weld bead contour according to DIN 8563. Then the optimum
values of the welding parameters such as welding
speed, pulse frequency, % on-time, base and pulse current,
and nitrogen content in the argon shielding gas in ¯at,
vertical and overhead positions were determined by starting
from the successful parameters in the preliminary welding
test in ¯at position. The accepted weld bead samples were
examined by radiographic tests for porosity and prepared for
metallographic observation and study. Only weld metal was
machined to small pieces for the analysis of the nitrogen
contents by a nitrogen determinator. The weld metal d-ferrite
contents were calculated using the quantitative metallography
method [6].