Papers by Keyword: TIG Welding

Abstract: This study investigates a hybrid manufacturing route combining heat-assisted Single Point Incremental Sheet Forming (SPIF) with Tungsten Inert Gas welding (TIG)-based material deposition for the local reinforcement of Mg–Zn–Zr (ZK61) alloy thin sheets. Flat and curved substrates extracted from SPIF-formed geometries were used to examine the influence of substrate thickness, forming temperature, and geometry on TIG deposition morphology and thermal distortion. The results indicate that heat input and substrate thickness strongly affect deposition morphology and dimensional stability, while SPIF sheet forming temperature influences the repeatability of the deposition process. In addition, deposition behavior exhibited limited sensitivity to substrate curvature for single depositions, whereas successive depositions resulted in increased thermal distortion due to cumulative residual stresses. Overall, this work identifies key process sensitivities and constraints associated with TIG deposition on SPIF-formed magnesium alloy sheets, providing a basis for the development of hybrid forming-deposition process chains for localized reinforcement applications.

Abstract: Titanium is the material of choice for high performances components, due to the combination of physical and mechanical properties it provides and is widely used in aerospace, automotive, biomedical and marine engineering due to their good hot and cold processing properties, fracture toughness, high specific strength and good deformability. Nevertheless, titanium is also characterized by very high production costs, which are approximately 6 times and 30 times higher, respectively, in comparison to those to obtain the same quantity of aluminum or steel relegating titanium to high demanding sectors. One possible way to reduce the cost of titanium is to use cheaper alloying elements instead of vanadium or niobium to stabilize the body-centered-cubic (B.C.C) β-phase. TIG-welding of high-strength low-cost pseudo-β titanium alloys is complicated, primarily due to the high content of alloying elements, such as iron, molybdenum, as well as the use of oxygen as an alloying elements. By the correct choice of welding modes in most cases, it is possible to obtain welded joints of high-strength pseudo-β titanium alloys with good microstructure and mechanical properties. In this article, we study the weldability and influence of TIG welding on the structure and mechanical properties of low-cost titanium alloy Ti–2.8Al–5.1Mo–4.9Fe.

Abstract: Welding induces various effects, including the generation of residual stress, deformation, alterations in shape, and changes in mechanical properties, particularly the hardness of the material in the welded zone due to the melting of the base material during the welding process. These factors can contribute to a reduction in product strength. This research aims to investigate the influence of solution treatment (ST) temperature on the hardness properties of aluminum 6061 with TIG welded joints. The study involves TIG welding to create joints, followed by a solution heat treatment process, during which the welded product is heated in a furnace at temperatures of 450, 475, and 500 °C, with a fixed holding time of one hour for each condition. Following the heat treatment, hardness tests are conducted to evaluate the condition of the TIG welded joints as influenced by the solution treatment temperature. The results demonstrate a significant effect of the solution treatment temperature on the hardness of the AA6061 alloy in the TIG welded joints. The highest hardness value, 80 HRE, is observed in the weld metal area of the ST 475 °C sample, while the lowest value, 37.17 HRE, is recorded in the base metal area of the ST 450 °C sample.

Abstract: The TIG welding technique in pulsed current using inverter welding equipment allows the realization of welds at a high technological and qualitative level due to the advantages that the process offers, the control of the welding pool, of the energy introduced in the components, the increase of the arc stability when using low welding currents or when welding at high speeds. Some manufacturers of welding equipment [1, 2] propose the option of using pulsed current on manual metal arc welding sources to increase the technological performance, primarily for the control of the welding pool by using low values of the current frequency below 10Hz, but with limited possibilities to modify the other parameters of the welded joint. The paper proposes the use of TIG welding equipment in pulsed current, in manual metal arc welding using the pulsed welding technique, starting from the advantages that this equipment offers in terms of the much greater possibility of adjusting all the parameters of the pulsed current according to the technological needs. This is possible because the two welding processes use welding equipment with identical external static volt-ampere characteristics.

Abstract: TIG (Tungsten Inert Gas) welding has more and more application options. To always create new ways of optimization, a more in-depth study of the effects on the components subject to joining is necessary. The paper includes a study on the hardness resulting in the specific areas of the welded joint, using TIG welding with high frequency pulsed arc, applied to join some stainless-steel plates. The relative variation of the hardness was determined and analysed, in correlation with the process parameters. The study is part of the research on obtaining a good energy efficiency in the welding process, based on the requirements imposed on the quality of the joints.

Abstract: Titanium alloys are widely used in aerospace, automotive, biomedical and marine engineering due to their good hot and cold processing properties, fracture toughness, high specific strength and good deformability. Nevertheless, titanium is also characterized by very high production costs, which are approximately 6 times and 30 times higher, respectively, in comparison to those to obtain the same quantity of aluminum or steel relegating titanium to high demanding sectors. One possible way to reduce the cost of titanium is to use cheaper alloying elements instead of vanadium or niobium to stabilize the body-centred-cubic (B.C.C) β-phase. TIG-welding of high-strength low-cost pseudo-β titanium alloys is complicated, primarily due to the high content of alloying elements, such as iron, molybdenum, as well as the use of oxygen as an alloying elements. By the correct choice of welding modes in most cases, it is possible to obtain welded joints of high-strength pseudo-β titanium alloys with good microstructure and mechanical properties. To study the influence of TIG welding on the structure and mechanical properties of low-cost titanium alloy Ti–2.8Al–5.1Mo–4.9Fe, two types of TIG-welding chosen: standard fusion TIG welding and TIG welding on the thin flux layer.

Abstract: Tungsten Inert Gas welding process (TIG) has been widely used in industries. A robotic arm has been adopted in the industry with objectives to replace or efficiently improved some severe welding conditions where it is dangerous for human and to increase productivity and quality. This research is aimed to find the optimal conditions of TIG welding process on AISI 304 stainless steel. The design of experiments used a statistical method to determine the optimal TIG welding conditions providing the strongest tensile strength across the weldment. The fractional factorial experimental design and then the central composite design were used as a response surface method to find the optimal TIG welding conditions for AISI 304 stainless steel using robotics system. The statistically significant factors and their optimal values are the welding current (136 Ampere), welding speed (13 cm/min), wire feed rate (93 cm/min), and the arc gap (2.5 mm). After that, the residual stress caused by TIG welding at the optimal condition was measured by X-ray diffraction (XRD) technique. The results showed that the weldment obtained from the optimal welding conditions provides compressive residual stresses which cause the materials to be stronger.

Abstract: Many of the features and advantages of TIG welding are well known. The paper presents in part the results of some experimental research using TIG welding with high frequency pulsed arc. A comparative study was performed between the application of TIG welding with high frequency pulsed arc technology and classical TIG welding, applied to achieve welded joints of stainless-steel parts. The conclusions are based both on the characteristics of the welding process (the hole main group of parameters) and the results of the applied non-destructive and destructive testing methods. Features like reduced deformations in the joint, low energy guaranteed ignition, wonderful focalization of the high current density arc, increased working speed and not the last, the special look of the welded plates recommends this procedure for some replacement possibilities for the expensive laser welding process. Aspects of improving the quality of welded joints are highlighted, given the low manufacturing costs.

Abstract: The paper aims to report preliminary researches towards to development of new hybrid welding system by coupling a microwave beam with a TIG torch. The main research was focused on the designing of hybrid system as well as to establish the heating/welding mechanism by coupling two different thermal sources. Therefore, a specific welding chamber was designed taking into consideration the limitations provided by microwave waveguide technical specs, geometrical shape and dimensions of the TIG torch as well as the temperature monitoring during welding process and video surveillance for data recording. A microwave generator with adjustable power from 0 to 1250 W was coupled with a TIG torch and welding power source in order to establish the main parameters for hybrid system. The preliminary researches reported that the MW-TIG hybrid welding could be applied to eutectic joining of materials using low power (up to 600 W) injected from microwave generator as well as low welding current (up to 20 A). The flow of shielding gas have been established initially to 2 l/m. The research related to stabilization of MW-WIG plasma arc have been studied by increasing the flow of shielding gas up to 10 l/m. The results have shown that the microwave generator and TIG torch can be coupled to obtain hybrid-welding process without any matching tuning devices but with risks for damaging the microwave generator. Further researches will be done in order to design auxiliary devices to optimize the hybrid-welding process and to avoid any unwanted plasma arc discharge from welded base materials to microwave generator. In terms of temperature monitoring, an infrared pyrometer has been used. The IR pyrometer was targeted to the base materials in order to be able to measure their temperature without any influences from plasma arc. The results obtained have shown a stable plasma at average microwave power around 400 W even without any TIG current.

Abstract: As intensive work is underway in leading material science centers in the USA, EU, Russia, and China, both to modernize existing titanium alloys and to create new ones, the E.O. Paton Electric Welding Institute of the National Academy of Sciences of Ukraine developed titanium alloys T110 (Ti-5.5Al-1.2Mo-1.2V-4Nb-2Fe-0.5Zr system) and T120 (Ti-6.5Al-3Mo-2.5V-4Nb-1Cr-1Fe-2.5Zr system), which according to their characteristics, belong to the group of modern two-phase high-alloyed alloys characterized by high strength and good ductility. With more and more attention is being paid to the expansion in the usage of welded structures and assemblies of high strength titanium alloys with UTS ≥ 1100 MPa, there’s urgent need in studying best ways to obtain welded joints from such alloys. The weldability of two-phase high-alloyed titanium alloys, the use of which can give big reduction in structural weight, is significantly worse than low-alloyed alloys, therefore for a new alloy it is necessary to ensure the possibility of obtaining welded joints with a strength of at least 90% compared to the strength of base material. The aim of this work is to study the influence of the welding thermal cycle and reducing of weld metal alloying degree on the structure and mechanical properties of welded joints of high-strength titanium alloy Ti-6.5Al-3Mo-2.5V-4Nb-1Cr-1Fe-2.5Zr with tensile strength more than 1200 MPa, as well as assessment of it welded joints properties in comparison with other high-strength titanium alloys.