Finding the Weight Loss Rate of Metallic Surfaces Exposed To Corrosion Presence of Vibration (Corrosion - Vibration)

Abstract

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