Electron Beam Welding 电子束焊接

Electron beam welding is a liquid state welding process. Liquid state welding are those welding processes in which, the metal to metal joint form in liquid or molten state. This is also classified as a new welding process because it uses electrons kinetic energy to fuse two metal work pieces. This welding is developed by the German physicist Karl-Heinz in 1958. In this welding process, a high jet of electrons strikes at welding plates where its kinetic energy converts into heat energy. This heat energy is sufficient to melt the work pieces and fuse them into one piece. This whole process carried out in vacuum otherwise the electrons collides with air particles and loses its energy.

电子束焊接是液态焊接工艺。液态焊接是那些金属与金属接头形成液态或熔融状态的焊接工艺。 这也被归类为一种新的焊接工艺,因为它使用电子动能来熔化两个金属工件。这种焊接是由德国物理学家Karl-Heinz于1958年开发的。在这种焊接过程中,高电子射流撞击焊接板,其动能转化为热能。这种热能足以熔化工件并将它们熔合成一体。 整个过程在真空中进行,否则电子与空气粒子碰撞并失去其能量。

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1 Principle 原理

This welding works on same principle of electron beam machining. This process uses kinetic energy of electrons to produce heat. This heat is further used to weld two welding plates. When a high jet of electrons strike at welding plates, its kinetic energy converts into heat energy. This heat energy is sufficient to fuse two metal plates together to form a weld joint.
这种焊接的工作原理与电子束加工相同。该过程使用电子的动能产生热量。该热量进一步用于焊接两个焊接板。当高速电子流撞击焊接板时,其动能转化为热能。该热能足以将两个金属板熔合在一起以形成焊接接头。

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2 Equipment 设备

2.1 Power Supply 能源

This process uses a power source to supply continuous beam of electrons for welding process. The voltage range of welding is about 5 – 30 kV for low voltage equipment’s or for thin welding and 70 – 150 kV for high voltage equipment’s or for thick welding.
该工艺使用电源为焊接工艺提供连续的电子束。对于低压设备或薄板焊接,焊接的电压范围约为5-30kV,对于高压设备或厚板焊接,焊接的电压范围约为70-150kV。

2.2 Electron Gun 电子枪

It is heart of electron beam welding. It is a cathode tube (negative pole) which generates electrons, accelerate them and focus it on a spot. This gun is mostly made by tungsten or tantalum alloys. The cathode filament heated up to 2500 degree centigrade for continuous emission of electrons.
它是电子束焊接的核心部件。它由一个阴极管(负极),产生电子,加速它们并将其聚焦在一个点上。这种枪主要由钨或钽合金制成。阴极灯丝加热至2500摄氏度便可以连续发射电子。

2.3 Anode 阳极

Anode is a positive pole which is just after the electron gun. Its main function is to attract negative charge, (in this case electron) provide them a path and don’t allow them to diverge from its path.
阳极是一个正极,就在电子枪之后。它的主要功能是吸引负电荷(在这种情况下是电子)为它们提供一条路径,并且不允许它们偏离其路径。

2.4 Magnetic Lenses 磁透镜

There are a series of magnetic lenses which allows only convergent electrons to pass. They absorb all low energy and divergent electrons, and provide a high intense electron beam.
有一系列磁透镜只允许会聚电子通过。它们吸收所有低能量和发散电子,并提供高强度电子束。

2.5 Electromagnetic lens and deflection coil 电磁透镜和偏转线圈

Electromagnetic lens used to focus the electron beam on work piece and deflection coil deflect the beam at required weld area. These are last unit of EBW process.
用于将电子束聚焦在工件上的电磁透镜和偏转线圈在所需的焊接区域偏转光束。这些是EBW工艺的最后一个单元。

2.6 Work holding device 工件固定装置

EBW uses CNC table for hold work piece which can move in all three direction. The welding plates are clamped on CNC table with the use of suitable fixtures.
EBW使用CNC工作台固定工件,可以向三个方向移动。使用合适的夹具将焊接板夹在CNC工作台上。

2.7 Vacuum Chamber 真空室

As we know, whole this process takes place in a vacuum chamber. Vacuum is created by mechanical or electric driven pump. The pressure ranges in vacuum chamber is about 0.1 to 10 Pa.
众所周知,整个工艺都是在真空室中进行的。通过机械或电动泵产生真空。真空室中的压力范围约为0.1至10Pa。

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3 Working 工作

Its working can be summarized as follow.
其工作可归纳如下。

  • First the electron gun, which is a cathode, produces electrons. These electrons move towards anode which is positive charged and placed right after electron gun.
    首先,作为阴极的电子枪产生电子。这些电子向带正电的阳极移动并放置在电子枪之后。
  • The anode accelerates the electrons and form a electron jet which is further move towards magnetic lenses.
    阳极加速电子并形成电子射流,电子射流进一步向磁透镜移动。
  • The magnetic lenses are a series of lenses which are used to absorb low energy electrons and does not allow to divergent electron to passes through it. It provides a high intense electron jet.
    磁透镜是一系列透镜,用于吸收低能电子并且不允许发散的电子通过它。它提高电子射流强度。
  • Now this electron beam passes through electromagnetic lens and defecting coil which are used to focus and deflect the electron beam at the required spot. This unit direct high velocity electron beam to the weld cavity where its kinetic energy converts into heat energy due to collision. This heat energy is used to create weld by fusion. This whole welding process carried out in a vacuum chamber otherwise the electrons collides with air particle in the way and loses its energy.
    现在这束电子束通过电磁透镜和偏转线圈,偏转线圈用来聚焦和偏转电子束到所需的位置。该装置将高速电子束直接导入焊接腔内,其动能因碰撞而转化为热能。这种热能用于熔合焊接。整个焊接过程都是在真空室中进行的,否则电子会与空气粒子发生碰撞,失去能量。

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4 Application 应用

  • It is used in aerospace industries and marine industries for structure work
    用于航空航天工业和海洋工业的结构工作
  • It is used to join titanium and its alloy.
    用于连接钛及其合金。
  • This type of welding is widely used to join gears, transmission system, turbocharger etc. in automobile industries.
    这种类型的焊接广泛用于汽车工业中的齿轮,传动系统,涡轮增压器等的连接
  • It is used to weld electronic connectors in electronic industries.
    用于焊接电子工业中的电子连接器。
  • This process is also used in nuclear reactors and in medical industries
    该工艺也用于核反应堆和医疗行业

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5 Advantages and disadvantages 优点与缺点

5.1 Advantages 优点

  • It can weld both similar and dissimilar metals.
    可以焊接相似和不同的金属
  • It provides high metal joining rate.
    提供较高金属连接率
  • Low operating cost because no filler material and flux are used.
    由于不使用填充材料和助焊剂,因此运行成本低
  • It provide high finish welding surface.
    提供高精度焊接表面
  • It can used to weld hard materials.
    可以用来焊接硬质材料
  • Less welding defects occur due to whole process carried out in vacuum.
    整个焊接工艺在真空中进行,焊接缺陷少。

5.2 Disadvantages 缺点

  • High capital or set up cost.
    投资高或成本高。
  • High skilled labor required.
    需要高技能工人
  • Frequently maintenance required.
    需要经常维护
  • Work pieces size is limited according to vacuum chamber.
    工件尺寸根据真空室大小而定
  • It cannot do at site due to vacuum.
    由于真空,不能在现场使用。