A welding arc model is proposed to determine the thermal cycle for var
ious materials and for different weld types. In this paper we discuss
the iterative procedure employed for non-linear heat transfer analysis
using the finite element method, and in particular the boundary condi
tions employed to determine the heat generated in the HAZ and its diss
ipation during welding. The model only focuses on the grain growth zon
e with the objective to compute the thermal regime that controls the m
icrostructural changes that occur during welding. Both solidified weld
and liquid-solid transition zones are excluded from the model. The he
at generated by the arc is applied to the vertical face of the welded
edge and is indifferent to the size of the HAZ. The analytical results
obtained for low carbon steel and for austenitic stainless steel, and
for GMA and GTA weld types, correlate well with the observed experime
ntal data reported in the literature.