UPA based 3D visualization of discontinuities in great thickness EBW seam 1

Electron beam welding (EBW) is a fusion welding process in which a beam of high-velocity electrons is applied to two materials to be joined.It is a complex high-temperature metallurgical process,and the quality of welding may deteriorate because of defects caused by improper welding parameters,especially in the EBW of thickened aluminum alloy plate.Ultrasonic phased array(UPA) technology has been applied more widely in the field of nondestructive testing because of its ability of effectively controlling the shape and direction of the emitted ultrasonic beam.In present research,a specimen with EBW seam on thickened aluminum plate was tested with a linear array ultrasonic phased array probe,and a large number of B-scan images of the weld were acquired by electronic scanning in probe combined with the mechanical scanning of the probe along the weld direction.This large number of B-scan images were stacked to construct the volume data,with which the 3D image of the weld discontinuities were reconstructed,and the 3D visualization was realized.More details about weld discontinuities' spatial distribution and orientation were revealed,and this approach also made the results of non-destructive ultrasonic testing more easily to understand.     

UPA based 3D visualization of discontinuities in great thickness EBW seam

Electron beam welding(EBW) is a fusion welding process in which a beam of high-velocity electrons is applied to two materials to be joined.It is a complex high-temperature metallurgical process,and the quality of welding may deteriorate because of defects caused by improper welding parameters,especially in the EBW of thickened aluminum alloy plate.Ultrasonic phased array(UPA) technology has been applied more widely in the field of nondestructive testing because of its ability of effectively controlling the shape and direction of the emitted ultrasonic beam.In present research,a specimen with EBW seam on thickened aluminum plate was tested with a linear array ultrasonic phased array probe,and a large number of B-scan images of the weld were acquired by electronic scanning in probe combined with the mechanical scanning of the probe along the weld direction.This large number of B-scan images were stacked to construct the volume data,with which the 3D image of the weld discontinuities were reconstructed,and the 3D visualization was realized.More details about weld discontinuities' spatial distribution and orientation were revealed,and this approach also made the results of non-destructive ultrasonic testing more easily to understand.     

聚乙烯管道电熔接头超声检测

由于聚乙烯材料超声波衰减系数大,以及电熔接头中金属丝信号对检测的干扰,使得传统的超声检测方法并不能有效地检出聚乙烯电熔接头中的各类缺陷。采用超声相控阵动态聚焦,结合B扫查成像技术,可以解决上述难题。将超声检测图像与接头实剖图进行对比,证明该方法能可靠地检出聚乙烯电熔接头中的各类缺陷,并在聚乙烯管道安装工程的实践检测中得到进一步验证。     

相控阵超声无损检测系统的研制

以探讨相控阵超声无损检测系统的研制为目的，从相控阵原理着手，对检测系统的工作机理及系统组成进行简略阐述，重点研究阵列探头设计、相位精确控制、超声信号模拟／数字处理及缺陷成像中的关键技术。最后利用系统进行了试块检测成像对比试验。初步试验和研究表明，相控阵超声无损检测系统比传统单探头超声无损检测具有信噪比高、缺陷分辨力强、有效探伤范围宽以及工作效率高等特点。     

基于双面阵探头的厚壁奥氏体不锈钢对接焊缝的相控阵超声检测

焊缝奥氏体组织具有晶粒粗大和各向异性等特点,线阵相控阵、常规超声和射线检测技术均存在一定的局限性和不足.基于DMA(双面阵)相控阵探头,采用以色列ISONIC 2009型相控阵检测仪器,对NB/T 47013.3-2015附录I中的3号对比试块进行了B扫和C扫成像,并对40 mm厚的模拟试块进行了检测比对分析,结果表明...     

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 随着中国列车运行的高速化发展,对车轮质量与检测水平的要求也越来越高。将超声波相控阵技术应用到车轮检测中,着重对车轮内部缺陷的相控阵扫描图像进行分析,还利用仿真软件对车轮产品中轮缘、轮缘根部以及踏面和一定深度内的轮辋区域进行相控阵声束覆盖模拟。研究表明,超声波相控阵技术丰富了车轮超声波无损检测的手段。     

超声相控阵成像方法研究

通过动态光弹法观察超声相控阵发射信号在固体中的传播特性,来确定超声回波信号同相位叠加积分路径。利用荷兰试块对以上方法进行验证,对获取的22路A扫描超声信号进行处理,以缺陷或试件边界处为虚拟焦点,逐点扫描。根据合成信号幅值不同,反映在图像上的灰度不同,实现B扫描成像,初步证明了该方法的可行性。     

钢轨铝热焊焊缝的超声相控阵检测技术

常规超声方法检测钢轨铝热焊焊缝时,不同区域焊缝的检测需更换不同K值的探头,检测速度慢且由于光斑和灰斑等缺陷反射很弱,很容易造成漏检。超声相控阵声束具有可偏转和聚焦的特点,使得声波反射能量足够大且不用频繁更换探头。通过对含已知机械加工缺陷和未知自然缺陷的钢轨铝热焊焊缝试样进行检测,验证了超声相控阵方法检测铝热焊焊缝的可行性和有效性。通过与常规超声检测方法进行对比,得出超声相控阵检测钢轨铝热焊焊缝具有速度快、效率高、重现性好和检测结果直观等优点。     

基于超声信号和图像融合的焊缝缺陷识别

超声无损检测已被广泛用来检测材料内部的缺陷,然而对缺陷性质的识别始终是检测的难点,为此研究了一种基于超声信号和图像融合的焊缝缺陷识别新方法.该方法充分利用检测数据,通过对缺陷回波信号特征与缺陷形态特征的数据融合,实现了焊缝缺陷的有效识别.利用自主研制的超声成像手动检测系统对含有气孔、夹渣、裂纹、未焊透和未熔合五类典型焊接缺陷的焊件进行了检测,分别提取缺陷的超声回波信号特征和缺陷图像的形态特征,构建神经网络实现超声信号和图像特征的数据融合.结果表明,该方法实现了多类缺陷的识别,提高了缺陷识别率,有助于焊缝质量评定.     

不锈钢焊缝缺陷的超声相控阵扫描图像特征分析

采用超声相控阵检测方法对预制了夹杂和气孔缺陷的奥氏体不锈钢焊缝进行检测,分析了缺陷的相控阵图像与A扫描信号特征。试验采用的是超声相控阵扇型扫查方式,同时用深度定标方法对仪器参数进行了优化,对缺陷的位置及尺寸进行测量并获得了能够判断缺陷类型的图像特征和A信号特征。研究结果表明:超声相控阵方法不但适用于不锈钢焊缝的检测,且具备更大的检测范围及更丰富的检测信息;通过检测图像特征及相关的A信号特征能够对这2类缺陷的位置及类型进行有效评价。     

高阶互谱超声成像

在超声成像中，由于缺陷信号易被噪声湮没，信噪比受到很大的削弱，针对该问题，讨论了高阶维格纳互谱对高斯噪声的抑制作用，提出了一种改进的基于该分布和似然比理论的超声成像算法。试验结果表明，用该算法能从强噪声中识别出缺陷点，提高成像的信噪比。     

SAFT成像技术在棒材超声成像检测中的应用

以变形钛合金棒材为检测对象,将超声合成孔径聚焦技术(SAFT)算法进行适当的改进,使其适合棒材检测。对棒材试块进行SAFT成像和B扫描成像,通过比较,发现SAFT成像能够增强缺陷信号,提高检测灵敏度。     

超声相控阵技术的仿真试验

超声相控阵技术是一种先进的超声无损检测技术。超声相控阵技术通过对超声阵列换能器中各阵元进行精确延时控制,获得灵活可控的合成波束,并可随意控制聚焦点的位置。利用仿真相控阵合成聚焦技术的方法,搭建了一个16阵元、超声信号发射、接收和处理试验系统。利用该系统对缺陷试块进行了检测试验,试验结果与实际试块缺陷情况吻合。通过对试块缺陷的检测试验,对比聚焦与不聚焦的检测效果,证明了相控阵合成聚焦技术可以极大地提高检测的信噪比和灵敏度,验证了相控阵聚焦可以提高检测能力。     

TA15钛合金激光熔化沉积制件超声相控阵检测

为了确保激光增材制件的质量安全,对其进行可靠的无损检测与评价尤为重要。 针对 TA15 钛合金激光熔化沉积制件,使用常规超声以及超声相控阵检测技术对其内部缺陷进行检测,重点研究了激光增材制件内部缺陷的超声检测特性以及超声相控阵检测技术在增材制件上的应用优势。 使用激光熔化沉积技术制备了含有熔合不良缺陷的试验样件,从 XYZ 3 个方向分别对样件进行了全面检测。 结果表明,激光增材制件内部的缺陷具有明显的方向性,因此, 为了确保激光增材制件检测结果可靠,应从 XYZ 3 个方向分别进行全面检测。 相比与常规超声检测,超声相控阵检测技术大大提高了检测效率,能够直接成像缺陷的轮廓边界,降低了技术依赖性及人工疲劳性,针对大型增材制件的检测需求具有广阔的应用前景。     

全聚焦法焊缝检测灵敏度特性

全聚焦法(TFM)是用后处理算法增强的超声技术.基于全矩阵捕获(FMC)采集数据,由TFM生成的图像几乎聚焦在每个像素上,因而能提高缺陷检出率,改善缺陷定量和表征技术.本文评析焊缝检测中某些方向性面型缺陷引起的信号波幅变化,并对此与其他技术——超声相控阵检测(PAUT)、射线检测(RT)和金相检测结果作了比较.强调声传...     

非标件压力管道加厚弯头凹坑腐蚀超声相控阵检测的应用

本文应用超声波相控阵技术,对非标件的压力管道加厚弯头凹坑腐蚀减薄进行了检测。检测发现,加厚弯头因其内部凹槽腐蚀特殊性,普通超声波测厚无法完成,而相控阵技术因其探头晶片聚焦功能可实现对加厚弯头腐蚀凹坑的识别,相控阵检测图像信号清晰完整,最后对检测有异常信号的弯头进行解剖,发现相控阵检测的缺陷信号与非标件弯头凹坑缺陷相符合,为今后检测非标件压力管道加厚弯头内部凹坑缺陷提供了有效的技术支持。     

基于相控阵超声的进动式锥摆线齿轮裂纹检测方法

为高效准确地完成进动式锥摆线齿轮裂纹定量分析,提出一种基于相控阵超声的齿轮裂纹检测方法。创建相控阵超声检测系统,在该系统内,利用高压脉冲生成、通道选择、回波信号处理等模块采集完整齿轮结构信息;并通过小波变换拆解超声时域信号,运用压缩传感法重构信号;使用经验模态分解法将信号分解成若干本征模函数,通过三次样条插值信号极值点,获取极值点构成的上、下包络线,将初始信号与包络线均值的差拟作单调函数,保留信号高频分量并输出分解后的超声信号,实现齿轮裂纹损伤位置检测。仿真结果证明：所提方法可有效提取超声信号中的时域与频域特征信息,裂纹检测精度高、效率快,鲁棒性强。     

热电厂薄壁小径管的相控阵超声检测

通过在薄壁小径管上预制模拟缺陷,采用数字射线检测和相控阵超声检测技术对其进行检测比对,验证了相控阵超声检测工艺的有效性.结果表明:相控阵超声检测技术操作简便,缺陷检出率高,且可以通过积累图谱,为缺陷的定性提供参考依据.     

Model-based simulation of focused beam fields produced by a phased array ultrasonic transducer in dissimilar metal welds

Phased array ultrasound testing (PAUT) can produce steerable and tightly focused ultrasonic beams, so it is widely used for detecting flaws. However, inspection of dissimilar metal welds (DMWs) using phased array ultrasound is not easy at all, since ultrasonic beams are skewed and distorted severely in the welds that are anisotropic and inhomogeneous elastic media. So, to increase focusing efficiency and have optimized conditions for inspecting the welds, quantitative prediction of phased array ultrasonic beams is needed. This paper proposes a modeling approach that includes modeling the grain orientation of the welds with buttering, calculating the ray path for the determination of focal laws, and applying the linear phasing multi-Gaussian beam model in order to focus the ultrasonic beams produced by a phased array transducer mounted on a wedge contacted to the interrogated DMW. This paper also presents an example of the model-based simulation of the focused beam fields produced in the DMW. The proposed model allows us to increase the focusing efficiency by accurately simulating the ultrasonic testing of welded components and to propose a new tool to associate welding design with the ultrasonic assessment of structural integrity.     

Simulation of phased array S-scan acoustic field in FSW joint of aluminum alloy extrudate with complex shape

The shape of aluminum alloy extrudate used in high-speed train is complex, structural noises from the surfaces of the extrudate will be received when using ultrasonic phased array to detect the flaws in FSW. To solve this problem, ultrasonic phased array acoustic field model and propagation simulation of acoustic waves were introduced to simulate the acoustic pressure distribution and the propagation of the acoustic waves. With the methods above, the detection parameters can be optimized and as a result, the experimental process can be simplified and the detection efficiency can be improved. Mean while, the echoes in the S-scan images can be predicted, which can help analyze the detection results and judge the defects.