Magnetic pipe flaw detector ДМТП

-A ДМТП magnetic flaw detector with transverse magnetization of pipes, which was designed at ZAO Spektr is described in brief. It is to be used for inspecting the state of buried gas-main pipelines, detecting mechanical, erosion, and corrosion flaws in them, and estimating their dimensions and location in the tested section. Performance characteristics of the flaw detector are compared with those of earlier designed flaw detectors with longitudinal magnetization of tested pipes.     

The development of theoretical foundations for electromagnetic flaw detection of oil and gas wells

Theoretical foundations of the development of nonstationary electromagnetic (EM) flaw detection of wells as applied to the problem of measuring the wall thickness of casing and lifting pipes of oil and oil-and-gas wells are considered taking into account the diversity of EM properties of metals. Analytical dependences and experimental data on measuring the EM fields formed in the presence of local inhomogeneities of a string, such as small-diameter holes, are analyzed. Main requirements for the engineering parameters of the equipment and principles of interpreting well-logging EM flaw detection are shown.Translated from Defektoskopiya, Vol. 40, No. 12, 2004, pp. 60–73.Original Russian Text Copyright © 2004 by Teplukhin.This revised version was published online in April 2005 with a corrected cover date.     

A decrease in the error of the statistical method for estimating the parameters of flaws in magnetic flaw detection

A method for increasing the accuracy of evaluating the dimensions of flaws during magnetic flaw detection in steel sheets and pipes, which is based on the division of a set of flaws into subclasses using a certain generalized parameter in accordance with the criterion of minimization of an appropriate estimate, is described. The results of applicability of this method to the evaluation of the depths of flaws of the metal loss type are presented.     

含裂纹管道的失效评定曲线的实例验证

验证含裂纹油气管道的失效评定曲线，实例来源于某输油管线现场水压试验中爆裂的三个管段。给出基于J积分理论的含裂纹管道的失效评定曲线的基本方程，并采用有限元方法计算裂纹管道的J积分。对三个破坏的含裂纹管段，根据现场测量的裂纹尺寸和管材的力学性能试验数据，建立失效评定曲线，并与水压实验结果作比较，表明所建立的失效评定曲线的准确性。     

On the analysis of in-tube flaw-detection results characterizing the state of a trunk gas pipeline with corrosion flaws

Today, results of in-tube flaw detection (ITFD) are used mainly to solve routine problems of the provision of service reliability of operating gas pipelines (via the removal or selective repair of damaged pipes). However, the task of nondestructive testing consists in not only the detection of flaws but also in the determination of the principal causes of their appearance. This calls for the use of quantitative indexes of flaw parameters for estimating steady tendencies toward the development of damaging, determining the most essential causes of the formation of detected flaws, and predicting possible dynamics of their propagation as the time of operation of a trunk gas pipeline (TGP) system increases. These tasks can be solved based on an analysis of primary results of ITFD by selecting and using steady quantitative indexes of the total damaging using statistical techniques.Translated from Defektoskopiya, Vol. 40, No. 10, 2004, pp. 79–88.Original Russian Text Copyright © 2004 by Gorchakov, Dolgov, Yu. Surkov, Rybalko, A. Surkov.     

自动超声探伤的抗干扰研究

在自动超声探伤领域中，传统的多通道超声波探伤仪的抗干扰性能不甚理想的主要原因是其相关报警电路的抑制干扰性能较差。本文介绍了设计新颖的干扰抑制电路——符合式缺陷脉冲鉴别电路的构成与工作原理，并进一步叙述了采用该电路的ＣＴＳ－４６型六通道超声波探伤仪的抗干扰性能实验及现场测试实验。结论表明符合式缺陷脉冲鉴别电路的抗干扰性能很强，对自动探伤用多通道超声探伤仪而言，是一个很好的相关报警电路。     

The Magnetizing System of an In-Tube Flaw Detector with Transverse Magnetization

Results of calculations of the magnetizing system for a flaw detector are presented. The device is intended to determine longitudinal stress-corrosion cracks in pipes in underground trunk pipelines. The calculation results are compared to the experimental data obtained with a special model of the magnetizing device. The optimum parameters of magnetizing elements, as well as their mutual location that ensures the magnitude and direction of the magnetic flux in a pipeline's wall that are required for reliable identification of longitudinal defects, are determined. The obtained results were used as a basis for designing the magnetizing system's module, which is the main unit in each in-tube flaw detector.     

Analysis of the development of stress corrosion cracking in pipelines of compressor stations

The problem of corrosion cracking in underground gas pipelines has been a focus of attention of gas-transporting enterprises for more than 15 years, but so far there is neither an unambiguous assessment of the main causes of this phenomenon nor acceptable methods for reducing it (except detection of stress corrosion cracking (SCC) flaws by means of in-tube flaw detection and the subsequent elimination of these flaws). One important feature of the manifestation of the problem of SCC in main gas pipelines is the selectivity of cracking (SCC is identified in a small fraction of pipes), the causes of which are unknown. It is still not clear whether this feature is due to the time delay of SCC or this effect has another origin and is associated with the resistance of the greater part of pipes to stress corrosion damageability. This issue is directly related to forecasting of the further development of stress corrosion damageability both for gas pipelines in which SCC has already been detected and for segments in which SCC problems have not yet arisen. An especially pressing task is assessing the possibility of the development of SCC in process pipelines of compressor stations situated in regions where the presence of the SCC process on linear segments has been identified, because equipment operation and the presence of maintenance staff on the station territory involve increased risk.     

基于弱磁探伤的钢丝绳无损检测技术

研究了基于弱磁探伤的钢丝绳无损检测原理与技术.通过对国内现有的钢丝绳弱磁探伤仪进行实验研究,展示了现有钢丝绳弱磁探伤技术的优势和劣势所在,并对存在的问题进行分析,针对问题提出了钢丝绳弱磁探伤技术未来发展的方向.     

联箱管座角焊缝超声检测专家系统的开发

为了快速、准确地检出联箱管座角焊缝中的缺陷，研究开发出管座角焊缝超声检测专家系统。该系统解决了管座角焊缝主、支管两侧探伤的缺陷信号识别和缺陷定位困难等问题，亦能够对工艺规范、操作方法等探伤全过程提供指导和专家咨询。该系统采用visual Basic6．0语言设计而成，人机界面友好，操作方便。     

Eddy-current nondestructive testing of long cylindrical components using spatial magnetic field components of different frequencies

The feasibility of the eddy-current nondestructive testing using two orthogonal harmonic components of the driving magnetic field has been studied. The paper describes the practical implementation of the method in a flaw detector testing ferromagnetic rods and pipes and designed for detecting elongated flaws with small gradients of longitudinal parameters.     

A model of a surface flaw of finite length under normal magnetization and calculation of the topography of its magnetostatic field

A calculated model of the magnetic field of a surface flaw with a rectangular cross section and a finite length under normal magnetization of the tested surface is proposed. Practically convenient expressions for calculating the phase angle ? between the imaginary and real magnetic components have been obtained. An algorithm for estimating the parameters of the flaw and principles of building devices for electromagnetic flaw detection and flaw measurement are proposed.     

基于二维光扫描的细长孔内壁疵病检测技术

细长孔内壁疵病检测是采用光学、机械、计算机等技术实现深孔内表面疵病的自动观察与检测.该测试系统由光扫描光学成像分系统、CCD摄像分系统、计算机控制及图像处理分系统等组成.被测面的反射像通过内窥镜成像在面阵CCD的光敏面上,CCD输出的视频信号经图像采集卡输入计算机,经图像拼接及图像处理,最终完成疵病的检测与尺寸测量,测量精度可达到0.2 mm.本文重点介绍了细长孔内壁疵病检测的原理、二维光扫描成像技术、图像拼接和图像处理技术,并对总体的检测精度进行了分析.该项检测技术不仅可计算出细长孔内壁疵病的面积大小、方位,还可检测出镀铬层脱落面的大小、方位,内壁裂纹的长度、方位等.     

Ultrasonic Flaw Echoes Detection Based on Generalized S-Transform

Micro defects usually lead to performance degradation of materials. Pulse-echo technique is an effective method of revealing micro defects in materials, and booming in which has been witnessed over the years. However, detection of flaw echoes submerged in intensive noise is challenging. In this paper, a method of flaw echoes detection based on generalized S-transform is proposed. The original signals are transformed to time-frequency domain by generalized S-transform in the first stage. Subsequently, the time-frequency spectrums are enhanced through image segmentation techniques, including global thresholding and dilation. Finally, clear flaw echoes are obtained by inverse generalized S-transform, contributing to further investigation of defects. Both the simulation and experimental results show effectiveness of the flaw echoes detection method.     

Toroidally focused ultrasonic flaw detectors

New-type toroidally focused ultrasonic flaw detectors, whose application provides an appreciable increase in the flaw detection rate with retention of high sensitivity to flaws, are considered. The construction of a flaw detector is presented, the sizes of a gauge for the formation of the toroidal surface of a lens are given, and the technology of the manufacturing of a toroidal lens is described.     

Application of the correlation method and optimal filtering in problems of flaw detection in trunk pipelines

The problem of flaw detection against a background of nonuniform structural noise is considered. The example of magnetic intratube flaw detection in seamless sections of trunk pipelines is analyzed. Synthesis of a two-dimensional optimal filter and application of the correlation method to a scaled model of a flaw are described. A comparative analysis of the application of this method to actual diagnostic signals is presented.     

[制造与维修工艺]基于相控阵的高速铁路钢轨超声探伤检测系统

针对现有车载自动探伤设备检测可靠性偏低、误报率高,存在漏报隐患,难以满足高铁工程技术发展和建设规划需求的现状,提出了一种新型钢轨超声探伤检测系统。研发了高速记录多通道数字探伤仪,用于实现钢轨高速检测条件下全波形数据的实时采集,采用相控阵超声系统检测钢轨焊接接头。通过试验验证了该系统的有效性。研究结果表明,该系统可进行高速探伤数据的采集,实现实时探伤、记录和智能化数据分析。     

Inspection of rotor disks of HPT and LPT of TK-10-4 gas-compressor units by the ultrasonic flaw detection method

The special features of diagnosing disks of gas turbines of gas-compressor units by the ultrasonic flaw detection method are considered. The efficiency of detecting crack-type defects in disks of HPT and LPT rotors under the first tooth of fir-tree slots of the disks in the area of trapezoidal grooves for tightening plates is shown. The application of the ultrasonic flaw detection method substantially increases the reliability of crack detection.     

The UMD-101M plant for automated bulk magnetic nondestructive testing of quality of electric-welded pipes

The optimal structural scheme and special features of the new automated plant for magnetic nondestructive testing of electric-welded pipes in a technological industrial line, which meets contemporary demands, are considered. It has been shown that the use of computer technologies and thin-filmed high-resolution transducers provides significant improvement of operating possibilities of a flaw detector and makes it possible to detect, not only such flaws as discontinuities in metal and displacement of edges, but also flaws caused by failures in welding regimes, such as burns and cohesion of edges near a welded joint.     

钢丝绳无损检测技术研究进展

针对钢丝绳应用及检测过程中安全性能、利用率、检测精度等问题,综合分析了现阶段钢丝绳无损检测国内外相关研究成果,总结并提出了今后的研究方向。首先,介绍了无损检测技术当前在实际工程中的应用,具体对比分析了两种主流探伤仪技术特点,以及在桥梁建筑等行业中的应用;接着,介绍了现在无损检测技术发展状况,着重论述了钢丝绳磁检测技术和非磁检测技术研究和应用现状,其中磁检测技术主要包括电磁法和永磁法,非磁检测主要包括电流法、声发射法和声-超声检测法;最后,在对比当前无损检测研究方法的基础上提出了集中钢丝绳无损检测的可行方法,指出了发展声-超声检测技术的研究趋势。