Asiful Hossain Seikh

Effects of Immersion Time and 5-Phenyl-1H-tetrazole on the Corrosion and Corrosion Mitigation of Cobalt Free Maraging Steel in 0.5 M Sulfuric Acid Pickling Solutions

The effect of exposure time and 5-phenyl-1H-tetrazole on the corrosion and corrosion mitigation of cobalt free maraging steel in 0.5 M H2SO4 pickling solutions has been reported using electrochemical and spectroscopic investigations. Potentiodynamic polarization data showed that the increase of immersion time from 0 min to 120 min increases the corrosion rate and decreases the polarization resistance of the maraging steel. On the other hand, the addition of PHTA and the increase of its concentration decrease all the corrosion parameters of the steel at all exposure test periods. Electrochemical impedance spectroscopy measurements agreed with the obtained polarization data. Scanning electron spectroscopy and energy dispersive X-ray investigations confirmed that the inhibition of the steel corrosion is achieved via the adsorption of the PHTA molecules onto the steel precluding its surface from being dissolved.

Influence of Heat Treatment on the Corrosion of Microalloyed Steel in Sodium Chloride Solution

Microalloyed Steels find wide application in car bodies and other engineering parts because of its high strength as well as high ductility. Very fine grained microstructure is the reason behind the combination of strength and ductility. It has been reported that repeated quenching leads to further refining of microstructure. In the present investigation, corrosion resistance property of E34 microalloy steel has been studied in 3.5% NaCl solution in different microstructural conditions such as the as rolled one and three repeated quenched conditions. Weight loss, potentiodynamic polarization method, and electrochemical impedance spectroscopy (EIS) techniques have been used. To reveal the corrosion resistance of different treated steels, some significant characterization parameters such as , , , and in linear polarization and EIS curves were analyzed and compared. It is found that with repeated recrystallization grains become finer, and corrosion rate increases suggesting that a compromise has to strike between high mechanical property and corrosion rate.

Microstructure characterization and corrosion resistance properties of Pb-Sb alloys for lead acid battery spine produced by different casting methods

The aim of this study is to find out the microstructure, hardness, and corrosion resistance of Pb-5%Sb spine alloy. The alloy has been produced by high pressure die casting (HPDC), medium pressure die casting (AS) and low pressure die casting (GS) methods, respectively. The microstructure was characterized by using optical microscopy and scanning electron microscopy (SEM). The hardness was also reported. The corrosion resistance of the spines in 0.5M H2SO4 solution has been analyzed by measuring the weight loss, impedance spectroscopy and the potentiodynamic polarization techniques. It has been found that the spine produced by HPDC has defect-free fine grain structure resulting improvement in hardness and excellent corrosion resistance.

Evaluation of residual stresses present in spirally welded API grade pipeline steel using the hole drilling method

Abstract The mechanical and microstructural characterization of a material prior to its installation for the desired service is imperative to avoid material or structural failures. Of the several mechanical properties affecting the performance of a material, the residual stresses (RS) constitute an integral part of the material property and arise mostly during the manufacturing processes. They can be either beneficial or detrimental to material performance depending on their nature and magnitude. In this study, the microhardness, the tensile and the nature and magnitude of RS present in the weldment zones, base material (BM), heat affected zone (HAZ) and weld nugget (WN) of spiral welded (SWP) API grade line pipe steel, were determined. The microhardness and tensile responses were observed to have significant demarcation depending on the location where examined. The RS were measured using a nondestructive X-ray diffraction (XRD) and a semidestructive hole drilling (HD) technique. The results from both measurement techniques are found to be in good agreement. The BM microstructure consisted of ferrite and pearlite phases with ferrite constituting the dominant phase. The WN comprised of multi-passes, which consisted of root (hot) and the reinforcing (filling) pass. The microstructure of the reinforcing passes can be described as columnar grains/structure.

Corrosion resistance performance of newly developed cobalt-free maraging steel over conventional maraging steel in acidic media

Abstract The corrosion resistance behaviour of newly developed M-23 and M-29 grades cobalt-free maraging steel over conventional C-250 maraging steel was investigated at ambient temperature in 1 M H2SO4 solution using linear polarisation and electrochemical impedance spectroscopy (EIS) techniques. To reveal the corrosion resistance performance, some significant characterisation parameters from linear polarisation and EIS curves were analysed and compared. The results show that the corrosion resistance of the M-23 and M-29 cobalt-free maraging steel is more than the conventional C-250 maraging steel in acid solutions at ambient temperature.

Effect of different compaction and sintering conditions on the thermo-mechanical properties of bulk aluminium produced using mechanical alloying

Abstract In the investigation reported here, coarse-grained Al powder (85 μm) was subjected to ball milling for 4 h in an attritor at room temperature under argon atmosphere. The bulk aluminium samples consisting of ultrafine and nanocrystalline grains were prepared from ball-milled powders using a high frequency induction sintering machine. The bulk samples were investigated for the enhancement in mechanical properties using uniaxial compression experiments to large strains. Vickers micro hardness measurements were made along the diametral line of the bulk samples. A comparative study on the effect of mechanical properties of bulk samples obtained through different processing conditions was addressed and an optimum processing condition is established. The variation in strain-rate sensitivity with different processing conditions of the bulk samples was also investigated.

Effect of Consolidation and Sintering Parameters on the Mechanical Responses of Nanocrystalline Al-Fe Alloy Processed by Mechanical Alloying

In this investigation, bulk ultra-fine grained and nanocrystalline Al-2 wt.% Fe alloy was produced by mechanical alloying (MA). The powder was mechanically milled in an attritor for 3 hours and yielded an average crystal size of ~63 nm. The consolidation and sintering was performed using a high frequency induction sintering (HFIS) machine at a constant pressure of 50 MPa. The prepared bulk samples were subjected to uniaxial compressive loading over wide range of strain rates for large deformation. To evaluate the effect of sintering conditions and testing temperature on the strain rate sensitivity, strain rate jump experiments were performed at high temperature. The strain rate sensitivity of the processed alloy increased with an increase in temperature. The density of the bulk samples were found to be between 95 to 97%. The average Vickers micro hardness was found to be 132 Hv0.1.

Corrosion inhibitory effect of thiourea on recrystallized E-34 microalloyed steels in acidic media

Purpose – The purpose of this paper is to evaluate the effect of thiourea (TU) on corrosion resistance property for rolled and recrystallized E-34 microalloyed steels by using electrochemical polarization techniques. Design/methodology/approach – To perceive the effect of TU on the corrosion inhibition efficiency, various concentrations of TU (from 1 × 10 − 4 to 1 × 10 − 2M) and different temperatures (20, 30 and 400°C) in 1N sulfuric acid are used. Findings – It is found that TU has significant inhibition effect on corrosion process. Moreover, it reveals that both the inhibitor concentrations and temperatures have a strong influence on the corrosion prevention efficiency of inhibitor. Thermodynamics studies confirm that the inhibitor adsorption follows the Langmuir adsorption isotherm model. Originality/value – To the best of the authors’ knowledge, it is the first work that has been disclosed the corrosion inhibitory effect of TU for recrystallized E-34 microalloyed steels in acidic media.