scholarly journals Effect of Pre-Heating and Post-Heating on Electron Beam Welding of Reduced Activation Ferrite/Martensite Steel

2021 ◽  
Vol 2 (3) ◽  
pp. 225-238
Author(s):  
Yong Zhang ◽  
Jiefeng Wu ◽  
Zhihong Liu ◽  
Songlin Liu ◽  
Mingzhun Lei ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Electron Beam ◽  
Electron Beam Welding ◽  
Laser Beam Welding ◽  
Welding Process ◽  
High Energy ◽  
High Energy Density ◽  
Post Heat Treatment ◽  
Rafm Steel

Reduced activation ferritic/martensitic (RAFM) steels are considered the main candidate material for the water-cooled ceramic breeder (WCCB) in a fusion reactor. High-energy density welding approaches, such as electron beam welding (EBW) and laser beam welding (LBW), are frequently utilized in the welding of RAFM steels. During the welding process, cracks and other defects are prone to appear. In this paper, EBW was selected for the welding of RAFM steels. Those with and without pre-heat and post-heat treatment by electron beams are studied by finite element simulation and trials. The results show that the experimental results are consistent with the simulation. In particular, in the case of similar deformation, the residual stress after electron beam heat treatment is far less than that without heat treatment. Without heat treatment, the residual stress near the weld is more than 400 MPa, while the residual stress after heat treatment is about 350 MPa. As the reduction of residual stress is essential to prevent the occurrence of cracks and other defects after welding, pre-heat and post-heat treatment by the electron beam is deemed as an effective way to greatly improve the welding quality in RAFM steel welding.

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.

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.

Measurement and Simulation of Residual Stresses of Electron Beam Welding Joint of Pure Aluminum

2012 ◽  
Vol 184-185 ◽  
pp. 649-652
Author(s):  
Gui Fang Guo ◽  
Shi Qiong Zhou ◽  
Liang Wang ◽  
Li Hao ◽  
Ze Guo Liu
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Electron Beam ◽  
Residual Stresses ◽  
Electron Beam Welding ◽  
Pure Aluminum ◽  
Research Result ◽  
Welding Process ◽  
Hole Drilling ◽  
Longitudinal Residual Stress

The effects of electron beam welding on the residual stresses of welded joints of pure aluminum plate 99.60 are studied by through-hole-drilling and blind-hole-drilling method. Meanwhile, based on the thermal elastic-plastic theory, and making use of ANSYS finite element procedure, a three - dimensional finite element model using mobile heat source of temperature and stresses field of electron beam welding in pure aluminum is established. The welding process is simulated by means of the ANSYS software. The results show that the main residual stress is the longitudinal residual stress, the value of the longitudinal residual stress is much larger than the transverse residual stress. But the residual stress in the thickness is rather small. And in the weld center, the maximum value of residual stresses is lower than its yield strength. The simulation results about the welded residual stresses are almost identical with the experimental results by measuring. So the research result is important to science research and engineering application.

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.

Dissimilar and Similar Laser Beam and GTA Welding of Nuclear Fuel Pin Cladding Tube to End Plug Joint

2017 ◽  
Vol 24 ◽  
pp. 40-47
Author(s):  
Aravind Murugan ◽  
R. Sai Santhosh ◽  
Ravikumar Raju ◽  
A.K. Lakshminarayanan ◽  
Shaju K. Albert
Keyword(s):  
Laser Beam ◽  
Laser Welding ◽  
Laser Beam Welding ◽  
Welding Process ◽  
High Energy ◽  
Optical Microscope ◽  
High Energy Density ◽  
Fuel Pin ◽  
Gtaw Process ◽  
Welding Processes

The end plug to cladding tube of fast reactor fuel pin is normally welded using Gas Tungsten Arc Welding (GTAW) process. The GTAW process has large heat input and wide heat-affected-zone (HAZ) than high energy density process such as laser welding. In the present study Laser Beam Welding (LBW) is being considered as an alternative welding process to join end plug to clad tube. The characteristics of autogenous processes such as GTAW and pulsed Nd-YAG laser welding on fuel cladding tube to end plug joints have been investigated in this study. Dissimilar combinations of modified stainless steel (SS) alloy D9 cladding tube to SS316L end plug, and similar combinations of SS316L cladding tube to SS316L end plug were successfully welded using the above two welding processes. The laser welding was performed at the butting surfaces of the cladding tube and the end plug, and also by shifting the laser beam by 0.2 mm towards the end plug side to compensate the heat balance and for improving the Creq/Nieq ratio in the molten pool. Helium Leak Test (HLT) and Radiography Test (RT) were carried out to validate the quality of the welds. The microstructures of the weld joints were analysed using optical microscope. In the present study, it has been demonstrated that it is possible to obtain welds free from hot cracks by shifting the laser beam by 0.2 mm towards end plug side, while the weld produced using the beam positioned at the interface shows cracks in the weld.

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.

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.

Effect of Joint Thickness on Residual Stress in Laser / Electron Beam Welded 9Cr-1Mo(V, Nb) Ferritic / Martensitic Steel

2014 ◽  
Author(s):  
Santosh Kumar ◽  
Peter J. Bouchard ◽  
Gautam K. Dey
Keyword(s):  
Residual Stress ◽  
Electron Beam ◽  
Welded Joints ◽  
Electron Beam Welding ◽  
Plate Thickness ◽  
Normal Component ◽  
High Energy ◽  
Energy Beam ◽  
Joint Thickness ◽  
Welding Processes

Residual stresses are invariably associated with welded joints because of local dilation/contraction of material against itself as well as clamp-imposed restraints. Plate thickness provides considerable self-restraint in the case of heavy section welded joints produced by laser and electron beam welding processes and therefore, is expected to affect the relative magnitudes of the three orthogonal direct components of residual stress — longitudinal, normal and transverse to the welding direction. Computation of residual stress in high energy beam welded 9Cr-1Mo(V, Nb) steel plates, of varying thickness in the 5 mm to 80 mm range, has been carried out using finite element based software, SYSWELD, for a systematic study of the effect of the joint thickness on the relative magnitude of the three orthogonal components of stress. The results show that the distributions of residual stress components can be ranked in order of significance in the order: longitudinal, normal and then transverse. The longitudinal and the normal components of stress show similar cross-weld profiles. The magnitude of the normal component peak shows a direct correlation with the joint thickness and eventually exceeds that of the longitudinal component for an 80 mm thick joint. The results are discussed in the context of our previous residual stress measurements made by neutron diffraction on a thin section laser welded 9Cr-1Mo(V, Nb) steel plate.

Research on Microstructure and Properties of Base Metal and Weld of Electron Beam Welding 0.30C-Cr-W Steel

2015 ◽  
Vol 817 ◽  
pp. 238-245
Author(s):  
Lin Tao Li ◽  
Mao Sheng Yang ◽  
Yun Ren
Keyword(s):  
Heat Treatment ◽  
Electron Beam ◽  
Base Metal ◽  
High Performance ◽  
Electron Beam Welding ◽  
Theoretical Calculations ◽  
Welding Process ◽  
Post Weld Heat Treatment ◽  
Aviation Industry ◽  
Temperature Impact

Due to the difficulty of manufacturing complex small pieces ofthe new bearing steel0.30C-Cr-W with high-performance in the aviation industry, the electron beam welding process are usually used for preparing the complex parts.Thewelding performance of 0.30C-Cr-W steelwas calculated by theory and confirmedby actual experiments.The base metal was preheated,then welded and heattreated for weldments.The purpose of this work is to study the properties and the microstructure changes of base metal after heat treatment, weldments before heat treatment and weldments after heat treatment.The results show that the base metalafter heat treatment is sorbitic,weldzone of weldments after heat treatmentismartensite and austenite, theprecipitated M23C6 and M6C in latter (the weld zoneof weldmentsafter heat treatment) were more thanthe former (the base metalafter heat treatment), and the strengthof the latter is 23.4%lower than the former, theroom temperature impact absorbing energy and hardness of the latter increased 13.5% and 6.6%. It may be considered that0.30-C-Cr-W steel is not suitablefor welding by the theoretical calculations, but after reasonable preheat and post-weld heat treatment, the mechanical properties of the weld afterheat treatment can satisfy the requirements.

Residual Stresses in Thick-Section Electron Beam Welds in RPV Steels

2016 ◽  
Author(s):  
Anastasia N. Vasileiou ◽  
Mike C. Smith ◽  
David Gandy ◽  
Arben Ferhati ◽  
Remi Romac ◽  
...  
Keyword(s):  
Residual Stress ◽  
Electron Beam ◽  
Finite Element Modelling ◽  
Electron Beam Welding ◽  
Welding Process ◽  
Structural Performance ◽  
Thick Section ◽  
Element Modelling ◽  
Section Electron ◽  
Made In

Low pressure electron beam welding offers the prospect of large increases in productivity for thick section welds in RPV steels. However, it is important to understand how this welding process affects the structural performance of the completed weld. This paper reviews and presents key results from a programme of weldment manufacture, materials characterisation, residual stress measurements, and finite element modelling of EB welds made in plate of three thicknesses, 30mm, 130mm, and 200mm, and in three steels: SA508 Gr 2, SA508 Gr 3 C1 1, and SA516 Gr 70.

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