A Study on the Comparison Between Activated TIG Variants …
79
Fig. 6 Bead profile geometric
reached 996 °C, as shown in the Temp versus Time graph in Fig. 5 and corresponding
highest heat input approximately 2.1 kJ/mm as per Table 4 with TiO 2 flux applied
on either side of the joint, which can also be seen from column bar chart in Fig. 6
and Table 5. Although TiO 2 flux showed appreciably good penetration depth and
depth-to-width ratio as 4 mm and 0.66, respectively, in the A-TIG process, in which
method, flux is usually applied along the weld line. TiO 2 and ZnO flux system, used
in combinations with FZ-TIG technique such as TiO 2 , applied on the weld centreline and ZnO applied on either side of the weld line resulted in full penetration up
to plate thickness, i.e. 6 mm in a single pass with a relatively less width of weld
zone approximately 4 mm and the measured value of depth-to-width ratio as 1.5, the
highest of all the A-TIG variants results as can be seen in Table 5 and Fig. 6. The
improved penetration depth in FZ-TIG with TiO 2 and ZnO flux system combinations of fluxes was assumed to be recognized as best combinations of activated flux
systems, causing arc constriction mechanism effectively for the P91 composition is
an important outcome of this study.
3.2 Effect of Oxide Fluxes on HAZ Width
The heat-affected zone measurement, as shown in Table 5 and Figs. 6 and 7 using an
automatic image analysis technique as per ASTM E1245 [16], showed no significant
noticeable change in HAZ width values in all bead-on-plate weld samples, except
with FZ-TIG due to its highest penetration behaviour. However, due to differently
achieved penetration profiles, the shape of the heat-affected zone varied a little but
overall dimensions, L1, L2 and L3 remained the same. Except for FZ-TIG weld
sample, L3 = 0 which is due to 100% weld penetration obtained exploiting the arc
79
Fig. 6 Bead profile geometric
reached 996 °C, as shown in the Temp versus Time graph in Fig. 5 and corresponding
highest heat input approximately 2.1 kJ/mm as per Table 4 with TiO 2 flux applied
on either side of the joint, which can also be seen from column bar chart in Fig. 6
and Table 5. Although TiO 2 flux showed appreciably good penetration depth and
depth-to-width ratio as 4 mm and 0.66, respectively, in the A-TIG process, in which
method, flux is usually applied along the weld line. TiO 2 and ZnO flux system, used
in combinations with FZ-TIG technique such as TiO 2 , applied on the weld centreline and ZnO applied on either side of the weld line resulted in full penetration up
to plate thickness, i.e. 6 mm in a single pass with a relatively less width of weld
zone approximately 4 mm and the measured value of depth-to-width ratio as 1.5, the
highest of all the A-TIG variants results as can be seen in Table 5 and Fig. 6. The
improved penetration depth in FZ-TIG with TiO 2 and ZnO flux system combinations of fluxes was assumed to be recognized as best combinations of activated flux
systems, causing arc constriction mechanism effectively for the P91 composition is
an important outcome of this study.
3.2 Effect of Oxide Fluxes on HAZ Width
The heat-affected zone measurement, as shown in Table 5 and Figs. 6 and 7 using an
automatic image analysis technique as per ASTM E1245 [16], showed no significant
noticeable change in HAZ width values in all bead-on-plate weld samples, except
with FZ-TIG due to its highest penetration behaviour. However, due to differently
achieved penetration profiles, the shape of the heat-affected zone varied a little but
overall dimensions, L1, L2 and L3 remained the same. Except for FZ-TIG weld
sample, L3 = 0 which is due to 100% weld penetration obtained exploiting the arc