UDK УДК 621.791.722
NUMERICAL SIMULATION OF ELECTRON-BEAM WELDING WITH A LONGITUDINAL OSCILLATION OF THE BEAM BASED ON THE EXPERIMENTAL DETERMINATION OF THE KEYHOLE FORM
G. L. Permyakov, D. N. Trushnikov, V. Ya. Belenkiy, T. V. Olshanskaya
Perm National Research Polytechnic University 29, Komsomolskiy Av., Perm, 614990, Russian Federation
The research examines the process of electron-beam welding in the keyhole mode with the use of beam oscillations with different focusing regimes on the example of stainless steel – grade 502. We study the impact of longitudinal beam oscillation and their parameters on the shape of the keyhole, the character of the processes of heat and mass transfer and weld’s parameters, to develop methodological recommendations for electron-beam welding with oscillation. A numerical three-dimensional mathematical model of electron beam welding is presented. The model was devel-oped on the basis of the combined solution of heat conduction equation and Navier–Stokes equation in the moving coordinate system with taking into account phase transitions at the interface of solid and liquid phase. The boundary conditions at the free surface of the weld pool and on the keyhole walls are presented by thermocapillary convection (Marangoni effect). As input parameters the form of keyhole and distribution of the beam energy on the keyhole walls based on experimental data on the parameters of the secondary signal in the plasma over the welding zone by using the method of a synchronous accumulation are used. The keyhole was approximated by an oblique elliptical cone with a spherical apex. Such an approach eliminates the need to take into account all the complex factors that affect the formation of the keyhole. Calculations of thermal and hydrodynamic processes have been carried on a cluster using a simulation package COMSOL Multiphysics. Comparison of the calculated and experimental cross sections of the welds showed good agreement. With the help of the proposed method during the research characteristic features of the beam power distribution for different focus modes were identified. The analysis of the significance of various factors on the formation of the keyhole geometry has been conducted.
Keywords: electron-beam welding, beam oscillation, the mathematical model, the method of a synchronous accumu-lation.
References

References

 

  1. Rai R., Palmer T. A., Elmer J. W., Debroy T. Heat transfer and fluid flow during electron beam welding of 304L stainless steel alloy, Welding Journal, March 2009, Vol. 88, No. 3, P. 54–61.
  2. Sudniky W., Radajz D. and Erofeew W. Computerized simulation of laser beam welding, modelling and verification, Journal of Physics D: Applied Physics, 1996, Vol. 29, No. 11, P. 2811–2817. Doi:10.1088/0022-3727/29/11/013.
  3. Cho W.-I., Na S.-J., Thomy C., Vollertsen F. Numerical simulation of molten pool dynamics in high power disk laser welding, Journal of Materials Processing Technology, 2012, Vol. 212, Iss. 1, p. 262–275. Doi:10.1016/j.jmatprotec.2011.09.011.
  4. Trushnikov D., Belenkiy V., Schavlev V., Piskunov A., Abdulin A., Mladenov G. Plasma charge current for control and monitoring at electron beam welding with the beam oscillation, Sensors, 2012, Vol. 12(12), P. 17433–17445. Doi: 10.3390/s121217433.
  5. Trushnikov D. N., Belen’kii V. Ya. Investigation of the formation of the secondary current signal in plasma in electron beam welding with oscillations of the electron beam, Welding International, 2013, Vol. 27, Iss. 11, P. 877–880. Doi: 10.1080/09507116.2013.796645.
  6. Max J. Méthodes et techniques de traitement du signal et applications aux mesures physiques, 3rd ed.; Jean-Louis Lacoume, Paris, France, 1981, Vol. I, P. 10–50.
  7. Orfanidis S. J. Optimum Signal Processing. An Introduction, 2nd ed.; Prentice-Hall : Englewood Cliffs, NY, USA, 1996, P. 5–30.
  8. Bachmann M., Avilov V., Gumenyuk A., Rethmeier M. Experimental and numerical investigation of an electromagnetic weld pool support system for high power laser beam welding of austenitic stainless steel, Journal of Materials Processing Technology, 2014, Vol. 214, Iss. 3, P. 578– 591. Doi: 10.1016/j.jmatprotec. 2013.11.013.
  9. Voller V. R., Prakash C. A fixed grid numerical modelling methodology for convection-diffusion mushy region phase-change problems, International Journal of Heat and Mass Transfer, 1987, Vol. 30, Iss. 8, P. 1709–1720. Doi: 10.1016/0017-9310(87)90317-6.
  10. Brent A. D., Voller V. R., Reid K. J. Enthalpy-porosity technique for modeling convection-diffusion phase change: Application to the melting of a pure metal, Numerical Heat Transfer, 1988, Vol. 13, Iss. 3, P. 297–318. Doi: 10.1080/10407788808913615.
  11. Zhang W., Kim C. H., DebRoy T. Heat and fluid flow in complex joints during gas-metal arc welding, Part I: Numerical model of fillet welding, Journal of Applied Physics, 2004, Vol. 95, Iss. 9, P. 5210–5219. Doi: 10.1063/1.1699485.
  12. Kou S., Sun D. K. Fluid flow and weld penetration in stationary arc welds, Metalurgical Transactions A, 1985, Vol. 16, Iss. 2, P. 203–213. Doi: 10.1007/ BF02815302.
  13. Kim C. H., Zhang W., DebRoy T. Modeling
    of temperature field and solidified surface profile during gas metal arc fillet welding, Journal of Physics, 2003, Vol. 94, Iss. 4, P. 2667–2679. Doi: 10.1063/1.1592012.
  14. De A., DebRoy T. Probing unknown welding parameters from convective heat transfer calculation and multivariable optimization, Journal of Physics D: Applied Physics, 2004, Vol. 37, No. 1, P. 140–150. Doi: 10.1088/ 0022-3727/37/1/023.
  15. De A., DebRoy T. A smart model to estimate effective thermal conductivity and viscosity in weld pool, Journal of Applied Physics, 2004, Vol. 95, Iss. 9, P. 5230–5240. Doi: 10.1063/1.1695593.

Permyakov Gleb L’vovich – postgraduate student, Welding Production and Technology of Constructional Materials department, Perm National Research Polytechnic University. E-mail: gleb.permyakov@yandex.ru.

Trushnikov Dmitriy Nikolaevich – Cand. Sc., senior researcher, Welding Production and Technology of Constructional Materials department, Perm National Research Polytechnic University. E-mail: trdimitr@yandex.ru.

Belenkiy Vladimir Yakovlevich – Dr. Sc., professor, Welding Production and Technology of Constructional Materials department, Dean of Mechanical Engineering Faculty, Perm National Research Polytechnic University. E-mail: Belenkiy@pstu.ru.

Olshanskaya Tatiana Vasil’evna – Cand. Sc., Docent, Welding Production and Technology of Constructional Materials department, Perm National Research Polytechnic University. E-mail: TVO66@rambler.ru.