外文翻译-相控阵对焊接接头的超声检查注意事项

XX大学毕业设计文献翻译与原文 题 目： 相控阵对焊接接头的超声检查注意事项 学 院： 测试与光电工程学院专业名称： 测控技术与仪器班级学号： 学生姓名： 指导教师： 二Oxx年 四 月 相控阵对焊接接头的超声检查注意事项格哈德格律恩国立焊接及材料测试 - ISIM蒂米什瓦拉电话：+ 40256491828，传真：-40256492797，电子邮件：ggruenisim.ro摘要：相比较于超声焊接接头的常规检查中加入的相控阵技术提出了一系列的措施以及这些新的检测技术的具体优势，两者之间，我们可以说：一个具有更高的检测速度，检测概率的不连续性更好，尺寸性能更好的不连续性，二维图像，所有的数据存储，高重现性和降低安全风险等优势。在目前的工作中的某些方面进行了关于手动检查程序的讨论，该检查要求根据不同的代码，仪器校准，检查区覆盖，扫描程序和扇形扫描数据解释。关键词：超声常规检查，相控阵技术，检测概率，二维图像1 引言最大的适用性的并在特定的便携式相控阵单元的相控阵方法是手动和半自动检查焊接和类似的部件。本文介绍了使用相控阵的方法焊接检验的基本原理，检验程序和采用手动和半自动s-扫描和E-扫描扫描焊缝的数据分析。2 人工检测方法使用相控阵技术检查的焊缝一般有两种形式：使用光栅扫描技术的手动单晶的常规技术仿真执行线性扫描以覆盖整个焊接表面这两个接近的方法如图1和2所示。根据图1，光栅扫描技术有模拟技术现状的优点，不需要新的检验码。该技术覆盖焊接表面的多个角度，其结果相比于单晶常规方法将更具有重复性，图像缺陷是级别太高。相控阵光栅扫描不提供通过相控阵超声检测带来的效益，具有更高速度和完整的数据存储。根据图2，线性或单向扫描的方法比光栅或单晶的常规技术要快得多。它可以保存所有数据的编纂。在本质上，这是一个简单的自动和半自动焊接检验便携式相控阵方法。线性扫描可以使用编码器，可以简单地进行手动。该方法具有一定的优势：线性扫描速度更快，也许比手动技术快5倍，节约成本所有数据可以使用半自动扫描保存（带编码器）甚至手动扫描，关键数据可以通过简单的冻结图像保存结果是高度可重复性，尽管第三方通过测试确认这项事实比单晶的常规技术的数据分析少而简单图1 传统光栅方法原理介绍扫描图2 图式介绍线性扫描的概念3 代码和校准 当有要求时，焊缝必须按代码或规范检查。通常情况下，指定的检查代码由大型组织ASME，AWS和API开发。这些检查码指定设备类型，其校准程序，扫描技术，尺寸和特性程序。4 E-扫描相对于传统的单晶体，相控阵天线可以在多角度产生超声波束。使用E-扫描（固定角度扫描电子光栅），会出现一些代码和校准的问题，因为这些人模仿传统的单晶检查；校准和设置与手动技术一样。如果采用线性扫描探头不振荡的检测是面向下其他角度的缺陷，扫描模式可能不同。总之，添加衍射时差会稍微弥补这方面。图3给出了一个在两个不同的角度E-扫描实例探索，例如，一个典型的代码检查。它总是先需要一个楔形延迟的校准。图3 A-扫描和C-扫描在超声波装置不同角度的双扫描5 S-扫描S扫描提供不同的扫描结果。而正常的代码程序包括在一个圆柱孔或一个恒定的超声波路径深度缺口校准，利用S扫描这个功能就更加困难了。每一个角度，该反射镜的距离随金属而变化。同样地，根据物理定律通过楔形梁的振幅的路径各不相同。这一方面如图4所示。图4 S-扫描圆柱孔校正的影响：不同角度，不同衰减，没有校正可能的近场效应选择固定深度圆柱孔校准是为了补偿通过校正半径角梁信号的幅度变化，如图5所示，提供了一个恒定的超声波路径，一个恒定的衰减和相同的所有角度的近场。图5 为在一个半径获得角度校正增益的校准（ACG）ACG要求与时间校正增益（TCG）为S扫描。因此，该校准反射器（或圆柱孔）应显示相同的振幅，无论它位于S-扫描馅饼”真正的深度是哪里。同样的事实用相控阵装置是很容易证明的。图6说明了一个A型包络圆柱孔套校准后具有几乎相同的振幅。图6 圆柱孔扫描使用一束55剪切波，与ACG和TCG（校准幅度低的变化）校准在实践中，ACG和TCG是利用有着相控阵仪器的自动TCG功能结合在一个单一的过程。尽管这些校准要求，它必须记住，S-扫描是一组在不同的角度进行扫描的A-扫描。再者，它总是要求一个楔形延迟的校准。其他对于S扫描是入射角“或BIA”的偏见是主要的结果。代码ASME不指定具体的生物，但他们声称必须使用“足够的角度”。不幸的是，混凝土的适当的角度是不明确的。一些代码请求特定的角度，但这种方法也有其自身的局限性。BIA的外观可以很容易在图7看到。根部缺陷的最佳检测对于探头的最佳位置在材料本身的角度和焊接的上表面是不同的。图7 对焊接的S-扫描检测原理介绍，中间部分是明显不同的根区最佳角度可以修改适当的角度来发现最佳的覆盖范围。图8展示了射线图，显示了要求提供BIA5正常的发病率的S-扫描次数：三种在不同距离的焊接中心的S-扫描。图8 射线图显示的需要BIA5相比于正常的S-扫描次数图9显示了BIA在10范围内，两次扫描可以提供足够的覆盖范围，扫描是非常方便的。例如，组件的厚度不决定S扫描次数，BIA的开放性角度是一个S-扫描指令数。这个问题还没有在代码中完全阐明。图 9 射线图说明要求通过BIA10到正常的S-扫描次数请求扫描的数量首先是一个几何效应，原则上，大孔径要求少扫描，虽然有其他的影响如近场的复杂问题。另一个问题是重点表示，虽然这是有效的解决码。它是应用于S扫描和E-扫描。如果是适当程序相控阵可以短距离电子集中，这将在焦点之后距离梁产生一个大的角度。这种效果如图10所示。在实践中，光束可能在远焦点之后制定有效的聚焦很弱几乎没有。图10 修改光束的焦点效应 左：不用天然焦集中在150毫米和2或4光束发散角右：电子聚焦在15毫米与20光束发散角然而代码用特殊方法分类聚焦方式，所有代码需要正确校准。这一事实意味着如果光束发散角非常强烈而信号很弱以至于树立正确的校准是不可能，焦点的变化是必须的。在ASME规范的情况下，焦距的标定同样适用于相控阵的制备。6 覆盖技术和程序必须证明焊缝、热影响区（HAZ）和封闭材料的充分覆盖，如代码中指定的。用一个方便的方法，绘制简单的光线程序通常足够表明覆盖面，如图11和12所示。图11说明了覆盖的焊缝使用E-扫描和图12示出了采用在焊缝中心线的参考点的实际扫描技术。图11 上：使用E-扫描焊接检验说明 下：使用E-扫描焊缝的覆盖图图12 E-扫描程序插图，呈现扫描模式和到焊缝中心的距离在此过程中，操作者必须记录扫描模式，偏移，位置和尺寸的技术部分。这方面必须请求指定代码。7 扫描技术一种关于板和管基材料与碳钢或不锈钢焊缝的超声波探伤相控阵技术已准备好。本程序将应用于12mm和25mm厚度之间（这给出了一个从0.5到1.5倍的合理面积，然后检查组件，或从6mm到38mm）。这项技术是根据ASME规范相控阵造影奥林匹斯无损检测系统指定。一个不隐秘测试（开放测试）是用来证明效率的。随着相控阵造影技术的编码器接口工具是可选的，例如，扫描可以是手动或半自动。楔形延迟和灵敏度校准是强制性的，汽车公司造影功能包括在一个单一程序ACG（角度校正增益）和TCG（时间校正增益）。相控阵扫描要求一个完整文档。具体来说，扫描计划必须证明，使用绘图或计算机模拟，适当的检查对于角焊缝的曲线角的准备（例如，40-60或5570）并将在考试过程中使用。该扫描计划必须被记录用来证明考试卷已被检查。该扫描计划已经成为最后的检查报告其中的一部分。如图2所示程序采用线扫描技术为一个快速检查，而不是一个光栅扫描技术。具体来讲，至少两次E-扫描或S-扫描是从焊缝中心和焊缝表面的两个不同的指数点进行来保证焊缝以及热影响区的范围。公称壁厚大于25毫米的材料需要多线扫描，为了覆盖指定的卷焊接与基体材料。以类似的方式，一般的程序，API和AWS的代码已被开发。8 S-扫描数据的解释该扫描数据的解释类似于传统的手动超声检测，具有改进的图像和数据记录。S-扫描提供其他优点是因为他们使用的多角度，提供更大的覆盖。图13说明具有缺陷定位技术的S-扫描。该S-扫描图像允许缺陷的快速评价，在本例中，与壁厚标记相比内部和外部直径上的缺陷可快速获得（B0内径根，T1外直径焊接上，B2一个检测步骤和半根等）。壁中间的缺陷会在B和T虚线之间出现。以类似的方式，使用S-扫描缺陷尺寸有着显着的优势。对于很多时候，缺陷的边缘可以被检测，以及底部，所以扩散的边缘信号可用于上浆。图14说明了裂纹识别的一个例子。在一般情况下，施胶技术与边缘扩散比基于振幅的测量技术更准确。图13 上：对外部和内部直径缺陷处的缺陷定位方法的评价 下：S-扫描槽结果代表图14 扩散分析有基地和裂纹顶端足够，类似的方法可用于在外部直径的裂缝和多裂缝9 手动和半自动检测技术研究与传统的单晶的检查相比所提出的检测技术具有显著的优点：速度：快许多倍图像：提供改进的缺陷表征和逆行扩散胶数据记录：允许在未来的时刻重新分析，不主观信任：缺陷必须由常规采用先进的图像检测重现性：需求论证Considerations about ultrasonic inspection of welded joints usingphased arrayGerhard GrnNational Institute for Welding and Material Testing ISIM TimisoaraPhone: +40 256 491828, Fax: -40 256 492797, e-mail: ggruenisim.roAbstract：In comparison with the ultrasonic conventional examination of welded joints the phased array technique presents a series of facilities and specific advantages of these new examination technique, between which we can mention: a higher examination speed, a better probability of detection of discontinuities, better performances of sizing of discontinuities, bidimensional images, storage of all data, a high reproducibility and reduced security risks.In the present work are discussed some aspects regarding the manual inspection procedures, theinspection requirements according to various examination codes, the instrument calibration, the coverage of the inspection zone, the scanning procedures and the interpretation of sectorial scanning data.Keywords: ultrasonic conventional examination, phased array technique, probability of detection, bidimensional images1. IntroductionThe largest applicability of the phased array method and in particular of the portablephased array units is represented by the manual and the semi-automatic inspection ofwelds and similar components. This paper presents basic principles of the weldsinspection using the phased array method, inspection procedures and data analysis inwelds using manual and semi-automatic S-scans and E-scans.2. Manual inspection methodsThere are two general ways to inspect welding seams using the phased array technique. The emulation of manual monocrystal conventional techniques using the rasterscanning technique. The execution of a linear scan in order to cover the entire welding surface bylinear passing over.These two approaching ways are graphic illustrated in figure 1 and 2.According to Figure 1, the technique of raster scanning offers the advantage ofsimulating current techniques. There is no need of new examination codes. Thetechnique covers the welding surface with multiple angles, so its results will be morereproducible then the ones of the monocrystal conventional approach. The images ofdefects are superior, too. The raster scanning using phased array doesnt offer thebenefits given by the ultrasonic inspection with phased array, which has much higherspeed and complete data storage.According to figure 2, the linear or the one-way scanning method is much faster thenraster or monocrystal conventional techniques. It can be codified to save all the data. In essence, this is a simple portable phased array approach for automatic and semiautomatic welding inspections. The linear scanning can be performed either using encoders, either simply, manually. This method offers certain advantages: The linear scanning is much faster, maybe 5 times faster then manualtechniques, being very effective in costs. All data can be saved using semi-automatic scans (with an encoder) Even for manual scans, key data can be simply saved by freezing the images. The results are highly reproducible, although third parties have to confirm thisfact by tests. Data analysis is less simple then using the monocrystal conventional technique,as shown in the S-Scan Data Interpretation” paragraph.Fig. 1. Schematic presentation of the approach method using conventional rasterscanningFig. 2. Schematic presentation of the concept of linear one line scanning3. Codes and CalibrationWhen requested, welds must be inspected according to a code or a specification.Normally, the specified inspection codes are developed by large organizations likeASME, AWS or API. These inspection codes specify the equipment type, thecalibration procedures, the scan techniques, the sizing and the characterizationprocedures.For phased array, all the codes that were mentioned before accept this new technology, although actual techniques and procedures need to be demonstrated. Each code has itsown section for accepting new techniques and procedures, based on performance demonstrations. Typically, based on a set of pieces that include defects, the new technique is compared with a consecrated one. An experimental approach for the ASME code, section V, was prepared using article 14 for new techniques for plates and up to 25 mm pipes using E-scans.4. E-scansAs opposed to conventional monocrystals, phased arrays may generate ultrasonic beams under multiple angles. Using E-scans (electronic raster scan at fixed angles), a few codes and calibration problems appear, because these ones emulate conventional monocrystal inspections; the calibration and setups are the same as the ones for the manual techniques.The scanning pattern may be different if it is performed using linear scan as the probedoesnt oscillate to detect defects that are oriented under other angles. Anyway, adding the time of flight diffraction will slightly compensate this aspect. Figure 3 presents an E-scan example with an exploring at two different angles, for example, a typical code inspection. It is always first asked for a calibration of the wedge delay.Fig.3. Double E-scan at two different angles on the ultrasonic apparatus,together with A- and C-scans5. S ScansThe S Scans offer different results. While the normal code procedure consists incalibrating on a cylindrical hole or a constant depth notch of ultrasonic path, with the S-Scans this feature gets more difficult. For every angle, the distance to the reflectorvaries in the metal. The path through the wedge and the beams amplitude vary in thesame manner, according to physical laws. This aspect is illustrated in Figure 4.16 elements, 0,6 mm pitch, N=39 mm shear wave in steelFig. 4.The effect of calibration on cylindrical hole with S-scan: different angles,different attenuation, no correction for possible near field effectsThe alternative to calibration on cylindrical hole at fixed depth is to compensate theangular beam signal amplitude variations by calibration on a radius, as shown in Figure5. This one offers a constant ultrasonic path, a constant attenuation and the same near field for all the angles.Fig. 5 The calibration on a radius for obtaining an Angle Corrected Gain (ACG).ACG is requested with a Time Corrected Gain (TCG) for S-Scans. Therefore, thecalibration reflector (or cylindrical hole) shows the same amplitude no matter where it is situated in the true depth S-Scan pie”. The same thing is easy demonstrated with the phased array apparatus. Figure 6 illustrates an A-scan envelope of a cylindrical hole set with almost identical amplitudes after calibration.Fig.6. Cylindrical hole scanned using a beam of shear waves at 55, with calibrated ACG and TCG (low variation of calibration amplitude).In practice ACG and TCG are combined in a single process using the Auto-TCG function with the phased array apparatus. Despite these calibration requests, it must bekept in mind that S-Scan is a set of A-scans performed at different angles. Once more, it is always requested a calibration of the wedge delay.The other major result regarding the S-Scans is the Bias Incidence Angle” or BIA.Codes like ASME dont specify concrete BIA, but they assert that adequate angles”must be used. Unfortunately, concrete adequate angles are not well defined. Some codes request specific angles, but this approach has its own limitations, too.BIAs appearance can be easily seen in Figure 7. The optimal position of the probe and the angles for the body and the upper side of the welding are different to the ones for the optimal inspection of defects at the root.Fig.7. Schematic presentation of the S-Scan inspection of welding. Optimal angles forthe middle section are clearly different to the ones for the roots area.Adequate angles may be modified to discover the optimal coverage. Figure 8 illustrates the rays drawing, showing the number of the S-Scans requested to provide a BIA at 5 to normal incidence: three S-Scans at different distances to the center of welding.Figure 8 The rays drawing showing the number of the S-Scan passing over requested for a BIA at 5 to the normal.Figure 9 shows that for a BIA at 10, two scans can provide an adequate coverage. The number of scans is conveniently scalable. For example, the components thickness doesnt dictate the number of S-Scans. The opening angle” of the BIA is the one that dictates the number of S-Scans. This problem hasnt been completely clarified in codes.Fig. 9. The rays drawing illustrating the number of the requested S-Scan passings overfor a BIA of 10 to the normal.The requested number of scans is first of all a geometric effect; in principle, largerapertures request less scans, although other effects, like the near field ones maycomplicate the problem.Another problem is represented by the focus, although this is effectively addressed incodes.It is applied both to S-Scans and E-Scans. Phased arrays can be electronically focused at short distances if they are appropriately programmed. This will generate a large angle beam at distances after the focal point. This effect is illustrated in Figure 10. In practice,the beams may be very weak far after the focal point making the effective focusing impossible.Fig.10. Focus effects modified on beam profiles. Left: not focused with natural focalpoint at 150 mm and beam divergence of 2,4. Right: with electronic focus at 15 mmwith beam divergence of 20.While no code clarifies the focusing in a specific manner, all the codes request a correctcalibration. This fact implies that if the beam divergence is so strong and the signals areso weak to make a correct calibration impossible, a change of the focal point is needed.In case of ASME code, phased array in preparation simply requests for scanning thesame focal laws as the ones used for calibration.6. CoverageThe techniques and procedures must demonstrate the adequate coverage of the weld, of the heat affected zone (HAZ) and of the close material, as specified in the code. In a convenient way, the programs for drawing simple rays are generally adequate todemonstrate the coverage, as shown in Figure 11 and 12. Figure 11 illustrates thecoverage of a weld using E-Scans and Figure 12 shows the actual scanning technique,using a reference point in the welds centre line.Fig. 11. Up: the illustration of the weld inspection using E-ScansDown: the illustration of the weld coverage using E-ScansFig.12. Illustration of the E-Scan procedure, presenting the scan pattern andthe distance to the centre of welding.For this procedure, the operator must record scanning patterns, offsets, locations anddimensions as part of the technique. This aspect must be specified in the coderequests.7. Scanning techniquesA technique for ultrasonic inspection phased array of plates and pipes base materialsand welds of carbon or stainless steel has been prepared. This procedure may be applied for components with a thickness between 12 mm and 25 mm. (This gives a qualified area from 0,5 to 1,5 times greater then the examined component, or from 6 mm to 38 mm).This technique is specified for the Phased Array OmniScan Olympus NDT Systemaccording to the ASME Code. A not-blind test (open test) is used to prove theefficiency. An encoder interfaced with the Phased Array OmniScan tool is optional; for example, the scan may be manual or semi-automatic.The wedge delay and the sensibility calibrations are compulsory. The auto-TCGOmniScan function includes both ACG (Angle Corrected Gain) and TCG (TimeCorrected Gain) in a single procedure.The phased array scanning requests a complete documentation. In detail the scanningplan must prove, using drawing or a computer simulation, the appropriate examination angles for the angles that prepare the welds curve (for example, 40 60 or 55 70) and which will be used during the examination. This scanning plan must be recorded to prove that the examination volume was examined. This scanning plan has to be part of the final examination report”.The procedure uses the one line scanning technique as shown in Figure 2 for a fastinspection, instead of a raster scanning technique. In detail, minimum two E-scans or S-Scans are performed at two different index points from the weld center on both weld sides to ensure the welding as well as the heat affected zone coverage. Multiple line scans are needed for the materials with a nominal wall thickness greater then 25 mm, in order to cover the specified volume of welding and base material. In a similar way, generic procedures for API and AWS codes have been developed.8. S-Scan data interpretationThe E-Scan data interpretation is similar to the conventional ultrason