石油天然气长输管道薄壁管环焊缝超声波探伤

结合齐鲁石化 -青岛管道工程实际 ,介绍了将高频大K值短前沿小径管探头 ,用于大口径薄壁管环焊缝超声波探伤 ,取得较好成效的做法 ,着重对长输管道薄壁管环焊缝探伤中探头试块的选用、回波信号的反射特点、缺陷波的一般判别方法和缺陷性质估判等方面进行了探讨和阐述     

超声波检测小径管对接焊缝的相关讨论

本文针对小径管对接焊缝的超声检测中探头的K值、合适的试块、合理的补偿量以及缺陷判定等几个方面来分析,讨论小径管超声波检测现场会出现的相关问题及解决方法。     

超声相控阵对小管径环焊缝缺陷检测能力研究

小径薄壁管在工业锅炉中应用较为广泛。由于其曲率半径较大,声束在其中扩散严重、反射率低,因此常规的超声检测手段,很难对其进行有效的检测。利用超声相控阵检测技术对小径薄壁管检测进行了研究。检测结果表明:超声相控阵检测技术有着较好的检出率,且解剖结果与超声相控阵检测结果基本吻合。     

小口径奥氏体不锈钢管对接焊缝超声波检测技术研究

开发了小口径奥氏体不锈钢管对接焊缝超声波检测专用探头,并设计制作了超声波检测对比试块。通过对比试验表明,采用该探头进行超声波检测具有信噪比高、杂波少、检测波束折射角大、传播距离长、缺陷定位准确、扫查范围不受焊缝余高限制等优点。该方法有针对性地解决了小口径奥氏体不锈钢管对接焊缝超声波检测的难题。     

织物增强橡胶件的无损检测

用超声波C扫描成像无损检测技术对织物增强橡胶件的内部质量进行无损检测,采用频率为5 MHz的探头检测,结果显示,存在声能衰减显著的区域。体视显微镜、金相观察结果表明,超声波C扫描声能衰减显著的区域不存在分层、气泡等内部质量缺陷,但超声波声能衰减显著区域的橡胶层厚度比声能衰减不显著区域的橡胶层厚度要厚0.228 mm。换用频率为1MHz的探头检测,结果显示,原来声能衰减显著的区域声能衰减已不再显著。橡胶层厚度较厚,橡胶材料衰减系数大的特性共同导致了超声波声能的显著衰减,适当降低探头频率可以减少由此带来的误判。     

发动机多层橡胶粘接结构超声波图像缺陷识别

针对发动机多层橡胶粘接结构缺陷识别问题,提出发动机多层橡胶粘接结构超声波图像缺陷识别方法.分析聚焦探头双模式检测法原理:针对多层橡胶粘接结构利用聚焦探头实施水浸斜声束检测可同时激励出横波和板波两种检测波形;依照此原理与超声波检测需求与技术要求,设计超声波图像检测系统,获取多层橡胶粘接结构超声波图像.以超声波图像为基础,...     

压力管道未焊透超声波检测的探头选择

未焊透是压力管道中最常见的危害性缺陷,超声波检测是压力管道检验中发现和评价未焊透的主要手段。闸述了压力管道未焊透超声波检测的现状和存在的主要问题,认为斜探头参数的合理选择是保证检测质量的关键。分析了斜探头晶片尺寸、探头频率、折射角(K值)、斜探头前沿长度对超声波检测可靠性的影响,计算出典型参数的平面单晶横波探头的声场特性值,提出了压力管道未焊透超声波检测横波探头的选择原则。     

大板梁翼板对接焊缝的超声波检测

介绍了电站锅炉大板梁140 mm厚翼板对接焊缝的超声波检测方法。主要论述了检测过程中探头的选取、扫查方式的确定以及利用CSK-Ⅳ试块制作DAC曲线的方法。     

CFRP蒙皮-CFRP胶接质量的原位超声检测技术

根据CFRP蒙皮-CFRP胶接结构的特点,采用窄脉冲超声反射法对其胶接质量进行原位检测;仿真分析了胶接结构中胶膜及界面脱粘对超声波反射信号的影响;并用自制的窄脉冲延迟块超声探头对脱粘试块进行检测。仿真分析表明:窄脉冲超声波反射信号能够检测Ⅰ界面脱粘;d/λ(胶膜厚度/超声波波长)≤0.5时,能够检测Ⅱ界面脱粘。实验结果表明:自制的5 MHz探头产生的脉冲周期不大于1.5周,达到窄脉冲的要求;采用超声反射法检测时自制的5 MHz探头能够检测出Ⅰ界面脱粘和厚度不大于0.5 mm胶膜的Ⅱ界面脱粘,满足实际产品的原位检测需求。     

小径管环向对接接头超声检测技术参数的选择

小径管是化学工业中输送化学介质最常见的特种设备之一,对于其焊接接头的质量控制,一般采用射线检测方法,但在压力管道定期检验时,经常遇到射线检测无法实施检验的部位,超声波检测是特种设备规范规定的一种替代方法。由于小径管的结构限制和超声检测的技术特点,超声波检测的技术参数选择对检测结果有重大影响。本文作者通过理论分析和试验论证,得出了采用高频率、大K值和化学浆糊的技术参数组合,能够最大限度地提高小径管缺陷检测信号幅值的结论。     

导波检测技术在“抚-鲅”线上的应用

用导波技术对管道缺陷检测进入工业现场应用阶段。介绍了超声导波技术的发展历史及基本理论。表述了导波检测技术"抚-鲅"线缺陷检测中的具体应用过程,检测缺陷结论经现场观测验证准确。表明管道缺陷导波检测技术在"抚-鲅"线上的应用成功。并指出随着超声导波技术的发展,其在管道缺陷检测工程中将得到广泛的应用。     

高温管道在线不停输检验技术研究

在压力管道在役检验领域,超声检测技术作为重要的检测手段已得到广泛应用。随着温度的变化,材料中超声波的声速、声压也会发生变化,掌握温度对超声波参数的影响规律,对高温状态下超声检测具有重要意义。讨论了在50~250℃温度之间,超声横波速度随温度变化的规律。研制了专门用于高温检测的超声横波斜探头。通过试验,给出了横波速度随温度变化的关系,用以修正不同温度下缺陷的实际位置和缺陷的尺寸大小。     

WALL SAMPLING FROM HORIZONTAL SLURRY PIPELINES

An experimental study of the errors associated with wall sampling from a horizontal slurry pipeline has been conducted. Experiments were performed for water-sand slurries flowing in a one inch horizontal pipeline. The effects of particle size (0.08 mm to 0.4 mm), upstream slurry solids concentration (4% to 12%, by volume), upstream bulk velocity (1.8 m/s to 4.0 m/s), sampler diameter (4 mm to 25.4 mm), sampler location, and sampling velocity ratio (defined as the ratio of the sampling velocity to the upstream bulk velocity, 0 to 4.5) on the sample solids concentration and sample particle size distribution were examined.

The experimental results show that the observed sample solids concentration and its particle size distribution are functions of the sampler location, sampler diameter and sampling velocity. For the case of sampling from the top or from the side of the pipe, the sampling efficiency (defined as the ratio of the sample solids concentration to the upstream solids concentration) was found to be always less than unity, and it increases as the sampling velocity increases. Also, the sample mean particle diameter is significantly smaller than that in the main pipe, especially at low sampling velocities. For sampling from the bottom of the pipe, the relation of the sampling efficiency to the sampling velocity ratio exhibits a maximum, and the sample mean particle diameter is very close to that in the main pipe.

The operating conditions upstream of the sampler also affect the sample solids concentration and its particle size distribution. The importance of the upstream bulk velocity, upstream solids concentration and particle size on the sample efficiency and sample particle size distribution depend on the sampler location.     

超声导波技术在压力管道缺陷检测中应用的局限性

超声导波检测技术是一种新型的长距离、快速检测手段。对影响超声导波检测结果的诸多因素进行了分析。在管线运行的状态下,利用MsS导波技术可以进行长距离管壁腐蚀等缺陷的检测。但该技术无法定量给出缺陷的形状、大小和性质,且具有诸多局限性,因而该技术的应用宜结合其他无损检测方法进行复验确认。     

The dependence of rapid crack propagation in polyethylene pipes on the plane stress fracture energy of the resin

The critical temperature [CT] for rapid crack propagation [RCP] was measured in 11 polyethylene [PE] 200 mm diameter gas pipes each with different resins. The plane stress fracture energy [PSFE] in thin Charpy impact specimens of the resin was found to correlate with the CT. The higher the PSFE, the lower the CT. This result was related to the observation that the PSFE decreases as the temperature decreases. It was found that the impact energy of specimens from compression molded pipe that was remelted at 180°C gave a better correlation with the CT than specimens that were machined from the inner wall of the pipe. Consequently, it is now possible to predict the CT of a pipe by measuring the PSFE of the resin without making the pipe.     

导波在石化企业高温管道腐蚀检测中的应用

超声导波检测应用的范围与导波激发的原理有关,根据高温管道的特点,选择采用磁致伸缩效应作为高温管道超声导波检测的激发原理。介绍了采用新型基于磁致伸缩效应的导波仪MsS 3030以高温管道的导波检测为例进行的现场检测,同时利用现场测厚验证导波检测的可靠性。结果证明,基于磁致伸缩效应的导波检测可以实现高温管道的在线检测,能有效发现腐蚀等面积缺陷,具有广泛的应用前景。     

Detection of Disbonds in Multi-layer Structures by Laser-Based Ultrasonic Technique

Adhesively bonded multi-layer structures are frequently used, mostly in the aerospace industry, for their structural efficiency. Nondestructive evaluation of bond integrity in these types of structures, both after manufacturing and for periodic inspection during service, is extremely important.

A laser-based ultrasonic technique has been evaluated for non-contact detection of disbonds in aluminum multi-layer structures. Two configurations have been used to detect disbonded areas: pitch-catch with unidirectional guided wave scan and through-transmission with bidirectional scan. Guided wave scanning was done with a laser line source and air-coupled transducer sensing at 500 kHz, 1 MHz, and 2 MHz. Signals showed attenuation of the main frequency component and frequency shift on disbonded areas, whereas, a regular and standard waveform is seen outside disbonds. In through-transmission the longitudinal wave at normal incidence was monitored with a 1 MHz probe. One sample showed, besides the introduced inserts, other disbonded areas. After the ultrasonic measurements the sample was cut to visually check adhesive and interfaces.

The guided wave pitch-catch scan allowed fast inspection and quick indication of disbonded zones, while the through-transmission C-Scan provided better definition of defects but was slower and required access from both sides of the test part.     

Wall thickness uniformity in plastic pipes: Computer simulations of the effectiveness of die mandrel offsetting and pipe rotation in combatting sag

A computer simulation, based on a thermoviscous model of cooling and gravity induced flow (sag) in plastic pipe manufacture, which has previously been described in detail and validated against experimental results, is here used to investigate the effectiveness of die mandrel offsetting and pipe rotation in combatting sag. SDR11 MDPE pipes of 315, 560, 800, and 1000 mm diameter are considered. Results are examined in terms of a waste percentage, representing polymer used in excess of that corresponding to the minimum wall thickness. With a concentric mandrel, waste is predicted to be 4.3, 14.0, 17.9, and 18.7% for the four sizes, respectively. Optimum offsets and minimum waste percentages are found to be: 2 mm, 0.8%; 15 mm, 4.6%; 42 m, 9.8%; 63 mm, 12.7%, respectively. For the largest pipe this corresponds to a wall thickness variation of 19.6 mm. Simulations of rotation of the 800 mm pipe show waste falling rapidly to 5% at 1 revolution/4800s, then a slower decrease, reaching 1.6% at 1 revolution/600s. The simulation is equally applicable to all grades and sizes of pipe, and provides a valuable computer aid for the design and operation of pipe cooling lines.     

Experimental Study on the Dynamic Strain of a Thin-Walled Pipe in the Gas Cloud Explosion with Ignition Energy

This paper describes an experimental study of the flame propagation mechanism for the combustible gas explosion in a closed pipe with a length of 12 m and an internal diameter of 0.125 m, which is carried out for different values of the ignition energy. The results show that an increase in the ignition energy results in greater explosive intensity, maximum peak pressure, and dynamic strain of the thin wall in the whole process. Moreover, the dynamic strain of the thin-walled pipe increases suddenly owing to arrival of a precursor shock wave and then vibrates for a long time, which is induced by the wave reflected back and forth. In addition, there is good agreement between the dynamic strain signals and pressure wave signals. These research results can provide a theoretical basis for industrial explosion accident assessments as well as explosion and shock resistance designs, which provides guidance not only for industrial safety, but also for prevention and mitigation of explosion accidents.     

聚四氟乙烯彩色微型管的加工应用技术

重点介绍了聚四氟乙烯（PTFE或F4）微型管的着色等加工应用技术。用此技术生产的外径2．4mm、壁厚0．2mm的红色微型管外观色泽鲜艳，质地均匀光滑，交流击穿电压达5．5kV。