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介绍采用射线方法检测功率管芯片与基座之间的焊接质量。试验证明,选用合适的透照参数可使X射线照相和X射线实时成像对焊接部位的检测均得到较高的对比灵敏度,但X射线照相法成本低廉,一次可透照多个工件,效率高,为该功率管焊接质量的理想检测方法。 相似文献
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小径管对接环焊缝有效透照厚度的计算 总被引:1,自引:0,他引:1
小直径管(直径D≤100mm)对接焊缝无损检测的常用方法是射线检测。但在检测中要准确确定透照厚度较困难,因为小直径管对接焊缝是特殊的变截面工件,其透照厚度在有效透照区域内是连续变化的而且变化很大,无论采用垂直透照法还是椭圆成像法都存在此类问题。透照厚度是射线检测的重要工艺参数,它决定了实际透照管电压和像质指数的选取,还与透照厚度比和有效透照区有关。国内外有关标准虽然近似规定了小直径管对接环焊缝的透照厚度,但不同标准的规定存在差异,这样将导致对同一焊缝检测时,管电压和像质指数等的选取不同,从而引起检测灵敏度不同。 相似文献
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国内现行数字射线成像检测标准对于管道环焊缝的最少透照次数都没有简单、有效的确定方法,而直接参照射线胶片检测的最少透照次数来确定有很大的局限性.依据标准SY/T 4109.5-2013,分别针对双壁单影透照法与中心内透照法,分析了影响最少透照次数的因素,并提出了确定最少透照次数的计算公式,以便于检测人员参考. 相似文献
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我单位生产的航空用小型圆筒壳体产品,多为薄壁管焊接而成,对这类产品的射线检测以环焊缝为主,根据射线头的结构形状,可以采用外透法和内透法.圆筒壳体分两种:短壳体圆筒外径为162mm,壁厚2.0mm,长210mm,焊缝2条;长壳体圆筒外径为162mm,壁厚1.4mm,长600mm,焊缝1条.我们从Seifert公司购进一台周向辐射棒阳极射线机,对环焊缝采用内透法照相,并用进口带状胶片,检测效率和检测质量都有了很大改善.但因每次开机只能透照一条环焊缝,故透照效率仍不能满足生产中大批量检测的要求.为此我们通过对各类射线机使用各种透照方法所得透照质量的分析和透照效率的计算,选择了最好的透照方案,并设计制造了透照夹具,在保证透照质量符合要求的基础上,提高了产品透照效率.1 透照方案的比较 相似文献
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In this study, we focus on the expansion of the weld pool in a welding process by tungsten inert gas (TIG). Use of high-speed imaging and metallographic investigations combined with electrical measurements allow us to determine the weld pool shape and dimensions evolution and the energy involved in the process for six durations of interaction (from 1 to 20?s) in a spot TIG configuration. Results show a fast increase of the weld dimensions on the first second. Otherwise, time does not seem to be an influent parameter on the weld shape. The comparison between experimental work and numerical model available in our team highlights differences between the predicted shapes and the observed ones. 相似文献
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研究了低频超声探头的谐振特性,并将这种谐振特性用于镀锌薄板的点焊检测中.采用接触式低频探头对点焊进行检测时,检测探头能够接收到未焊薄基板产生的半波谐振高频信号,这些半波谐振信号的高频部分处于探头频带外的奇数次谐振频率附近.通过小波包变换的方法可以将这些高频信号从检测信号中分离出来并用于点焊的质量评价.分析小波包变换中各尺度信号,获取了能够评价焊核质量的超声波特征值并将这些特征值与点焊力学性能联系起来,提供了一种能够定量评价点焊质量的超声无损评价方法.此外,采用低频探头对点焊进行检测较之普通检测方法将大大降低检测成本. 相似文献
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T. Saravanan H. Das K. Arunmuthu J. Philip B. P. C. Rao T. Jayakumar 《Science & Technology of Welding & Joining》2014,19(2):125-132
A digital X-ray radiography methodology is proposed for quality assessment of aluminium–zinc coated steel dissimilar lap joints produced by a friction stir welding process. This methodology uses digital frame integration for acquisition of data to reduce the image noise followed by high pass filtering to sharpen the image by gradient operation and contrast adjustments to detect micro defects in FSW joints. The effect of welding parameters such as rotational and travel speed of weld tool and penetration depth on quality of the weld is studied. The new methodology has resulted in three-fold increase in signal-to-noise ratio (SNR) with improved defect detection sensitivity. The present study clearly shows that the weld tool rotational speed, travel speed and plunger depth have a decisive role on the quality of the weld obtained by the friction stir welding process. 相似文献
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火电厂厚壁管道的焊接质量关系到机组安全运行。介绍了焊缝中间射线检验时胶片紧贴焊缝和胶片紧贴管壁两种透照方式的工艺特点。分析了不同布片方式对射线照相质量的影响。通过对比试验,验证了不同透照方式对缺陷检出的影响效果。 相似文献
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《Science & Technology of Welding & Joining》2013,18(5):449-454
AbstractResistance spot welding is one of the major joining techniques widely used for car body assembly. Weld quality may significantly influence the durability and reliability of the automobile body. Automotive manufacturers often rely on destructive testing and monitoring variables which indirectly reflected weld quality to assess the weld quality and control the welding process. However, these approaches have inherent limitations and are difficult to be implemented in plant environments. Therefore, it is imperative to develop an online inspection method to evaluate weld quality. In the present study, a method of producing a series of substantially uniform spot welds between two metal parts using a servomotor driven movable electrode and an axially opposing fixed electrode is proposed. The indentation in the workpiece surface is suitably measured by the displacement of the movable electrode as it applies an electrode force and welding current is passed through the weld site of the workpiece. The optimal indentation range is determined by peel test and metallographic examinations with respect to various sheet gages and grades. Consequently, online weld quality inspection results are achieved based on developed optimal indentation range. 相似文献
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A.J. den Bakker R.J. Werkhoven W.H. Sillekens L. Katgerman 《Journal of Materials Processing Technology》2014,214(11):2349-2358
Longitudinal weld seams are an intrinsic feature in hollow extrusions produced with porthole dies. As these joins occur along the entire extruded length, it is desirable that these weld seams have a minimal impact on the structural integrity of the extrudate. In particular, defects associated with weld seam formation should be avoided. In this research, the occurrence of defects related to material flow inside the extrusion tooling is studied. In lab-scale experiments, EN AW-6060 and EN AW-6082 aluminium alloy billets are formed into strips by means of the direct hot extrusion process. By utilising model dies with an internal obstruction similar to the supports present in porthole dies, a strip with a central longitudinal weld seam is formed. The effects of different geometries of the weld-chamber and the processing conditions on the quality of the weld seam are investigated. Characterisation is performed through mechanical testing, focusing on the ability of the weld seam area to accommodate plastic deformation, and microstructural analysis provides insight into the defects related to unsound metal flow. Through computer simulations, conditions related to weld seam formation are modelled and correlated with the experimental results. The experimental results demonstrate that metal flow controlled by the die geometry causes defects leading to inferior mechanical performance of the extrudate. It is further argued that current weld seam formation criteria utilised in finite element modelling need enhancement to incorporate these flow related defects. 相似文献
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在ASG管脚焊缝超声检测中,受探头、工件结构、焊缝成形等因素影响,会出现缺陷的定位不准的困难,从而影响检测过程及结果。讨论了一种适应现场复杂工况的定位方法。通过使用改良过的作图法和公式相辅助的方法,准确确定了缺陷的位置,可以加快现场工作效率,从而更好地完成现场检测工作。 相似文献