flow rate is kept as constant (20 lpm).
Prior to welding, the plates are cleaned with stainless steel
brush and swabbed by acetone for cleanness. Based on the preliminary welding trials the process parameters were chosen and
they are presented in
Table 2
. The inter-pass temperature was kept
below 150
°
C with the help of thermo chalk due to thermal con-
ductivity of austenitic stainless steel. The photographs of the dif-
ferent shielded welds are shown in
Fig. 3
a–g.
The test specimens were obtained from the weld plate. The
specimens were mounted later flatted and then polished using
SiC abrasive paper with grit ranges from 180 to 1200. Then the
samples were then lightly polished using 3
l
m diamond paste.
Samples were then washed, cleaned by acetone and then dried, fol-
lowed by electrolytic etching in 10% oxalic acid at 9v for 30 s
[19]
and ASTM: E3-11. Chemical composition of the weld metal is found
from spectra chemical analysis. Ferrite percentages were measured
using ferrite scope and also the percentage of ferrite is calculated
using Cr
eq
and Ni
eq
. The specimens for Charpy test were taken as
perpendicular to weld direction according to the ASTM: E23 stan-
dards. The impact tests were conducted at room temperature,
100
°
C and
196
°
C. Micro hardness measurements were taken
at parent metal, HAZ and weld zone with a load of 1kgf for 20 s
during measurements. The face bend testing of the material was
conducted according to ASTM: E190-92 standards to know the
development of the cracks and fissures which will help to know
the ductile nature of the weld material. Finally microstructural
examinations were carried out at various cross sections of the weld
using optical microscope.