This research seeks to localize the technology of plasma arc welding (PAW), the best
alternative against tungsten arc welding (TIG). So a quantitative comparison between these
two technologies has been made, according to the particular case that is
DC current.
involving heat efficiency, heat input, tensile strength, relative elongation at fracture, micro
hardness and angular distortion.
In this research, a study of the influence of arc welding
parameters on the thermal cycle was conducted, where the thermal
cycle within the welded plate of stainless steel 304L by plasma arc
welding (PAW) with weld-on-plate was measured using
the
rmocouples for several welding parameters (intensity of the
welding current, welding velocity, flow rate of plasma gas) and
comparing the influence of this parameters on the thermal cycle
within the plate.
Design of experiments (DOE)
had been used in the study, and the results had been evaluated by the
surface response method. The results showed that the welding
current is the main parameter by its effect on the mechanical studied
properties and the parameters values which give the best responses
had been determined.
Tensile and bending tests modeling have been undertaken for various welded joints
which were different in shape and design. Also, the hot spot stress was calculated at critical
failure areas using the finite elements analysis method. There was a go
od similarity
between experimentally defined critical areas in certain certified literature and those in our
modeling. It appeared that the information listed in the international institute for welding
(IIW) in regards of hot spot stress method gives relatively accurate values for the welded
joints possibility to endure fatigue loading and keep their desired mechanical properties
even those joints that could fail only at the connecting area with the base metal.
This study includes an experimental work to determine the effect of dilution on
Hardfacing welding of clinker hammer crusher. In this work, samples have been prepared
from the same metal type of hammer’s, of which is X120Mn12. Then the samples had
been hardfaced using deferent kind of hardfacing Shielded Metal Arc Welding electrodes,
and using deferent welding parameters (current, polarity), the calculation and measuring of
dilution had done and then performed the hardness tests, wear tests, and their relation with
dilution.
This study showed that the reduction of heat input decreases dilution as the hardness
of hardfaced samples increases and wear decreases.
Direct current electrode positive (DCEP) increase dilution as the hardness of
hardfaced samples decreases and wear increases, but the quality of the welding became
better. Results showed that percentage of chromium and carbon in electrodes have positive
effect on hardness.
Welded joints corrosion phenomena for some kinds of stainless steels and nickel alloy was studied in
polluted phosphoric acid 37.7%H3Po4 using electrochemical techniques like Tafel polarization. Corrosion
rate of base metal and weld metal had calcu
lated & compared among these alloys.
Laboratory Test results showed the change in both corrosion rate and corrosion current densities (Icorr)
for tested alloys, and there is a clear difference between base metal and weld metal in most of tested alloys
, which lead to high corrosion rates of welded joint, and change in its properties then gets out of service in
some service conditions. The stainless steel 904L has low corrosion rates and low difference in corrosion
rates between base metal and weld metal, so it may be the most suitable alloy, among all the studied
alloys, for exploitation in polluted phosphoric acid 37.7%H3Po4 produced at the General Fertilizer
Company in Homs city.
