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通过分析对比几种常见的无损检测技术,提出用涡流探伤检测高频薄壁铝焊管焊缝质量的新方法,并针对输出的检测信号非线性、非平稳的特点,探讨了几种现代信号分析方法,并分析了它们的优缺点和经验模态分解(EMD)方法在检测涡流探伤信号上的应用优势,指出经验模态分解方法的应用前景。 相似文献
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铝合金建筑型材薄壁化必然给铝型材生产带来一系列的技术和安全问题,应该十分慎重对待。为了帮助务型材厂提高铝型材薄壁化后的质量,从合金材质,模具设计和制造,挤压工艺等方面谈些参考意见,仅供参考。 相似文献
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美国波士顿地铁是中国轨道装备首次登陆美国,更是我国装备行业首次对世界高端市场实现的技术输出。该项目是我国轨道客车首次正式运用激光叠焊技术,并结合不锈钢车体激光叠焊的结构特点,开发了电磁超声自动在线检测技术对激光叠焊质量进行在线检测,用于不锈钢激光叠焊焊接熔合深度的检测与评估。研究了电磁超声技术(EMAT)在不锈钢车体激光叠焊检测方面的应用,EMAT具备无需耦合剂、检测精度高、探头不易磨损等优点,能够实现对不锈钢激光叠焊质量的自动化检测和评判,避免焊接不良等问题,对保证不锈钢车体激光叠焊质量具有重要意义。 相似文献
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实心铝型材挤压导流模应用研究 总被引:3,自引:0,他引:3
本文探讨了导流模内挤压铝型材的流动规律。提出了确定导流模最小厚度的理论依据。用流函数法确定了实心薄壁铝型材挤压变形动可容速度场、应变速率场及上限功率。讨论了变形程度等参数对导流模最小理论厚度、挤压载荷的影响。得出实心薄壁铝型材导流模厚度的理论最小值为 (0 .7~ 0 .8) b0 。为导流模优化设计提供了理论依据。 相似文献
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为解决汽车半主动悬架(Semi-Active Suspension,SAS)与电动助力转向(Electric Power Steering,EPS)集成系统在线故障诊断的问题,提出将小波分析方法应用到SAS与EPS集成系统传感器和ECU的故障诊断中。首先根据故障状态下传感器和ECU输出电压信号的突变特性,利用小波分析奇异性检测原理检测出突变信息。随后为能更精确地检测出突变信息,先使用小波阈值法对电压信号消噪,再对消噪后的电压信号进行检测。最后以SAS与EPS集成系统中扭矩传感器和ECU故障诊断为例进行试验研究。结果表明,小波分析方法能有效抑制信号噪声,并准确检测出故障和故障发生时刻,对集成控制系统的安全运行及故障诊断具有重要的工程应用意义。 相似文献
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Numerical control(NC) bending experiments with different process parameters were carried out for 5052O aluminum alloy tubes with outer diameter of 70 mm, wall thickness of 1.5 mm, and centerline bending radius of 105 mm. And the effects of process parameters on tube wall thinning and cross section distortion were investigated. Meanwhile, acceptable bending of the 5052O aluminum tubes was accomplished based on the above experiments. The results show that the effects of process parameters on bending process for large diameter thin-walled aluminum alloy tubes are similar to those for small diameter thin-walled tubes, but the forming quality of the large diameter thin-walled aluminum alloy tubes is much more sensitive to the process parameters and thus it is more difficult to form. 相似文献
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Marcin Górny Magdalena Kawalec 《Journal of Materials Engineering and Performance》2013,22(5):1519-1524
This research studies the effects of titanium added in an amount up to 0.13 wt.% on the microstructure and mechanical properties. The research was conducted for thin-walled iron castings with 3-5 mm wall thickness and for the reference casting with 13 mm wall thickness to achieve various cooling rates. Microstructural changes were evaluated by analyzing quantitative data sets obtained by image analyzer and also using scanning electron microscope. Metallographic examination revealed in thin-walled castings a significant effect of the addition of Ti to compacted graphite, much stronger in comparison with castings with thicker sections. Moreover, thin-walled castings with high degrees of inoculation and which have been solidified under high cooling rates have a homogeneous structure, free of chills, and good mechanical properties, which may predispose them for potential use as substitutes for aluminum alloy castings in diverse applications. 相似文献
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为提高某厂1 700 mm罩退平整机板形控制能力,改善薄规格带钢的板形控制质量,以平整机辊型配置优化为基础,对平整轧制力、弯辊力、张力、延伸率等工艺参数进行了优化,并优化了罩退机组对上游产线的板形控制要求,在酸轧采用统一的双边浪板形目标曲线,形成了一整套针对薄规格带钢的板形控制工艺技术,并在生产中得到稳定应用。宽规格带钢板形一检不合格率由11.47%降至1.24%以内,中间规格带钢板形一检不合格率由4.91%降至0.74%以内,窄规格带钢局部浪一检不合格率由95.5%降至8.4%,支撑辊辊型不均匀磨损得到改善,服役吨位提高了30%。 相似文献
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薄壁门窗型材挤压的有限体积分步模拟 总被引:5,自引:0,他引:5
研究了有限体积分步求解方法,实现了各分步有限体积模拟系统的数据传递和信息继承.针对薄壁门窗型材制品壁薄且纵向尺寸大的特点,采用了有限体积分步模拟方法对其挤压成形进行了模拟,并与有限元模拟、有限体积一步模拟进行了对比.结果表明:1)有限元模拟往往会因为网格重划分问题造成模拟结果严重失真;2)有限体积法-步模拟又对计算机资源有较高要求,往往会因为内存不足造成计算无法进行下去;3)有限体积分步模拟方法模拟精度最高,可以很好地解决大尺寸薄壁型材制品挤压成形的数值模拟问题. 相似文献
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Development of pressure control system in counter gravity casting for large thin-walled A357 aluminum alloy components 总被引:3,自引:0,他引:3
Counter gravity casting equipments(CGCE) were widely used to produce large thin-walled A357 aluminum alloy components. To improve the pressure control precision of CGCE to get high quality castings, a pressure control system based on fuzzy-PID hybrid control technology and the digital assembled valve was developed. The actual pressure tracking experiment results show that the special system by applying PID controller and fuzzy controller to varied phases, is not only able to inherit the small error and good static stability of classical PID control, but also has fuzzy control's advantage of fully adapting itself to the object. The pressure control error is less than 0.3 kPa. By using this pressure control system, large complex thin-walled A357 aluminum alloy castings with high quality was successfully produced. 相似文献
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G.Y. Zhao Y.L. Liu C.S. Dong H. Yang X.G. Fan 《Journal of Materials Processing Technology》2010,210(9):1224-1231
The rotary-draw bending process for thin-walled rectangular tube of aluminum alloy may produce a wrinkling phenomenon if processing parameters are inappropriate, especially for tubes with thin wall and small bending radius. To predict this wrinkling rule rapidly and accurately, here, a wrinkling wave function was proposed and a wrinkling prediction model was developed based on the deformation theory of plasticity combined with the energy method, and then the minimum bending radius without the occurrence of wrinkling in the process was obtained. Furthermore, the effects of geometrical parameters and the material properties of the tube on the minimum bending radius were analyzed. The results show that larger thickness-to-width ratio (t/b) and thickness-to-height ratio (t/h) are beneficial to improve the wrinkling limit of the tube. The minimum bending radius becomes smaller with an increase in strain-hardening exponent of the tube, whereas with the strength coefficient decreasing. And the Young's modulus has little effect on the wrinkling limit. These achievements are helpful to develop the bending technique and provide a guideline in rotary-draw bending process for thin-walled rectangular aluminum alloy tube. 相似文献
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主体壁厚为3mm的铝合金壳体铸件,成形比较困难。因此,设计两种方案,利用3D打印砂型进行低压铸造浇注验证。结果表明,选择合适的浇注位置并设计合理的浇注系统,有利于薄壁铸件的成形,并利用CAE软件模拟优选出合理的铸造工艺方案。 相似文献
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Q. Pang Z. L. Hu X. Pan X. Q. Zuo 《JOM Journal of the Minerals, Metals and Materials Society》2014,66(10):2137-2144
In this article, the large-diameter thin-walled aluminum alloy tubes were produced using a hybrid process combining friction-stir welding (FSW) and spinning. For this novel process, rolled aluminum alloy sheets with a thickness about 2–3 times the wall thickness of target tube, were FSW to form cylinders, and then the cylinders were subjected to spinning to get thin-walled aluminum alloy tubes. Both experimental and simulation study were conducted to investigate the deformation characterization of the FSW tube during hydraulic bulge testing, and the stress and strain states and thickness distribution of the FSW tube were investigated. It was found that the common defects of FSW tube can be significantly improved by specific welding devices. The ductility of the tube is considerably improved with nearly two times higher bulge ratio than as-spun tube after annealing treatment at 300°C. But the annealed tube still shows a high nonuniform wall thickness distribution due to the inhomogeneous deformation characteristics. With increasing deformation of the tube, the gap between the hoop and axial stress for the weld and base metal (BM) decreases. However, the hoop and axial stress of the weld are always greater than those of the BM at the same pressure. 相似文献