小口径薄壁管在役超声波检测

为能更好地保证核电站辅助工艺管道系统中的小口径薄壁管在役时的运行状态良好，有效检出其内外壁轴向缺陷十分重要。介绍了小口径薄壁管在役超声波检测的系统组成、技术方法、超声波探头参数的选择、设计原理、在役检测时局部水套的设计制作基本原理以及检测实施过程中的要点。经过大量的试验和现场检测，证明采用聚焦探头和局部水套的水浸聚焦法检测小口径薄壁管内外壁的轴向缺陷能够达到理想的检测效果。     

Remote field eddy current technique applied to non-magnetic steam generator tubes

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.     

钢管内壁缺陷涡流检测的机理研究

钢管涡流检测多采用磁饱和技术以抑制磁导率波动引起的信号噪声,检测实践中发现此时内壁缺陷被检出,这与趋肤效应原理相矛盾。建立了含内壁刻槽的钢管磁饱和下的仿真和试验模型,剖析了内壁缺陷检出机理。仿真和试验结果表明:钢管缺陷漏磁场在探头内引起低频响应经相敏检波后被滤除,对信号无作用贡献,内壁缺陷在钢管外壁引起的磁导率畸变是影响信号的真正根源。研究结果明确了磁饱和下钢管涡流检测机理,可望指导钢管的工程实践检测。     

Coupled approach VIM–BEM for efficient modeling of ECT signal due to narrow cracks and volumetric flaws in planar layered media

Rapid and accurate modeling of Eddy Current Testing (ECT) signal is required in many industrial areas. For example, crack detection via ECT is widely employed in aeronautics and aerospace industry to inspect riveted planar multilayered structures. In these structures, small narrow cracks (e.g. micro-cracks) may initiate at the edge of rivet holes (which can be considered as large volumetric flaws) and propagate through the PMS. This paper proposes a new and efficient model, based on a coupled approach between Volume Integral Method (VIM) and Boundary Element Method (BEM), simulating ECT probe signals due to the presence of both narrow cracks located near volumetric flaws within a given PMS. Simulation results are compared with experimental and simulated signals obtained with a numerical code. The performance of the method, in terms of accuracy and computational time, is discussed and the perspectives opened are presented.     

核电厂两根"内含缺陷"管的运行跟踪检查及研究

通过长期跟踪检查及相关理论的研究，纠正了役前检查时两根定为内部有缺陷管子的错误结论，并作了较确切的定性。     

Emissivity measurements on aeronautical alloys

The emissivity of three Ni and Co based aeronautical alloys is analyzed in this paper. These alloys are employed in high temperature environments whenever good corrosion resistance, high temperature resistance and high strength are essential. Thus, apart from the aeronautical industry, these alloys are also used in other technological applications, as for example, aerospace, nuclear reactors, and tooling. The results in this paper extend the emissivity data for these alloys available in the literature. Emissivity dependence on the radiation wavelength (2–22 μm), sample temperature (200–650 °C) and emission angle (0–85°) has been investigated. In addition, the effect of surface finish and oxidation has also been taken into consideration. The data in this paper have several applications, as temperature measurement of a target by pyrometry, low observability of airplanes and thermal radiation heat transfer simulation in airplane nozzles or furnaces.     

Image fusion of ultrasonic and thermographic inspection of carbon/epoxy patches bonded to an aluminum plate

Inspecting damaged structures repaired with composite patches is one of the most challenging issues of different industries, especially in aeronautical vehicles. Various inspection methods such as ultrasonic (UT) and thermographic methods are commonly applied to the patches and bondings. Although, both ultrasonic and thermographic inspections have their own capabilities, they are also associated with some limitations especially in the inspection of complicated structures such as multilayers. Different data fusion techniques can be used to overcome these limitations, by exploiting the advantages of each inspection technique to achieve the goal to have a more precise and reliable defects assessment. In this paper, different image fusion algorithms are used to fuse the UT C-scan and thermal images obtained from thermographic inspection of carbon/epoxy patches bonded to an aluminum plate. The inspected specimen contained several delaminations of various sizes and locations along with some disbond defects which were artificially embedded in five samples of composite patches. The resulting images of 28 fusion algorithms and the input images have been quantitatively compared using Average Differences (AD) to clarify the efficiency of the fusion algorithm. Comparing results revealed that contrast pyramid was selected as the best image fusion algorithms which can be used for NDE fusion of carbon/epoxy patches bonded to an aluminum plate.     

玻璃纤维结构风电叶片的超声相控阵检测方法研究

随着中国风电行业的兴起和逐渐成熟,对风电系统本身的质量要求也越来越高,尤其是叶片检测越来越受到各个叶片制造企业的关注。但常用的敲击手段、光照手段等已经无法满足更高的质量要求,即使是使用常规超声技术,由于探头尺寸的限制,无法实现大面积的快速扫查,且数据判读和缺陷检出率受人为因素影响较大。基于上述原因,介绍了一种利用超声相控阵技术,并结合专用的风电叶片检测探头对风电叶片进行检测的方法。通过近3年的实验,证明了使用超声相控阵技术可以快速准确地检测风电叶片内部缺陷,包括玻璃纤维外壳内部的分层和干丝缺陷,以及玻璃纤维外壳和内部支撑结构之间的脱粘缺陷,并基本掌握了风电叶片的检测方法和要点。其优势包括直观C扫描成像、检测效率高、易于存储记录等诸多优点,因而在风电制造行业有着广泛地应用前景。     

核一级截止阀堆焊缺陷的成因分析及改进

针对某核电厂发现核一级截止阀发生内漏的情况,进一步检查发现是由于该阀门密封面堆焊的硬质合金(铁基)产生裂纹,从而导致阀门内漏.通过化学成分分析、金相组织分析、硬度检测、SEM分析和EDS分析对裂纹产生原因进行研究,对工艺及焊接过程控制进行了改进,基本解决了铁基堆焊裂纹问题.对后续各核电厂同类核级阀门铁基堆焊密封面缺陷的...     

重水堆压力管超声检查数据偏差分析

对核电站压力管前后两次在役检查缺陷数据变化的原因进行了分析，认为缺陷表面不平整和检查系统误差是影响检查精度的主要因素，两者共同作用使检查数据服从正态分布规律。经过分析，得到缺陷并未明显扩展的结论。     

中国航空结构用新型钛合金研究

中国钛产业近几年来得到了快速发展，钛材产量已经位居世界第4位，但航空结构用钛合金产品（锻件和大棒材等半成品）只占10％左右，距离世界水平的50％差距甚远。所以，加强航空结构用新型钛合金材料技术及其应用研究，提高航空结构用钛合金的加工技术和应用水平，建立具有中国特色的航空结构用钛合金材料体系，是提高钛合金在航空工业用量的重要推动力和保障。本文从分析国内外钛合金产业结构特点出发，重点阐述航空结构用新型钛合金材料和新型热工艺技术的最新研究进展。     

Flaw inspection of welded joints in titanium alloys by the eddy current method

The eddy current transducer (ECT) of the transformer type is used to construct a sensor for investigating titanium sheets joined by a welded joint. The characteristics of the ECT are presented. The measurement method for controlling the occurrence of defects in the welded joints in titanium alloys is described. The experimental results obtained by the ECT on two welded titanium sheets are presented. The depth of penetration of the field of eddy currents into the investigated object is determined and the dependences describing the response of the ECT at different depths of the defect are outlined. The relationships can be used for evaluating the quality of welded joints and determining the reliability of welding.     

汽轮机转子叶片根部超声相控阵检验应用与分析

由于汽轮机转子叶片运行工况复杂多变,极易在根部产生裂纹等危害性缺陷,对超声检验的专业性、安全性、稳定性及便捷性等提出了更高的要求。如何发现超声检验中的不足并加以改进,使之能更好地适应现场检查成为被关注的议题。简单介绍超声相控阵检验技术工作原理,重点对检验工艺和检验器材的选定、超声相控阵检验工艺和检验过程中问题等进行详细论述,并针对存在的问题提出改进建议。最终确定的相控阵检验技术在现场实际应用中发现了重大危害性裂纹缺陷,可在核电无损检验领域进行推广。     

国产核岛主设备焊接技术现状及发展趋势分析

为探究核电厂主管道窄间隙焊缝射线检验出现的疑似线性缺陷的产生机理,采用扫描电镜、原子探针等方法分析了存在疑似线性缺陷的焊缝微观组织与显微硬度,讨论了显微组织中的微细孔隙形成原因,并采用孔隙率表征了微细孔隙分布。研究表明,疑似线性缺陷不是真正的焊接缺陷,存在疑似线性缺陷的焊缝组织均由奥氏体与δ铁素体构成,不同区域的δ铁素体含量基本相同,存在疑似线性缺陷的焊缝的孔隙率为0.06%,高于无疑似线性缺陷区域的0.03%。显微组织中微细孔隙率的差异是导致疑似线性缺陷产生的主要原因,但孔隙率的差异不影响焊缝的显微硬度分布。该研究为类似射线检验出现的疑似线性缺陷提供了评判新思路。

     

反应堆压力容器安全端异种金属焊缝超声检查技术

堆焊层、奥氏体粗晶材料的存在以及焊缝几何结构的复杂性使得反应堆压力容器安全端异种金属焊缝的超声检查非常具有挑战性。为提高安全端异种金属焊缝超声检查的可靠性和检查效率,利用常规双晶纵波检查技术及相控阵检查技术开展了安全端异种金属焊缝超声检查技术研究。试验结果表明,常规双晶纵波检查技术及相控阵检查技术均可有效检出安全端异种金属焊缝中的缺陷,且缺陷定量精度满足相关规范要求。其中,常规双晶纵波检查技术现已应用到核电站的役前检查及在役检查中,相控阵检查技术的缺陷定量精度及检查效率均优于常规双晶纵波检查技术。     

核电厂低压缸汽轮机转子叶片的渗透检测

针对国内某核电厂运行期间发生汽轮机叶片断裂事件,通过对叶片运行时的受力情况及易产生缺陷区域进行分析,明确了缺陷不能被完全检出的原因;通过比较试验法,改进并确定了最优的渗透检测工艺,并在核电厂大修中取得良好效果.     

Using phased array ultrasonic technique for the inspection of straddle mount-type low-pressure turbine disc

Discovery of stress corrosion cracking (SCC) in the blade attachment region of nuclear power plant low-pressure steam turbine discs leads to industry concern about this problem. Reliable inspection methods for the detection of SCC in steam turbine blade attachment area are essential to the rotor run/repair/retire decision making process. The conventional broad beam ultrasonic inspection technique usually has inadequate resolution for flaw sizing and tendency for false calls. But the phased array technique by improved detection capability and resolution could increase coverage of the examination areas with less scanning required. Using phased array ultrasonic technique to straddle mount-type low-pressure turbine disc in nuclear power plant located in Korea was studied in this paper.     

Localization of defects in steam generator tubes using a multi-coil eddy current probe dedicated to high speed inspection

Steam generator (SG) tubing of pressurized water reactor in nuclear plants must be rapidly and accurately checked in order to detect defects in their early stages. In this paper, the authors present a multi-coil eddy current (EC) probe allowing both high speed inspection and circumferential localization of defects in the tube wall. A method of multi-coil EC signal processing, based on a continuous wavelet transform combined with a maximum likelihood diagnosis, is elaborated in order to enhance the detection performances and to provide automatic localization of defects. The inspection of SG tube samples shows good localization performances for defects as small as 10% deep, 15 mm long and 100 μm wide outer diameter notches, of both circumferential and axial orientations.     

核电站小径薄壁管插接焊缝的相控阵超声检测

小径薄壁管是核电站运行中最容易生成缺陷和发生泄漏的部件和位置。小径薄壁管插接焊缝一般采用射线法进行检测,但是射线检测存在辐射风险,检测区域需要隔离且检测工期较长,并不适于核电站大修期间的大范围应用。通过自然缺陷试块进行小径薄壁管插接焊缝相控阵超声波检测工艺分析及检测能力验证研究。在此基础上,成功将相控阵超声检测技术应用于核电大修现场并发现缺陷。     

超超临界机组锅炉异种钢小径管镍基焊接接头超声波检测

针对超声检测火力发电厂锅炉小径管奥氏体钢与低合金钢对接异种钢焊缝的技术难题,文章通过理论分析、试验研究及现场检测验证,研究了常规小径管探头异种钢焊缝超声波检测方法。结果表明,对于如熔合线裂纹类缺陷选用小角度探头(K1～1.5)效果较佳;对于焊缝内缺陷宜选用大角度探头(K2～2.5)。利用该方法能有效检测出焊缝内各种缺陷,保证了机组安全运行也取得了较好的经济效益,对异种钢焊缝小径管超声波检测具有较强的借鉴意义。