-party re-inspection.

2. The method for rapid determination and handling of responsibility for after-sales quality abnormalities of round steel and wire rod as described in claim 1, characterized in that: The weight allocation for each level in the five-level discrimination logic is as follows: defect morphology discrimination weight 35%, oxidation and decarburization discrimination weight 20%, work hardening degree discrimination weight 15%, inclusion discrimination weight 10%, and process rationality and stress correlation discrimination weight 20%.

3. The method for rapid determination and handling of responsibility for after-sales quality abnormalities of round steel and wire rod as described in claim 1, characterized in that: The determination of the degree of work hardening specifically involves: measuring the hardness values ​​of the crack edge region and the matrix region far from the crack, and calculating the hardness increase ratio ΔH = (H... 裂纹边缘— H 基体 ) / H 基体 ×100%; if ΔH≥20%, it indicates a processing defect; if ΔH<10%, it indicates a raw material defect; if 10%≤ΔH<20%, ​​it is considered neutral.

4. The method for rapid determination and handling of responsibility for after-sales quality abnormalities of round steel and wire rod as described in claim 1, characterized in that: The results of the three-level determination are as follows: Category A: P 原材料 For ≥80%, the handling methods include explaining the basis to the customer, proactively replenishing materials or providing compensation, and informing them of the corrective measures. Category B: P 加工 For ≥70%, the handling methods include tactful explanation, free dispatch of personnel to assist in inspecting the process / mold / lubrication, and providing process optimization suggestions; Category C: Other situations. Handling methods include providing insufficient information, suggesting that both parties jointly take samples for third-party testing, guiding the customer to temporarily adjust the process, and handling it as Category A or Category B based on the analysis results.

5. The method for rapid determination and handling of responsibility for after-sales quality abnormalities of round steel and wire rod as described in claim 1, characterized in that: The typical raw material defect feature library includes typical features of subsurface cracks in continuously cast billets, rolling folds, internal shrinkage cavities / porosity, and non-metallic inclusions; the typical processing defect feature library includes typical features of drawing cracks, cold heading cracks, bending cracks, processing folds, and heat treatment cracks.

6. The method for rapid determination and handling of responsibility for after-sales quality abnormalities of round steel and wire rod as described in claim 1, characterized in that: The fifth level of discrimination includes three sub-items: discrimination of the rationality of the customer's processing technology and the force correlation discrimination. The discrimination of the mold and lubrication status and the correlation between the defect location and the force direction are determined by majority voting.

7. The method for rapid determination and handling of responsibility for after-sales quality abnormalities of round steel and wire rod as described in claim 6, characterized in that: The criteria for judging the rationality of the process parameters include: a single-pass reduction rate of more than 25% or a total reduction rate of more than 80% is unreasonable; cold heading deformation greater than the material's recommended value is unreasonable; bending radius less than the material's minimum bending radius is unreasonable; and heat treatment temperature or cooling rate deviating from the process specifications is unreasonable.

8. The method for rapid determination and handling of responsibility for after-sales quality abnormalities of round steel and wire rod as described in claim 1, characterized in that: The tiered dispute resolution mechanism includes the following: Level 1 internal rapid review, which includes: on-site data upload, remote consultation with an expert group, communication between the manufacturer's experts and the customer, and on-site retesting when necessary, with all costs borne by the manufacturer; Level 2 third-party re-inspection, which includes: joint sampling and sealing by both parties, sending to a third-party testing institution recognized by both parties, using the third-party report as the final basis, and bearing the costs according to the attribution of responsibility.

Images