A method for calculating the fused zone profile of laser keyhole welds

Abstract

The characteristics of thermal absorption by the workpiece during penetration welding with a laser can be represented by a combination of point and line sources on the axis of the keyhole. This gives an insight into the way in which the beam interacts with the material being welded. The analysis is worked out for a workpiece of finite thickness, and then applied to a series of lap welds in galvanised steel plates. This shows that in many of these welds the absorption is very substantial near the surface of the workpiece, but in some cases it falls rapidly before increasing again with depth. In some examples, there is a pronounced maximum at the junction of the two plates being welded together.

Spectroscopic, energetic and metallographic investigations of the laser lap welding of AISI 304 using the response surface methodology

“…In order to predict the weld shape, several works have been devoted to model the deep penetration welding process by combining a point and line source of heat. [21,22]. Here, the line source represents absorption down the keyhole and the point source characterizes the plasma radiation from the plume.…”

The effect of Ar and He shielding gas on fibre laser weld shape and microstructure in AA 2024-T3

“…Formation of plasma above the keyhole in some aspect, can be considered beneficial as it assists in coupling the beam energy to the weld pool. Heating of the workpiece occurs by significant absorption of beam energy from the keyhole and from the vapour plume above the weld, which releases the absorbed laser energy into the weld near the surface to create a wider face width [16]. The observed weld shapes can therefore, be controlled by the balance between these mechanisms.…”

<title>The use of conduction model in laser weld profile computation</title>

“…The models employ a linear 1,2,3 , or point heat source 1 , or the superposition of linear and point heat sources 4,5 . In the present paper, the semi-analytical conduction model solved with Green's function method was chosen to compute the weld profiles.…”