Electron Beam Welding Parameters Research Articles

Structure and properties of welds in electron beam welding of iron-chromium-nickel alloy EP718

This article presents the results of a study focused on the formation of structural characteristics and properties of welded joints in the EP718 alloy with a 13 mm thickness (accounting for a 3 mm technological substrate). The study explores variations in electron beam welding parameters, such as beam current and the speed of its movement across the specimen’s surface, to determine the optimal welding mode for this alloy. This alloy is crucial in the production of high-pressure stators for aircraft engines, as the component operates under low-cycle loads at high stress levels, making its performance critical. Specimens that were welded with a beam speed (ν) of 0.0042 m/s and a beam current (i) of 85 mA exhibited a minimum tensile strength of 1160 MPa. On the other hand, specimens welded with ν = 0.006 m/s and i = 65 mA demonstrated a maximum tensile strength of 1270 MPa. However, it’s noteworthy that specimens welded at 0.006 m/s with beam currents of 120 mA and 75 mA experienced fracture along the weld, while specimens welded at 0.006 m/s with a beam current of 65 mA and at 0.0042 m/s with a beam current of 85 mA exhibited fracture in the heat-affected zone at a distance of 0.5–3.0 mm from the weld. Examination of the structure of specimens welded at ν = 0.006 and 0.0042 m/s and i = 120 mA, 75 mA, and 85 mA revealed expanded grain boundaries in the heat-affected zone. Consequently, the optimal welding mode was identified as having a beam speed of 0.006 m/s and a beam current of 65 mA. In this mode, no thickened grain boundaries were detected, and a maximum tensile strength of 1270 MPa was achieved.

Microstructure and mechanical properties of electron beam welded TC4 titanium alloy structure with backing plate

This study investigates the microstructure characterization and residual stress differences of a welded TC4 titanium alloy structure to determine the optimum electron beam welding parameters. A finite element model is constructed on the basis of the actual weld morphology under different welding parameters, and the Mises stress of the titanium alloy electron beam joint is compared. The residual stress distribution in the shell structure with a backing plate under superimposed working stress conditions is analyzed. Results show that the change of microstructure and mechanical properties of each area do not show remarkable changes with variations in welding speed. However, the macroscopic morphology varies greatly, and the microhardness and maximum shear strength distribution appears as follows: the weld metal > heat affected zone > base metal. The finite element simulation reveals that the peak residual stress of WM along the longitudinal and transverse directions is 782 MPa and 583 MPa respectively, which is consistent with the distribution of the measured results. The finite element calculation results of the shell structure under internal pressure show that the Mises stress of the WM appears the smallest value when the welding speed reaches 8 mm/s, and its value is 650.59 MPa. Therefore, a smaller the welding speed (from 14 mm/s to 8 mm/s) of the shell structure has a positive effect on service behavior.

Influence of Electron Beam Welding Parameters on the Properties of Dissimilar Copper–Stainless Steel Overlapped Joints

Influence of Electron Beam Welding Parameters on the Properties of Dissimilar Copper–Stainless Steel Overlapped Joints

Evaluation of the impact of electron beam welding parameters on the mechanical properties and microstructure of the resulting joint for 39CrMoV13 and M50NiL steel grades

The paper covers a study consisting on the implementation of the electron beam welding process of two steel grades: 39CrMoV13 and M50NiL. The welding process was carried out for two values of electron beam debunching, obtaining a joint having different widths. Then, for the samples, after each welding variant, heat treatment was carried out consisting of double tempering at 520 °C for 3 h, and single freezing at − 84 °C for 3 h, combined with single tempering at 520 °C for 3 h. The impact of the parameters of the electron beam welding process and the subsequent heat treatment process on the mechanical properties and microstructure of the resulting joint was analysed. The conducted tests allowed to select the optimum welding technology combined with the heat treatment process for the tested steel grades ensuring that a weld is obtained in which the level of mechanical properties was close to the level of values obtained for the base material.

Preface

The 4th International biannual conference “Electron Beam Welding and Related Technologies (EBW2021)” was held at National Research University “Moscow Power Engineering Institute (MPEI)” on November 16-19 2021 in Moscow, Russia. The host university MPEI is one of the leading academic institutions in Europe that conducts research in heat and electricity generation, electrotechnical instrumentation design and power engineering machinery building.The conference is dedicated to research, innovations and novel engineering solutions in electron beam welding (EBW), metals heat treatment, and electrotechnical engineering. More than 40 reports were presented in various areas of EBW technologies:• processing of metals with condensed energy flows;• technologies of electron beam wielding;• additive technologies;• equipment for electron beam wielding;• related fields of materials sciences.Reports subjects included the following areas: modeling of EBW processes (thermal fields, heat and mass transfer, electron beam energy, metal ionization, etc.), control of EBW parameters and welding equipment, additive manufacturing, diagnostics of mechanical and service properties of welded joints, electron beam welding equipment.List of Scientific Committee, Organizing Committee, Editor are available in this pdf.

Influence of Electron Beam Welding Parameters on the Microstructure Formation and Mechanical Behaviors of the Ti and Ni Dissimilar Metals Welded Joints

Commercially pure titanium Ti Grade 2, 2 mm in thickness, was welded to 2 mm thick nickel alloy 201 with electron beam welding. Various welding parameters were used to create the butt-welded joints. The innovation herein consists of welding two dissimilar metals that are declared non-weldable. The welding current used for electron beam welding was 40–70 mA and welding speeds were 20–50 mm/s. In this experiment, we tested two offsets of the electron beam, which were 100–300 μm to the nickel side and 200 μm to the titanium side. It was observed that the offset of the beam had no effect on the weld joint’s strength. The samples were subjected to a visual test in which longitudinal and transverse cracks were recorded along the whole weld. Only four samples retained the integrity of the joint. Microstructures of the weld joints were examined by scanning confocal and scanning electron microscopy. Energy dispersive spectroscopy (EDS) analysis confirmed the phase constitution inside the weld regions and the fusion interfaces. Tensile strength and microhardness tests were used to evaluate the mechanical parameters of the Ti/Ni welded joint. The results showed that cracking of brittle Ni–Ti intermetallic phases in electron beam welded joints occurred. The microstructure in the fusion zone’s center part was primarily NiTi and Ti2Ni. No clear correlation was found between heat input or welding parameters—welding current and welding speed—and tensile strength. The strain–tensile strength curve resulted in brittle fracturing. The hardness of the weld zone was five times higher than that of the base metal and heat-affected zone. The amount of heat input into the welded metal is as critical as the large asymmetry in heat transport that controls the process of solidification from each side of the base metal.

Effect of electron beam welding parameters on temperature and stress field of AISI P20 tool steel in vacuum roll-cladding process

Vacuum roll-cladding (VRC) is an effective method to produce high-quality ultra-heavy AISI P20 plate steel. In the process of VRC, reasonable welding process of electron beam welding (EBW) can significantly avoid welding cracks and reduce the cost. In this paper, the electron beam welding process of AISI P20 tool steel was simulated by using a combined heat source model based on finite element method, and the temperature field and stress field under different welding parameters were studied respectively. The results showed that welding parameters have a greater effect on weld penetration than that of weld width, making the aspect ratio increases with the increase of welding current, and decrease with the increase of welding speed. The weld morphologies were consistent with those of the modeling, and the measured thermal heat curves were in good agreement with those of simulated, which verified the feasibility and effectiveness of temperature fields. The results of stress fields under different welding parameters indicated that welding speed of 300mm/min and welding current of 60mA result in lower residual stress at welded joint, which means lower risk of cracking after EBW. The results of this study have been successfully applied to industrial production.

Influence of electron beam welding parameters on the weld seam geometry of Inconel 718 at low feed rates

Abstract Ni-based superalloys are well established in various industrial applications, because of their excellent mechanical properties and corrosion resistance at high temperatures. Despite the high development stage and a common industrial use of these alloys, hot cracking remains a major challenge limiting the weldability of the materials. As commonly known, the hot cracking susceptibility during welding increases with the amount of precipitation phases. Hence, a large amount of highstrength Ni-Alloys is rated as non-weldable. A new approach based on electron beam welding at low feed rates shows great potential for reducing the hot cracking tendency of precipitation-hardened alloys. However, geometry and properties of the weld seam differ significantly in comparison to the common process range for practical uses. The aim of this study is to investigate the influence of welding parameters on the seam geometry at low feed rates between 1 mm/s and 10 mm/s. For this purpose, 25 bead on plate welds on a 12 mm thick sheet made of Inconel 718 are carried out. First, the relevant parameters are identified by performing a screening. Then the effects discovered are further studied by using a central composite design. The results show a significant difference between the analyzed weld seam geometry in comparison to the well-known appearance of electron beam welded seams.

Influence of electron beam welding parameters on the weld seam geometry of Inconel 718 at low feed rates

Abstract Ni-based superalloys are well established in various industrial applications, because of their excellent mechanical properties and corrosion resistance at high temperatures. Despite the high development stage and a common industrial use of these alloys, hot cracking remains a major challenge limiting the weldability of the materials. As commonly known, the hot cracking susceptibility during welding increases with the amount of precipitation phases. Hence, a large amount of highstrength Ni-Alloys is rated as non-weldable. A new approach based on electron beam welding at low feed rates shows great potential for reducing the hot cracking tendency of precipitation-hardened alloys. However, geometry and properties of the weld seam differ significantly in comparison to the common process range for practical uses. The aim of this study is to investigate the influence of welding parameters on the seam geometry at low feed rates between 1 mm/s and 10 mm/s. For this purpose, 25 bead on plate welds on a 12 mm thick sheet made of Inconel 718 are carried out. First, the relevant parameters are identified by performing a screening. Then the effects discovered are further studied by using a central composite design. The results show a significant difference between the analyzed weld seam geometry in comparison to the well-known appearance of electron beam welded seams.

Electron beam welding of aerospace alloy (Inconel 825): A comparative study of RSM and ANN modeling to predict weld bead area

Electron beam welding (EBW) is an energy intensive beam welding method widely used for joining hard to weld metals found application in aerospace, nuclear, automotive industries. This work investigates the influence of EBW parameters on a popular aerospace alloy (i.e., Inconel 825). Welding speed (S), beam current (I), accelerating voltage (V) and beam oscillation (O) are considered as EBW process parameters to study the weld bead area (WA) of the weldments. Predictive modeling is developed using two different approaches viz., statistical approach based response surface methodology (RSM) and soft computing based artificial neural network (ANN) and their model effectiveness is compared. Parametric analysis shows effect of EBW variables on WA. Welding speed found as the dominant process parameter followed by accelerating voltage and beam current; the maximum WA found at welding speed of 900 mm/min having beam current of 46 mA with an accelerating voltage in the range of 54−60 kV. ANN model developed with 3 layers with 11 hidden layer neurons is found optimum network architecture to predict WA of the weldments. Predictive performance of ANN and RSM models exhibited excellent agreement with confirmation data sets with mean percentage error less 5%. ANN model is found statistically robust and accurate in prediction of WA with model accuracy of 98 %.

Influence of Electron Beam Technological Movements on Aluminium Alloy AW2099 Welded Joints Properties

The electron beam welding (EBW) parameters have significant influence on weld surface appearance and porosity formation. Besides basic welding parameters, such as acceleration voltage, welding current, focusing current and welding speed, the beam oscillation during EBW plays an important role in weld metal formation and directly impacts the final welded joints properties. The influence of technological movements during EBW on the properties of aluminium-lithium alloy welded joints was studied. The same frequency and different amplitude as well as same amplitude and different frequency were chosen. The other welding parameters were constant.

Experimental Study of Nickel Electron Beam Welding

The scope of this study was to ascertain the weldability of Nickel 201 alloy sheets using an electron beam welding method. Weld joints of the Nickel 201 alloy sheets 2,0 mm thick were welded by electron beam without an additional material at a flat position. The influence of electron beam welding parameters on weld quality and mechanical properties of test joints was studied. The study of quality and mechanical properties of the joints were determined by metallographic evaluation, tensile and hardness tests.

Preface

The 3rd International biannual conference “Electron Beam Welding and Related Technologies (EBW2019)” was held at National Research University “Moscow Power Engineering Institute (MPEI)” on November 12-15 2019 in Moscow, Russia. The host university MPEI is one of the leading academic institutions in Europe that conducts research in heat and electricity generation, electrotechnical instrumentation design and power engineering machinery building.The conference is dedicated to research, innovations and novel engineering solutions in electron beam welding (EBW), metals heat treatment, and electrotechnical engineering. More than 50 reports were presented in various areas of EBW technologies, welding materials science, as well as quality control of welded joints. Reports subjects included the following areas: modeling of EBW processes (thermal fields, heat and mass transfer, electron beam energy, metal ionization, etc.), control of EBW parameters and welding equipment, additive manufacturing, diagnostics of mechanical and service properties of welded joints, electron beam welding equipment.The target audience of the event was not only academics and students but also industry experts and state officers. The conference was attended by 150 participants from technical universities, research and production companies, factories and power plants. The showcases of the event are highly recognizable among the industrial community not only in Russia but all over the continent. This year the events were attended by delegates from such countries as Belarus, Bulgaria, Germany, China, India, Syria, Mongolia, Pakistan, Slovakia, France, and Israel.This distinguished volume contains the most significant and novel academic research papers presented at the conference and recommended by the organizing committee. All the manuscripts went through a thorough editorial process and were peer-reviewed by two invited referees.On behalf of the Organizing Committee, we express our gratitude to the sponsors of the conference for financial and informational support. It was a great honor for the editors to work with all the authors, reviewers and organizers.With the best regards,Viktor Dragunov,The Organizing committee Chairman EBW2019 conference,Science editor, professor of MPEI

Electron beam welding of copper using plasma spraying for filler metal deposition

Due to physical properties like high thermal and electrical conductivity, joining of copper is of special interest in steelmaking or electrical industry. Unfortunately, joining of thick-walled copper components using electron beam welding (EBW) tends to welding defects like insufficient root formation or varying penetration depth. In previous investigations, Cu-DHP (deoxidised high phosphorus copper) plates were successfully joined by EBW utilising a CuSn6 sheet as filler material. The investigation resulted in a stable EBW parameter window. Nevertheless, using CuSn6 sheets lead to challenges concerning joint preparations, and is not usable for arbitrary weld configurations. To meet these challenges, atmospheric plasma spraying (APS) is used to apply a thin interlayer in the welding zone and substitute the CuSn6 sheet filler metal. This continuative work includes further improvements of the main EBW parameters and uses APS as a new approach for filler metal deposition. Furthermore, determining and enhancing the service properties of the copper joints is of main interest and reported here.

Effects of Welding Parameters on Mechanical Properties in Electron Beam Welded CuCrZr Alloy Plates

CuCrZr alloys are attractive structural materials for plasma-facing components (PFC) and heat sink element in the International Thermonuclear Experimental Reactor (ITER) fusion reactors. This material has gained so much attention because of its high thermal conductivity and fracture toughness, high resistance to radiation damage and stability at elevated temperatures. The objective of this work is to study the effects of electron beam welding parameters on the mechanical strength of the butt welded CuCrZr joint. Taguchi method is used as the design of experiments to optimize the input parameters, such as accelerating voltage, beam current, welding speed, oscillation amplitude and frequency. The joint strength and ductility are the desired responses, which are measured through ultimate tensile strength and percent elongation, respectively. Accelerating voltage and welding speed are found to have significant influence on the strength. A combination of low amplitude and high-frequency oscillation is suggested for the higher joint strength and ductility. There is a close agreement between Taguchi predicted results and experimental ones. Fractographic analysis of joint and weld zone analysis are carried out to study the failure behaviour and microstructural variation in the weld zone, respectively.

Influence of electron beam welding parameters on microstructure and Charpy impact properties of boron-added modified 9Cr-1Mo steel weld

The effect of electron beam welding parameters on microstructure and ductile-to-brittle transition temperature (DBTT) of a boron-added modified 9Cr-1Mo steel weld is presented in this paper. Compared to the base metal, for the weld, the upper shelf energy is lower and the DBTT is significantly lower. While the influence of welding parameters on the upper shelf energy of the weld is insignificant, its influence on the transition region and the lower shelf region is quite significant due to the presence of delta-ferrite in the weld. High welding speed reduces the time available for transformation of delta-ferrite to austenite and results in retention of delta-ferrite in weld. Lower welding speed promotes completion of delta-ferrite to austenite transformation as cooling rate reduces which improves lower shelf energy.

Influence of Electron Beam Welding Parameters on Microstructure and Mechanical Properties of Boron-Added Modified 9CR-LMO Steel Weld

Modified 9Cr-lMo steel is used in high temperature applications due to its good thermo-physical, mechanical, weldability and formability. This steel is susceptible to Type IV cracking, in which failure of the weld joint occurs on creep exposure in the intercritical region of the heat- affected zone (ICHAZ). Improved resistance to Type IV cracking in modified 9Cr-1Mo steel weld joints can be achieve by addition of 100 ppm boron along with controlled nitrogen. However, in the absence of boron-added welding consumables, weld joints of this steel are presently being made using boron-free welding consumables. Consequently, during creep, the microstructure of boron-free weld metal is relatively less resistant to coarsening compared to the boron-added base metal and HAZ. The objective of the present investigation is to understand the effect of electron beam welding parameters on the microstructure and mechanical properties of the welds. Weld joints of the boron-free (P91) and boron-added (P91B) modified 9Cr-lMo steels were prepared by varying the welding parameters during electron beam welding. The soundness of the weld joints was confirmed by radiographic examination and bend testing. The tempering behavior of weld metal and base metal was studied and compared. The test results show that the ductile-to-brittle transition temperature of the P91B steel is comparable to that of the P91 steel but lower than that of boron-free weld metal. This paper discusses the influence of electron beam welding parameters on themicrostructure and mechanical properties of boron-added modified 9Cr-lMo steel welds.

Microstructure and hardness studies of electron beam welded Inconel 625 and stainless steel 304L

In this study, electron beam welding of dissimilar Inconel 625 and SS 304L alloys was successfully performed by employing optimized electron beam welding parameters. The welded joint was characterized using SEM/EDS, XRD and micro-hardness tester. The welded joint was found homogeneous, well bonded and defect free. Two types of microstructure i.e. columnar dendritic and cellular dendritic were observed in the fusion zone. The development of different microstructures in the fusion zone was attributed to the localized cooling effects during solidification. Few micro-cracks along with dendrites splitting were observed in the vicinity of end crater that was mainly due to the segregation of S element. A significant variation of Ni and Fe was observed across Inconel/FZ and FZ/SS interfaces due to their fast diffusion in the melt pool. Micro-hardness measurements across Inconel/FZ and FZ/SS interfaces showed an increasing trend in the FZ from SS 304L towards Inconel base alloy.

Development of Reduced Activation Ferritic–Martensitic Steels and fabrication technologies for Indian test blanket module

For the development of Reduced Activation Ferritic–Martensitic Steel (RAFMS), for the Indian Test Blanket Module for ITER, a 3-phase programme has been adopted. The first phase consists of melting and detailed characterization of a laboratory scale heat conforming to Eurofer 97 composition, to demonstrate the capability of the Indian industry for producing fusion grade steel. In the second phase which is currently in progress, the chemical composition will be optimized with respect to tungsten and tantalum for better combination of mechanical properties. Characterization of the optimized commercial scale India-specific RAFM steel will be carried out in the third phase. The first phase of the programme has been successfully completed and the tensile, impact and creep properties are comparable with Eurofer 97. Laser and electron beam welding parameters have been optimized and welding consumables were developed for Narrow Gap – Gas Tungsten Arc welding and for laser-hybrid welding.

Evaluation on the Effect of Weld Shape on Fatigue Performance by Analytic Hierarchy Process

Four different weld shapes were obtained by choosing appropriate electron beam welding parameters, which are respectively named as bell shape, funnel shape, nail shape, and wedge shape. Fatigue examinations of the electron beam welded joints with different shapes were carried through. The influence of weld shape on fatigue performance of the joints was synthetically evaluated by analytic hierarchy mathematical model. The results show that weld shape effects fatigue property of the joint by electron beam welding. The sequencing of fatigue performance of the joints with four different shapes by analytic hierarchy process is bell shape, funnel shape, wedge shape, and nail shape. It is validated by practical trial results that the analytic hierarchy mathematical model is effective and practical.