Keyhole Welding : The Solid and Liquid Phases

• Deep penetration laser welding relies on the evaporation of material by a high power laser beam in order to drill a vapour capillary , usually referred to as a keyhole . During continuous welding the keyhole is kept open by the pressure in the vapour which evaporates continuously from its wall; the pressure acts continuously against the surface tension pressure that favours contraction, as well as against the welding speed. In contrast to pulsed wave (pw-) laser welding, during continuous wave (cw-) laser welding quasi-steady state conditions of the accompanying temperature field, and thus of the shape of the keyhole and melt pool, are established. Nevertheless, in the keyhole and melt pool complex fluid mechanical mechanisms take place. The most important thermodynamic and melt flow phenomena in keyhole laser welding will be briefly discussed and for some of them mathematical models and calculation results will be presented, complementing two comprehensive surveys. Notation employed in this chapter is given in Table 4.1. The mathematical models presented complement two comprehensive surveys, one of them published earlier [1], the other recently [2].

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Bearbetnings-, yt- och fogningsteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Manufacturing, Surface and Joining Technology (hsv//eng)

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Manufacturing Systems Engineering

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