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The purpose of this paper is to predict and optimize the width of heat affected zone (HAZ) with better mechanical properties using suitable welding process and parameters for the fabrication of jet blast deflector (JBD) (high strength low alloy material of grade A588-B was used for fabrication) so that the JBD can sustain high exhaust parameters, because there are different welding zones formed due to the rapid cooling of weld metals. Out of the various zones of welding, HAZ remains the weakest zone in the entire weldment.

The present work describes the modeling, simulation, Modeling of three-dimensional plate and mess generation process are carried out using ICEM CFD software. FLUENT 16.0 software is used for ANSYS simulation where various models are used for analysis and results are validated with the experimental outcomes. High strength low alloy plates are welded by using shielded metal arc welding and tungsten inert gas (TIG) welding processes with two different electrodes. Optical microscopy and scanning electron microscopy were used for metallurgical study. The mechanical properties were evaluated by tensile strength test, vickers microhardness test and impact test. The corrosion resistance was evaluated by performing the potentiodynamic polarization test.

The present study indicated for better mechanical properties and improved corrosion resistance for TIG welded joints with type 308 L filler.

In aeronautical, defense, space and research organizations.

It can be shown from the scanning electron microscope technique that sound weld joint is produced with very good mechanical properties and joint also showed better corrosion resistance.

This paper aims to examine dissimilar joints for various applications in chemical, petrochemical, oil, gas, shipbuilding, defense, rail and nuclear industry.

This study examined the effects of cold metal transfer welding on stainless steel welds for 316L austenitic and 430 ferritic dissimilar welds with ER316L, ER309L and without (autogenous) fillers. The microstructural observation was done with an optical microscope. The mechanical test was done to reveal the strength, hardness and toughness of the joint. The electrochemical polarization tests were done to reveal intergranular and pitting corrosion in the dissimilar joints.

This microstructural study shows the presence of austenitic and ferritic phases with vermicular ferrite for ER309L filler weld, and for ER316L filler weld specimen shows predominately martensitic phase in the weld region, whereas the autogenous weld shows lathy ferrite mixed with martensitic phase. Mechanical test results indicated that filler welded specimen (ER316L and ER309L) has relatively higher strength and hardness than the autogenous weld, whereas ER316L filler weld exhibited the highest impact toughness than ER309L filler weld and lowest in autogenous weld. The electrochemical corrosion results displayed the highest degree of sensitization (DOS) in without filler welded specimen (45.62%) and lower in case of filler welded specimen ER309L (4.95%) and least in case of ER316L filler welded specimen (3.51%). The high DOS in non-filler welded specimen is correlated with the chromium carbide formation. The non-filler welded specimen shows the highest pitting corrosion attack as compared to the ER316L filler weld specimen and relatively better in ER309L filler welded specimen. The highest pitting corrosion resistance is related with the high chromium content in ER309L composition.

This experimental study is original and conducted with 316L and 430 stainless steel with ER316L, ER309 and without fillers, which will help the oil, shipbuilding and chemical industries.

The purpose of the study is to evaluate Cr-Mn ASS weld using different heat inputs for its microstructure, mechanical properties and electrochemical behavior. The microstructural examination used optical and scanning electron microscopy. It was observed that ferrite content decreases with increasing heat input. The length of dendrites, inter-dendritic space and volume of lathy ferrite increase with increasing heat input. The increasing heat input caused grain coarsening near the fusion boundary and produced wider heat-affected zone (HAZ). It also decreases hardness and tensile strength. This is attributed to formation of more δ ferrite in the weld. The electrochemical evaluation suggested that the δ ferrite helps in improving the pitting potential in 3.5 per cent NaCl solution saturated with CO₂. Whereas in 0.5-M H2SO4 + 0.003-M NaF solution, higher passivation current density was observed because of dissolution of dferrite. The interphase corrosion resistance decreased with increasing heat input.

The Cr-Mn austenitic stainless steel or low-nickel ASS was procured in form of 3-mm sheets in rolled condition. The tungsten inert gas welding was performed at three different heat inputs (100 A, 120 A and 140 A), argon as shielding gas with a flow rate of 15 L/min. Different welded regions were observed using optical microscope and scanning electron microscope. Electrochemicals test were performed in solutions containing 3.5 per cent NaCl with saturated CO₂ solution and 0.5 M sulfuric acid + 0.003 M NaF at a scan rate of 0.1667 mV/s at room temperature (30 °C ± 1 °C) using a potentiostat.

The test steel Cr-Mn ASS is suitable with the selected electrode (308 L) and it produces no defects. Vermicular ferrite and lathy ferrite form in welds of various heat inputs. The increase in heat input reduces the formation of lathy ferrite. The width of HAZ and un-mixed zone increases with increase in heat input. The weld zone of low heat input (LHI) has the highest hardness and tensile strength because of higher δ ferrite content and small grain size in the weld zone. The hardness at high heat input (HHI) is found to be lowest because of grain coarsening in the weld. With increase in δ ferrite, the pitting resistance increases. In 0.5-M sulfuric acid + 0.003-M NaF, the increase in ferrite content reduces the passivation current density. Interphase corrosion resistance increases with increase in δ ferrite content as higher per cent degree of sensitization was observed in LHI welds as compared to medium heat input and HHI welds.

This work focuses on welding of ASS by tungsten inert gas welding at different heat inputs. Welding is a critical process for joining metals in most of the fabrication industries and proper heat input is required for getting desired microstructure in the weld metal. This would highly affect the strength and corrosion behavior of the alloy. This paper would give an understanding of how the change in heat input by tungsten inert gas welding affects the microstructural and corrosion behavior in the weld metal.

Low nickel austenitic stainless steel (ASS) has attracted much attention worldwide because of its economical price. This study aims to investigate the effect of different corrosive environments on the corrosion behavior of chrome-manganese (Cr-Mn) ASS. The tests were carried out as a function of H₂SO₄ concentrations, temperature and addition of ammonium thiocyanate (NH₄SCN) (0.01 M). Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques were used to study the corrosion behavior of Cr-Mn ASS. It was observed that with increasing H₂SO₄ concentration, temperature and with the addition of NH₄SCN solution, icorr, icrit and ipassive values increased. EIS data show decreasing charge transfer resistance value with increasing concentration and temperature. Higher corrosion rate with increasing temperature and concentration of H₂SO₄ is related to the anions (SO₄²⁻), which is responsible for reducing the stability of passive films. With the presence of 0.01 M NH₄SCN thiocyanate (SCN⁻ anion), there is a higher dilution of the passive film resulting in a higher corrosion rate. Energy-dispersive spectroscopy (EDS) analysis reveals the adsorption of sulfur on the surface in NH₄SCN containing a solution. The significant presence of counter ions and the adsorbed sulfur species on the steel surface play a vital role in corrosion behavior.

All the experiments were performed on a 3 mm thick sheet of Cr-Mn ASS (202 ASS) in hot rolled condition. The samples were then annealed at 1,050°C for 1 h, followed by water quenching. For microstructural examination, they were electrochemically etched in 10 Wt.% oxalic acid solution at 1 amp for 90 s. A computer-controlled Potentiostat (Biologic VMP-300) was used. After the cell was set up, the working electrode (WE) was electrostatically cleaned at −1 V vs saturated calomel electrode (SCE) for 30 s to remove the air-formed film. Then, WE were allowed to attain stable open circuit potential (OCP) for 1 h, following by the EIS test and potentiodynamic polarization test. The polarization test was started from a cathodic potential (−1.2 V vs SCE) and continued up to an anodic potential (1.6 V vs SCE) a scan rate of 0.1667 mV/s. EIS experiment was conducted on the same instrument by using a sinusoidal AC signal of 10 mV in a frequency range of 1,000,000 to 0.01 Hz at OCP.

Potentiodynamic polarization graph shows that with the increase in sulphuric acid concentration. Increasing temperature from 20°C to 80°C in 0.5 M H₂SO₄ solution increases the corrosion rate (icorr) of Cr-Mn ASS. On the addition of 0.01 M NH₄SCN to the sulfuric acid solution (0.1, 0.5 and 1 M) the corrosion rate increases drastically almost four to five times. EDS and XRD analysis shows the presence of sulfur over the oxide film and preferential site for dissolution of Cr and Mn at the steel surface when NH₄SCN is added to the sulfuric acid solution.

A study on the corrosion behavior of Cr-Mn ASS is scanty according to the author’s knowledge. Therefore, the present study will investigate the corrosion behavior of Cr-Mn ASS on SO₄⁻² anions, temperature and the addition of SCN⁻ ion in sulfuric acid.