A Study on the Comparison Between Activated TIG Variants …
73
Fig. 2 Welding setup
understand the effect of insulating flux, a contact type thermocouple (“K” type) was
used. The thermocouple probe was positioned at the canter of plate length and 10 mm
away from the welding travel line as shown in Fig. 4, while process temperature was
recorded with a mobile phone camera and then temperature versus Time graph was
prepared after every 5 s for each trial, as depicted in Fig. 5. Total four numbers of
bead-on-plate test coupons prepared with normal TIG, A-TIG, FB-TIG and FZ-TIG
process using different variants as shown in Fig. 3.
Standard metallographic techniques were used to prepare macrostructure of all the
bead-on-plate weld for investigation, and an optical microscope were used to measure
the weld depth, bead width and heat-affected zone width at 10X magnification.
Specimens of weld samples were mechanically polished to 0.05 µm finish, and
Vilella’s Reagent etchant (picric acid: 1 g, Hydrochloric acid: 5 ml, Ethanol: 100 ml)
was used. This test was carried out as per ASTM E340 [15]. Heat-affected zone
measurement was accomplished by quantitative metallographic tools using automatic
image analysis technique as per ASTM E1245 [16] as shown in Table 5, and heataffected zone measurement is graphically plotted as shown in Fig. 7.
73
Fig. 2 Welding setup
understand the effect of insulating flux, a contact type thermocouple (“K” type) was
used. The thermocouple probe was positioned at the canter of plate length and 10 mm
away from the welding travel line as shown in Fig. 4, while process temperature was
recorded with a mobile phone camera and then temperature versus Time graph was
prepared after every 5 s for each trial, as depicted in Fig. 5. Total four numbers of
bead-on-plate test coupons prepared with normal TIG, A-TIG, FB-TIG and FZ-TIG
process using different variants as shown in Fig. 3.
Standard metallographic techniques were used to prepare macrostructure of all the
bead-on-plate weld for investigation, and an optical microscope were used to measure
the weld depth, bead width and heat-affected zone width at 10X magnification.
Specimens of weld samples were mechanically polished to 0.05 µm finish, and
Vilella’s Reagent etchant (picric acid: 1 g, Hydrochloric acid: 5 ml, Ethanol: 100 ml)
was used. This test was carried out as per ASTM E340 [15]. Heat-affected zone
measurement was accomplished by quantitative metallographic tools using automatic
image analysis technique as per ASTM E1245 [16] as shown in Table 5, and heataffected zone measurement is graphically plotted as shown in Fig. 7.