The presentation is about the electron beam welding process and its capabilities. It is research-oriented to give the reader a thorough knowledge about its applications.
2. CONTENTS
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Chapter Topics Slide Number
1
Electron Beam Welding
1.1 Need of EBW 3
1.2 Working Principle 4-8
1.3 Setup and Equipments 9-10
1.4 Process Parameters 11-12
1.5 Microstructural Analysis 13-15
1.6 Advantages, Disadvantages, and Applications 16-17
1.7 Acknowledgement 18
3. NEED?
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Figure 1. Comparison of single pass EB
weld profile with multi pass submerged
arc welded joint in 100mm thickness C-
Mn steel. (Image courtesy by:
https://www.twi-global.com)
Figure 4. Comparison of EBW over TIG. (Image
courtesy by https://www.ebpglobal.com)
Figure 2. Penetration depth
of EB weld. (Image courtesy
by https://www.ptreb.com)
Figure 3. Comparison of EBW
over conventional welding.
(Image courtesy by PHM
Industries GmbH)
• Dr. Karl Heinz (German) – Development of first practical welding machine in 1958.
4. WORKING PRINCIPLE
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• Electron beams are composed of electrons that are charged particles having a rest
mass of 9.1x10-31 kg and can be accelerated in electron guns to relativistic velocities,
giving them high kinetic energies.
• At 10 kV (13 hp), electrons travel at approximately 20% of the speed of light, while at
200 kV (270 hp) they travel at approximately 70% the speed of light.
• The higher the potential difference between cathode and anode, the higher would be
the acceleration of the electrons. The electrons get the speed in the range of 50,000 to
200,000 km/s.
5. WORKING PRINCIPLE
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Use kinetic energy of electrons to produce heat.
High energy electrons
impinged on the surface
generate localized heat
spots
This heat is further used to
weld two welding plates
Figure 6. Electron Beam Welding (Image
courtesy of: http://www.twitraining.com)
Figure 5. (a):The Cathode Ray Oscilloscope (Image courtesy
of: http://www.schoolphysics.co.uk); (b) Electron Gun Cross
Section (Image courtesy of: https://commons.wikimedia.org)
(a)
(b)
6. WORKING PRINCIPLE
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Figure 8. Electron Gun schematic (Image courtesy of:
https://physics.stackexchange.com)
• ELECTRON GUN
Notes: LaB6: lanthanum hexaboride
Figure 7. A LaB6 filament.
(Image courtesy by:
http://www.snaggledworks.com)
7. SETUPAND EQUIPMENTS
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Figure 9. EBW Process (Image courtesy of:
https://www.mech4study.com)
[1] M. Chiumenti, M. Cervera, N. Dialami, B. Wu, L. Jinwei, and C. Agelet de Saracibar, “Numerical modeling of the electron beam welding and its experimental validation,” Finite Elem. Anal. Des., vol. 121, pp. 118–133, 2016.
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 [1].
Figure 10. Molten Pool during EBW [1]
8. Wednesday, June 16, 2021 Presenter: Sahil Dhiman 8
SETUPAND EQUIPMENTS
POWER SUPPLY
•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.
ELECTRON GUN
•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.
ANODE
•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.
MAGNETIC LENSES
•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.
ELECTROMAGNETIC LENS AND DEFLECTION COIL
•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.
WORK HOLDING DEVICE
•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.
VACUUM CHAMBER
•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.
9. PROCESS PARAMETERS
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PROCESS
PARAMETERS
Accelerating
Voltage
Beam Current Welding Speed Beam Focusing
10. PROCESS PARAMETERS - VOLTAGE
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•A value of electrical potential, usually expressed in kilovolts, being utilized to accelerate
and increase the energy of the electrons being emitted by an electron beam gun.
•Increase in the voltage results into increase in the speed of electrons.
Figure 11. Relationship between electron speed with acceleration voltage. (Image
courtesy by: https://www.didaktik.physik.uni-muenchen.de)
11. PROCESS PARAMETERS – BEAM CURRENT
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• Close relation between electron beam current and depth of penetration.
• Beam current: measure of the quantity of charge (i.e., number of electrons), usually
expressed in units of milli amperes (mA), that flow per unit time in an electron beam.
Figure 13. Variation in Hardness at Weld and HAZ with
Increase in Beam Current [2]
Figure 12. Variation in DOP with Beam Current [2]
[2] A. K., “Effect of Beam Current, Weld Speed and Dissolution on Mechnical and Microstructural Properties in Electron Beam Welding,” Int. J. Res. Eng. Technol., vol. 02, no. 06, pp. 1020–1029, 2013.
12. PROCESS PARAMETERS - SPEED
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• Welding speed directly affects on depth of penetration of electron beam into work piece
• Higher speeds results into lower depth of penetration
Figure 15. Variation in Hardness at Weld and HAZ with
Increase in Welding Speed [2]
Figure 14. Variation in DOP with Welding Speed [2]
[2] A. K., “Effect of Beam Current, Weld Speed and Dissolution on Mechnical and Microstructural Properties in Electron Beam Welding,” Int. J. Res. Eng. Technol., vol. 02, no. 06, pp. 1020–1029, 2013.
13. PROCESS PARAMETERS - SPEED
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[3] S. K. Dinda, M. Basiruddin Sk, G. G. Roy, and P. Srirangam, “Microstructure and mechanical properties of electron beam welded dissimilar steel to Fe–Al alloy joints,” Mater. Sci. Eng. A, vol. 677, pp. 182–192, 2016.
Figure 17. (b) Optical microstructure of different regions of dissimilar joint at higher welding speed (1500mm/min) condition [3].
(a)
(b)
Figure 16. (a) Optical microstructure of different regions of dissimilar joint at lower welding speed (1000mm/min) condition [3].
14. MICROSTRUCTURALANALYSIS
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• Microstructural analysis of fusion and heat affected zones in electron beam welded ALLVAC®
718PLUSTM superalloy
Figure 18. Optical microstructure of the as-received 718 Plus alloy. [4]
[4] K. R. Vishwakarma, N. L. Richards, and M. C. Chaturvedi, “Microstructural analysis of fusion and heat affected zones in electron beam welded ALLVAC ® 718PLUSTM superalloy,” Mater. Sci. Eng. A, vol. 480, no. 1–2,
pp. 517–528, 2008.
15. MICROSTRUCTURALANALYSIS
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• Fusion zone microstructures
Figure 19. (a) Typical nail head type of weld profile of 718 Plus welds with porosity at the bottom; (b)
heat affected zone cracking as observed in the shoulder region of the nail head-shaped weld profile of
718 Plus alloy; no cracking was observed in the fusion zone [4].
[4] K. R. Vishwakarma, N. L. Richards, and M. C. Chaturvedi, “Microstructural analysis of fusion and heat affected zones in electron beam welded ALLVAC ® 718PLUSTM superalloy,” Mater. Sci. Eng. A, vol. 480, no. 1–2,
pp. 517–528, 2008.
(a)
(b)
Fusion zone consisting of cellular dendritic microstructure with an average
secondary dendrite arm spacing of 4m.
16. MICROSTRUCTURALANALYSIS
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• HAZ microstructures
[4] K. R. Vishwakarma, N. L. Richards, and M. C. Chaturvedi, “Microstructural analysis of fusion and heat affected zones in electron beam welded ALLVAC ® 718PLUSTM superalloy,” Mater. Sci. Eng. A, vol. 480, no. 1–2,
pp. 517–528, 2008.
Figure 20. SEM micrograph of HAZ showing
partially melted zone and liquation cracking
[4].
17. 0.097mm
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ADVANTAGES & DISADVANTAGES
• It can weld both similar and dissimilar metals.
• It provides high metal joining rate.
• Low operating cost because no filler material and flux are used.
• It provide high finish welding surface.
• It can used to weld hard materials.
• Less welding defects occur due to whole process carried out in vacuum.
ADVANTAGES
• High capital or set up cost.
• High skilled labour required.
• Frequently maintenance required.
• Work pieces size is limited according to vacuum chamber.
• It cannot do at site due to vacuum.
•60 kV 4 kW (610 mm3) electron beam welder including CNC controlled work
manipulation systems £220,000.00 i.e. 17609882.40 INR (1 £ = 80.02 INR)
DISADVANTAGES
18. 0.097mm
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APPLICATIONS
APPLICATIONS:
1
• It is used in aerospace industries and marine industries for structure work
2
• It is used to join titanium and its alloy.
3
• This type of welding is widely used to join gears, transmission system, turbocharger etc. in automobile
industries.
4
• It is used to weld electronic connectors in electronic industries.
5
• This process is also used in nuclear reactors and in medical industries