When we visited the United Arab Company for Spinning and Weaving In the capital, Damascus, we found
a lot of problems in the units of feeding steam, and the most prominent of these problems occur corrosion
in the pipe of steam boilers, And the coll
apse in the heat exchanger on the thread dyeing machine (the
collapse of the body and pipes), so we took a group of samples in the places that suffer problems in order
to determine the mechanical and chemical properties, we found through analysis that the boiler tubes
were made of carbon steel, while the tubes and the body of heat exchanger was made of stainless steel, has
been shown through research that pipe boilers of carbon steel suffers of problems as a result overheating,
hydrogen damage and an attack Oxide, And the body of heat exchanger was suffering from an corrosion
Cracking result of the high proportion of chromium in it (chromium ratio up to 17%), has been
developing a set of solutions represented to be the metal surfaces clean and homogeneous, and must be
feed water free of salts, suspended solids, and gases
This research showed the great importance for following studies of the effect of polluted phosphoric acid,
produced in General Fertilizer Company, on the high corrosion resisting alloys, to reach suitable alloys
for equipments and machines used for
its production, because of its high corrosion rates that create many
corrosion problems in these equipments and machines.
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.
