Investigation of Effects of Mig Welding on Corrosion Behaviour of AISI 1010 Carbon Steel
This paper presents the corrosion behaviour of welded low carbon steel at different welding voltages and filler materials. The welding process was conducted on butt joint 
specimens using the metal inert gas (MIG) technique at a welding voltage range of 19 to 21 V with 1 V interval, and the filler materials used were ER 308L and ER 70S-6 with 
1.2 mm diameter. Heat treatment through full annealing was done to the welded low carbon steel, and the corrosion behaviour was tested using a synthetic seawater 
environment with 3.5 wt% NaCl. Microstructure changes were observed using a scanning electron microscope (SEM). The results showed that the corrosion rate decreased when the welding voltage increased, as it directly affected the welding heat input. The welding heat input was found to have a significant effect on the corrosion rate as it changed the ferrite content in the microstructure of the specimens. Decrease in the corrosion rate was also found when the full annealing process was done to the 
specimens and ER 308L filler material was used. From a metallographic study, iron oxides and pitting were found on the surface of the exposed area after the corrosion test. 
It is apparent that the combination of higher welding voltage, heat treatment and the use of ER 308L filler material can reduce the corrosion rate of AISI 1010 carbon steel.
Corrosion Behavior of Mild Steel in Hydrochloric Acid Solutions
The corrosion behaviour and mechanism for mild steel in hydrochloric acid solutions was studied by chemical (hydrogen evolution, HE & mass loss, ML) and electrochemical (electrochemical impedance spectroscopy & potentiodynamic polarization) methods at 25 C. The chemical results revealed that mild steel corrodes in HCl solutions with a rection constant of 0.56 and the corrosion rate increases with the increase in acid concentration. Microstructural studies for mild steel after immersion in HCl solutions of different concentrations showed general and pitting corrosion and the latter becomes more pronounced at higher level of HCl concentration. Accordingly, it was found that Rct value decreases while both Cdl and icorr. values increase with increasing HCl concentration. PDP results revealed that the steel dissolution is anodically controlled. Estimation of the ratio Z/vs from PDP data indicated that mild steel dissolution occurs via multistep mechanism. This mechanism involves two steps each of them is characterized by one electron release and one of them is the rate determining step. The rate determining step may involve adsorbed [FeOH]ads and/or [FeClOH] ads groups.
Mechanical behaviour and durability of high volume fly ash cementitious composites
The purpose of this research is to separate different morphological particles of ASTM class F fly ash, and study their effect on mechanical behaviour and durability of high volume cementitious mixtures. In this research wet separation of raw fly ash is carried out, which resulted in three layers of different morphological particles. The first layer of particles float, comprise of about 1-5% of fly ash, is identified as cenospheres or hollow spheres. The second layer of particles is measured to be 55-60% of raw fly ash and consisting of porous spherical and rounded particles rich in Si and Al. The third layer particles is measured to be about 35-40% of raw fly ash. High volume fly ash cementitious composites containing second or third layer particles are tested under compression and bending, highlighting a higher strength and ductility in comparison to cementitious ones containing raw fly ash particles. KEYWORDS. Cementitious matrix; Raw fly ash; Second layer particles; Third layer particles.