共查询到19条相似文献,搜索用时 62 毫秒
1.
2.
3.
4.
5.
6.
正公开了一种螺旋焊缝钢管管体缺陷的横波探测方法及其探伤装置,属于超声波无损探伤领域。该探测方法通过在两螺旋焊缝之间布设垂直于焊缝的横波探头,来检测钢管表面及焊缝的缺陷,保证了检测面积达到了100%。探伤装置包括可自由升降的探头架和基本检测单元,探头架内部固设有横杆,横杆上套接有一对基本检测单元;基本检测单元由横向调节装置、探头升降装置、固定座及探头组成,横向调节装置一端与横杆套接,横向调节装置的另一端与探头升降装置连接,探头升降 相似文献
7.
8.
飞机多层金属铆接结构中铆钉周边裂纹的检测是无损检测领域中的一个难点和热点。基于脉冲涡流检测技术,设计检测探头,并对探头的激励线圈匝数、检测频率、接收传感器距铆钉距离等参数进行优化,研制一种使探头能够围绕铆钉进行旋转检测的装置。检测探头参数和传感器与铆钉之间的距离参数的变化对检测灵敏度的影响较大。旋转装置检测时:激励匝数为180匝、检测频率为100 Hz、探头与铆钉距离4 mm时,对于长度为1、2 mm的铆钉孔周边裂纹检测效果较好;对于长度大于2 mm的铆钉孔周边裂纹,探头距离铆钉10 mm的时候检测灵敏度较高。利用旋转装置检测和纯手动检测的结果对比表明,旋转检测装置能够很好地抑制探头与铆钉之间的距离变化带来的对信号的干扰,减少伪缺陷并提高检测效率。 相似文献
9.
10.
《硬质合金》2016,(1):48-54
本文通过不同尺寸截面硬质合金产品的侧壁效应程度、不同长度硬质合金棒材的底波反射幅度高低、同一灵敏度下不同规格探头的始波占宽等测试,研究了硬质合金棒材直径和长度、探头的频率等因素对硬质合金棒材内部缺陷检测率的影响规律。利用现有的探头灵敏度测试试块,验证了现有探头的缺陷检测率。研究结果表明,硬质合金棒材直径越小,侧壁效应越明显,缺陷检测率越低;棒材长度越大,反射回波能量越低,缺陷检测率也越低;探头的频率影响棒材内部缺陷检测率;现有探头的缺陷检测率不高,不能满足硬质合金棒材内部质量控制要求。根据硬质合金棒材内部大多数的缺陷方位与棒材检测面成一定夹角的特点,对探头发射波声束线的角度进行了改进,通过比较两种改进探头的脉冲波形及频谱性能,指出了脉冲波形比较平稳、频谱比较窄的改进探头能提高棒材内部缺陷的检测率,并通过实验得以验证。 相似文献
11.
Z.W. Xu Q.L. Zhao T. Sun L.Q. Guo R. Wang S. Dong 《Journal of Materials Processing Technology》2007,190(1-3):397-401
A simple and reliable welding method was developed to fabricate carbon nanotube probe used in atomic force microscopy here. First, apply less than 20 V voltage between silicon probe and carbon nanotube when they were in close proximity under direct view of optical microscope. Then, let carbon nanotube contact with silicon probe and increase the external voltage to 30–60 V until carbon nanotube was divided and attached to the end of silicon probe. The fabricated carbon nanotube probe could be shortened to appropriate length by electron bombard. The weld strength of carbon nanotube probe was calculated by drawing the ordinary AFM probe and measuring the probe's deflections. For one carbon nanotube probe with 75 nm diameter, the weld strength was calculated more than 268 nN. Carbon nanotube probe showed higher aspect ratio and could more accurately reflect the true topography of sample than silicon probe. 相似文献
12.
13.
14.
This article describes research on the reliability of ultrasonic testing methods for hot-rolled steel bars of 40–60 mm diameter. Comparison of testing methods is made using direct contact with the bars along the circumferential surface using a straight beam probe (‘S’ probe), a twin crystal probe where the probe face is contoured to the bar curvature (‘SR’ probe) and a straight beam probe with a delay block. The distribution state diagrams of the echo sound pressure and the effective testing range in the cross-section of the bars are obtained. The conclusion is that methods using the SR probe and the straight beam probe with the delay block produce better quality results for steel bars with diameters equal to or smaller than 60 mm, but the S probe is not suitable. 相似文献
15.
Factors which influence CMM touch trigger probe performance 总被引:1,自引:0,他引:1
P.A Cauchick-Miguel T.G King 《International Journal of Machine Tools and Manufacture》1998,38(4):363-374
Since the introduction of Co-ordinate Measuring Machines (CMMs), probe systems have been a matter of concern with regard to machine's error sources. Initially CMMs used (and sometimes still use) solid probes, but for the last 20 years they have extensively employed touch trigger probes. Using either probe type, CMM measurement results are affected by probing errors. This paper presents some results from probe performance verification, i.e. results from tests on a kinematic-resistive touch trigger probe to quantify its accuracy. The paper also emphasizes sources of errors which affect probe performance as well as probe repeatability. 相似文献
16.
热电偶在探头中位置变化对冷却曲线的影响 总被引:2,自引:0,他引:2
为了加深对冷却曲线的了解,采用ISO9950标准探头和平板探头(热电偶安置在三个不同位置)对N32油、PAG类水溶性介质和水的冷却曲线进行了测量。结果表明,由于探头形状的不同使表面的传热能力存在较大的差异,导致表面湿润条件也不相同,其结果使两种形状探头测量的冷却曲线产生差异,其中平板探头可以反映出更多的冷却机理方面信息。 相似文献
17.
18.
19.
针对机床触发式测头进行系统误差校正时,需要通过数控机床控制器进行计算,从而导致操作困难且精度不高的问题,提出了一种新的测头系统误差补偿方法。该方法可以通过修改该方向上的测量速度,来对给定方向上的测头预行程进行校正,从而显著降低测头的误差。由于可以离线计算所有测量速度,因此控制器无需进行任何运算。分别在实验室和真实在机测量环境中,使用三维触发式测头对所提方法进行了测试。研究结果表明:该方法能够通过误差变速补偿实现触发式测头在机测量,无需控制器的复杂计算并且将误差降低了大约10倍,测头的误差从16.8μm减小到1μm。 相似文献