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.

Both Zirconium-based alloys and 321 stainless steel are widely used as engineering alloys due to their good mechanical properties. Conventional fusion welding techniques for Zr alloys and stainless steel are not feasible due to the formation of brittle interMETALlic compounds such as (Zr3Fe, ZrFe2 and Zr2Fe) and corrosion cracking. Brazing is one of the most widely used techniques for joining dissimilar alloys.Using titanium base FILLER METAL decreases the diffusion and the formation of brittle interMETALlic compounds. In this study, wetting experiments were done at 820, 850, 865oC and 3, 5, 7 and 10 min. Also, joining of these two alloys was carried out at 850 and 865oC for 10 and 15 minutes. Optical microscope, scanning electron microscope (SEM), XRD, shear test and micro-hardness test were used for METALlurgical and mechanical investigations. The results show that 20oC/min heating and cooling rates at 850oC and 10 min brazing condition lead to a proper joint without any brittle interMETALlic compounds.

The influence of FILLER METALs on the microstructure and corrosion behavior of AISI 316L welds was investigated. Gas Tungsten Arc welding (GTAW) process was applied to join the AISI 316L plates using ER 316L and ER 312 FILLER METALs. The obtained microstructures were characterized by optical METALlography and scanning electron microscope (SEM). Corrosion assessments were conducted in 3. 5% NaCl using a three electrode cell. Open circuit potential and potentiodynamic polarization examinations were conducted on the welds and base METAL. Microstructural evaluations indicated that a combination of austenite and ferrite phases was formed in the welds fabricated by both FILLER METALs. Based on the micro hardness tests, the weld fabricated by ER 312 FILLER exhibited superior harness compared to the ER 316L weld. Corrosion evaluations also show that the weld METAL obtained from two FILLER METALs has a lower corrosion rate due to the higher amount of chromium and higher ferrite compared to the base METAL. Also, the lower corrosion current of ER 312 weld METAL compared to ER 316L weld METAL is for this reason. In contrast to the base METAL compared to the two welding METALs, the result of the two FILLER METALs has shown better pitting corrosion results according to the electrochemical tests and also the examination of the surfaces using an optical microscope after these tests, that these results are due to The presence of two phases of austenite and ferrite in the vicinity of each other in weld METALs and the intensification of galvanic corrosion is due to the discharge of the austenite phase from chromium and molybdenum.

Welding connection of 316L stainless steel has great importance in the oil and gas industry. In this research, welding of 316L stainless steel was investigated using GTAW with the aim of evaluation of the mechanical behaviour of FILLER METALs. Three FILLER METALs of ER309L, ER316L and ER309LMO were used for this purpose. The microstructure results of different regions of welding sections showed that welding structures of three types of FILLER METALs are similar and have structure of Austenite and Ferrite delta. Also, there is a slight difference in the distribution amount of Ferrite delta in the Austenite background. Hardness evaluation results showed that the average hardness of FILLER METAL of ER309LMO is higher than average hardness of FILLER METALs of ER316L and ER309. Also, hardness of impacted region by connection heat of 316L steel in each of FILLER METALs had been increased. The final strength of connection of all three FILLER METALs was higher than 545 MPa. It was in such a way that sample of tensile test was failed and ruptured in the base METAL location. The average of impact energy was (156J) for weld METAL of ER316L which was higher than average of impact energy (96J) for weld METAL of ER309L and average of impact energy (58J) for weld METAL of ER309LMO. This reduction in impact energy in two weld METAL of ER309 is due to microstructure of Ferrite delta. Using FILLER METAL ER316L with V connection design is better for this connection due to improved impact energy.

In this study, the microstructure and mechanical properties of dissimilar joining of Inconel 718 superalloy to AISI 316 austenitic stainless steel were investigated using the tungsten-gas arc welding method with two FILLER METALs 718 (ERNiFeCr-2) and 625 (ERNiCrMo-3). After welding, the microstructure and mechanical properties of different joint areas were evaluated using an optical microscope and scanning electron microscope. The precipitates in the interface and their chemical composition were determined using energy-dispersive spectroscopy analysis. Also, the mechanical properties of the joint were evaluated using tensile, impact, and microhardness tests. Microstructural investigations showed that the freezing structure of FILLER METAL 718 has an austenitic microstructure with a dendritic network along with carbide distribution and FILLER METAL 625 has also created an austenitic microstructure with a dendritic network. In the tensile test, FILLER METAL 718 has the highest tensile strength of 528 MPa and the failure of all tested samples occurred in the area of the austenitic stainless steel base METAL 316. The results of the impact test showed that the maximum amount of fracture energy is 50J for FILLER METAL 625. The micro-hardness test also determined that the 718 FILLER METAL has the highest hardness of 214 Vickers.

Joining of titanium alloys to other materials especially steels has attracted much attention in recent years due to the exceptional properties of titanium such as excellent corrosion resistance and mechanical properties and its increasing application in various industries. According to the Fe-Ti binary phase diagram, these two elements do not have complete solubility. This leads to difficulties during fusion welding of these two alloy. One of the best methods for joining dissimilar alloys is brazing. In this research, the METALlurgical and mechanical properties of brazing lap joints of steel to commercially pure titanium using a commercial FILLER METAL (BAg-8) made under different time and temperature conditions were investigated. The study of the microstructure interface shows the formation of a chemical layer close to the titanium side of the joint, while no chemical compounds were created on the steel side. A coarse structure is formed at the interface between the steel and silver solder alloy. The observed coarse grain structure is related to the grain growth along with recrystallization in the steel substrate at high temperatures. Analysis of the joints was carried out by optical microscopy, scanning electron microscopy, X-ray diffraction and hardness measurements. The results show that with increasing temperature, as well as brazing time, the average shear strength decreases due to the increased thickness of the intermediate layer.

Nutritional and economic value of wheat flour necessitates the utilization other potential material such as by-products of pulp and paper industry, especially Kraft lignin, as possible FILLER-extender in urea formaldehyde resin, in the presence of METAL ion catalysts. The variables were the amount of Kraft lignin powder and the type of catalyst. Water absorption and thickness swelling of samples after being submerged in water for 2 and 24 hours, modulus of elasticity and bending strength in parallel and perpendicular to grain and shear strength were evaluated according to AFNOR, ASTM and ISO standards and the results were analyzed. The results of this study show that the water absorption and dimensional stability of the boards examined improve with using 30 percent of lignin Kraft powder in the absence of catalyst and, furthermore, mechanical properties of the boards will improve if 30 percent of lignin Kraft powder is used together with zinc acetate catalyst.

In this research the interface structure of dissimilar joint between AISI 4130 and AISI316L steels produced by GTAW process was evaluated. ERNiCr-3 was used as a FILLER METAL for this joint. After welding the microstructure of different areas including weld METALs, heat affected zones and interfaces were studied by optical microscope (OM), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) analysis. It was found that the weld METAL entirely has astenitic microstructure with relatively equiaxed grains and denderitic morphology. The results also showed that the grain growth in 4130 steel-weld METAL interface was unepitaxial due to the severe difference in chemical composition between the base and weld METALs. Microhardness measurements showed that the welded sample indicated the highest microhardness in the heat affected zone of 4130 steel because of the presence of tempered matensite and bainite in this area. In the weld zone a decrease in hardness value from AISI 4130 steel to AISI 316L can be seen. This reduction in microhardness can be due to the less amount of carbon in the weld area in vicinity of the AISI 316L base METAL.