Showing 3 results for Corrosion Behavior
M. Sabzi, S. Moeni Far, E. Najafi Birgani,
Volume 1, Issue 1 (1-2016)
Abstract
In this investigation, the effect of heat input of SMAW process on the corrosion behavior of Hadfield steel weld joints was investigated. For this purpose, 4 annealed sheets with thickness 25 mm prepared from Hadfield steel and then welding applied by SMAW process with 6.75 and 11.25 kJ/mm heat input values. For corrosion behavior evaluation of base metal and weld metal areas, potentiodynamic polarization and electrochemical impedance spectroscopy methods were used in the 3.5% NaCl solution. The result of corrosion tests indicated that by increasing the heat input in the SMAW process, the corrosion resistance in the weld metal were reduced. It was also found that in both heat input values, base metal had more corrosion resistance compared to weld metal.
M. Ansaripour, A. Soltanpoor, A. Ghasemi, M.r. Dehnavi,
Volume 2, Issue 1 (8-2016)
Abstract
The aim of this study was to evaluate the mechanical properties and corrosion behavior of friction stir welding (FSW) connection of A517 (B) steel plate. Mechanical properties and corrosion behavior of weld zone were evaluated after reaching to optimum FSW microstructure with the lowest martensite phase. Thus, after the identifying phase microstructure by SEM and XRD analysis, mechanical properties were analyzed by micro-hardness and tensile test. Micro hardness data shows slight increases in stir zone (SZ) compared with the base metal (BM); although a reduction of about 17% in hardness of heat-affected zone (HAZ) was sensible. Reduction of hardness in the HAZ was appeared as drop by about 12 percent of the yield strength and 19 percent of ultimate strength compared with BM. SEM images from fracture surface of the tensile sample showed bi-modal distribution of large and small Dimples being sings of softness of HAZ .Comparing corrosion behavior in solution consist of 3.5 wt% of NaCl showed that there was no passive layers to prevent dissolution of the metal in the SZ and BM. while BM and SZ had fairly similar corrosion rates, Difference of 50 mV between corrosion potential of SZ and BM showed that in galvanic condition, corrosion resistance of BM could be lower than SZ.
A. Mahab, M. Farzam, R. Dehmolaei,
Volume 4, Issue 1 (8-2018)
Abstract
The effect of heat input of submerged arc welding process on the corrosion bahavior of weld metal of API X42 gas pipeline steel weld joint was investigated. For this purpose, 6 annealed sheets of 15mm thickness were prepared from the X42 microalloyed steel. Submerged arc welding process with varying heat input of 37.8, 18.9 and 12.6 kJ/mm was used for joint welding. Then potentiodynamic polarization and electrochemical impedance spectroscopy methods were used to evaluate the corrosion behavior of the welded joints (in 3.5% NaCl solution). The evaluation of the microstructures of the welded metals in the weld joints were conducted using the scanning electron microscopy. X-ray diffraction was used for the analysis of the phases formed in the weld metal microstructure. Scanning electron microscopy observations and patterns obtained from the X-ray diffraction showed that the increase in heat input resulted in the increase in the amount of ferrite. The grain size also increased. Corrosion test results showed that by increasing the heat input of the weld process, the corrosion resistance increased..
