Author
Abstract
In this research the structural steel type (A36) samples were prepared by
traditional preparation operations , chemical composition of samples was analyzed
, hardness tested, then testing corrosion was achieved for two major cases, a
general corrosion case when the corrosive medium (sea water) is static for five
days period ,and the second case is the corrosion with presence of mechanical
vibration, which included two branch cases , first case; corrosion of vibrated
samples with the vibrated corrosive medium, and the second case when the
samples are fixed and corrosive medium is vibratory , a total test period is five
hours for each case ,then found weight loss and the corrosion rate of all cases of
corrosion mentioned by a traditional weight loss method , as well as study the
microstructures before and after the corrosion cases and to find an experimental
mathematical formula that illustrate the relationships between corrosion and
corrosion with presence of vibration, note that the used device to study the
mechanical vibration effect was locally designed and manufactured, according to
the modified American Standard (ASTM G32).Observed that the weight loss and
corrosion rate reached the highest value in the second case of corrosion with
presence of mechanical vibration (fixed samples and corrosive medium is
vibratory), followed by the first case of corrosion with presence of mechanical
vibration (vibrated samples with the vibrated corrosive medium), and less the value
of the corrosion rate and weight loss is the state of general corrosion (corrosion in
the static medium). It was noted that the microstructure of the structural steel
became uniformly corroded after general corrosion case (in static corrosive
medium) and corrosion regions were spread or scattered over all parts of the
sample surface on a regular basis, while the microstructure in the two cases of
corrosion with presence of mechanical vibration containing irregular corrosion
cavitations and scattered randomly on the surface, and more deeply especially the
second case (fixed samples and corrosive medium is vibratory). Illustrated from the
results and carves there was relationship between mentioned corrosion cases, it was
an experimental mathematical formula:
Acc.C.R.= Vib-C.R2 – ( Vib-C.R1 +Static C.R.)
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