Signal emitted from plasma during electron-beam welding with deflection oscillations of the beam

Koleva, Elena; Mladenov, G.; Трушников, Д. Н.; Belenkiy, Vladimir

doi:10.1016/j.jmatprotec.2014.03.031

Cited by 12 publications

(9 citation statements)

References 10 publications

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“…A thermal model based on differential equations for thermal conductivity in the mobile coordinate system with a fixed source was used to construct a fusion form and thermal welding cycles. This model was obtained by an analytical method using Green's functions [1,[3][4][5]. A standard integral solution to a thermal conductivity problem in the mobile coordinate system for an endless plate, with different types of dynamic electron beam positioning taken into account, is…”

Section: Methodsmentioning

confidence: 99%

“…Electron beam welding (EBW) is being increasingly implemented in various applications [1], including the manufacturing of essential products. In some cases, EBW is used at the final stage of manufacturing the products from thermally-hardened materials with a given set of properties, which makes it difficult or impossible to carry out subsequent heat treatment of welded joints.…”

Section: Introductionmentioning

confidence: 99%

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Application of Dynamic Beam Positioning for Creating Specified Structures and Properties of Welded Joints in Electron-Beam Welding

et al. 2020

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The application of electron beam sweep makes it possible to carry out multifocal and multi-beam welding, as well as combine the welding process with local heating or subsequent heat treatment, which is important when preparing products from thermally-hardened materials. This paper presents a method of electron beam welding (EBW) with dynamic beam positioning and its experimental-calculation results regarding the formation of structures and properties of heat-resistant steel welded joints (grade of steel 20Cr3MoWV). The application of electron beam oscillations in welding makes it possible to change the shape and dimensions of welding pool. It also affects the crystallization and formation of a primary structure. It has been established that EBW with dynamic beam positioning increases the weld metal residence time and the thermal effect zone above the critical A3 point, increases cooling time and considerably reduces instantaneous cooling rates as compared to welding without beam sweep. Also, the difference between cooling rates in the depth of a welded joint considerably reduces the degree of structural non-uniformity. A bainitic–martensitic structure is formed in the weld metal and the thermal effect zone throughout the whole depth of fusion. As a result of this structure, the level of mechanical properties of a welded joint produced from EBW with dynamic electron beam positioning approaches that of parent metal to a greater extent than in the case of welding by a static beam. As a consequence, welding of heat-resistant steels reduces the degree of non-uniformity of mechanical properties in the depth of welded joints, as well as decreases the level of hardening of a welded joint in relation to parent metal.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Application of Dynamic Beam Positioning for Creating Specified Structures and Properties of Welded Joints in Electron-Beam Welding

et al. 2020

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“…The amplitudes of the waveform of the secondary current in plasma at the focus scanning frequency were computed with samples of experimental data using a synchronous detection method [31][32][33]. The method's algorithm is explained by the circuit in Figure 3 if necessary: fm sin( ⋅ − ).…”

Section: Model Of the Formation Of A Secondary Waveform During Ebwmentioning

confidence: 99%

Use of a Secondary Current Sensor in Plasma during Electron-Beam Welding with Focus Scanning for Process Control

2016

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We consider questions of building a closed-loop focus control system for electron-beam welding. As a feedback signal, we use the secondary current in the plasma that forms above the welding zone. This article presents a model of a secondary current sensor in plasma during electron-beam welding with focus scanning. A comparison of modeled results with experimental data confirms the adequacy of the model. We show that the best results for focus control are obtained when using phase relationships rather than amplitude relationships. We outline the principles for building an EBW focus control system based on parameters of the secondary current in plasma. We simulate the work of a control system’s circuits and demonstrate the stability of the synthesized system. We have conducted pilot tests on an experimental prototype.

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“…The measurement of secondary emission was already successfully used in electron beam welding (EBW), to study keyhole oscillations. [16] The new in operando ELO approach would not increase the build time and is supposed to deliver information about the process quality in real time. A similar monitoring principle was already investigated for selective laser melting (SLM) and is implemented in many industrial SLM systems.…”

Section: Introductionmentioning

confidence: 99%

In Operando Monitoring by Analysis of Backscattered Electrons during Electron Beam Melting

2019

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Additive manufacturing by electron beam melting (EBM) is a complex process, which still lacks reliable tools for process monitoring. Demanding processing conditions such as high temperature, high vacuum, and X‐ray radiation impede the continuous operation of standard process monitoring devices such as light‐optical camera systems. To overcome this deficit, the detection of backscattered electrons (BSEs) is a highly promising approach. A detection system for BSEs is used for recording the in operando signal during melting inside an EBM system. The acquired data are postprocessed by mapping the data points to spatial coordinates. A comparison between the obtained intensity map and the as‐built surface shows a remarkable correlation, which might be suitable for process monitoring and quality control purposes.

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Signal emitted from plasma during electron-beam welding with deflection oscillations of the beam

Cited by 12 publications

References 10 publications

Application of Dynamic Beam Positioning for Creating Specified Structures and Properties of Welded Joints in Electron-Beam Welding

Application of Dynamic Beam Positioning for Creating Specified Structures and Properties of Welded Joints in Electron-Beam Welding

Use of a Secondary Current Sensor in Plasma during Electron-Beam Welding with Focus Scanning for Process Control

In Operando Monitoring by Analysis of Backscattered Electrons during Electron Beam Melting

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