Weitere Artikel dieser Ausgabe durch Wischen aufrufen
Manuscript submitted March 13, 2014.
In this paper, a computational fluid mechanics model is developed for full penetration laser welding of titanium alloy Ti6Al4V. This has been used to analyze possible porosity formation mechanisms, based on predictions of keyhole behavior and fluid flow characteristics in the weld pool. Numerical results show that when laser welding 3 mm thickness titanium alloy sheets with given laser beam focusing optics, keyhole depth oscillates before a full penetration keyhole is formed, but thereafter keyhole collapses are not predicted numerically. For lower power, lower speed welding, the fluid flow behind the keyhole is turbulent and unstable, and vortices are formed. Molten metal is predicted to flow away from the center plane of the weld pool, and leave a gap or void within the weld pool behind the keyhole. For higher power, higher speed welding, fluid flow is less turbulent, and such vortices are not formed. Corresponding experimental results show that porosity was absent in the melt runs made at higher power and higher welding speed. In contrast, large pores were present in melt runs made at lower power and lower welding speed. Based on the combination of experimental results and numerical predictions, it is proposed that porosity formation when keyhole laser welding may result from turbulent fluid flow behind the keyhole, with the larger the value of associated Reynolds number, the higher the possibility of porosity formation. For such fluid flow controlled porosities, measures to decrease Reynolds number of the fluid flow close to the keyhole could prove effective in reducing or avoiding porosity.
Bitte loggen Sie sich ein, um Zugang zu diesem Inhalt zu erhalten
Sie möchten Zugang zu diesem Inhalt erhalten? Dann informieren Sie sich jetzt über unsere Produkte:
Swift-Hook D T, Gick A E F, 1973: Penetration welding with lasers. Welding Journal, 52(11): 492s-499s.
Andrews J G and Atthey D R, 1976: Hydrodynamic limit to penetration of a material by a high-power beam. Journal of Physics D: Applied Physics, 9, 2181-2194. CrossRef
Klemens P G, 1976: Heat balance and flow conditions for electron beam and laser welding. J. of Applied Physics, 47: 2165-2174. CrossRef
Cline H E, Anthony T R, 1977: Heat treating and melting material with a scanning laser or electron beam. J. of Applied Physics, 48(9): 3895-3900. CrossRef
Mazumder J and Steen W M, 1980: Heat transfer model for cw laser material processing, J. of Applied Physics, 51(2): 941-947. CrossRef
Davis M, Kapadia P, Dowden J, 1986: Modelling the fluid flow in laser beam welding. Welding Journal, 65(7): 167-172.
Dowden J, Postacioglu N, Davis M, and Kapadia P, 1987: A keyhole model in penetration welding with a laser. J. of Physics D: Applied Physics, 20, 36-42. CrossRef
Steen W M, Dowden J, Davis M and Kapadia P, 1988: A point and line source model of laser keyhole welding. J. of Physics D: Applied Physics, 21:1255-1260. CrossRef
Postacioglu N, Kapadia P and Dowden J, 1991: A theoretical model of thermocapillary flows in laser welding, J. of Physics D: Applied Physics, 24(1): 15-20. CrossRef
J. Mazumder, M.M. Chen, C.L. Chan, D. Voelkel, and R. Zehr: Proc. of Symposium on Joining of Materials for 2000 AD, 1991, 693–708.
Mundra K, DebRoy T, Zacharia T and David S A, 1992: Role of thermophysical properties in weld pool modelling. Welding Journal, 71(9): 313s-320s.
Kroos J, Gratzke U and Simon G, 1993: Towards a self-consistent model of the keyhole in penetration laser beam welding. J. of Physics D: Applied Physics, 26: 474-480. CrossRef
Metzbower E A, 1993: Keyhole formation. Metallurgical Transactions B, 24(5), 875-880. CrossRef
Sudnik W, Radaj D and Erofeew W, 1996: Computerized simulation of laser beam welding, modelling and verification. J. Phys. D: Appl. Phys., 29: 2811–2817. CrossRef
Semak V V, Damkroger B and Kempka S, 1999: Temporal evolution of the temperature field in the beam interaction zone during laser material processing. J. of Physics D: Applied Physics, 32, 1819-1825. CrossRef
Zhao H, DebRoy T, 2003: Macroporosity free aluminium alloy weldments through numerical simulation of keyhole mode laser welding. J. of Applied Physics, 93(12): 10089-10096. CrossRef
Jin X, Li L and Zhang Y, 2002: A study on Fresnel absorption and reflections in the keyhole in deep penetration laser welding. J. Phys. D: Appl. Phys., 35(18): 2304–2310. CrossRef
Jin X, Berger P and Graf T, 2006: Multiple reflections and Fresnel absorption in an actual 3D keyhole during deep penetration laser welding. Journal of Physics D: Applied Physics, 39(21): 4703-4712. CrossRef
Cho J H and Na S J, 2006: Implementation of real-time multiple reflection and Fresnel absorption of laser beam in keyhole. J. of Physics D: Applied Physics, 39(24): 5372-5378. CrossRef
R. Rai and T. DebRoy: J. Phys. D, 2006, 39(6), pp. 1257–66. CrossRef
H. Ki, P.S. Mohanty, and J. Mazumder: Metall. Mater. Trans. A, 2002, vol. 33A, pp. 1817–30. CrossRef
H. Ki, P.S. Mohanty, and J. Mazumder: Metall. Mater. Trans. A, 2002, vol. 33, pp. 1831–42. CrossRef
Zhou J, Tsai H L and Wang P C, 2006: Transport phenomena and keyhole dynamics during pulsed laser welding. ASME J. of Heat Transfer, 128(7): 680-690. CrossRef
Zhou J and Tsai H L, 2006: Investigation of transport phenomena and defect formation in pulsed laser keyhole welding of zinc-coated steels. J. of Physics D: Applied Physics, 39(24): 5338-5355. CrossRef
Zhou J and Tsai H L, 2007: Porosity formation and prevention in pulsed laser welding. ASME J. of Heat Transfer, 129(8): 1014-1024. CrossRef
Zhou J and Tsai H L, 2007: Effects of electromagnetic force on melt flow and porosity prevention in pulsed laser keyhole welding. International J. of Heat and Mass Transfer, 50(11-12): 2217-2235. CrossRef
Pang S, Chen L, Zhou J, Yin Y, Chen T, 2011: A three-dimensional sharp interface model for self-consistent keyhole and molten pool dynamics in deep penetration laser welding. J. of Physics D: Applied Physics, 44(2): 025301 CrossRef
H.Y. Zhao, W.C. Niu, B. Zhang, Y.P. Lei, M. Kodama, T. Ishide: J. Phys. D, 2011, vol. 44 (48), p. 485302. CrossRef
Zhang W H, Zhou J, Tsai H L, 2003: Numerical modelling of keyhole dynamics in laser welding. Proc. of SPIE, Vol.4831, 180-184. CrossRef
Amara E H and Fabbro R, 2008: Modelling of gas jet effect on the molten pool movements during deep penetration laser welding. Journal of Physics D: Applied Physics, 41(5), 055503. CrossRef
Zhang L J, Zhang J X, Zhang G F, Bo W, Gong SL, 2011: An investigation on the effects of side assisting gas flow and metallic vapour jet on the stability of keyhole and molten pool during laser full-penetration welding. J. of Physics D: Applied Physics, 44(13), 135201. CrossRef
Tsukamoto S, 2011: High speed imaging technique part 2 – high speed imaging of power beam welding phenomena. Science and Technology of Welding and Joining, 2011, 16(1): 44-55. CrossRef
S. Katayama, S. Kohsaka, M. Mizutani, K. Nishizawa, and A. Matsunawa: Proceedings of ICALEO, 1993, pp. 487–97.
S. Katayama, N. Seto, M. Mizutani, and A. Matsunawa: Proceedings of ICALEO, Section C, 2000, pp. 16–25.
Katayama S, Mizutani M and Matsunawa A, 2003: Development of porosity prevention procedures during laser welding. Proc. SPIE, 4831, 281-288. CrossRef
Matsunawa A, Kim J, Seto N, Mizutani M, S Katayama, 1998: Dynamics of keyhole and molten pool in laser welding, J. of Laser Applications, 10(6): 247-254. CrossRef
Matsunawa A, Kim J, Seto N, Mizutani M, S Katayama, 2000: Dynamics of keyhole and molten pool in high power CO 2 laser welding, Proc. SPIE, 3888: 34-45. CrossRef
Matsunawa A, Kim J, Seto N, Mizutani M, S Katayama, 2001: Observation of keyhole and molten pool in high power laser welding mechanism of porosity formation and its suppression method, Trans. JWRI, 30: 13-27.
Matsunawa A and Katayama S, 2003: Understanding physical mechanisms in laser welding for construction of mathematical model. Welding Research Abroad, 49 (4): 27-38.
N. Seto, S. Katayama, and A. Matsunawa: Proceedings of ICALEO, Section E, 1999, pp. 19–27.
Seto N, Katayama S and Matsunawa A, 2000: Porosity formation mechanism and suppression procedure in laser welding of aluminium alloy. Q. J. Japan Weld. Soc. 18, 243-255. CrossRef
Seto N, Katayamat S, Mizutan M and Matsunawa A, 2000: Relationship between plasma and keyhole behaviour during CO 2 laser welding, Proc. SPIE, 3888, 61-68. CrossRef
Seto N, Katayama S and Matsunawa A, 2001: Porosity formation mechanism and reduction method in CO 2 laser welding of stainless steel. Q. J. Japan Weld. Soc., 19, 600-609. CrossRef
S. Tsukamoto, I. Kawaguchi, G. Arakane, and H. Honda: Int. Congress on Applications of Lasers & Electro-Optics (ICALEO), Jacksonville, FL, 2001, pp. 400–08.
I. Kawaguchi, S. Tsukamoto, H. Honda, and G. Arakane: International Congress on Applications of Lasers& Electro-Optics (ICALEO), Laser Institute of America, Section A, Orlando, FL, 2003, vol. 1006, pp. 168–75.
J.E. Blackburn and C.M. Allen: “Modulated Twin Spot and High Beam Quality Laser Welding of Titanium Alloys”, TWI Industrial Member Report, No. 967, 2010.
Kaplan A, Mizutani M, Katayama S, Matsunawa A, 2002: Unbounded keyhole collapse and bubble formation during pulsed laser interaction with liquid zinc. J. of Physics D: Applied Physics, 35(11): 1218-1228. CrossRef
J.E. Blackburn: Ph.D. Thesis, University of Manchester, 2011.
Hughes WF and Brighton JA, 1999: Schaum’s outline of fluid dynamics, USA: McGraw-Hill.
- Fluid Flow Characteristics and Porosity Behavior in Full Penetration Laser Welding of a Titanium Alloy
- Springer US
in-adhesives, MKVS, Hellmich GmbH/© Hellmich GmbH, Zühlke/© Zühlke