文献翻译-压力容器无损检测--球形储罐的无损检测技术

外文翻译 Nondestructive Testing of Pressure Vessels - spherical tank of non-destructive testing technology Abstract: The spherical tank is the storage of different types of gases and liquefied gases, one of the commonly used pressure vessel, in the petroleum, chemical, metallurgical and urban gas supply, etc. are widely used. Spherical storage tanks in the manufacturing, installation and use may occur at different stages of the shortcomings and, respectively, with the various non-destructive testing methods, including radiation detection, ultrasonic testing, magnetic particle testing, penetrant testing, eddy current testing, acoustic emission detection and magnetic memory testing techniques. , Respectively, of these characteristics of non-destructive testing methods. Keywords: pressure vessel; spherical tank; non-destructive testing; Summary Sphere in a comprehensive inspection by the general method of using conventional non-destructive testing and acoustic emission detection mode. Conventional non-destructive testing method of the model, both inside and outside the surface of the weld and welding parts scar 100% magnetic particle or penetrant testing, Butt Weld within 20% 100% ultrasonic testing, ultrasonic testing to find defects in the internal standard for-ray tests to determine the nature of defects and to determine the exact location of rework; this detection method is generally used to weld the internal standard of known defects or no defects over a small sphere, but the detection time required for testing relatively long. Acoustic emission detection method using the model, after the first suspended sphere pressure test and acoustic emission testing, and then detection of acoustic emission activity of the specified source to the surface of the site testing and ultrasonic testing repeatability and, where appropriate, the expansion of the surface detection ratio to more than 20% of the ultrasonic testing found excessive internal defect detection-ray camera to determine the nature of defects and to determine the exact location of rework; this detection method is generally used or known to weld there may exist a large number of standard spherical defects, acoustic emission testing can identify a large number of defects over the activity of repairing defects; for defect-free over the sphere, the use of such models can be significantly shortened the time to open cans tested and reduce production losses. However, It is worth recalling that, for some small surface cracks, pressure test may not have targeted the source of acoustic emission signals, therefore, sometimes acoustic emission testing can not be found in a small surface crack. 1.1 Surface Detection Surface detection method is in the sphere of production to conduct a comprehensive inspection of the non-destructive testing method of choice. Surface detection of the docking site for the spherical tank weld, fillet weld, the Department of welding fixtures to remove surface traces. Iron Butt Weld surface magnetic materials commonly used methods of magnetic particle testing, commonly used outside of the sphere and wet magnetic particle testing, the internal conditions as a result of poor lighting, usually fluorescent magnetic particle testing, fillet can not be detected using magnetic penetrant testing can be used. Non-ferrous magnetic permeability of the surface testing, pressure vessel, the internal use of fluorescent penetrant testing, pressure vessel infiltration of the external detection of the use of shading. Based on years of testing experience, spherical surface crack prone parts of the main Department of Public Works to remove welding fixtures track surface, the pillars of fillet, installation ring assembly of the final weld (normally weld the loop on the pole) the outer surface, medium surface parts of the inner surface of the weld. 1.2 eddy current surface crack detection Weld surface crack detection of the magnetic powder or infiltration need to be seized prior to clean weld surface treatment, surface coating or to remove dirt, so not suitable for online detection sphere. In addition, the sphere 100% open cans both inside and outside the surface of weld testing found that more than 80% of the spherical surface without any cracks, even if the spherical surface crack was found, in general there is only a few surface crack, or seam length of l % or less, so a lot of grinding on the one hand, an increase of spherical tank production test time and cost, on the other hand, reduces the spherical shell thickness weld parts. Using eddy current technology can not remove the surface coating in the case of metal materials from the surface to detect cracks, however, conventional eddy current testing method is only applicable to materials on the surface of the crack, the crack of the weld due to weld it in the fusion of high temperature ferromagnetism arising from the changes and weld surface appear rugged and disorderly magnetic interference can not be detected. To solve these problems, people have developed the complex plane based on the analysis of weld metal material electromagnetic eddy current testing technology, there are anti-corrosion layer, the points can also be a special probe on the weld surface for rapid scanning, and lift-off effect on the test results the impact of very small 7 9. Based on the analysis of the complex plane eddy current surface crack detection apparatus using magnetic disturbance current probe eddy current testing technology to detect surface weld cracks, this method allows more rough weld surface or with a certain thickness of coating, it can be used for ball can run the course of the outer surface of the weld of the rapid detection of cracks, can also be used for spherical tank inspection at the time of production. Then the method can be used for rapid detection of the weld, and then parts of suspicious powder or penetration testing repeatability to determine the exact location of surface cracks and size. The current market in the coating apparatus can be 0.2mm, the detection sensitivity is higher than 0.5mm deep surface crack length of 5mm; 2mm in the case of coating, detection sensitivity is higher than lmm long 5mm deep surface cracks ; The instrument can also be of 5mm deep Determination of crack depth. 1.3 Ultrasonic Testing Spherical tank with a comprehensive test methods commonly used ultrasonic testing of butt weld or 100% for random testing, to detect internal weld fatigue crack may occur or the existence of hidden defects in welding, for the spherical tank is not easy to open can also be detected from the outside seam of the inner spherical surface crack, the external spherical layer of insulation covering the situation, or from the internal sphere of the outer surface of weld cracks were detected there, but the method of ultrasonic testing in general can only be found more than 5mm long lmm deep surface cracks. Ultrasonic flaw detector as a result of small size, light weight, very easy to carry and operate, and compared with the ray is harmless to human body, so the use of spherical tanks are widely used in testing. At present, the ultrasonic testing of the spherical tank found directly generated internally weld fatigue crack is very rare, the main findings of ultrasonic testing of the installation process or undetected spherical pores, slag, non-fusion and lack of penetration welding defects, such as the original. Many cases of excessive welding defects in the safety assessment of defects of the method shall be maintained, and safety assessment of need to know their own deficiencies in the length and height. The characteristics of ultrasonic detection method is more accurate in the detection of weld defects in their length and height of the safety assessment for defects in the provision of defective data geometry. JB 4730 The newly amended provisions of ultrasonic flaw detection method itself highly defective endpoint diffraction wave method, the end of the largest and 6dB echo law, but use the highest measurement accuracy is defective endpoint diffraction wave method, the accuracy of O . 5 lmm. In addition, the TOFD ultrasonic testing abroad and holographic imaging has been to promote the application of mature, these internal defects can be more intuitive and more accurate data, the current is also activated these methods of research and application work, so the future these methods in the sphere of the regular testing will play an important role. 1.4-ray detection Pressure vessels used for the comprehensive test-ray detection method mainly used for thickness 12mm of Pressure Vessels Weld Testing internal buried defects, for sheet metal using ultrasonic testing a certain degree of difficulty, and does not require the use of high-ray detection tube voltage. Spherical tank as a result of a general wall thickness of 20mm, suitable for ultrasonic testing, the most comprehensive in the test with spherical-ray detection method seldom used. But for the 80s before the 20th century, manufacture and installation of the sphere, due to strict quality control at the time, the existence of a number of weld defects in a large number of standard, so often used when a comprehensive test 7-ray detection method. Detection of the source will be 7 on the center of the internal sphere, a few hours to complete the transillumination Butt Weld 100% detection efficiency. In addition, ultrasonic testing found excessive defects, often used to complex inspection-ray detection in order to further determine the nature of these deficiencies and specific areas, to provide a basis for repairing defects. 1.5 Acoustic emission testing Acoustic emission method may be used to detect the existence of spherical active defects, but also can be used to evaluate the activity of known defects 10,111. Acoustic emission testing is different from other non-destructive testing methods, testing must be carried out during the loading of the spherical tank, commonly used for pressure vessel loading methods to stop running after the water pressure or air pressure test, the work can be directly used to load media . Defects of the activity detected in the loading process is used in a number of acoustic emission sensors on the spherical shell to the overall monitoring, to discover the source of acoustic emission activity and its host site, and then through the activity of acoustic emission source on the surface and internal defect detection, rule out the interference source and found that the existence of spherical defects. Known defects in the activity of evaluation is carried out in the loading process acoustic emission monitoring, if the entire load in the course of defective parts of the source position have a silent launch, it is a non-activity of defects, on the contrary, if a large number of acoustic emission location source signals, that is the activity of the defects. Through the center of a special prosecutor last decade in the field of more than 100 cans of acoustic emission billiards comprehensive analysis of test data and found that the acoustic emission source of conventional non-destructive testing repeatability results, Table l gives the spherical sound field emission testing may encounter a variety of typical acoustic emission source categories, and describe the source location and mechanism generated. 1.6 Magnetic Memory Testing Metal magnetic memory testing technique is Professor Du Bofu Russia in the 20th century, early 90s and late 90s developed a detection material stress concentration and fatigue damage of the new method of nondestructive testing and diagnosis. Metal magnetic memory testing is the use of the principle of ferromagnetic workpieces contained in the course of their work, stress and deformation in the region resulting from irreversible changes in magnetic state 12. Occurred in the region with the magnetostrictive nature of the magnetic domain-oriented organizations and non-reversible re-orientation, and the magnetic state of irreversible changes in the work load will not only retain, after the elimination, but also the role of stress related to the largest. Magnetic memory testing materials can be found after stress caused by fatigue damage, and even lead to the emergence of crack; but on the mechanism of magnetic memory phenomenon is not very clear understanding of the general and other non-destructive testing methods used to prevent the leakage defect seized. With the same eddy current detection methods for magnetic memory testing on the welds do not have to deal with surface polished, with paint layer can be directly detected rapid scanning, so this method is particularly suitable for on-line Tank detection. Electromagnetic eddy current testing methods with different detection method is a magnetic memory is found to exist in the sphere of high stress concentration areas, and often in these areas prone to stress corrosion cracking and fatigue damage. Detection of spherical tank, the usual magnetic memory testing apparatus for spherical tank welding seam for quick scanning to detect the existence of pressure vessel weld parts of the stress peak, and then the peak stress on these parts of local surface magnetic particle testing and internal super - sound detection, to detect possible surface cracks or internal defects. Conclusion Non-destructive testing technology in the sphere of manufacturing, installation and use of process, to ensure quality and safe operation of its very important role to play. For the manufacturing process in order to shell plate-based ultrasonic detection methods; the installation process, to the Weld-ray or ultrasound-based detection methods; for periodic inspection by the process to the surface of detection methods for detection of acoustic emission main. In addition, eddy current testing and magnetic memory testing and other new technology in the online testing has begun to be applied. It can be expected, with the new non-destructive testing technology, is bound to have some faster detection, higher sensitivity and reliability, defect showed a more intuitive new methods of detection in the sphere of application. 压力容器无损检测 -球形储罐的无损检测技术 摘要 ：球形储罐是储存各种气体和液化气体的常用压力容器之一，在石油、化工、冶金和城市燃气供应等方面得到广泛使用。球形储罐在制造、安装和使用过程中不同阶段可能出现的缺陷和分别采用的各种无损检测方法，包括射线检测、超声检测、磁粉检测、渗透检测、电磁涡流检测、声发射检测和磁记忆检测等技术。分别介绍了这些无损检测方法的特点。 关键词 ：压力容器；球形储罐；无损检测；综述 目前在用球罐全面检验一般采用常规无损检测方法和声发射检测方法两种模式。常规无损检测方法的模式为，对内外表面焊缝和焊疤部位进行 100 磁粉或渗透检测，对接焊缝内部进行 20 100超声检测，对超声检测发现的内部超标缺陷进行射线检测以确定缺陷的性质，并为返修确定具体部位；这种检测方法一般用于焊缝内部无已知超标缺陷或超标缺陷很少的球罐，但这种检测方法所需的检验时间相对较长。采用声发射检测方法的模式为，球罐停用后首先进行水压试验和声发射检测，然后对声发射检测指定的活性源部位进行表面检测和超声检测复验，并适当扩大表面检测的比例到 20 以上，对超声检测发现的内部超标缺陷进行射线检测照相以确定缺陷的性质，并为返修确定具体部位；这种检测方法一般用于已知焊缝内部存在或可能存在大量超标缺陷的球罐，声发射检测可以从大量超标缺陷中识别出活性缺陷进行返修；对于无超标缺陷的球罐，采用此种模式，也可大大缩减开罐检验的时间，减少停产损失。然而，值得提醒的是，对于一些较小的表面裂纹，耐压试验过程中可能不产生声 发射定位源信号，因此，声发射检测有时不能发现小的表面裂纹。 1.1表面检测 表面检测方法是在球罐停产进行全面检验中首选的无损检测方法。表面检测的部位为球罐的对接焊缝、角焊缝、工卡具拆除处的焊迹表面等。铁磁性材料对接焊缝的表面一般采用磁粉检测方法，球罐的外部一般采用湿式黑磁粉检测，内部由于照明条件不好，通常采用荧光磁粉检测，角焊缝无法采用磁粉检测时可用渗透检测。非铁磁性材料的表面采用渗透检测，压力容器的内部采用荧光渗透检测，压力容器的外部采用着色渗透检测。 根据多年的检验经验，球罐容易出现表面裂纹的部位主要有工卡具拆除处的焊迹表面、支柱角焊缝、安装时组装的最后一道环焊缝 (一般为上极圈环焊缝 )的外表面，介质液面部位的焊缝内表面。 1.2 电磁涡流表面裂纹检测 焊缝表面裂纹的磁粉或渗透检测都需要将被检焊缝表面事先进行清洁处理，除去表面防腐层或污垢，因此不适合球罐的在线检测。另外，球罐开罐 100焊缝内外表面的检测发现， 80以上的球罐无任何表面裂纹，即使发现表面裂纹的球罐，一般也是只存在几处表面裂纹，占焊缝总长的 l以下，因此大量的打磨一方面增加了球罐停产检验的时间和费用，另一方面也减小了球罐焊缝部位壳体的壁厚。 采用涡流技术可在不去除表面涂层的情况下来探测金属材料的表面裂纹，然而，常规涡流方法只适用于检测表面光滑母材上的裂纹，对焊缝上的裂纹却会因焊缝在高温熔合时产生的铁磁性变化和焊缝表面高低不平而出现杂乱无序的磁干扰而无法检测。针对这些问题，人们研究出基于复平面分析的金属材料焊缝电磁涡流检测技术，在有防腐层时，也可用特殊的点式探头对焊缝表面进行快速扫描检测，而且提离效应对检测结果的影响很小 7 9。 基于复平面分析的电磁涡流表面裂纹检测仪器采用电流扰动磁敏探头的涡流检测技术来检测焊缝的表面裂纹，此方法允许焊缝表面较为粗糙或带有一定厚度的防腐层，因此可用于球罐运行过程中的焊缝外表面裂纹的快速检测，也可用于球罐停产时的全面检验。这时可先采用该方法对焊缝进行快速检测，然后对可疑部位进行磁粉或渗透检测复验，以确定表面裂纹的具体部位和大小。目前市场上销售的仪器可在涂层 0.2mm的情况下，检测灵敏度高于 0.5mm深 5mm长的表面裂纹；在有2mm涂层的情况下，检测灵敏度高于 lmm深 5mm长的表面裂纹；该仪器还可对5mm深的裂纹进行深度测定。 1.3超声检测 在用球罐的全面检验一般采用超声检测方法对对接焊缝进行抽查或 100检测，以发现焊缝内部可能出现的疲劳裂纹或已存在的焊接埋藏缺陷，对于不易打开的球罐也可从外部检测球罐焊缝的内表面裂纹，对于球罐外部有保温覆盖层的情况，也可从球罐的内部对焊缝外表面出现的裂纹进行检测，但超声检测方法一般只能发现 lmm深 5mm长以上的表面裂纹。由于超声波探伤仪体积小、重量轻，十分便于携带和操作，而且与射线相比对人体无害，因此在在用球罐检验中得到广泛使用。 目前，对球罐的超声检测中直接发现焊缝内部产生的疲劳裂纹是很少见的，超声检测主要发现的还是球罐安装过程中漏检的气孔、夹渣、未熔合和未焊透等原始焊接缺