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Mathematical modeling of the geometrical differences between the weld end crater and the steady-state weld pool

Artinov, Antoni; Karkhin, Victor; Bachmann, Marcel; Rethmeier, Michael

The geometrical characteristics of the weld end crater are commonly used as a means of validating numerical results in welding simulations. In this paper, an analytical model is developed for calculating the cooling stage of the welding process after the moving energy source is turned off. Solutions for various combinations of heat sources and heated bodies are found. It is shown that after turning off the energy source, additional melting of the base material in the longitudinal direction may occur due to the overheated liquid metal. The developed technique is applied to complete-penetration keyhole laser beam welding of 2 mm thick austenitic stainless-steel plate 316L at a welding speed of 20 mm s−1 and a laser power of 2.3 kW. The results show a theoretical increase in the weld end crater length of up to 19% compared to the length of the steady-state weld pool. It is found that at the moment of switch off, the weld end crater center, where solidification of the liquid metal ends, is shifted from the heat source axis toward the weld pool tail. The solidification rate and the direction of crystallization of the molten material during the welding process and those in the weld end crater differ significantly. A good agreement between the computational results and the welding experiments is achieved.
Published in: Journal of Laser Applications, 10.2351/7.0000068, Laser Institute of America (LIA), American Institute of Physics (AIP)
  • This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in A. Artinov et al., Journal of Laser Applications 32, 022024 (2020) and may be found at https://doi.org/10.2351/7.0000068.