Figure 12 Numerical-experimental comparison of HAZ, during the first (A)
and the second pass (B).
By comparing the numerical results with the experimental ones, it is
possible to state that the used methodology is suitable to predict very
accurately the temperatures distribution in the welded joint, without
the need to perform a tuning process to opportunely calibrate the heat
source.17,27,32,33,34,44
3.2 Mechanical analysis
The longitudinal residual stressesσy , induced from the longitudinal expansion and
contraction of the material during the welding process, along thex -direction at the midsection (y = 124 mm, z = 4
mm) are shown in Figure 13A (line with marker). The self-equilibrium of
the weldment is such that the tensile and compressive residual stresses
are present at the weld seam and away from the welding line
respectively. High tensile residual stresses are present in
correspondence of the zones nearby the Welding Centre Line (WCL), due to
the contraction resistance of the material as the cooling phase begins.
Then, they decreased to zero, as the distance from the (WCL) increases,
becoming compressive for the zones far from the weld seam. The
transversal residual stresses σx along thex -direction in the midsection (y = 124 mm, z = 4
mm) are shown in Figure 13B. Tensile residual stresses are present in
correspondence of the zones nearby the (WCL). Subsequently, they
decreased as the distance from the (WCL) increased, up to 0, almost.