A comprehensive evaluation method for purity of ultra-high-grade pipeline steel
By combining metallographic and electrolytic methods, ultra-high grade pipeline steel is sampled and electrolyzed, solving the problem of inaccurate inclusion assessment in existing technologies. This enables a comprehensive evaluation of the purity of ultra-high grade pipeline steel, improving the accuracy of analysis and the objectivity of evaluation.
Patent Information
- Application Number
- CN202110943742.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-08-17
- Publication Date
- 2026-02-17
- Estimated Expiration
- 2041-08-17
AI Technical Summary
Existing technologies are insufficient to accurately assess the content and hazards of large inclusions in ultra-high grade pipeline steel, leading to safety risks in pipeline systems. Furthermore, existing methods are complex and cumbersome to operate, failing to meet the purity evaluation requirements for ultra-high grade pipeline steel.
By combining metallographic and electrolytic methods, samples of ultra-high grade pipeline steel are taken. After preliminary evaluation using metallographic methods, samples with large or oversized inclusions are electrolytically treated. The comprehensive evaluation results of the inclusions are obtained by weighing and comparing with standards.
It improves the accuracy of inclusion analysis and the objectivity of evaluation results, reduces quality disputes, provides a basis for assessing the hazards of large inclusions, and enhances the purity of pipeline steel.
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Figure CN115901525B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of material physical property detection, and particularly relates to a comprehensive evaluation method for the purity of ultra-high-grade pipeline steel. BACKGROUND
[0002] Pipeline transportation, which has the advantages of high efficiency, economy and safety, has become the preferred mode of long-distance oil and gas transportation. In recent years, China's oil and gas industry has developed rapidly. In order to improve the transportation capacity of the pipeline and reduce the construction cost of the pipeline, the demand for high-grade pipeline steel in the future oil and gas industry is expected to show a steady increasing trend. Ultra-size inclusions usually exist in the form of independent phases in the pipeline steel, which destroys the continuity of the steel matrix and increases the inhomogeneity of the steel structure, thus inevitably having many adverse effects on the service performance of the pipeline steel, such as Figure 1 .
[0003] Based on the potential hazards of ultra-size inclusions to the service performance of high-grade pipeline steel, accurate evaluation of the content of large inclusions in high-grade pipeline steel has become an important means to further improve the performance of pipeline steel and the safety and reliability of oil and gas pipeline.
[0004] Due to the advantages of simplicity, intuitiveness and rapidness, the evaluation method for the content of inclusions in the existing acceptance standard for high-grade pipeline steel generally adopts the A method (worst field method) in ASTM E45 or the A method in GB / T 10561. In the process of using these two metallographic methods to evaluate the content of inclusions in high-grade pipeline steel, the technicians usually classify the inclusions according to the morphology, and the level of each type of inclusion is also usually required to be limited in the acceptance standard for high-grade pipeline steel. However, for some ultra-size inclusions with a thickness exceeding the critical value of the coarse system, only the size of the inclusions is required to be recorded in the commonly used metallographic evaluation method, and no further evaluation method is proposed for the hazards of these ultra-size inclusions and the content of inclusions in high-grade pipeline steel. This leads to the fact that many pipeline steel manufacturers do not pay enough attention to the ultra-size inclusions found in the metallographic test, and it is also not conducive for the acceptance evaluation personnel to evaluate the purity of high-grade pipeline steel with ultra-size inclusions, thereby bringing potential risks to the safe operation of the pipeline system. Although the electrolysis (or non-aqueous solution electrolysis) method has higher accuracy in evaluating the content of inclusions in high-grade pipeline steel and is beneficial to the comprehensive evaluation of the content of large inclusions in high-grade pipeline steel, this method has the disadvantages of long evaluation period, complex operation process and tediousness, and it is not yet ready to be completely popularized in the process of evaluating inclusions in pipes.
[0005] For the ultra-high grade pipeline steel, the potential harm of large inclusions is higher than X70, X80 and other pipeline steel products due to the thinner wall thickness of the pipe, so it is necessary to propose a comprehensive evaluation method suitable for the content of large inclusions of ultra-high grade pipeline steel (X90, X100). SUMMARY
[0006] In order to solve the problems in the prior art, the purpose of the present application is to provide a comprehensive evaluation method for the purity of ultra-high grade pipeline steel, which can evaluate the harm of large inclusions and the purity of high-grade pipeline steel with large inclusions, and can be widely used in the evaluation of the content of large inclusions in various ultra-high grade pipeline steels.
[0007] To achieve the above purpose, the present application provides the following technical solution: a comprehensive evaluation method for the purity of ultra-high grade pipeline steel, comprising the following specific steps:
[0008] S1, sampling on the ultra-high grade pipeline steel to obtain a first sample, obtaining the inclusion parameters in the first sample by metallographic method, and grading the inclusions in the first sample according to the inclusion parameters;
[0009] S2, when the inclusion level in the first sample is greater than or equal to 2.0 or there is an oversized inclusion, taking a second sample on the ultra-high grade pipeline steel, electrolyzing the second sample by electrolysis method, collecting the inclusions in the second sample, weighing, and obtaining the total weight of the inclusions in the second sample;
[0010] S3, comparing the weight of the inclusions in the second sample with the standard level value to obtain a comprehensive evaluation result.
[0011] Further, in step S1, the sampling is carried out according to the provisions of ASTM E45 or GB / T 10561.
[0012] Further, in step S1, the grading of the inclusions is carried out according to the A method of ASTM E45 or the A method of GB / T 10561.
[0013] Further, in step S2, the second sample is sampled at the 1 / 4 position of the inner arc side in the width direction of the ultra-high grade pipeline steel.
[0014] Further, in step S2, the second sample is 2Kg.
[0015] Further, in step S2, during electrolysis, the anode is the second sample, the cathode is a stainless steel sheet, and the electrolyte is an organic solution with anhydrous methanol as the solvent.
[0016] Further, in step S2, during electrolysis, ice bath treatment is carried out.
[0017] Further, in step S2, the inclusions in the obtained second sample are subjected to ultrasonic cleaning, elutriation, magnetic separation, washing, drying, and then weighed.
[0018] Further, in step S3, the standard level value is the average weight of inclusions in X90 and X100 products produced by a plurality of large pipeline steel manufacturers in China after electrolysis, and the standard level value is 0.423 mg / 1 kg.
[0019] Further, in step S3, the comprehensive evaluation result is specifically:
[0020] When the weight of inclusions in the second sample is greater than 0.423+(0.423×35%), the comprehensive evaluation result is high;
[0021] When the weight of inclusions in the second sample is less than 0.423-(0.423×5%), the comprehensive evaluation result is low;
[0022] When 0.423-(0.423×35%)≤the weight of inclusions in the second sample≤0.423+(0.423×35%), the comprehensive evaluation result is medium.
[0023] Compared with the prior art, the present application has at least the following beneficial effects:
[0024] The present application proposes a comprehensive evaluation method for the purity of ultra-high-grade pipeline steel, which combines the simplicity, intuitiveness and rapidity of metallographic method, and introduces the main means of quantitative detection of inclusions-electrolysis method, thereby effectively improving the accuracy of ultra-high-grade pipeline steel inclusion analysis, greatly ensuring the objectivity and fairness of the evaluation result, and effectively avoiding the quality disputes between pipeline steel manufacturers and users. At the same time, the large inclusion analysis results and inclusion morphology and size data obtained by using the evaluation method can also provide a basis for further evaluating the harm of large inclusions, which is beneficial to the further improvement of the purity of ultra-high-grade pipeline steel by manufacturers. BRIEF DESCRIPTION OF DRAWINGS
[0025] Figure 1 The macroscopic morphology of hydrogen blistering on the surface of the X100 steel pipe sample after HIC test.
[0026] Figure 2 The schematic diagram of the sampling position.
[0027] Figure 3 Flowchart of evaluation of large inclusion content in ultra-high-grade pipeline steel. DETAILED DESCRIPTION
[0028] The present application will be further described below in combination with the drawings and specific embodiments.
[0029] Referring to Figure 3 , the present application comprises the following steps:
[0030] 1) Sampling the ultra-high grade pipeline steel according to the provisions of ASTM E45 or GB / T 10561 to obtain a first sample, obtaining the inclusion parameters in the first sample by metallographic method, and grading the inclusions in the first sample according to the inclusion parameters using ASTM E45 method A (worst field method) or GB / T 10561 method A, if the inclusion level is less than 2.0 (the acceptance condition commonly used in the technical conditions for high-grade pipeline steel for natural gas pipeline engineering at present) or there is no oversized inclusion, the evaluation is ended, and the inclusion grading result in the ultra-high grade pipeline steel is given according to the relevant provisions of ASTM E45 or GB / T 10561 method A.
[0031] 2) When the inclusion level is greater than or equal to 2.0 or there is an oversized inclusion, a second sample with a total weight of 2Kg is taken at the 1 / 4 position of the inner arc side in the width direction of the ultra-high grade pipeline steel (see Figure 2 ), electrolysis is performed on the second sample, the inclusions in the second sample are collected and weighed to obtain the weight of the inclusions in the second sample;
[0032] Preferably, electrolysis is performed in an electrolytic cell, and during the electrolysis process, the second sample is the anode, the stainless steel sheet is the cathode, and the electrolyte is an organic solution with anhydrous methanol as the solvent, which comprises: surfactants, complexing agents, buffers and appropriate reducing agents.
[0033] Preferably, in order to prevent the influence of oxygen in the air on the electrolysis process, nitrogen is continuously introduced into the electrolytic cell during electrolysis.
[0034] Preferably, in order to reduce the surface activity of the inclusions, an ice bath device is used for treatment.
[0035] Preferably, the second sample is an electrolytic sample or a non-aqueous solution electrolytic sample.
[0036] Preferably, the main process of electrolytic separation of inclusions in the second sample is: sample electrolysis → ultrasonic cleaning of the anode → elutriation → magnetic separation → washing → drying → weighing to obtain the weight of the inclusions in the second sample, i.e. the quantitative result.
[0037] 3) Comparing the weight of the inclusions in the second sample with the standard level value, the acceptance evaluation personnel can obtain three comprehensive evaluation results of high / medium / low purity of the ultra-high grade pipeline steel.
[0038] Preferably, the average of the electrolytic results of the X90 and X100 products from the main large pipeline steel manufacturers in the country are used as the standard level value, so the standard level value for comparison of the inclusion quantification results of the ultra-high grade pipeline steel is 0.423 mg / lkg, and the specific test values are shown in Table 1.
[0039] Table 1 Inclusion quantification analysis results of X90 and X100 pipeline steel samples from main manufacturers
[0040]
[0041] The eight manufacturers in the above table include Baosteel, Ansteel and other main X90 / X100 manufacturers, so the final standard level value is representative.
[0042] Example 1
[0043] The present application uses a systematic analysis method to detect and evaluate the inclusions in ultra-high grade pipeline steel, evaluates the cleanliness of the sample by using different detection methods, and quantitatively evaluates the inclusion level of ultra-high grade pipeline steel from multiple aspects. The sample conditions of the main X90 and X100 pipeline steel manufacturers in the country are shown in Table 2:
[0044] Table 2 Sample conditions of main X90 and X100 pipeline steel manufacturers in the country
[0045]
[0046]
[0047] First, the pipeline steel products of these typical manufacturers are sampled according to the provisions of GB / T 10561, the inclusions in the samples are measured by metallographic method, and the evaluation is carried out according to the provisions of method A in GB / T 10561, and the evaluation results of each manufacturer are shown in Tables 3-14.
[0048] Table 3 Inclusion content metallographic evaluation results of sample A of manufacturer A
[0049] Sampling site Non-metallic inclusions Coil head A0.5, B0.5, D0.5 Coil tail A0.5, B0.5, D0.5
[0050] Table 4 Inclusion content metallographic evaluation results of sample A of manufacturer A
[0051] Sampling site Non-metallic inclusions Coil head A0.5, B2.0, D1.5, D0.5e Coil tail A0.5, B2.0e, DS0.5
[0052] Table 5 Inclusion content metallographic evaluation results of sample A of manufacturer A
[0053] Sampling site Non-metallic inclusions Coil head A0.5, B0.5, D1.0, DS0.5 Coil tail A0.5, B0.5, D1.0
[0054] Table 6 Inclusion content metallographic evaluation results of sample A of manufacturer A
[0055] Sampling site Non-metallic inclusions Coil head A0.5, B0.5, D0.5, DS1.5 Coil tail A0.5, B0.5, D1.0
[0056] Table 7 Inclusion content evaluation results of samples from manufacturer E by metallographic method
[0057] Sampling site Non-metallic inclusions Coil head A0.5, B0.5, D1.0, DS1.0 Coil tail A0.5, B1.0e, D1.0
[0058] Table 8 Inclusion content evaluation results of samples from manufacturer F by metallographic method
[0059] Sampling site Non-metallic inclusions Coil head A0.5, B1.0, B1.0e, D0.5e, DS2.0 Coil tail A0.5, B1.0e, D0.5e, DS2.0
[0060] Table 9 Inclusion content evaluation results of samples from manufacturer G by metallographic method
[0061] Sampling site Non-metallic inclusions Plate head A0.5, B1.0, D0.5e, DS1.5 Plate tail A0.5, B2.0, B1.0e, D0.5e, DS2.0
[0062] Table 10 Inclusion content evaluation results of samples from manufacturer H by metallographic method
[0063] Sampling site Non-metallic inclusions Plate head A0.5, B1.5, B1.5e, D0.5e, DS2.0 Plate tail A0.5, B1.5, D0.5e
[0064] Table 11 Inclusion content evaluation results of samples from manufacturer I by metallographic method
[0065] Sampling site Non-metallic inclusions Plate head A0.5, B1.0e, D0.5, DS1.0 Plate tail A0.5, B1.5, D0.5e
[0066] Table 12 Inclusion content evaluation results of samples from manufacturer J by metallographic method
[0067] Sampling site Non-metallic inclusions Plate head A0.5, B0.5, D0.5, D0.5e, DS1.5 Plate tail A0.5, B0.5, D0.5, D0.5e, DS1.5
[0068] Table 13 Inclusion content evaluation results of samples from manufacturer K by metallographic method
[0069]
[0070]
[0071] Table 14 Inclusion content evaluation results of samples from manufacturer L by metallographic method
[0072] Sampling site Non-metallic inclusions Plate head A0.5, B1.0, D0.5, DS0.5 Plate tail A0.5, B1.0, B1.5s, D0.5, DS0.5
[0073] Note: The tail sample has oversized Class B inclusions with a maximum thickness of 26 μm.
[0074] Second step, according to the metallographic evaluation results, the samples from manufacturer F, manufacturer G and manufacturer H have inclusions with a rating of 2.0, and the sample from manufacturer L has oversized inclusions, so further quantitative evaluation of the inclusion levels of these samples is needed.
[0075] Thirdly, for the X90 and X100 super-high grade steel samples of the manufacturers F, G, H and L, the second samples or non-aqueous solution second samples with a total weight of 2 Kg were taken from the 1 / 4 position of the inner arc side in the width direction, and then the electrolytic analysis was performed on the taken samples to obtain the mass of inclusions in the second samples. The mass of inclusions in the second samples was compared with the standard level value to obtain the comprehensive evaluation result, as shown in Table 15:
[0076] Table 15 Comparison conclusion of inclusion quantitative analysis of super-high grade pipeline steel samples
[0077]
[0078] Note: According to the inclusion quantitative analysis results of the X90 and X100 pipeline steel samples of the main manufacturers, the standard deviation of these data is 0.270, and the proportional relationship between the standard deviation and the mean value is (0.423-0.270) / 0.423=36%, which is rounded to 35%.
[0079] As can be seen from Table 15, when the weight of inclusions in the second sample is >0.423+(0.423x35%), the comprehensive evaluation result is high level;
[0080] When the weight of inclusions in the second sample is <0.423-(0.423x35%), the comprehensive evaluation result is low level;
[0081] When 0.423-(0.423x35%)≤the weight of inclusions in the second sample≤0.423+(0.423x35%), the comprehensive evaluation result is medium level.
[0082] Pipeline steel manufacturers and users can comprehensively evaluate the purity level of pipeline steel according to the above evaluation conclusion, or use the evaluation method to obtain large inclusion analysis results and inclusion morphology and size data, to provide a basis for users to further evaluate the harm of large inclusions, and require manufacturers to further effectively improve the purity of super-high grade pipeline steel.
Claims
1. A comprehensive evaluation method for the purity of ultra-high grade pipeline steel, characterized in that, The specific steps are as follows: S1. A sample is taken from ultra-high grade pipeline steel to obtain the first sample. The inclusion parameters in the first sample are obtained by metallographic method. The inclusions in the first sample are rated according to the inclusion parameters. S2, when the impurity level in the first sample is greater than or equal to 2.0 or there are oversized inclusions, take a second sample from the ultra-high grade pipeline steel, electrolyze the second sample using the electrolysis method, collect the inclusions in the second sample, weigh them, and obtain the total weight of the inclusions in the second sample. S3. Compare the weight of inclusions in the second sample with the standard level value to obtain a comprehensive evaluation result; In step S1, the sampling is carried out in accordance with the provisions of ASTM E45 or GB / T 10561; In step S1, the inclusions are rated according to Method A in ASTM E45 or Method A in GB / T 10561; In step S3, the standard level value is the average weight of inclusions in X90 and X100 ultra-high grade pipeline steel after electrolysis, and the standard level value is 0.423 mg / 1 kg; In step S3, the comprehensive evaluation result is specifically as follows: When the weight of inclusions in the second sample > At that time, the overall evaluation result was high. When the weight of inclusions in the second sample is < At that time, the overall evaluation result was low. when ≤Weight of inclusions in the second sample≤ At that time, the overall evaluation result was intermediate.
2. The comprehensive evaluation method for the purity of ultra-high grade pipeline steel according to claim 1, characterized in that, In step S2, the second sample is taken from the ultra-high grade pipeline steel at a position 1 / 4 of the inner arc side in the width direction.
3. The comprehensive evaluation method for the purity of ultra-high grade pipeline steel according to claim 1, characterized in that, In step S2, the second sample weighs 2 kg.
4. The comprehensive evaluation method for the purity of ultra-high grade pipeline steel according to claim 1, characterized in that, In step S2, during electrolysis, the anode is the second sample, the cathode is a stainless steel sheet, and the electrolyte is an organic solution with anhydrous methanol as the solvent.
5. The comprehensive evaluation method for the purity of ultra-high grade pipeline steel according to claim 1, characterized in that, In step S2, an ice bath treatment is performed during electrolysis.
6. The comprehensive evaluation method for the purity of ultra-high grade pipeline steel according to claim 1, characterized in that, In step S2, the inclusions in the second sample are subjected to ultrasonic cleaning, washing, magnetic separation, washing, drying, and then weighing.