Welding Method Research Articles

Experimental evaluation of aluminothermic welds

The article presents a study of the mechanical processes occurring during the aluminothermic reaction using experimental methods (strain gauges, digital image correlation, thermography, scanning electron microscopy, profilometry). The aluminothermic reaction is a highly efficient welding method due to its exothermic behaviour, however, it places considerable demands not only on the welding technique, but also on the capabilities of the experimental methods used; these limitations are also discussed in the article. The aluminothermic reaction is associated with the formation of a localised heat source with a time evolution dictated by the technological procedure, which manifests itself in heat propagation to the surrounding weld material. The unequal evolution of the temperature field is the fundamental cause of the appearance of the heat affected zone or local deformations or surface curvature, which was the focus of the experimental methods deployed above and the results of which are shown in the article.

Fabrication and characterization of weld attributes in hot gas welding of alkali treated hybrid flax fiber and pine cone fibers reinforced poly-lactic acid (PLA) based biodegradable polymer composites: studies on mechanical and morphological properties

The contemporary times have witnessed a lot of interest in fabricating green composites because of its biodegradability, durability, affordability, ease of manufacturing and its potential to replace existing commercial goods in the field of engineering applications. The green composites are envisaged to replace synthetic polymer-based composites since the green composites are fabricated using the biodegradable polymers reinforced with natural fibers. In this research work, Flax Fiber and Pine Cone Fibers are reinforced in Poly-lactic Acid (PLA) matrix. The green composites are fabricated using compression moulding technique in different nominations as per the weight fraction such as (90:10), (80:20) and (70:30). It was noticed that a higher tensile strength of 27 MPa is observed in case of group 2 (80:20) specifically for the composite having 80% of matrix and 14% flax and 6% pine cone fibers. An IoT based automatic hot gas welding method was used to join the fibers by considering various input parameters like stand of distance, weld rate, specimen groove geometry, and composition. The mechanical testing of the weld specimens was carried. It was observed that the weld joints having higher stand of distance were observed to have less tensile strength as compared to others and the fracture points of such specimens were observed to be at the weld bead. SEM analysis of the fracture point validated the observations from the mechanical characterization.

Fabrication and characterization of incorporated nickel coatings with different loadings of tungsten carbide microparticles: Investigation of mechanical and chemical properties

This study aims to investigate the strengthening effect of incorporated nickel coatings with different weight percentages (wt.%) of tungsten carbide (WC) microparticles on the various properties of the applied coatings on plain carbon steel. Therefore, different applied coatings, including pure and reinforced nickel with various wt.% of tungsten carbide were applied to the samples using the tungsten inert gas (TIG) welding method. Then, the microstructure, wear behavior, hardness, and corrosion of the coated samples with pure and incorporated nickel with 5, 10, and 20% tungsten carbide were obtained and compared with the uncoated sample. The obtained results show that reinforcing the applied coatings with WC has improved the behavior of the coatings in different properties so that the filled coating with 20% of tungsten carbide had the best results. For example, the wear rate of coated surfaces reinforced with 5, 10 and 20% of tungsten carbide was 12.56, 7.52, and 5.28 mg/m, respectively, which was much lower than the uncoated sample with a value of 24.41 mg/m. The maximum coating hardness equal to 49.6 Rockwell C was obtained for nickel coating reinforced with 20% of tungsten carbide, which can be due to the high percentage of powder compared to other samples, and the formation of finer grains. The corrosion results of the samples using cyclic polarization diagrams showed the improvement of the corrosion behavior by adding tungsten carbide so that the nickel coating reinforced with 20% of tungsten carbide had a corrosion current density of 7.15 × 10−7 amps/cm2. Finally, the obtained results show that strengthening the applied coatings by the TIG method using different wt.% of tungsten carbide up to 20% can improve the various properties of the coating.

Tozaltı Ve Gazaltı Kaynak Yöntemleri İle Birleştirilen Gemi İnşa Çeliğinin Kaynak Bölgesinin Mekanik Özelliklerinin İncelenmesi

Merchant ships are generally built by joining steels with various welding methods. When the welding methods used in shipyards are examined, it is seen that gas metal arc welding (GMAW), submerged arc welding (SAW), covered electrode arc welding and tungsten inert gas (TIG) welding come to the fore. In the assembly of ship hull sheets, GMAW and SAW are generally preferred. In this sense, it is extremely important to characterize the mechanical properties of the weld zone after welding of the shipbuilding steel joined by these two welding methods. When the studies examined, although there are few studies on the joining with GMAW and SAW of shipbuilding steels, no study has been found on the comparative examination of these two welding methods. In this context, within the scope of the study, 3701 shipbuilding steel, which is used extensively in shipbuilding, was joined with SAW and GMAW methods and the hardness, tensile, impact and bending properties of the welding zone were examined comparatively. In consequence of the tests, it was determined that higher mechanical properties were obtained than the base metal in both welding methods. Also, it was found that the welding zone of the shipbuilding steel joint by the SAW method had relatively better mechanical qualities.

REVIEW OF ADVANCED WELDING AND TESTING FOR SAFETY IN OFFSHORE OIL AND GAS

The offshore oil and gas industry plays a crucial role in meeting global energy demands; however, it is fraught with inherent safety risks that necessitate constant welding and testing techniques advancements. This research paper reviews the significance of advanced welding and testing for safety in offshore oil and gas operations. This article explores traditional welding methods and their limitations in ensuring structural integrity and safety. It delves into a comprehensive analysis of advanced welding technologies, including friction stir welding, laser welding, and electron beam welding, highlighting their potential benefits in mitigating safety concerns. Moreover, the study examines the role of non-destructive testing (NDT) methods, such as ultrasonic testing, radiographic testing, and magnetic particle inspection, in evaluating weld quality and structural integrity. An emphasis is placed on integrating advanced welding techniques with NDT, demonstrating how this symbiotic relationship enhances safety and effectively identifies flaws and defects. Real-life case studies exemplify the practical implementation of these technologies in safeguarding offshore structures. The paper also addresses the challenges of adopting advanced welding and testing methods and envisions potential future developments in these technologies. Furthermore, it sheds light on existing regulatory frameworks and standards governing welding and testing in offshore operations, underscoring their role in ensuring safety and compliance.

A novel strategy to improve melting efficiency and arc stability in underwater FCAW via contact tip air chamber

The conventional method of underwater flux-cored arc welding (UWW-FCAW) is characterized by water around the welding torch's electric parts, the tubular wire, the molten pool and the workpiece. In the present work, underwater FCAW was performed by keeping the contact tip dry, inside a specially developed torch, and as in conventional underwater welding. The welds were carried out in a flat position at simulated depths of 0.3 m, 10 m and 30 m using a hyperbaric chamber. Welding electrical signals of voltage and current and contact tip temperature were acquired and processed to determine process behavior. As a result, the welding current was reduced when the contact tip was kept dry inside the torch because of the higher temperature achieved by resistance heating when it was insulated from the water. The ambient surrounding the contact tip interfered with the coefficient of heat transfer and, consequently, with its temperature. Welds performed with the dry contact tip also presented slight variations in bead shape parameters in different water depths. Higher arc stability was achieved by welding with the contact tip inside the air chamber, as minor variations of electric signals and fewer arc extinction events were observed compared to conventional underwater welds. The combination of improved arc stability with higher electrode temperature may also have contributed to minor porosity and smaller variation of the reinforcement along the weld bead.

Grain refinement of aluminium welds by Ti, TiB_2, and TiC filler wire inoculation

A fine-grained fusion zone characterises a tough aluminium weld. To improve the solidification characteristics and refine the grains in aluminium welding, different inoculation particle combinations were introduced to the filler wire by solid state metal screw extrusion. Filler wires were I-joint welded with two different welding methods to reveal the potency for grain refinement. Grain size, microstructure, porosity content, and hardness across the weld was revealed. Gas metal arc welding with a Ti-TiC inoculated filler wire exhibited a remarkable grain refinement of 91% compared to a base reference of commercial pure aluminium. The Al_3Ti intermetallic phase was found as nucleation point. Gas tungsten arc welding showed lower grain refinement potency, and no Al_3Ti phase was found in any weld. Thus, the effect of welding method must be taken into consideration upon development of inoculant containing filler wires.

Effect of process parameters on surface quality and bonding quality of brass cladding copper stranded wire prepared by continuous pouring process for clad

Brass cladding copper stranded wire with an outer diameter of 10 mm and core material of d2.12mm × 7 strand was prepared by solid-liquid composite method with continuous pouring process for clad. Compared with the cladding welding method which requires multiple drawings to make the composite welding wire achieve metallurgical bonding, it saves a lot of manpower and material resources and shortens the production cycle. The bonding mechanism of brass and copper was analyzed by experiments, meanwhile, the effects of brass melt temperature and casting speed on the surface quality and interface bonding quality of the composite wire were investigated. The results show that, on the one hand, increasing the melt temperature of brass and reducing the casting speed can inhibit the surface defects of the composite. On the other hand, reducing the temperature of the brass melt and increasing the casting speed can inhibit the excessive element diffusion at the bonding interface, thereby reducing the degree of surface erosion of the copper strand. The final reasonable process parameters are as follows: the brass melt temperature is 970 °C–990 °C, the traction speed is 40 mm/min∼80 mm/min, and the cooling water volume of the crystallizer is 450L/h. The prepared brass cladding copper stranded wire has good quality, Vickers hardness is between 80 - 85HV, and tensile strength is between 265 - 297 MPa. Elongation after fracture is 40.3%∼43.9%, conductivity is 53.8–62.1% IACS.

Water-augmented vaporizing foil actuator welding: Process performance and mechanisms clarifications

This paper proposes a novel impact welding method named water-augmented vaporizing foil actuator welding, in which liquid water is introduced to alter the foil’s vaporization process, thus altering the induced driving pressure and the final welding performance. A series of comparative experiments were performed to confirm the effectiveness of the process and to understand the underlying mechanism. The proposed process decreased the lower-bound required discharge energy by 58–69%, increased the peel strength by 30–60%, and significantly reduced the variability in the critical standoff distance at the lower bound of the weld window. In addition, the proposed process resolved the robustness issue by producing a much more regular and repeatable shape of the weld area compared to conventional VFAW. Furthermore, three potential mechanisms have been proposed to explain the process improvement: the added water 1) increased the electrical energy deposition, 2) introduced additional energy from the aluminum-water chemical reaction, and 3) provided a more efficient force-transfer medium. In summary, this paper introduces a novel impact welding method with much improved process capability and robustness compared to conventional vaporizing foil actuator welding. In addition, due to its simplicity, this method may be easily extended for other forms of impulse metalworking, which may stimulate a wide interest for the community of high velocity metalworking.

A novel welding method for extra-thick high-strength steel: Double-sided narrow gap oscillating laser and oscillating laser-TIG hybrid welding

A novel welding method for extra-thick high-strength steel: Double-sided narrow gap oscillating laser and oscillating laser-TIG hybrid welding

THERMAL ANALYSIS OF STEEL PIPE

This study is based on the general heat transfer between two pipe joints. Three sample tubes are used in this study. A different connection method is treated Arc welding method is used to connect pipes. Two identical pipe sections are joined together. In this study, the thermal conditions of heat transfer between the pipes are determined using Ansys software. Key Words: Welding, Pipe, Heat Transfer, Temperature...

Study of the Effect GMAW and SMAW Welding Combination with WAAM Method

The development of technology and science is multiplying, so it affects the industrial sector in Indonesia, namely the industry that manufactures machine elements, especially in the automotive sector, which commonly uses metal as raw material. The manufacturing sector's production in the automotive industry tends to increase annually. The need for metal as raw material is constantly increasing. The WAAM welding method be utilized as one of the innovations in the industrial world that potentially reduces the use of raw metal materials by replacing them with the results of the WAAM process. In this study, a combination of GMAW and SMAW welding using the WAAM method was carried out by adding material in layers and switching between the two types of welding. The welding process is carried out by varying the current (high, medium, and low). Then, a tensile test was carried out to determine the mechanical properties of the combination results. Based on the tensile test results, it is known that the high current variation gives the best results, the increasing current lead to an enhancement of the mechanical properties. Finally, using high currents will give the best result for application in the engineering and automotive sector.

Multifunctional heating film as susceptor for induction-welded single-lap carbon fiber reinforced polyetherketoneketone thermoplastic composite joints: Thermal and mechanical behavior

In this study, a novel multifunctional film known as susceptor, containing silver nanoparticles, was proposed to improve the induction welding performance of unidirectional carbon fiber-reinforced polyetherketoneketone (CF/PEKK) thermoplastic composites. A group of Ag/PEKK films was synthesized with different amounts of silver nanoparticles. Good thermal performance was obtained, including the maximum temperature and thermal growth time constant, leading to the selection of films with 60 wt.% and 70 wt.% silver nanoparticles. In addition, the mechanical performance was evaluated for single-lap joints fabricated with the selected films and stainless-steel mesh. Specifically, the highest interlaminar shear strength and single-lap shear strength of 25.2 MPa and 20.9 MPa, respectively, were achieved with a susceptor containing 60 wt.% silver nanoparticles. The mechanism of these increases in thermal and mechanical performance is discussed using numerical and experimental methods (non-destructive test and optical microscope observation). In conclusion, the multifunctional heating film incorporated into the adhesive can improve the thermal and mechanical efficiency of single-lap joints of thermoplastic composites fabricated using the induction welding method.

Mechanical Properties of Welded by Friction Stir Welding Aluminium Alloy AA 5754

Friction stir welding is one of the most original methods for welding devised in recent years. As this welding method possesses advantages compared to conventional fusing welding methods, scientific research on its features and improvement is increasing. The advances in the knowledge of the process of friction stir welding allow its increasing application in different areas, such as aircraft and automotive industries, railway transport, nuclear industries etc. During friction stir welding the joined parts are in a solid state. This welding method is mainly used for joining aluminium and its alloys.The stirring and mixing of the material and the temperature during friction stir welding are the main factors that determine the possibility of obtaining weldments with precise mechanical properties.The present study aims to research the influence of the pin`s configuration on different quality aspects of the weldments at chosen parameters of the welding mode. To achieve this, pins with different geometry and coatings were used. Results that demonstrate the influence of the pin`s geometry and the process parameters on the temperature, structure, and mechanical properties of joined by friction stir welding weldments of aluminium alloy AA 5754 4 mm thick are presented. The influence of the pin`s geometry on defect formation during welding was determined.

Pengaruh Variasi Kecepatan Putar Dan Jarak Penekanan Terhadap Kekuatan Impak Pada Sambungan Baja AISI 4140 Dan AISI 4340 Dengan Metode Pengelasan Gesek (Friction Welding)

Welding is one of the means to achieve better economic production and has a role in the construction and metal fields. Friction welding is one of several types of welding methods. The parameters that affect the strength of the joints in friction welding are rotational speed, pressing distance and friction time. Therefore, to produce connection strength in a production, appropriate parameters are needed. This study aims to determine the effect of variations in rotational speed and pressing distance on impact strength in AISI 4140 and AISI 4340 steel joints. mm. In this study, the results obtained were that the higher the rpm rotation and the greater the pressure distance given, the melting area in the welding joint area is wide and evenly distributed which makes the weld joint strong. This is proven, using a rotational speed of 1400 rpm and a pressing distance of 4 mm has the highest impact energy yield value of 138.349 Joules and the highest impact price yield value of 1.7293 Joules/mm2 . Meanwhile, the lowest value of the impact energy yield is 14.266 Joules and the lowest value of the impact price is 0.1783 Joules/mm2 using a rotational speed of 720 rpm and a pressing distance of 2 mm.

Energy absorption and toughness analysis on FSW butt joint of AA 5052 and AA 5083

Friction Stir Welding (FSW) is an efficient and effective welding method with good-quality welds. Aluminum Alloy (AA) has been widely used for various automotive needs, including in vehicle manufacturing. AA series 5XXX is a type of material used for vehicle manufacturing because it has good strength properties even after the joining process. A similar butt joint using the FSW method was carried out on material AA 5052 and AA 5083. The results of the welding were then given radiographic testing to determine the general condition of the welds. The impact test was carried out according to the procedures standard of ASTM on the welding results to analyze the energy absorption and toughness properties of welds by getting the impact value of the welded joint, and then looking for the quantity ratio to the impact value of the base material. After that, the results and discussion were obtained that the welded areas showed different impact strength and absorbed energy value, which is compared to the base material the range is below with a decrease in value of between 34% and 68% of the initial toughness strength of the parent material. The reduction in toughness strength can be attributed to the influence of mechanical properties during the welding process. Nevertheless, the welds demonstrated good quality and integrity, highlighting FSW's efficacy in joining aluminum alloys. This research significantly contributes to comprehending the energy absorption and toughness analysis of FSW butt joints in aluminum alloys, crucial for vehicle body technology applications.

Fenomena Las Gesek (Friction Welding) Dengan Variasi Waktu Gesek Pada Material AISI 1040 Dengan Kuningan

Friction welding is one of the metal joining methods, by utilizing the heat generated from the physical contact of two metals in the form of friction that occurs continuously on the two metals to produce a welding joint. This research aims to find out what phenomena occur in the connection between AISI 1040 and Brass. The materials used are AISI 1040 solid cylinder with a diameter of 16 mm and brass solid cylinder with a diameter of 16 mm. This research uses experimental method. The friction time used is 6 minutes, 7 minutes, and 8 minutes with a variation of pressing distance of 3 mm, 4 mm, 5 mm with a rotating speed of 1000 rpm. The free heat process of 200 ℃ was carried out on AISI 1040 before the welding process. From the time variation and pressing distance variation that has been carried out in this study, the results obtained from the two materials do not occur. There are several phenomena seen after the welding process such as the occurrence of plastic deformation in brass and the formation of a brass thermoplastic layer attached to the surface of AISI 1040, in the time variation of 6 minutes and 7 minutes the brass thermoplastic attached to AISI 1040 is small and thin, while in the time variation of 8 minutes the brass thermoplastic layer attached to AISI is quite a lot and thick but no connection has occurred. This friction welding method is likely to connect the AISI 1040 material with brass by increasing the friction time performed.

A Review on Hardfacing, Process Variables, Challenges, and Future Works

Hardfacing is an efficient and economical surfacing technique widely used by heavy industries to remediate worn components in service or to enhance the component’s wear characteristics components prior to use. Efficient hardfacing for any targeted application requires precise consideration and understanding of the deposition process, consumables, and substrates. It is also essential to understand the process variables and issues that can occur during the deposition processes, such as dilution and defects in the deposit, including residual stress-induced cracking. Significant research has been published over many years on several aspects of hardfacing, primarily focusing on abrasive wear, corrosion, and impact characterisation using different welding methods and alloy compositions. This paper primarily focuses on reviewing the prior hardfacing literature to systematically summarise the considerations and selection criteria for hardfacing processes and materials. It also presents a discussion on key process variables, such as welding parameters and number of surfacing layers, highlighting their influences during the hardfacing deposition procedure. This paper further discusses issues and challenges in hardfacing practices, such as dilution and cracking. One significant issue investigated is the thermal damage to high-strength steel substrates, with the measurement and characterisation of the damage being key elements. The focus of this investigation is to discuss the optimisation of hardfacing high-strength steel substrates and to communicate potential research areas and prospective applications in the hardfacing industry.

Electron beam welding of dissimilar Titanium to aluminium: Interface microstructure and mechanical properties

Welding of dissimilar metals, titanium–aluminium having wide differences in mechanical and thermal properties was highly challenging. In the present investigation, the electron beam welding method was used to join titanium alloy with pure aluminium. The results show that at the optimum parameter levels such as beam current of 6 mA, welding speed of 8 mm/s, and beam offset of 70:30 (Ti:Al) toward titanium, a defect-free joint with the higher mechanical strength of 120 MPa was achieved compared to the other combination of parameters. The percentage contribution of significant parameters was welding speed of 62%, and beam current of 25%. The scanning electron microscope was used to study the Ti–Al interface microstructure in detail. A significant increase in the micro-hardness in the weld zone was due to a change in titanium microstructure from equiaxed α-phase to acicular α and the formation of Ti-Al intermetallics in the fusion zone. X-ray diffraction analysis was used to analyze the phases present in the fusion zone. It was confirmed that there were mainly Al-Ti compounds like Al2Ti, Al3Ti, AlTi, AlTi2, Al11Ti5. These phases are harmful and contributed to higher hardness and brittleness in the fusion zone. At optimum conditions, a defect-free joint without intermetallics was obtained without an increase in hardness in the fusion zone.

Effects of different profiled pins used in friction stir welding of Al 6061 T6

Abstract In this study, Al 6061 T6 alloy was joined by friction stir welding method with the same parameters using with different profiled pins. As a result of the experiments carried out, the samples were subjected to metallographic examination, hardness measurements, tensile test and bending test. As a result of the examinations carried out, changes in welding performances were determined with the change of pin profiles. As a result of these changes, it was determined that the pin profile suitable for the applied welding parameters was pyramid. It has been concluded that in the use of triangular profile pins, the welding parameters in question should be higher, and the most important reason for this is that the stir zone is larger.