共查询到20条相似文献,搜索用时 125 毫秒
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一、电子束焊接原理与特点电子束焊接是利用汇聚的高速电子流轰击工件接缝处所产生的热能 ,使金属融合的一种焊接方法。电子束是从电子枪中产生的。通常电子是以热发射的方式从发射体 (阴极 )逸出。在 2 5~ 30 0kV电压的作用下 ,电子被加速到 0 .3~ 0 .7倍的光速 ,具有极大的动能。经电子枪中静电透镜和电磁透镜的作用 ,电子汇聚成能量密度很高的电子束。这种电子束撞击到工件表面 ,电子巨大的动能就转变为热能 ,使金属迅速融化和蒸发。在高压金属蒸汽的作用下融化的金属被排开。电子束就能继续撞击深处的固态金属 ,很快在被焊工件上钻… 相似文献
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董振先 《机械工人(热加工)》1999,(9):30-30
电子束焊接技术,在汽车齿轮制造行业已广泛应用,该项技术对节约材料,减轻产品加工难度,减少加工工序,降低生产成本等具有较为广泛的推广应用价值。 1、焊接原理 电子束焊接是利用电子枪产生的电子,被高压电场(30~200kV)加速到极高的速度(约1/2光速)。经磁透镜聚焦,形成高密度、高能量(10~5~10~7W/cm~2)的电子流,作用在焊缝处,能量发生转换(动能转化为热能),使焊缝处的材料迅速熔合为一体,在极短的时间内冷却凝固(冷却速度约 相似文献
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电子束飞行轨迹的实验研究 总被引:1,自引:0,他引:1
阐述了电子束技术的概况,以及电子束的产生和形成。使用60kW功率、20kV加速电压的电子束轰击炉,通过实验分析研究电子束电子的实际飞行轨迹,并利用实验数据验证理论结果。 相似文献
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利用ANSYS有限元分析软件以及APDL的二次开发,编写了不锈钢材料0Cr15Ni5Cu2Ti的电子束焊的模拟程序。建立了圆周焊缝电子柬焊接的有限元模型,用数值模拟的方法从理论上分析焊接过程、焊缝应力分布和收缩变形。通过研究焊接过程中焊接时序、温度控制等关键问题,摸索出最佳电子束焊接工艺参数。试验表明,该工艺方法获得了较好的焊缝质量。有限元分析方法为焊接工艺参数的选择及优化提供了理论指导和参考,缩短了工艺试验周期,节约了费用。 相似文献
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我厂生产的离合器齿轮以往因受工艺技术条件的制约,只能采用二氧化碳气体保护焊,容易产生较大的齿部热影响区和齿形受热变形,达不到图纸设计要求。后经从结构上加以改进设计和从工艺上采取一些减少焊接受热变形等措施,但仍不能达到设计和使用要求,只能依靠进口配套件或直接进口动力换档变速箱。由于我厂采用了电子束焊接及其夹具进行加工离合器齿轮,保证了变速箱的质量、性能与使用要求。电子束焊接的特点是(1)可实现精加工后零件的焊接,(2)焊接件的焊接质量高,焊缝为一条很窄的线,热影响区小,(3)由于电子束焊接所具有的特… 相似文献
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研究了8mm厚某铝合金圆筒真空电子束对接焊接工艺,分析了各个焊接规范参数特征区域的特征,探讨了特征参数与接头性能之间的对应关系,并通过一系列工艺试验,得出了该铝合金筒真空电子束焊对接的最佳焊接规范参数。 相似文献
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介绍了15—5PH马氏体沉淀硬化不锈钢材料的特点和应用场合,着重论述了该材料的真空电子束焊接工艺试验。试件经X射线探伤显示焊缝质量满足国军标I级,焊接接头在室温下的力学性能指标均满足设计和使用要求,从而验证了15—5PH不锈钢材料具有优异的真空电子柬焊接性能。该工艺方法已成功应用于某产品天线座转台的研制。 相似文献
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分析了电子柬轰击炉电子枪的工作原理。利用SolidWorks软件建立了电子束轰击炉电子枪的三维模型,并通过对实体模型进行干涉检查、数据测量等分析,来模拟电子束轰击炉电子枪的实际工作情况。 相似文献
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L. I. Kuznetsov V. G. Prikhod’ko V. N. Yarygin 《Instruments and Experimental Techniques》2000,43(1):106-109
An electron-beam method for studying the local density of impulse jets ejected from a supersonic nozzle into vacuum for several
seconds is developed. The method is based on a linear dependence of the intensity of bremsstrahlung excited by fast electrons
in a gas on the atomic concentration in the gas. The radiation intensity is evaluated as a function of the temporal resolving
power. The measurement scheme and results of studying transverse density profiles in a supersonic impulse jet are presented. 相似文献
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A. M. Chlenov D. M. Ivashchenko N. G. Mordasov A. P. Metelev V. D. Shiyan 《Instruments and Experimental Techniques》2010,53(1):8-14
A diagnostic system has been developed for the YHH-10 high-current electron accelerator with a beam current of ≤ 60 kA, an electron energy of ≤4 MeV, and a pulse duration of ≤80 ns. The X-ray diagnostic method is used in the diagnostic system to determine the energy of accelerated electrons at the entrance into the converter target. A measuring transducer of the electron energy is based on determining the static transfer characteristic of the converter target, which relates (under the known conditions) the energy of accelerated electrons to the beam current and the dose rate at a selected point of the bremsstrahlung field on the electron beam transport axis. Physically, the transducer is located in the target unit of the accelerator. 相似文献
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The problem of measuring weld penetration during electron-beam welding by an ultrasonic method is considered. The results of calculations and data of experimental studies are reported. The efficiency of introducing the ultrasonic method for testing weld penetration during electron-beam welding is demonstrated.Translated from Defektoskopiya, Vol. 41, No. 1, 2005, pp. 29–31.Original Russian Text Copyright © 2005 by Sadadinov, Pyankov. 相似文献
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B. K. Paul 《Scanning》1997,19(7):466-468
In electron-beam (EB) lithography, it is common practice to prepare the resist for exposure using a metal over-layer or an ion shower to eliminate the charging of the resist. Recent efforts to prototype micromechanical structures using EB lithography methods have avoided the need for resist preparation by using low-pressure EB lithography methods. While a great deal of research has centered around high-vacuum electron-beam (EB) lithography, little research has been conducted concerning the effect of gas chamber pressure on linewidth in low-pressure EB lithography. In this paper, experimental data are presented linking the gas pressure in low-pressure EB lithography with lithography line profiles. The results show that as gas pressure is varied, a compromise exists between line broadening and the charging-up effect. 相似文献
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PETR WANDROL 《Journal of microscopy》2007,227(1):24-29
The new scintillation detector of backscattered electrons that is capable of working at primary beam energy as low as 0.5 keV is introduced. Low energy backscattered electrons are accelerated in order to generate a sufficient number of photons. Secondary electrons are deflected back by the energy filter so that the true compositional contrast of the specimen is obtained. The theoretical models of the detector function are described and first demonstration images are presented. 相似文献
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植物生长过程中对太阳光谱的吸收具有选择性。由于植物在光合作用和生长发育中对蓝紫光和红光较为敏感,因此设计并镀制了一种滤光片,目的是从太阳光谱中过滤掉植物吸收很少、且可能有害的黄绿光,从而采集植物生长所需要的蓝紫光和红光。通过离子源辅助电子枪蒸镀的物理沉积方式在大尺寸的K9玻璃基底上镀制了宽带负滤光片,镀膜后的滤光片在400~470nm和630~750nm波长范围内平均透过率大于90%,而500~580nm波长范围内平均透过率小于0.2%。结果表明该宽带负滤光片膜系的镀制满足植物培育实验的使用要求。 相似文献
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The sources of magnetization of parts subjected to welding and the consequences this magnetization can have in welding are described. The residual magnetization values allowable in arc and electron-beam welding are reported. The MX-10 magnetometer is proposed for testing the residual magnetization of parts. 相似文献
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Corneliu Dimitriu 《Journal of microscopy》1991,164(1):89-93
Time relation curves are given for Formvar membrane contraction or collodion membrane dilation under electron-beam irradiation. Also, numerical values are given for the contraction or dilation measured in different zones of the Formvar or collodion support membranes. 相似文献
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《Ultramicroscopy》1987,21(1):13-21
Recent studies have indicated that focussed beams of high energy electrons can cause significant elemental redistribution in materials in the electron microscope. This redistribution can be attributed to a variety of effects, e.g., electron-beam sputtering, radiation-induced segregation (RIS) and electron-beam mixing, which are exacerbated by the use of a focussed electron probe. In most imaging situations focussed probes are neither necessary nor desirable. However, in an Analytical Electron Microscope (AEM) highly focussed probes are routinely employed to obtain high spatial resolution in microanalysis. In this work X-ray Energy-Dispersive Spectroscopy (XEDS) has been used to investigate elemental redistribution by displacement damage in an alloy of A1-1.95at%Zn during microanalysis in one of the new series of medium-voltage (300–400 kV) analytical electron microscopes. The results indicate that for low specimen temperatures (T < 0.4Tm) and sufficiently high electron fluxes (> 3 × 104 A/m2), the atomic displacement effects do not significantly alter the results of XEDS analysis (probe size range 300 to 7.5 nm). Electron beam knock-on sputtering may remove several tens of nanometres of surface material, if the specimen surfaces are clean. However, this produces compositional changes only if one or more of the alloy components sputter preferentially, or if there is Gibbsian segregation to the foil surface. 相似文献