Simplified surface heat source distribution for GMAW process simulation based on the EDACC principle
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RESEARCH PAPER
Simplified surface heat source distribution for GMAW process simulation based on the EDACC principle O. Mokrov 1
&
M. S. Simon 1
&
R. Sharma 1
&
U. Reisgen 1
Received: 31 July 2020 / Accepted: 27 November 2020 # The Author(s) 2020
Abstract A simplified surface heat source for gas metal arc welding (GMAW) process simulation based on the principle of evaporation determined arc cathode coupling (EDACC) is presented. It allows for a simple implementation in any GMAW weld pool simulation and is dependent on the width of the arc, as well as the weld pool surface temperature, but it can also be applied with the temperature and iron vapor density of the plasma instead of the width of the arc, if available. While it is considered separately from the droplets, it gives the heat flux as well as the current density distribution onto the weld pool surface, which are in general not axis-symmetric. The heat source distribution is normalized and multiplied to the value of any total heat and total current and it allows to calibrate for the maximum weld pool surface temperature. For the ionization and evaporation, only iron atoms are considered, and the shielding gas is assumed as argon. The result is given in graphical form as well as in the form of easy to implement functions for a reasonable range. Keywords GMAW . Cathode . Heat flux . Current density . Weld pool . EDACC
1 Introduction As part of the initiative Industry 4.0, digitalization has increasingly become a requirement for manufacturing processes. Therefore, also the simulation of these processes plays a major role in meeting these requirements. The welding simulation can be distinguished, as introduced in [1], into three interconnected areas of process simulation, where the size and shape of the weld pool should be calculated, structural simulation, where the effects of the temperature field upon the entire work piece are calculated, and material simulation, where the properties of the material under the thermal conditions of the process are being calculated. In gas metal arc welding (GMAW) process simulation, the hydrodynamics in the weld pool play a
Recommended for publication by Study Group 212 - The Physics of Welding * M. S. Simon [email protected] 1
RWTH Aachen University, ISF–Welding and Joining Institute, Pontstr. 49, 52062 Aachen, Germany
major role in the distribution of the heat and therefore the formation of the weld pool shape. It is therefore important to accurately take into account all driving forces of the liquid melt. One of the drivers is the electromagnetic Lorentz force which scales quadratic with the electric current density. To accurately model this force, the current density in the attachment of the arc to the work piece needs to be taken into account, while this attachment is particularly determined by the cathode sheath processes. However, in current GMAW process simulations, the current density is either assumed to be distributed in a Gaussian way [2, 3] or following directly from the Maxwell equations while
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