Shielded Metal Arc Welding Research Articles

Analysis of Shielded Metal Arc Welding (SMAW) with Current Variations Against Tensile Strength, Bending Strength, and Microstructure of API 5L X52

Analysis of Shielded Metal Arc Welding (SMAW) with Current Variations Against Tensile Strength, Bending Strength, and Microstructure of API 5L X52

Demonstration of proton acceleration using laser-driven EMP field in dispersion-free slow wave tube

We demonstrate the laser-driven post-acceleration experiment, utilizing a miniature slow-wave structure. Experiments on a terawatt laser system showed a significant increase in proton cutoff energy, highlighting the technique's potential, especially for high-power laser systems. The slow-wave structure consists of a helix and a shielded metallic shell covered on the outside. The transmission properties of electromagnetic pulses (EMPs) generated by laser–foil interactions along the structure are studied. Through an electromagnetic field perspective, we derived dispersion relations for helices with and without metallic shield. Our findings, supported by theory, simulations, and experiments, demonstrate the structure's ability to transmit high-frequency EMPs with limited dispersion.

Development of Lead-Free Materials for Radiation Shielding in Medical Settings: A Review.

Radiation protection is an essential issue in diagnostic radiology to ensure the safety of patients, healthcare professionals, and the general public. Lead has traditionally been used as a shielding material due to its high atomic number, high density, and effectiveness in attenuating radiation. However, some concerns related to the long-term health effects of toxicity, environmental disease as well as heavy weight of lead have led to the search for alternative lead-free shielding materials. Leadfree multilayered polymer composites and non-lead nano-composite shields have been suggested as effective shielding materials to replace conventional lead-based and single metal shields. Using several elements with high density and atomic number, such as bismuth, barium, gadolinium, and tungsten, offer significant enhancements in the shielding ability of composites. This review focuses on the development and use of lead-free materials for radiation shielding in medical settings. It discusses the drawbacks of traditional lead shielding, such as toxicity, weight, and recycling challenges, and highlights the benefits of lead-free alternatives.

Combined Gas Tungsten Arc Welding and Shielded Metal Arc Welding Processes for Joining Tube to Tubesheet in Shell and Tube Heat Exchangers

Abstract Flawless tube and tubesheet joints are necessary for shell and tube heat exchanger with high leakproof ability and durability. The consequence of mixing of transfer fluids due to the defective welded or expanded tube-to-tubesheet joint results in complete malfunctioning of the heat exchange process. In this case, there is a high demand for quality assessment of the fabricated tube-to-tubesheet joints (TTS) based on the international standards. Additionally, the literature on assessing the mechanical and metallurgical characteristics of tube-to-tubesheet joints using any one welding technique is available; however, articles dealing with the use of multiple welding techniques are scanty. In the current work, the quality assessment of strength welded and light expanded (3%) tube-to-tubesheet joints followed by light expansion was performed whereas for welding, combined gas tungsten arc welding (GTAW) and shielded metal arc welding (SMAW) as root pass and cap pass were adopted in the fabrication stage. Quality and sound tube-to-tubesheet joints were produced using welding and tube expansion process. Linear and circular indications representing the cracks were absent on the developer in the liquid penetration test. The minimum leak path (MLP) was greater than the two-third of tube wall thickness. The results strongly qualify the use of combined gas tungsten inert gas and shielded metal arc welding process for manufacturing of tube-to-tubesheet joints. The methodology and results in the current article are beneficial for researchers and industrialists working close to shell and tube heat exchangers and boilers.

Estimation Of Welding Wire Requirements (Electrode) For Installation Of 300 Feet Barge Sideboard Assembly

Installation of the sideboard assemblies on a 300 feet barge requires an estimate of the need for welding wire, besides that an estimate of the need for oxygen and LPG gas is also required for the work of cutting the old sideboard. This is so that the repair work does not experience errors in estimating the amount of consumables used so as not to result in losses for the shipyard company. The objectives obtained during the research were to determine the need for welding wire in the welding process of the 300 feet barge sideboard. The design of this study uses a quantitative approach and there are several variables used including independent variables such as the thickness of the material, the length of the welding, and cutting areas. Dependent variables such as the number of electrodes, oxygen, and LPG gas used. Control variables such as the SMAW welding process using AWS A5.1 E6013 electrodes and cutting using an oxygen and LPG gas cutting blender. The data collection techniques in this study were literature study, observation, and interviews. Based on the calculation, the total need for welding wire for the installation of the 300 feet sideboard assembly is 95.87 kg total oxygen requirement of 241.51 kg and LPG gas of 177.35 kg for cutting the old sideboard.

Numerical Investigation of Steel Section Remaining Tensile Capacity During SMAW Welding

Numerical Investigation of Steel Section Remaining Tensile Capacity During SMAW Welding

NUMERICAL ANALYSIS OF STEEL MEMBER REMAINING COMPRESSIVE CAPACITY DURING SMAW WELDING

This study investigates the influence of Shielded Metal Arc Welding (SMAW) welding parameters on the remaining compressive capacity of angle-shaped steel members used for structural strengthening. The analysis focuses on members with thin hot-rolled profiles (40.4 x 40.4 x 4.0 mm, 50.5 x 50.5 x 5.0 mm, and 60.6 x 60.6 x 6.0 mm). A finite element model simulates the heat distribution caused by welding, leading to a temperature increase within the member. Welding scenarios are simulated using various combinations of current strength and welding speed based on the specifications for electrode type E6013. The remaining compressive capacity is determined by segmenting the cross-section based on temperature intervals and considering the member's slenderness. The analysis reveals a clear correlation between welding parameters and compressive capacity loss. Employing a higher current and lower welding speed leads to a more significant reduction in capacity due to the resulting extensive heat-affected zone (HAZ). Conversely, the lowest current and highest speed scenario minimizes the HAZ, resulting in the highest remaining compressive capacity. The analysis demonstrates that the 40.4 x 40.4 x 4.0 mm member can retain up to 51.15% of its original capacity under these optimal conditions, while the 50.5 x 50.5 x 5.0 mm and 60.6 x 60.6 x 6.0 mm members can retain 57.79% and 75.78%, respectively. In contrast, the worst-case scenario employing high current and low speed significantly reduces the remaining capacity, with reductions down to 6.79%, 10.87%, and 10.54% for the respective member sizes. These findings highlight the importance of optimizing welding parameters to minimize the negative impact on the compressive capacity of steel members during strengthening operations.

Investigations on Transient Temperature Distribution and Distortion in Shielded Metal Arc Welding of SA 516 Gr. 70 Steel

Efforts are made in this article to investigate the thermal and mechanical phenomena by presenting a coupled thermal and structural analysis of SA516 Grade-70 steel. This material has wide applicability in the fabrication of pressure vessels, boilers, etc., due to its excellent weldability and formability. An actual ongoing problem from a reputed industry, related to distortion during the shielded metal arc welding process, is considered and experiments are carried out on the chosen steel. Results are evaluated employing a two- step methodology, involving simulation. The first step encompasses thermal analysis, providing insights into transient temperature distribution, while the subsequent mechanical analysis offers data on residual stresses and distortion. In the case of heat input, a volumetric heat source with double ellipsoidal heat distribution is used whereas a plasticity material model with rate-independent bilinear kinematic hardening is adopted for the structural analysis. Additionally, temperature-dependent material properties are factored into both scenarios. The data derived from numerical analysis align closely with experimental findings, presenting valuable insights for fabricating industries.

Wide-range, durable, and adaptable miniature pressure sensor based on planar capacitance

Capacitive pressure sensor (CPS) is widely used in the field of industrial equipment, because of the merits of fast dynamic response and high resolution. However, the traditional laminated CPS makes it difficult to achieve a wide detection limit in a small size, and this structure is susceptible to electromagnetic interference. Here we developed a miniature planar capacitive pressure sensor (MPCPS) with high performance, which can realize the response to external touching stimuli through the deformation of the packaging material and the change of the equivalent resistance. A metal shielding layer was added under the insulating substrate to effectively isolate the external interference. The thickness of the sensor is about 200 μm, and the diameter of the core sensing area is less than 1 mm. Two types of electrodes with different shapes were designed, among which the spiral electrode MPCPS (S-MPCPS) has better performance than the linear electrode MPCPS. The S-MPCPS has a sensitivity of 99.2% MPa−1 in the low-pressure range (0–0.1 MPa), fast response (20 ms), wide detection limit (>1 MPa), and high durability (>2000 cycles). In addition, MPCPS is proven to have good resistance to high temperature and oil contamination. Finally, practical applications such as contact pressure measuring on the meshing surface of spur gears and mechanical gripper clamping force monitoring were successfully demonstrated. These results shed light on the potential application of the MPCPS in the pressure detection of industrial equipment.

Experimental and Numerical Investigation on Ballistic Performance of Ultra High Hard Armour Steel Joints Welded Using Shielded Metal Arc Welding Process and Austenitic Stainless Steel Electrode

Experimental and Numerical Investigation on Ballistic Performance of Ultra High Hard Armour Steel Joints Welded Using Shielded Metal Arc Welding Process and Austenitic Stainless Steel Electrode

Corrosion behavior of austenitic stainless steel and nickel-based welded joints in underwater wet welding

Marine structures such as ports, bridges, pipelines, vessels, and platforms are an essential part of modern infrastructure, where the use of higher-strength steel provides savings in logistics and construction. However, the repair of higher-strength steels can be challenging, especially underwater. Wet shielded metal arc welding is the most widely used and least expensive method for underwater welding repairs, but is very susceptible to hydrogen-induced cracking. Thus, researchers and welding engineers aim to reduce the amount of hydrogen in the weld material. Recent success has been achieved through the use of austenitic welding consumables, such as austenitic stainless steel and nickel-based electrodes. The use of these consumables drastically reduces the amount of diffusible hydrogen in the weld metal. However, these austenitic materials usually have different corrosion potential as compared to the structural steel the weld beads are applied to. This creates the risk of severe galvanic corrosion. In the presented study, the corrosion behavior of welds created with austenitic stainless steel and nickel-based electrodes were studied. Samples were aged for 1.5 years in the Baltic Sea. Simultaneously, the effectiveness of corrosion protection systems such as coating and Impressed Current Cathodic Protection (ICCP) were evaluated. Localized corrosion occurred in the heat-affected zone when austenitic electrodes were used in the corrosive environment. The localized corrosion depth after 1.5 years in the Baltic Sea and in the salt spray layer was approximately 250 µm and 390 µm, respectively. The ICCP system and the use of a coating were effective in preventing localized corrosion. The low pitting corrosion density of 2.5 × 103 m−2 corresponds to grade A1 according to the standard and was found to be negligible as compared to the localized corrosion in the heat-affect zone.

Element transfer, microhardness and metallurgical analysis of weld-bead using CaF2−CaO−Al2O3−BaO fluxes

This study investigates the influence of shielded metal arc welding electrode coating flux on microhardness, microstructure and element transfer. A series of multi-pass bead-on-plate studies were conducted using laboratory-developed electrodes. The flux composition has shown a significant effect on all the responses. An increase in [Formula: see text] and [Formula: see text] has shown a positive influence on nickel transfer, whereas an increase in [Formula: see text] reduces nickel transfer. The slag detachability was found good for ratio [Formula: see text]:: 1.76:0.73:0.51. Energy dispersive spectroscopy has shown inclusions rich in aluminum and oxygen with trace amounts of Ca, Mn, Ti and Si. Artificial neural network models have been developed and then compared to conventional regression predictions.

EVALUATION OF WELDED JOINT (SMAW) AFTER POST WELD HEAT TREATMENT (PWHT)

Joining of two materials having similar physical, chemical, and thermal properties and to make the joint tough and stiff, special attention and investigation are required. In this research, the welding joint between two mild steel (MS) of IS 2062 grade E, was accomplished by using shielded metal arc welding (SMAW). To investigate the effect of electrode in the welding joint, MS electrode was exercised. For post-weld heat treatment (PWHT), temperature of 700 °C were investigated over the welded specimen. To explore the optimum welding process and PWHT process for this joint, both tensile and bending tests were carried out. Destructive tests have suggested that PWHT at 700 °C is better for the SMAW process with MS electrode. As the smallest hardness values were observed in the heat-affected zone (HAZ) which makes the sample susceptible to failure. The hardness values have decreased after PWHT which justified the achievement of higher ductility after heat treatment.

An appropriate approach and computational studies for evaluating metal shielding features using diazenyl naphthalen analogues as sustainable corrosion inhibitors

An appropriate approach and computational studies for evaluating metal shielding features using diazenyl naphthalen analogues as sustainable corrosion inhibitors

Physical survey on the health hazards of welding activities on welding operators in Uyo, Nigeria

Background: Welding operators are subjected to several forms of hazards during welding activities. Aim: The study aimed to identify the common practices in welding operations, assess the potential health hazards associated with these practices, and propose recommendations for improving the well-being of welding operators. Methodology: The survey was conducted at different welding workshops in Uyo, Akwa Ibom State, Nigeria. A total of 100 welding operators were observed and interviewed to gather data on their working practices and the health effects they experienced. Results: The findings revealed that the most common welding practices included manual metal arc welding, gas metal arc welding, and gas tungsten arc welding. These practices involved exposure to various hazards such as fumes, gases, noise, and ultraviolet radiation. The survey also found that a significant number of welding operators reported experiencing health issues such as respiratory problems, skin irritation, eye injuries, and hearing loss. These health effects were attributed to the lack of proper ventilation, inadequate personal protective equipment, and poor ergonomic practices in the welding workshops. Conclusion: The findings of this study highlights the importance of addressing the health hazards associated with welding operations to ensure a safer and healthier work environment for improved work conditions and well-being of welding operators. In light of the findings, several recommendations including the implementation of proper ventilation systems, provision of adequate personal protective equipment, regular health screening for welding operators, and training programs on safe welding practices is proposed in order to improve the well-being of welding operators

ANALYSIS OF THE MICROSTRUCTURE AND MECHANICALPROPERTIES OF DUPLEX STEEL JOINTS

The article presents a study, the aim of which was to analyze the microstructure and mechanical propertiesof welded joints of austenitic-ferritic duplex steel X2CrMnNiN21-5-1. This steel is characterized by goodresistance to various types of corrosion, good strength properties and good weldability. Due to all theseadvantages, it is used in many industry sectors, and the main joining techniques are welding technologies. Inthis study, two joining techniques were used, SMAW (Shielded Metal Arc Welding) and GTA (Gas TungstenArc). The obtained welded joints were subjected to: macroscopic and microscopic metallographic tests,mechanical tests (static bending test and microhardness measurements), diffraction tests, and wear resistancetests. The results showed that the microhardness of the welds is similar and does not depend on the weldingmethod used. In the microstructure of the analyzed joints there are two phases: austenite (γ) and ferrite (δ),with different morphologies depending on the welding conditions, which affect the phase transformations.Material wear within the weld is greater than in the base material.

EFFECT OF ELECTRODE ON JOINING TWO DISSIMILAR METALS (SS & MS

This study examines the challenges associated with joining dissimilar metals, specifically stainless steel and mild steel, and investigates the impact of electrode selection on joint quality and characteristics. Various welding processes, including shielded metal arc welding (SMAW), is explored. Experimental findings indicate that electrode choice significantly influences the formation of intermetallic compounds, fusion zone morphology, and mechanical strength of the joint. Alloying elements in electrodes are found to enhance weldability and performance by facilitating metallurgical bonding and reducing the formation of brittle phases. Furthermore, the study explores variations in welding parameters to optimize the process for desirable joint properties. By deepening our understanding of electrode roles in welding dissimilar metals, this research offers insights crucial for selecting appropriate techniques and parameters, ensuring reliable joints. These insights have broad applicability across industries such as automotive, aerospace, construction, and manufacturing, where dissimilar metal joining is common. Key Words: dissimilar metals, intermetallic compounds, Weldability, morphology, mechanical strength.

Comparison of SMAW and GTAW Welding Properties

Low carbon steel is a type of welding with good formability, machinability, hardenability, and weldability. It can be welded without preheating or postheating processes. Notch strength and sensitivity to weld cracking are the factors that influence the weldability of low carbon steel. SMAW and GTAW welding techniques were applied in this study. In addition to its mechanical properties, parameters and the type of welding process also affected the corrosion of the welded joint. Local corrosion attacks were easier to occur on one than the other welded joint due to significant differences in chemical composition and microstructure. Welded joints in a chlorine-rich environment have a high corrosion rate. In comparison to base metal, low-weld metal triggers high corrosion.

Microstructure, mechanical properties and sensitization of ultra-low nickel Cr–Mn austenitic stainless steels

The present study deals with the effect of shielded metal arc welding (SMAW) and gas metal arc welding (GMAW) processes with different welding speeds on microstructural and mechanical properties including intergranular corrosion susceptibility of ultra-low nickel chrome-manganese austenitic stainless steel (ASS). The microstructural analysis was performed by an optical microscope. The Fisher Ferritscope was used for determining ferrite content in the weldment. The microstructural analysis shows that the size of dendrites of δ ferrite and the width of heat affected zone (HAZ) decreases when welding speed increases. It was found more δ-ferrite in SMAW weld compared to GMAW weld. It was also found that when welding speed increases, tensile strength, impact strength and hardness values decrease for both welding processes. From the U-bending test, it was found that the welded joints are strong enough to withstand bend at 1800 without any cracks for both welding processes. It was also found that Cr-Mn ASS weld becomes susceptible to intergranular corrosion on welding. For both welding processes, the degree of sensitization value decreases with an increase in welding speed for both the welding processes as evaluated by the double loop electrochemical potentiodynamic reactivation (DLEPR) test. Also, the weld joint made using the GMAW process is more susceptible to intergranular corrosion than that made using the SMAW process.

A comparison of different experimental approaches in the determination of dynamic fracture toughness (J1d) behavior for RHA steel cost sustainable MMAW weldments

In the present investigation, the low hydrogen ferrite consumable weldment (weldment-1) and austenitic stainless steel consumable weldment (weldment-2) of rolled and homogenous armor steel (RHA) have been prepared with manual metal arc welding (MMAW). Further, the influence of weldments (weldment-1 and weldment-2) microstructure on the dynamic fracture toughness (J1d), strength, ductility and hardness has been evaluated and compared. The three different approaches have been utilized to estimate J1d for RHA weldments. Further, all three approaches’ outcomes have been compared with the elastic-plastic fracture mechanics (EPFM) approach through Jp-R curve. The results revealed that weldment-1 (yield strength 504.24 MPa and ultimate tensile strength 763.03 MPa) exhibited 26.93 and 25.07% more yield and tensile strength respectively than weldment-2 (yield strength 384.55 MPa and ultimate tensile strength 593.05 MPa). Further, the elongation of weldment-2 (elongation 42%) is 26.72% more than weldment-1 (elongation 32.10%). The joint efficiency and fusion zone hardness of weldment-1 are 5.85 and 57.56%, respectively more than weldment-2. The EPFM approach has good agreement with the correction factor approach (approach 2) and the compliance change rate approach (approach 3) with less than 7% difference in the estimation of dynamic fracture toughness of base metal and weldments (weldment-1 and weldment-2). Further, the percentage difference between maximum load point approach (approach 1) and the EPFM approach is more than 15% difference. The fractographic investigation confirms the ductile fracture in all under-investigated materials.