An investigation has been done to identify the heat source model suitable for numerical modeling of the Gas Metal arc Welding (GMAW) welding process. In the present investigation, a numerical model was constructed to simulate the GMAW welding process through transient thermal analysis for different thermal heat source models for weld deposition of Mild steel considering semi-cylindrical weld bead geometry. The Gaussian heat source with radial coordinate system and double ellipsoidal thermal heat source have been considered to develop a Finite Element Analysis (FEA) model. Validation of numerical analysis results has been confirmed through experimental investigation. Numerical modeling confirms the utilization of both heat sources, i.e. Gaussian and Double ellipsoidal for the prediction of the weld bead deposition profile. However, the numerical modeling developed using a double ellipsoidal heat source has more resembles experimental investigation due to the utilization of bead profile data. However, the Gaussian heat source is found to be suitable in the case of the unavailability of experimental data. The experimental studies show a variation in the weld bead geometry, along its welding direction due to multiple environmental factors. The microstructural investigation also shows the development of a fine columnar grain structure at the welding bead & weld penetration zone, and the grain structure became coarser at the Heat Affected Zone (HAZ).
In the present paper, plasma-assisted physical vapor depositions (PAPVDs) have been used to extract the TiN and titanium aluminum nitride (TiAlN). Further, plasma nitriding (PN) has been used prior to thin-film deposition of TiN on AISI 304 stainless steel material using intentional biasing (in the coating). PAPVD is integrated to investigate the thermal resistant effect coating of AISI 304 stainless steel by TiN coating using finite-element analysis. The morphology of elements on the coating was studied by field emission scanning electron microscopy, X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy. From XRD analysis, it has been observed that at the coated zone Ti, TiN was found on the AISI 3O4 stainless steel. The results in microhardness through the Vickers microhardness tester have been measured up to 350 Hv for the base sample at a 10 g load. Moreover, TiN/(PN + TiN) coated samples were measured with an average microhardness of 2220, 963, and 720 Hv for the nitride sample. In addition to this, the microhardness of TiAlN was found up to 1890 and 2400 Hv for different samples. The thickness of the film is around 1.4279 µm (TiN) and 1.888 µm (TiAlN) in 1 h of deposition.
Electrostatic Precipitators (ESP) are control devices widely used for collection of fly ash in Indian coal based thermal power plants. The design, performance, sizing, collection and operation of ESP depend largely on the properties and quality of the coal burned and the fly ash generated in the boilers. This study presents the influence of fly ash composition on the resistivity of Indian fly ash generated from coal based power plants, which is one of the critical parameter required to make accurate predictions of ESP in terms of their collection efficiency. The fly ash electrical resistivity measurements were conducted over a wide range of temperature in both ascending and descending cycles in the range of 90 to 455ºC at 9% moisture as per IEEE-Standard 548 (1991). The earlier developed Empirical relations used for calculating fly ash electrical resistivity for western coals were modified for the calculations of electrical resistivity of Indian fly ashes and new empirical relations have been developed based on experimental results and chemical composition of fly ash samples collected from different coal based power plants in India which have different chemical composition in comparison to western coals. Results in the newly developed correlations show better agreements with experimentally determined resistivity compared to those developed by Bickelhaupt and others.
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