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《中国焊接》2016,(2)
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. 相似文献
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The basic principle and features of ultrasonic phased array imaging are discussed in this paper,Through the ultrasonic phased array technology,the electron beam welding defects and frozen keyholes characterization and imaging were realized.The ultrasonic phased array technology can detect kinds of defects in electron beam welding (EBW) quickly and realized.The ultrasonic phased array technology can detect kinds of defects in electron beam welding (EBW) quickly and easily. 相似文献
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为解决中国聚变工程实验堆316L不锈钢焊缝超声波检测时,探头扫查空间受限、检测信噪比低的难题,提出了基于双晶面阵探头的相控阵超声检测方案.通过CIVA仿真,分析了不同聚焦参数下DMA探头的声场特征,确定对接接头的检测工艺.参考NB/T47013.3-2015《承压设备无损检测第3部分:超声检测》附录I,设计并制作了对比试块,验证了检测工艺下的声束覆盖和φ2 mm侧横孔信噪比.结果表明,DMA探头可以在有限的扫查空间内实现焊缝声束全覆盖,对比试块中不同位置的φ2 mm侧横孔信噪比大于15 dB.试验结果可为316L类不锈钢对接焊缝相控阵超声检测工艺制定提供参考. 相似文献
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A research about the ultrasonic phased array imaging principle from A-scan signal to B-scan image for non-destructive testing (NDT) was conducted in this paper, the ultrasonic phased array inspection imaging system used in industrial field was developed and the experiment was performed on the steel testing block by the system with 64 elements, 5 MHz phased array transducer. Experimental results show that the flaws could be accurately detected and the flaws size could be estimated from the B-scan images, and the B-scan images could clearly show the location of the flaws, but the quality of B-scan images needs to be enhanced by digital signal processing and controlling dynamic focusing for improving the image resolution. 相似文献
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采用解析几何理论与方法,对TKY管节点焊缝进行了数学模型的构建.在获得管节点焊缝截面图形基础上,按照规定尺寸绘制焊缝接头,并依据实物尺寸绘制相控阵探头轮廓和超声波的声束线.运用计算机辅助技术实现了焊接接头声束覆盖范围可视化效果,较好地指导了相控阵检测工艺设计,能够对TKY管节点焊缝超声检测盲区进行评估,从而克服了相控阵超声检测参数设置的盲目性.对人工设计的Y形管节点焊缝试样检测表明,利用超声相控阵成像技术和计算机辅助技术相结合手段有助于管节点焊缝作快速检测和评价. 相似文献
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对比了相控阵超声和常规超声对接焊缝的检测仿真和试验,分析了对接焊缝相控阵超声检测的可靠性,为承压设备相控阵超声检测标准的制订提供相应参考。仿真与试验得出:相控阵超声检测的缺陷检出率总体上要高于常规超声检测。对于有着严重危害且对声束指向性要求较高的面状缺陷,相控阵超声的检出率要高于常规超声。对于夹渣、未焊透等体积性缺陷,相控阵与常规超声的检出率均非常高。但是对于气孔类回波较小的体积性缺陷,相控阵超声的检出率明显高于常规超声。对于工件厚度较大的焊缝,相控阵超声较常规超声技术可以扫描检测到更厚的焊缝区域。在缺陷测长方面,相控阵超声的测长结果相对于常规超声技术总体偏大,测长精度并无明显优势。 相似文献
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A manual inspection of large-diameter tubular joints is difficult. As a result a scanner with three degrees of freedom (DOFs) was developed based on the scanning principle of ultrasonic phased array. The weld tracing is realized by a 2D0F motion of scanner. The pose of ultrasonic probe is controlled by the third one. The control strategy is put forward based on a programmable multi-axis controller. Four kinds of scanning modes can be implemented simultaneously employing this ultrasonic inspection system. Experiments on reference blocks of tubular joints reveal that the automatic ultrasonic phased array inspection system has the same inspection accuracy as a manual ultrasonic inspection. This system is superior to the manual ultrasonic system in terms of reliability and repeatability. The artificial defects of weld at tubular joint can be detected accurately with the presented inspection system. 相似文献
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借助超声相控阵技术对耐候钢对接接头开展疲劳失效过程动态监测. 基于超声波探头的信号特征,研究其扇形扫描反射过程,建立实时扫查方案, 并对10 mm厚的耐候钢对接接头实施实时监测.结果表明,当疲劳寿命为5 × 104次时,相控阵检测到多个裂纹从对接接头焊趾部位萌生,并沿着板厚扩展,当疲劳寿命超过3.5 × 105次时,裂纹开始快速扩展. 与疲劳试验断口对比发现,基于相控阵检测得到的裂纹尺寸与试验结果基本一致,验证了相控阵裂纹动态检测的准确性. 根据裂纹深度a、裂纹长度2c与循环次数N关系,明确了裂纹动态演化行为,并获得中厚板耐候钢对接接头表面裂纹的扩展演化规律. 相似文献
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利用K110型电子束焊机焊接50 mm厚的304不锈钢板,并对焊接接头深度方向的微观组织及硬度进行分析. 结果表明,利用电子束焊接方法能够一次性焊透50 mm厚不锈钢板,得到成形良好的焊接接头. 焊缝深宽比较大,约为18:1. 焊缝组织由奥氏体和铁素体组成. 从焊缝上表面到深约39 mm处,铁素体形态依次为网状,板条状/骨架状和树枝状分布于奥氏体枝晶间或晶界处. 在焊缝的下层,亚稳的胞状奥氏体将取代稳定铁素体相作为初生相直接从熔体中析出. 沿焊缝中心深度方向,接头的凝固模式由primary ferrite with second-phase austenite,FA转变成primary austenite with second-phase ferrite,AF模式,晶粒尺寸减小,硬度呈波动性增加趋势. 相似文献
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为减少大厚板5A06铝合金激光焊接缺陷,提高焊接过程稳定性,采用激光光束以一定方式运动的扫描焊接的新焊接方法,研究了激光束不同的运动轨迹、幅度、频率对铝合金激光深熔焊接焊缝气孔率的影响,并在焊接坡口设计优化基础上应用窄间隙扫描激光填丝焊接技术进行130 mm厚5A06铝合金焊接试验. 结果表明,采用圆形扫描方式,当激光光束的扫描幅度大于1 mm,扫描频率选择最高频率附近时,能够大幅降低焊缝气孔率;采用窄间隙激光扫描填丝的焊接方法,获得了焊缝平均气孔率1%,无侧壁未熔合、层间未熔合、裂纹等焊接缺陷的130 mm厚5A06铝合金优质焊接接头. 相似文献
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激光焊接是连接钛合金的一种主要的工艺方法.由于焊缝中气孔形成倾向较大,需要进行严格的无损检测.文中概述了超声自动检测过程中工件表面不平度的不利影响,重点分析了焊缝余高对检测结果的影响.采用不同频率的探头对模拟试件进行超声水浸检测,通过对焊缝的不同位置进行测试得到适用的探头频率及其它检测参数.结果表明,通过选择合适的探头频率和检测工艺,可以减小表面不平度对检测灵敏度的影响,可以发现工件表面以下深度为1.0~2.5 mm、最小直径为0.3 mm的气孔缺陷,从而提高超声自动检测的可靠性. 相似文献
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介绍20世纪末国外相控阵超声探伤瓣技术在管道环焊缝检测上的成功应用。通过多压电元件相控阵探头纵向电子扫描和对管子的周向机械扫查,可对管道环焊缝作快速检验,为保证相控阵探头在主要性上等效于普通斜探头,用聚苯乙烯作楔块材料,用高分子聚合物作换能器材料,并用曲面声透镜改善探头在管子轴向和周向的声束特性。 相似文献
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扼要介绍超声相控阵技术的发展及原理。着重介绍10A16E32环形相控阵换能器的原理、聚焦特性及其在航空锻件水浸超声波探伤中的应用。对比试验和应用实例表明,环形相控阵检测速度快、灵敏度高、有效探伤深度范围大。 相似文献
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选用镍基高温合金GH4169进行试验,分析了不同种类活性剂对焊缝成形的影响规律,发现添加不同的氧化物对焊缝表面成形、熔深均有影响,而添加氟化物却影响不大.在此基础上,进行配比和优化,得到了能改善焊缝成形,提高表面质量的电子束焊活性焊剂.分析活性剂改善电子束焊接焊缝成形的原因,认为添加活性剂改变了熔池内部的表面张力梯度,从而影响了熔池的流动方式,形成了窄而深、表面成形较好的焊缝.结果表明,活性剂电子束焊接能改善焊缝表面成形,并可进一步消除咬边等表面缺陷,这对薄板的电子束焊接技术很有帮助. 相似文献