Determination of the degree of ionization of the vapour phase of the penetration channel in electron beam welding

Novokreshchenov, V. V.; Rodyakina, R. V.; Myakishev, Yu. V.; Слива, А. П.

doi:10.1080/09507116.2012.715895

Cited by 3 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Several hypotheses have been put forward to describe the observed phenomena. However, the proposed theories are insufficient to fully interpret the obtained results [4,5]. We need a detailed model of the processes occurring in the plasma.…”

Section: Introductionmentioning

confidence: 99%

“…However, these methods have limitations due to the difficulty placing additional sensors within the vacuum chamber, which creates complications when used in industrial conditions. Moreover, a number of studies indicate that electron beam welding is accompanied by high-frequency processes [1][2][3][4] that often carry the most information about the thermal characteristics of the electron beam's interaction with the metal in the penetration channel. Frequencies up to 20 kHz are inherent to these processes, which makes it possible to study them using X-ray radiation sensors.…”

Section: Introductionmentioning

confidence: 99%

“…Methods based on registration of the secondary plasma current originating above the welding zone [5] are promising. Several methods have been developed to study and control electron beam welding [1][2][3][4][5] processes. Similar works in the area of laser welding have been widely conducted recently.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Modeling the Influence of the Penetration Channel’s Shape on Plasma Parameters When Handling Highly Concentrated Energy Sources

Трушников

Саломатова

Bezukladnikov

et al. 2017

Advances in Materials Science and Engineering

View full text Add to dashboard Cite

In our work to formulate a scientific justification for process control methods when processing materials using concentrated energy sources, we develop a model that can calculate plasma parameters and the magnitude of the secondary waveform of a current from a non-self-sustained discharge in plasma as a function of the geometry of the penetration channel, thermal fields, and the beam's position within the penetration channel. We present the method and a numeric implementation whose first stage involves the use of a two-dimensional model to calculate the statistical probability of the secondary electrons' passage through the penetration channel as a function of the interaction zone's depth. Then, the discovered relationship is used to numerically calculate how the secondary current changes as a distributed beam moves along a three-dimensional penetration channel. We demonstrate that during oscillating electron beam welding the waveform has the greatest magnitude during interaction with the upper areas of the penetration channel and diminishes with increasing penetration channel depth in a way that depends on the penetration channel's shape. When the surface of the penetration channel is approximated with a Gaussian function, the waveform decreases nearly exponentially.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Modeling the Influence of the Penetration Channel’s Shape on Plasma Parameters When Handling Highly Concentrated Energy Sources

Трушников

Саломатова

Bezukladnikov

et al. 2017

Advances in Materials Science and Engineering

View full text Add to dashboard Cite

show abstract

Numerical model of the plasma formation at electron beam welding

Трушников

Mladenov

2015

Journal of Applied Physics

View full text Add to dashboard Cite

The model of plasma formation in the keyhole in liquid metal as well as above the electron beam welding zone is described. The model is based on solution of two equations for the density of electrons and the mean electron energy. The mass transfer of heavy plasma particles (neutral atoms, excited atoms, and ions) is taken into account in the analysis by the diffusion equation for a multicomponent mixture. The electrostatic field is calculated using the Poisson equation. Thermionic electron emission is calculated for the keyhole wall. The ionization intensity of the vapors due to beam electrons and high-energy secondary and backscattered electrons is calibrated using the plasma parameters when there is no polarized collector electrode above the welding zone. The calculated data are in good agreement with experimental data. Results for the plasma parameters for excitation of a non-independent discharge are given. It is shown that there is a need to take into account the effect of a strong electric field near the keyhole walls on electron emission (the Schottky effect) in the calculation of the current for a non-independent discharge (hot cathode gas discharge). The calculated electron drift velocities are much bigger than the velocity at which current instabilities arise. This confirms the hypothesis for ion-acoustic instabilities, observed experimentally in previous research.

show abstract

The model of formation of a non-self-sustained discharge in the plasma in electron beam welding

Трушников

Belenkiy

2017

Welding International

View full text Add to dashboard Cite

Determination of the degree of ionization of the vapour phase of the penetration channel in electron beam welding

Cited by 3 publications

References 0 publications

Modeling the Influence of the Penetration Channel’s Shape on Plasma Parameters When Handling Highly Concentrated Energy Sources

Modeling the Influence of the Penetration Channel’s Shape on Plasma Parameters When Handling Highly Concentrated Energy Sources

Numerical model of the plasma formation at electron beam welding

The model of formation of a non-self-sustained discharge in the plasma in electron beam welding

Contact Info

Product

Resources

About