Gas Tungsten Arc Welding (GTAW) was applied to create a composite layer on the surface of cast aluminum alloy A380. Different mixtures of aluminum, silicon and silicon carbide powders with Sodium silicate solution were pasted on the substrate. After drying and preheating, surface melting was conducted by TIG process. A composite layer of Al-SiC was created on the surface by this process. Evaluation of microstructure and properties of obtained composite clad was done by X-ray diffraction (XRD), optical and scanning electron microscope (SEM), elemental microanalysis (EDS) and microhardness testing methods. The results showed uniform distribution of SiC particles in Aluminum dendritic matrix. SiC particles are dissolved partially during heating and melting of the preplaced layer and may lead to the formation of Si and Al4SiC4 phases with a Vickers hardness of about 1000 HV. Surface hardness can be increased by further addition of silicon in preplaced powders.

This paper deals with the investigation of the microstructure and hardness of steel samples cladded with satellite 6-WC composites by using gas tungsten arc welding (GTAW) process. For this purpose, steel samples were coated with unreinforced and reinforced stellite (by 20, 30 and 40 wt.% WC). The cladded samples were evaluated by metallographic studies, microhardness measurement and X-ray diffraction analysis. In order to reduce dilution and to increase the hardness, samples were coated by two layers of similar chemical composition. The results indicated that in samples cladded by reinforced stellite, with an increase in tungsten carbide content, the amount of hypoeutectic phase (g+ (g+WC)) increased. This is accompanied by an increase in hardness.

Despite the increased use of aluminium alloys in several industries, their common concern is the difficulty of joining dissimilar alloys using welding techniques. Based on this, the primary purpose of this research is to assess the mechanical characteristics of dissimilar joining of heat-treatable 6061 and non-heat-treatable 5083 aluminium alloys by gas tungsten arc welding and to discover the link between microstructure and mechanical properties. Similar welds were also implemented and evaluated in order to more properly analyze and compare the outcomes. The quality of the weld generated after establishing the health of the joint using non-destructive testing was evaluated by destructive bending, tensile, metallographic, and hardness tests to check the mechanical and microstructural qualities. The intended dissimilar weld was produced under the parameters of pulse current 120-80 amps, voltage 20 volts, welding speed 15 cm/min, and filler 5356. It should be highlighted that the dissimilar weld had the maximum joint efficiency, and with perfect control of welding settings and the absence of flaws, only 36% loss of strength was recorded when compared to the base metal. Metallographic images revealed that the formation of hot cracks in the dendritic structure of the weld metal is the major cause of strength loss for 5083 similar weld and the production of numerous porosities in the weld metal for 6061 similar welds.

In this study, gas-tungsten arc welding was used for the cladding of two high entropy alloys of AlCoCrFeNi (Al1) and Al0. 7CoCrFeNi (Al0. 7) onto plain carbon steel plates. The welding process was carried out at a welding current of 180 A and a welding speed of 1. 4 mm/s. The microstructures, craking behavior, phase composition, and hardness of the clads were characterized using various methods, such as optical microscopy (OM), field emission scanning electron microscopy (FESEM), X-ray diffractometry (XRD) analysis, and microhardness measurements. The results indicated that the Al1 clad had a petal-like structure of the BCC and Cr-rich phases. Both intergranular and transgranular cracks were identified in the Al1 alloy, which were recognized to be solidification cracks. Thermal stress and brittleness of the BCC phase promote cracking of the Al1. On the other hand, in the Al0. 7 alloy, in addition to the BCC phase, a new FCC phase was formed with various Widmanstatten and dendritic morphologies in the clad microstructure and the Cr-rich phase was not observed. Furthermore, in this alloy with lower Al content, a crack-free clad was obtained. The crack prevention in the Al0. 7 alloy was attributed to a combination of factors, including a decrease in the solidification range, formation of the FCC phase, and reduction in hardness.

In this method has been studied mechanism and causes and ways of deleting or decreasing of hot cracking in welding Nickel base super alloy (UDIMET 520) in the way of GTAW in this study it has been used scanning electron microscopy (SEM) machine and quantometry. The results of this tests show that interesting to solidification hot cracking at the time of the super alloy welding with internal temperature above the melding and increasing percentage of Al.Ti is numerous and interesting to melting hot cracking because of heterogeneity of melting structure and segregation it become stronger for quick warming in welding.

In this research, microstructure and mechanical properties of AISI316 to AISI430 dissimilar joint were investigated. For this purpose, GTAW process using ER316L and ER2209 filler metals with diameter of 2. 4 mm was used. The microstructure and fracture surface of the welded samples were characterized by optical microscopy and scanning electron microscopy. Also the mechanical properties of the welded samples were evaluated by tension, impact and microhardness tests. It was found that the microstructure of the welded sample with ER316L filler metal contained widmanstatten austenite with inter-dendritic and lathy ferrite. Also, in the welded sample with ER2209 filler metal, Austenite phase in ferrite matrix was seen. In tension test, all samples were fractured from AISI430 side of the joint in a ductile manner. ER2209 weld metal indicated low impact energy about 27 J, while ER316L weld metal indicated higher impact energy about 43 J. The surface fracture in both welded samples indicated brittle fracture mode. The microhardness of the weld metal of the welded sample with ER316L filler metal was higher than the welded sample with ER2209 filler metal due to the presence of alloying elements, proper distribution of delta ferrite and finer microstructure.

This study attempts to investigate the micro structure and wear behavior done on the surface of carbon steel. In doing so, specimens of carbon steel were filled through gas tungsten arc welding (GTAW) applying pulse and continuous currents by filler metal. The cross-section samples were examined by light microscopy and electron microscopy. The hardness test, the hardness of the samples was determined. Pin on disc wear test to evaluate the wear resistance of plain carbon steel specimens coated and welded something done. The wear surfaces were examined by scanning electron microscopy. Therefore, a sample with pulse configuration the lowest wear rate is the highest surface hardness. In order to optimize the welding conditions and the impact of each of the factors used to determine the degree of difficulty in pulsed mode, the Taguchi experimental design technique and the use of S / N ratio have been used. Finally, the overall results of the analysis revealed that the variable factors, peak flow and low flow, respectively, are considered the most influential factors on the response.

Argon or Gas-Tungsten Arc welding (GTAW) is known as an important method of joining metals in industrial applications. Due to the importance of the controlling welding-parameters to prevent any defect formation during the process; in this research, weldcurrent, pre-heating temperature and electrode-traveling speed are adopted as the input welding-parameters. Then, using the Grey Analysis Method, the effect of the aforementioned welding-parameters on the ultimate-strength, hardness and angular distortions of the welded joints are obtained and optimized. Grey-diagrams are plotted by calculating the Grey-ratio, Grey coefficient and Greydegree. Finally, based on these diagrams, the effect of the welding-input variables is established in percent and the optimum values are obtained with the effect of input parameters on the output values. Experimental tests are carried out based on the optimum values for the input and output parameters to verify the results of the Grey analyses.