Fig. 12 illustrates the evolution of the ferrite volume
fraction with annealing temperature in the HAZ, fusion zone
and base metal. The figure shows that the amount of δ ferrite
increases with annealing temperature, with a faster rate in the
HAZ than in the base metal and fusion zone. The amount of δ
ferrite in the HAZ increases from 53% to 77% with an increase
in the annealing temperature from 1050 to 1250 °C. This figure
shows also that the weld metal was less sensitive to annealing
heat treatment than the HAZ and base metal.