Fusion Zone Shapes in Electron-Beam Welding Dissimilar Metals

2000 ◽  
Vol 122 (3) ◽  
pp. 626-631 ◽  
Author(s):  
P. S. Wei ◽  
Y. K. Kuo ◽  
J. S. Ku
Keyword(s):  
Electron Beam ◽  
Fusion Zone ◽  
Electron Beam Welding ◽  
Beam Power ◽  
Strong Mixing ◽  
Width Ratio ◽  
Dissimilar Metals ◽  
Measured Concentration ◽  
Joint Plane ◽  
The Difference

Experiments on welding dissimilar metals, such as aluminum or copper to iron with an electron-beam welder, are conducted. It is found that the observed depth-to-width ratio of the fusion zone in aluminum can be greater than unity while that in iron is around unity. The former is attributed to the formation of a cavity resulting from a high vapor pressure. The difference in depths increases with beam power. The observed depth-to-width ratios of fusion zones in welding copper to iron can be greater than unity. A unique maximum depth is near the joint plane, as a result of strong convective mixing and high incident flux, even though the melting temperatures are different. Strong mixing is confirmed by measured concentration profiles across the fusion zones of dissimilar metals. To a first approximation fusion zone depths with depth-to-width ratios greater than or identical to unity are determined from scale analyses of heat conduction equations in welding the same metals with a high and low-power-density beam, respectively. The propositions are verified by experimental results. [S0022-1481(00)00103-1]

Analysis on the Weld Defects of the AZ91D Magnesium Alloy Joints

2009 ◽  
Vol 610-613 ◽  
pp. 931-935
Author(s):  
Hong Ye ◽  
Zhong Lin Yan ◽  
Bin Shen ◽  
Z.F. Xue
Keyword(s):  
Electron Beam ◽  
Magnesium Alloy ◽  
Fusion Zone ◽  
Electron Beam Welding ◽  
Boundary Surface ◽  
Incomplete Fusion ◽  
Az91d Magnesium Alloy ◽  
Process Characteristics ◽  
The Difference ◽  
Cast Magnesium

In this study, taking die-cast magnesium alloy AZ91D as investigation objects, the process characteristics of electron beam welding (EBW) was studied. The microstructure and familiar defects in the welded joints were analyzed. The main reasons of these defects were discussed. The experimental results showed that boundary surface between fusion zone and heat affected zone in the joint of AZ91D magnesium alloy by electron beam welding is obvious, the fusion zone (FZ) consisted of fine-equiaxed grain. Pore and crack are the main defects in AZ91D magnesium alloy joints. Magnesium has higher hydrogen solubility in liquid than in solid. The difference in the solubility between the solid and liquid phase is the major reason of the pore of magnesium alloys during welding. The crack was caused because of α + β-Mg17Al12 phase with low melting point and pores in the fusion zone. There were other defects found in the joints such as incomplete fusion and penetration.

Electron Beam Deflection When Welding Dissimilar Metals

1990 ◽  
Vol 112 (3) ◽  
pp. 714-720 ◽  
Author(s):  
P. S. Wei ◽  
T. W. Lii
Keyword(s):  
Electron Beam ◽  
Incident Angle ◽  
Electrical Contact ◽  
Beam Deflection ◽  
Beam Power ◽  
Dissimilar Metals ◽  
Electrical Contact Resistance ◽  
Energy Beam ◽  
Relative Magnetic Permeability ◽  
The Difference

High-intensity electron beam deflection due to thermoelectric magnetism generated during the welding of dissimilar metals is systematically and analytically investigated. A simple thermoelectric model is proposed and the temperature field, penetration depth of the fusion zone, magnetic field, and motion of an electron are determined. Deviation of the fused zone from a joint is affected by the incident angle of the energy beam, the difference in Seebeck coefficients of workpieces, relative magnetic permeability, beam power, welding speed, thermal and electrical conductivities, and the effective electrical contact resistance. Their effects are clearly interpreted in this study. Analytical results for the deviation of the fused zone from the joint between the materials to be welded show good agreement with available experimental data.

Some Issues of Repairing Manned Space Vehicles in Outer Space Using Electron Beam Welding

2021 ◽  
Vol 315 ◽  
pp. 101-105
Author(s):  
Leonid M. Lobanov ◽  
E.A. Asnis ◽  
Ye.G. Ternovy ◽  
Yu.V. Zubchenko ◽  
I.I. Statkevich ◽  
...  
Keyword(s):  
Electron Beam ◽  
Open Space ◽  
Electron Beam Welding ◽  
Outer Space ◽  
Beam Power ◽  
Space Vehicles ◽  
Automatic Mode ◽  
Manned Space ◽  
Robotic Devices ◽  
New Generation

A new generation of electron beam tool for welding during assembly and repair-restoration works on board of manned space vehicles in open space was demonstrated. The tool includes a small-sized electron beam gun (EBG) with an electron beam power of up to 2.5 kW and a high-voltage power source with a voltage of 10 kV. The design of the electron-optical system of EBG allows using it in both manual as well as in automatic mode applying robotic devices. Applying the manufactured EBG and manipulator, in vacuum chamber the works on simulating the repair of a spacecraft’s section of aluminum 2219 alloy were carried out. The obtained results of studying the structure and mechanical characteristics and also sealing of welds confirmed the high quality of welded joints and a reliability of the technology for repairing a damaged fragment of a spacecraft's body using electron beam welding.

Microstructural Characterization and Tensile Behavior of TA1 Titanium Alloy Sheet Welded by Electron Beam Welding

2021 ◽  
Vol 1027 ◽  
pp. 149-154
Author(s):  
Sen Dong Gu ◽  
Ji Peng Zhao ◽  
Rui Jie Ouyang ◽  
Yong Hong Zhang
Keyword(s):  
Titanium Alloy ◽  
Electron Beam ◽  
Fusion Zone ◽  
Heat Affected Zone ◽  
Electron Beam Welding ◽  
Base Material ◽  
Optical Microscope ◽  
Alloy Sheet ◽  
Tensile Behavior ◽  
Electron Backscattered Diffraction

In the present study, TA1 titanium alloy sheets with a thickness of 0.8mm were welded by electron beam welding. Microstructure of the welded region was investigated using optical microscope and electron backscattered diffraction. Then, the tensile test was conducted to analyse the tensile behavior of the welded sheets as well as the fractography of the fracture surfaces. It is shown that the mean grain size in the heat-affected zone is smaller than that in the fusion zone and base material. The strength of the base metal is lower than that of the fusion zone and heat-affected zone. The average values of the yield strength, tensile strength and elongation of the tensile specimens are 224MPa, 335MPa and 35%, respectively. In addition, the tensile specimens of the welded sheets suffer both ductile and brittle deformation during the tensile tests.

Comparison of microstructure, mechanical properties, and residual stresses in tungsten inert gas, laser, and electron beam welding of Ti–5Al–2.5Sn titanium alloy

2017 ◽  
Vol 233 (7) ◽  
pp. 1336-1351
Author(s):  
Massab Junaid ◽  
Khalid Rahman ◽  
Fahd Nawaz Khan ◽  
Nabi Bakhsh ◽  
Mirza Nadeem Baig
Keyword(s):  
Electron Beam ◽  
Residual Stresses ◽  
Power Density ◽  
Fusion Zone ◽  
High Power ◽  
Electron Beam Welding ◽  
Inert Gas ◽  
High Power Density ◽  
Cooling Rates ◽  
Zone Width

Electron beam welding (EBW), pulsed Nd:YAG laser beam welding (P-LBW), and pulsed tungsten inert gas (P-TIG) welding of Ti–5Al–2.5Sn alloy were performed in order to prepare full penetration weldments. Owing to relatively high power density of EBW and LBW, the fusion zone width of EBW weldment was approximately equal to P-LBW weldment. The absence of shielding gas due to vacuum environment in EBW was beneficial to the joint quality (low oxide contents). However, less cooling rates were achieved compared to P-LBW as an increase in heat-affected zone width and partial α′ martensitic transformation in fusion zone were observed in EBW weldments. The microstructure in fusion zone in both the EBW and P-TIG weldments comprised of both acicular α and α′ martensite within the prior β grains. Hardness of the fusion zone in EBW was higher than the fusion zone of P-TIG but less than the fusion zone of P-LBW weldments due to the observed microstructural differences. Notch tensile specimen of P-LBW showed higher load capacity, ductility and absorbed energy as compared to P-TIG and EBW specimens due to the presence of high strength α′ martensite phase. Maximum sheet distortions and tensile residual stresses were observed in P-TIG weldments due to high overall heat input. The lowest residual stresses were found in P-LBW weldments, which were tensile in nature. This was owing to high power density and higher cooling rates in P-LBW operation. EBW weldment exhibited the highest compressive residual stresses due to which the service life of EBW weldment is expected to improve.

Investigation of Spiking in Electron Beam Welding Using Stationary Stochastic Models

1977 ◽  
Vol 99 (2) ◽  
pp. 323-326 ◽  
Author(s):  
M. S. Phadke ◽  
A. M. Joglekar ◽  
S. M. Wu
Keyword(s):  
Electron Beam ◽  
Regression Models ◽  
Electron Beam Welding ◽  
Mechanistic Model ◽  
Beam Current ◽  
Heat Energy ◽  
Random Fluctuation ◽  
Beam Power ◽  
Model Parameters ◽  
Order Continuous

The spiking phenomenon in electron beam welding is characterized using the second-order continuous autoregressive model. The model parameters are then physically interpreted in terms of the random fluctuation in the beam power and the diffusion of heat energy in the plates being welded; and a mechanistic model is proposed for the spiking phenomenon. Finally, regression models are obtained to relate the spiking behavior to the accelerating voltage, the beam current, and the welding speed.

Mechanical Properties of Forged Ti-6Al-4V Structure by Electron Beam Welding

2012 ◽  
Vol 455-456 ◽  
pp. 308-313
Author(s):  
Hong Yu Qi ◽  
Jian Xie ◽  
Shao Lin Li ◽  
Xiao Guang Yang
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Fusion Zone ◽  
Electron Beam Welding ◽  
Welded Joint ◽  
Base Material ◽  
Structure Design ◽  
Large Gradient ◽  
Welded Structure ◽  
Aero Engine

The blisk (bladed disk) is a new structural component of the modern aero-engine and plays an important role in improving its performance. Ti-6Al-4V alloy joints welded by electron beam have been widely used for compressor blisk in advanced aero engine. It is necessary to analyze microstructure and mechanical properties of Ti-6Al-4V welded structure by electron beam welding (EBW) for failure analysis and structure design of blisk. Microstructure of Ti-6Al-4V welded structure by EBW was investigated by microscopic observation and micro indentation testing. Experiment results show grain coarsening in fusion zone (FZ) and heat affected zone (HAZ) appears large gradient organization structure, which presents significant local heterogeneity. On the centerline perpendicular to the welding direction, Vickers microhardness was measured in increments of 1mm, 0.5mm, 0.25mm and 0.1mm. Due to the presence of martensite, microhardness of the fusion zone is about 20% higher than that of the base material. The size of joints in different regions was acquired, 2.5 to 3.0-mm-wide in FZ and about 0.7-mm-wide in HAZ respectively. Three different types of EBW samples were designed for tensile test, including welded structure, welded joint and base material. Three different stress-strain curves of specimens were acquired, including welded joint. The experiment data indicates that the tensile strength of welded joints is 8% more than that of the base metal.

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