The Evaporation Effect of Front Keyhole Wall in Penetration Welding with an Electron Beam

2011 ◽  
Vol 686 ◽  
pp. 355-360 ◽  
Author(s):  
Yi Luo ◽  
Jin He Liu ◽  
Chang Hua Du ◽  
Hui Bin Xu ◽  
Chun Tian Li
Keyword(s):  
Heat Transfer ◽  
Electron Beam ◽  
Magnesium Alloy ◽  
Electron Beam Welding ◽  
Process Condition ◽  
High Energy ◽  
High Energy Density ◽  
Deep Penetration ◽  
Heat Transfer Theory ◽  
Keyhole Effect

The process of vacuum electron beam welding is characterized by deep-penetration with the action of keyhole effect. The assumption of simple cylindrical physical model of keyhole is reasonable according to the thermal transfer of the keyhole effect during welding. There is an intensive evaporation arises from the front keyhole wall owing to the high energy density of electron beam. Therefore, an analysis model of heat transfer at the interface of vapor phase and front keyhole wall was proposed to the temperature calculation on the basis of heat transfer theory. The evaporation of the primary elements, which are Mg, Al, Zn and Mn in AZ series magnesium alloy, can be analyzed by the model, as well as the influence of keyhole radius varying on the temperature at vapor-solid interface offront keyhole wall. And dimensionless parameters are introduced to analyze the influence of the process condition on the thermal effect. The calculation results show that Mg and Zn are vulnerable to vaporize loss during the vacuum electron beam welding on AZ series magnesium alloy, and the evaporation of Mg occurs earlier than Zn. A longer electron beam acting duration and smaller keyhole size will increase the temperature of the front keyhole wall significantly, which has a considerable influence on the evaporation effect of the elements.

Heat Transfer Modeling for Vaporizing in Vacuum Electron Beam Welding on Magnesium Alloy

2013 ◽  
Vol 681 ◽  
pp. 314-318
Author(s):  
Yi Luo
Keyword(s):  
Heat Transfer ◽  
Electron Beam ◽  
Magnesium Alloy ◽  
Electron Beam Welding ◽  
High Energy ◽  
High Energy Density ◽  
Deep Penetration ◽  
Transfer Model ◽  
Metal Elements ◽  
Short Period

A heat transfer model for vaporizing in vacuum electron beam welding on magnesium alloy is developed based on the laws of heat conduction and energy conservation. The vaporizing time of the main metal elements in AZ series magnesium alloy is calculated using the model. The results show that the vaporization of Mg element will precede the Zn element under the affecting of high energy density electron beam. The vaporizing times of alloying elements are not entirely dependent on the level of the boiling point, to a certain extent, also dependent on the thermal diffusivity and are closely related to the latent heat of vaporizing and melting of the materials. The change of beam spot diameter of electron beam also greatly alters the heat transfer characteristics of electron beam heat source beam. As the strong vaporizing effect of Mg element will occur within several milliseconds, the keyhole induced by the metal elements vaporizing is formed only within several milliseconds, but also the deep penetration welding effect of vacuum electron beam welding of magnesium alloys will be obtained in a very short period of time.

scholarly journals Experimental Evaluation and Characterization of Electron Beam Welding of 2219 AL-Alloy

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Mohamed Sobih ◽  
Zuhair Elseddig ◽  
Khalid Almazy ◽  
Mohamed Sallam
Keyword(s):  
Electron Beam ◽  
Aluminum Alloys ◽  
Weld Joint ◽  
Electron Beam Welding ◽  
High Energy ◽  
High Energy Density ◽  
Welding Parameters ◽  
Deep Penetration ◽  
Al Alloy ◽  
Aircraft Industry

Aiming to reduce the weight of components, thus allowing a profit in terms of energy saving, automotive industry as well as aircraft industry extensively uses aluminum alloys. The most widely used joining technology in aircraft industry is riveting, while welding seems to be used in the car industry in the case of aluminum alloys. However, welding technology is characterized by many defects, such as gas porosity; oxide inclusions; solidification cracking (hot tearing); and reduced strength in both the weld and the heat affected zones which could limit its development. Many techniques are used for aluminum alloys welding, among them is electron beam welding (EBW), which has unique advantages over other traditional fusion welding methods due to high-energy density, deep penetration, large depth-to-width ratio, and small heat affected zone. The welding parameters that yield to optimal weld joint have been previously obtained. These optimal parameters were validated by welding a specimen using these parameters. To evaluate this optimal weld joint, complete, microstructural observations and characterization have been carried out using scanning electron microscopy, optical microscopy, and energy dispersive X-ray analysis. This evaluation leads to description and quantification of the solidification process within this weld joint.

Development of Cathode Filament Power Supply for EBW Based on ARM

2014 ◽  
Vol 960-961 ◽  
pp. 1300-1303
Author(s):  
Ze Ting Wang ◽  
Peng Liu ◽  
Sheng Wen Fan
Keyword(s):  
Electron Beam ◽  
Power Supply ◽  
Electron Beam Welding ◽  
High Volume ◽  
High Energy ◽  
High Energy Density ◽  
Shipping Industry ◽  
Soft Start ◽  
Power Frequency ◽  
Low Efficiency

The electron beam welding has high energy density, and has been widely applied in air space, the car and shipping industry. Traditional electron beam welding machine power supply system adopts the technology of the power frequency or medium frequency, with high volume, low efficiency and poor stability of electron beam. I put forward a digital filament power control scheme based on STM32, and introduce the hardware and software implementation method in detail. Experiments show that it can realize soft-start and soft-down process, and also be quickly identified and promptly forbid the output when filament fracture, which realize the intellectualization of filament power supply.

Simulation on the Thermal Behavior in Vacuum Electron Beam Welding of Magnesium Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 3317-3325
Author(s):  
Yi Luo ◽  
Jin He Liu ◽  
Hong Ye
Keyword(s):  
Electron Beam ◽  
Magnesium Alloy ◽  
Thermal Behavior ◽  
Thermal Effect ◽  
Electron Beam Welding ◽  
Metal Vapor ◽  
Welding Parameters ◽  
Deep Penetration ◽  
Temperature Distributions ◽  
Metal Vapor Plasma

The thermal behavior during electron beam welding on magnesium alloy were analyzed and simulated. According to the thermal effect of the electron-beam-generated keyhole, a mathematic model of rotary Gaussian body heat source with incremental power-density-distribution was developed. This model can be useful for simulating the thermal effect of metal vapor plasma on the surface of the workpiece and the deep-penetrating effect of the electron beam. By the action of thermal model, the characteristics of temperature field during vacuum electron beam welding on AZ61 magnesium alloy were studied by the method of finite element analysis. And then, the influence of welding parameters on the temperature distributions and the weld contours were analyzed. The simulations and experiments showed that the different deep-penetration effects and temperature distributions were achieved with the varying welding energy inputs, and the metal vapor plasma has a significant impact on the weld contour of magnesium alloy.

Digital Filament Power Supply Designed for Electron Beam Welder

2013 ◽  
Vol 392 ◽  
pp. 382-385
Author(s):  
Ze Ting Wang ◽  
Peng Wang ◽  
Sheng Wen Fan ◽  
Tao Chen
Keyword(s):  
Electron Beam ◽  
Power Supply ◽  
Electron Beam Welding ◽  
High Volume ◽  
High Energy ◽  
High Energy Density ◽  
Soft Start ◽  
Control Scheme ◽  
Power Frequency ◽  
Low Efficiency

The electron beam welding has high energy density, and the advantages of small welding deformation, in the defense, automotive, shipbuilding, precision machinery and other industries has been widely applied. Traditional electron beam welding machine power supply system adopts the technology of the power frequency or medium frequency, high volume, low efficiency and poor stability of electron beam. Combining with the characteristics of electron beam welding power source and the existing shortcomings, I put forward a digital filament power control scheme based on STM32, and introduce the hardware and software implementation method in detail. Experiments show that it can realize soft-start and soft-down process, and also be quickly identified and promptly forbid the output when filament fracture, which realize the intellectualization of filament power supply.

Evaluation of Electron Beam Welded AISI 415 Stainless Steel

2014 ◽  
Author(s):  
Sheida Sarafan ◽  
Priti Wanjara ◽  
Henri Champliaud ◽  
Denis Thibault ◽  
Louis Mathieu
Keyword(s):  
Power Generation ◽  
Electron Beam ◽  
High Energy ◽  
High Energy Density ◽  
Deep Penetration ◽  
Process Conditions ◽  
Hydro Power ◽  
Gauge Section ◽  
Turbine Runner ◽  
Power Generation Systems

Sustainable manufacturing for assembly of turbines used in hydro power generation systems is driving the development of advanced technologies targeted to reduce life-cycle costs whilst assuring high performance over the prolonged product life-span. The turbine runner, a critical component in hydro power generation systems, requires weld assembly between the crown, band and blade sub-components. With due consideration of the thick-gauge sections involved, design and fabrication of a turbine runner that would integrate a high energy density technology for assembly, such as vacuum electron beam welding (EBW), has marked potential to achieve deep penetration with a low heat input, thereby rendering a weldment with narrow heat-affected zones (HAZ) and low distortion. In this study, the weldability of thick-gauge section AISI 415 martensitic stainless steels that are widely utilized in hydro turbine manufacturing was investigated by EBW. Particularly, bead-on-plate (BOP) welding of 88 mm-thick AISI 415 plate was carried out using a 42 kW high vacuum EBW system. The characteristics of the weldments, such as fusion zone (FZ) and HAZ microstructures and hardness were evaluated. The microstructural constituents across the weldment for process conditions that rendered near-complete penetration were studied and related to the microhardness evolution.

Effect of the temperature gradient on hot cracking susceptibility for electron beam welding Alloy 247 LC

2020 ◽  
Vol 62 (7) ◽  
pp. 721-726 ◽  
Author(s):  
A. Senger ◽  
T. Jokisch ◽  
S. Olschok ◽  
U. Reisgen
Keyword(s):  
Electron Beam ◽  
Temperature Gradient ◽  
Electron Beam Welding ◽  
Rupture Strength ◽  
Cast Alloy ◽  
Welding Process ◽  
High Energy ◽  
Hot Cracking ◽  
High Energy Density ◽  
Welding Parameter

Abstract Conventionally cast Alloy 247 LC is characterized by good creep rupture strength and corrosion resistance at high temperatures and is therefore frequently used for cast components in the aero-engine and power generation industries. From a welding technology point of view, the precipitation- hardening nickel-based alloy has an increased susceptibility to hot cracking. Due to its high segregation tendency and its γ’ precipitation formation, the material is even classified as non-weldable. However, electron beam welding in a vacuum as the method of choice for joining and repairing nickel-based components in industrial practice, provides a variable beam welding process with high energy density. This allows varied temperature gradients to be implemented. In this paper, results of welding parameter optimization with regard to hot crack reduction are presented. For this purpose, a comprehensive crack analysis was carried out using scanning electron microscopy, metallography and X-ray microtomography and was then compared with the temperature gradient along the fusion line. Two hot cracking phenomena were identified and differentiated. Thereby, a clear dependence between temperature gradient and crack reduction becomes obvious.

Optimization of EBW Parameters for 2219 AL-Alloy Using Grey Relation Method

2012 ◽  
Vol 591-593 ◽  
pp. 507-514 ◽  
Author(s):  
Mohamed Sobih ◽  
Zuhair Elseddig ◽  
Khalid Almazy ◽  
Amro Youssef ◽  
Mohamed Sallam
Keyword(s):  
Electron Beam ◽  
Heat Affected Zone ◽  
High Energy ◽  
Fusion Welding ◽  
High Energy Density ◽  
Welding Parameters ◽  
Deep Penetration ◽  
Al Alloy ◽  
Bead Geometry ◽  
Grey Relation

Aluminum alloys are the subject of increasing interest in the automotive, as well as aircraft industries. Concerning the assembly, welding was extensively applied in the car industry. Nevertheless, welding defects generated during the process result in reduction in strength of both the weld; and heat affected zone which could limit its applications. Electron beam welding (EBW) has unique advantages over other traditional fusion welding methods due to its high-energy density, deep penetration, large depth-to-width ratio and the resulting very small heat affected zone. Optimization of EB welded joint of 2219 Al-alloy, from the yield strength, hardness and bead geometry point of view, is the topic of this study. Taguchi methodology with grey relation analysis has been applied to find the optimal welding parameters for welding of a sheet of the mentioned aluminum alloy with electron beam. The optimal welding parameters have been selected and verified experimentally.

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