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提高中大直径钢管涡流探伤灵敏度的理论研究 总被引:2,自引:0,他引:2
针对中大直径钢管穿过式涡流探伤灵敏度低的问题,分析了影响探伤灵敏度的主要因素。从电磁等效的原理出发,研究了穿过式探头激励线圈在各种激励方式下的电磁等效直径。结果表明,在恒流激励方式下的激励磁场最强,且具有聚焦效果,因而可有效地提高涡流探伤的灵敏度。 相似文献
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加热器碳钢管内插式探头涡流探伤试验 总被引:1,自引:0,他引:1
用内插式探头磁化涡流和远场涡流检测技术对8个电厂48台加热器碳钢管进行了检测,试验结果表明,磁化涡流对碳钢管道孔和内壁缺陷检测灵敏度较高,对外壁缺陷检测灵敏度较低,容易区分内外壁缺陷;远场涡流对碳钢管通孔检测灵敏度较低,地内外壁缺陷检测灵敏度较高,但难以区分内外壁缺陷。 相似文献
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对高精度薄壁管材进行涡流探伤时,由于其壁厚很薄(目前壁厚最薄的产品已经达到了0.2mm),对产品表面的缺陷有了更高的检测要求。而单独使用穿过式探头进行涡流检测的方法无法满足实际的生产需要,最佳方案是探头式及穿过式组合涡流检测方法。既弥补了穿过式检测线圈对长条形缺陷的漏检,又避免了探头式检测线圈对短缺陷的漏检。 相似文献
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概括了影响钛管涡流探伤可靠性的主要因素,并提出解决途径。研制出新型多线圈差动结构穿过式探头,建立了钛管试验频率范围计算经验公式。试验结果表明,该方法具有检测灵敏度高、重复性好、抗干扰性能优等特点,可满足航天、核用钛管涡流检测技术要求。 相似文献
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从涡流无损检测的基本原理出发,利用电磁测量的通用设备和自制的穿过式探头构成自组式涡流探伤仪,对铜管的人工缺陷和自然裂纹缺陷进行检测,介绍了该装置的特点。 相似文献
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分析了影响管材涡流检测可靠性的主要原因,介绍了探伤仪器、穿过式探头及装置所采取的技术改进措施及其在涡流自动检测系统中的应用情况以及检测效果。 相似文献
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针对传统的涡流检测激励频率确定方法存在与实际情况不符和难以得到最佳检测频率的问题,基于大型通用有限元软件ANSYS建立了外径19 mm、壁厚2 mm的1Cr18Ni9Ti不锈钢管材涡流检测内插式探头和穿过式探头的仿真模型,根据差动探头的特性,通过计算距人工缺陷不同距离时检测线圈电流的实部IREAL、虚部IIMAG和线圈的阻抗差ΔZ,进而得到缺陷仿真信号,通过比较不同频率下缺陷信号的幅值和相位,确定穿过式探头的最佳检测频率为50 kHz。 相似文献
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Haoyu Huang Nozomu Sakurai Toshiyuki Takagi Tetsuya Uchimoto 《NDT & E International》2003,36(7):515-522
This paper describes an arrayed multi-coil probe, newly developed for the testing and crack sizing of steam generator tubes by eddy current testing (ECT). The testing speed, the high sensitivity to shallow cracks and the crack sizing are the present requirements in ECT. Because of the multi-coil arrangement, the arrayed probe has a high detection speed around the whole tube, without the need for rotation. It is realized from former studies that knowing the number of cracks, their directions, and their positions beforehand is of great help in crack sizing. Thus, not only the sensitivities but also the spatial resolutions are important. Numerical simulations are applied to help the design of the probe from the viewpoint of the crack sizing of steam generator tubes. Experiments show that the present probe provides both a high detectability and a remarkable capability of reconstructing the shallow cracks of a tube. 相似文献
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法兰表面及近表面检测的目前使用方法是渗透和磁粉,而这2种方法的检测效率低,检测结果误差较大,难以满足国家电网公司对特高压输电项目中钢管塔的法兰盘安全服役的要求。阵列涡流具有检测速度快,表面及近表面缺陷检测盲区小,灵敏度高等多种优点。本研究针对法兰盘颈根部位的结构特点,设计了R角柔性阵列涡流检测探头;从阵列涡流检测仪、检测参数设定、数据分析方法入手,结合试样检测、现场检测,开发了铁塔法兰盘的阵列涡流检测工艺方法。经试验和现场检测证明:阵列涡流检测设备和工艺可消除法兰自身结构不同而带来的信号偏差,减少了人为因素影响,并提高了检测效率和检测结果的可靠性,是一种快速、简单、有效的新型检测方法。 相似文献
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流体输运钢管外部加一层保护性钢套管,会使从外部检测内管腐蚀更加困难。本研究基于脉冲涡流检测技术,设计一种扁平U型结构传感器,可在双层钢管间隙中检测内管腐蚀情况而不受套管影响,且该检测方法一次扫查可同时获得内管的内壁和外壁减薄信息。使用圆柱型探头和U型探头检测试件3处缺陷,同时将钢管间隙减小到25、35 mm,与不加套管时的检测缺陷结果进行对比。结果表明:和传统同轴式圆柱形探头相比,U型传感器对外部保护钢管有着较强的抗干扰的能力,对衰减曲线影响较小,在间隙间检测内管腐蚀缺陷有较高的灵敏度,能够满足工业现场要求。 相似文献
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Remote field eddy current (RFEC) technique is an effective method for measurement of ferromagnetic tube. However, traditional RFEC is unable to differentiate the internal and external defect and the probe has a long length. Pulsed eddy current techniques excite the induction coil with a pulsed waveform and have the richness of frequency harmonics. The wideband excitation is thought to be a potential in providing more information about the flaw. In this paper, pulsed RFEC technique is used to inspect ferromagnetic tube. The finite element analysis and experiment method is used to give a thorough analysis of the influence effect with the variations of the system parameters. Results show that this technique effectively combines the advantages of RFEC and pulsed excitation, which not only acquires more inspection information, including measurements of inner diameter of tubes, internal and external defects, but also reduces the length of probe and power consumption. The agreement between simulation and experiment shows that the present method is correct. 相似文献
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Unlike the impedance plane analysis form of common eddy current testing (ECT), the remote field eddy current (RFEC) technique is a through-transmission effect that reduces problems such as lift-off normally associated with ECT. In the inspection of steam generator (SG) tubes, the real issue is to detect the minute cracks growing up from the outside. However, using ECT, it is considered infeasible to accurately find them from the inside because of the limitations of penetration of eddy currents. This paper describes a finite-element approach to the solution of time-harmonic electromagnetic fields for the RFEC technique based on a magnetic vector potential and an electric scalar potential. A comparison is made of experimental and finite-element predictions of electromagnetic phenomena under the inspection of non-magnetic tubes. For the cracks outside demanding high sensitive and precise measurements in the SG tube inspection, numerical results are given for parameters to design a RFEC probe. 相似文献
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压力容器无损检测--涡流检测技术 总被引:7,自引:4,他引:7
综述了压力容器用管材制造和压力容器使用过程中的涡流检测技术,包括制造过程中的铁磁性钢管和非铁磁性金属管材的涡流检测技术、在用铁磁性钢管的远场涡流检测技术、在用非铁磁性金属管的涡流检测技术和金属压力容器壳体焊缝表面裂纹的复平面分析涡流检测技术。 相似文献
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针对管材涡流探伤中存在的一些问题,研制出可匹配低激励电压ET-204型涡流仪的三点式探头,并采用阻抗平面显示技术选择最佳信噪比相位。实验结果表明,该方法具有远距离检测、高灵敏度、抗干扰的特点。 相似文献