Manual Welding Research Articles

Effect of Orbital Welding Parameters on the Weld Geometry

In orbital welding technology, it is difficult and time-consuming to make a standard weld by manual welding. This requires a skilled weld. Therefore, a more optimal welding method than automatic rotary welding has been created to replace the conventional manual welding method. This significantly improves weld quality and reduces welding time. In this explanation, we have experimented with an automatic orbital welding device that integrates a filler wire-feeder device into the welding process. We refer to the American National Standard AWS D18.1/D18.1M: 2009 documents to review the weld results. We then analyze the advantages and disadvantages of the weld and propose solutions.

Structure and Properties of the Welded Joints of Rolled Austenitic High-Nitrogen Steel Fabricated by Manual Consumable-Electrode Arc Welding

Structure and Properties of the Welded Joints of Rolled Austenitic High-Nitrogen Steel Fabricated by Manual Consumable-Electrode Arc Welding

Effect of Residual Stress on Hydrogen Diffusion in Thick Butt-Welded High-Strength Steel Plates

Thick high-strength steel plates are increasingly being used for ship structures. Moreover, hydrogen enters the process of manufacturing and service, and large residual tensile stress occurs near the weld. Such stress can facilitate the diffusion and accumulation of hydrogen in the material, leading to hydrogen embrittlement fracture of the shell. Therefore, residual-stress-induced diffusion and accumulation of hydrogen in the stress concentration region of thick butt-welded high-strength steel plate structures need to be studied. In this study, manual metal arc welding was realized by numerical simulation of residual stress in a thick butt-welded high-strength steel plate model using the thermoelastic–plastic theory and a double ellipsoidal heat source model. To analyze residual stress, a set of numerical simulation methods was obtained through comparative analysis of the test results of relevant literature. Residual and hydrostatic stress distributions were determined based on these methods. Then, hydrogen diffusion parameters in each region of the model were obtained through experimental tests. Finally, the results of the residual stress field were used as the predefined field of hydrogen diffusion to conduct a numerical simulation analysis. The distribution of hydrogen diffusion under the influence of residual stress was obtained based on the theory of stress-induced hydrogen diffusion. The weak area of the welding joint was found to be near the weld toe, which exhibited high hydrostatic stress and hydrogen concentration. Further, the maximum hydrogen concentration value of the vertical weld path was approximately 6.1 ppm, and the maximum value of the path parallel to the weld centerline and 31 mm away from the weld centerline was approximately 6.22 ppm. Finally, the hydrostatic tensile stress in the vertical weld path was maximized (~345 MPa), degrading the material properties and causing hydrogen-related cracking. Hence, a reliable method for the analysis of hydrogen diffusion according to residual stress in thick high-strength steel plates was obtained. This work could provide a research basis for controlling and eliminating the adverse effects of hydrogen on the mechanical properties of ship structures and ensuring the safe service of marine equipment.

Statistical Characterization of Stress Concentrations along Butt Joint Weld Seams Using Deep Neural Networks

In order to ensure high weld qualities and structural integrity of engineering structures, it is crucial to detect areas of high stress concentrations along weld seams. Traditional inspection methods rely on visual inspection and manual weld geometry measurements. Recent advances in the field of automated measurement techniques allow virtually unrestricted numbers of inspections by laser measurements of weld profiles; however, in order to compare weld qualities of different welding processes and manufacturers, a deeper understanding of statistical distributions of stress concentrations along weld seams is required. Hence, this study presents an approach to statistically characterize different types of butt joint weld seams. For this purpose, an artificial neural network is created from 945 finite element simulations to determine stress concentration factors at butt joints. Besides higher quality of predictions compared to empirical estimation functions, the new approach can directly be applied to all types welded structures, including arc- and laser-welded butt joints, and coupled with all types of 3D-measurement devices. Furthermore, sheet thickness ranging from 1 mm to 100 mm can be assessed.

Numerical and experimental investigation on distribution of residual stress and the influence of heat treatment in multi-pass dissimilar welded rotor joint of alloy 617/10Cr steel

In the present study, numerical and experimental investigation of stress distribution pattern has been performed for thick walled nuclear rotor pipe joint of Alloy 617 and 10Cr steel. Hot wire Tungsten Inert Gas (HW-TIG) welding process has been adopted for multipass narrow groove welding since it yields better mechanical properties at low heat input than manual TIG welding and decreases the accumulation of residual stress significantly. The residual stress generated at the surface of the welded joint was evaluated experimentally using the Blind hole drilling technique (BHD), and consequently, the distribution of stresses along the thickness of the welded joint was masured using the Deep hole drilling (DHD) method. According to the findings, shrinkage at the HAZ area of the weld influences the stresses generated at the cylinder outer surface. The distribution of residual stresses in the weld region is driven mostly by the bending effect produced during the welding process. The influence of post weld heat treatment (PWHT) on residual stress distribution has also been investigated using both experimental and numerical approaches. Numerical investigations have been performed using ABAQUS finite element method. A 2D finite element model has been developed to simulate the welding process and the subsequent heat treatment, using coupled thermo-mechanical analysis. The residual stress results obtained from the numerical approach were validated with the experimentally obtained results and a good correlation has been found. The lumped pass model along with an equal density heat source has been implemented to minimize the computation complexity without affecting the accuracy of the simulated results. The obtained findings revealed that apart from weld centerline, hoop tensile residual stresses were higher around the buttered layer of Alloy 617 and 10Cr steel in an as-welded state. It has been found that nearly 80% of the stresses generated along the weld section have been released after PWHT.

The effect of flux composition on tensile strength of re-engineered E308H-16 electrode

A stainless steel flux for manual metal arc welding (MMAW) has been developed. The coated electrode is a rutile electrode whose basic components are titanium (IV) oxide and stainless steel powder. Some of the other components were substituted; the more popular but expensive potassium silicate binder was replaced with readily available sodium silicate binder. For the binder to perform effectively, it was enriched with potassium carbonate, which was sourced locally from palm bunch. Cellulose, a good gas former was replaced with starch, which was gotten from cassava. The components were sieved into 75 µm particle size. The experimental design was set up using Central Composite Design in Design Expert software. The design varied the percentage composition of calcium carbonate, binder, titanium (IV) oxide, silicon (IV) oxide, and stainless steel powder. Twenty-six (26) test samples were produced using the central composite design tool of the design expert software and tested for tensile strength. The experimental results were analyzed and optimized using Response Surface Methodology and Validated using the ANOVA tool of the Design Expert software. An optimal composition of 10% CaCO3, 13% Binder, 13% Titanium oxide, 12% silicon (IV) oxide, and 36% stainless steel powder were obtained to give a corresponding 539.7 N/mm2 tensile strength.

A visuo-haptic extended reality–based training system for hands-on manual metal arc welding training

A visuo-haptic extended reality–based training system for hands-on manual metal arc welding training

Determining patterns in the generation of magnetic fields when using different arc welding techniques

This paper reports a study into the levels of magnetic fields induced by arc welding equipment in various ways in order to assess their impact on the body of welders. It is known that welders are exposed to a magnetic field of high intensity. Depending on the welding technique and the type of welding equipment, it may exceed the maximum permissible levels (MPL). Note that new Ukrainian sanitary standards for magnetic fields have been introduced, which regulate their levels depending on the frequency range. Therefore, it became necessary to carry out their hygienic assessment according to the new standards in order to devise appropriate methods for protecting welders. To this end, it was required to choose a new generation of devices to determine the intensity of magnetic fields induced by welding equipment. Based on the analysis of the constructed oscillograms and spectrograms of magnetic fields, it was found that semi-automatic welding with a metal electrode in carbon dioxide is characterized by an increased level of magnetic field in the frequency range of 50‒1000 Hz. With automatic arc welding under the flux, there are no excess of the maximum permissible levels of individual harmonics of the magnetic field but there is an excess of the total value of all harmonic components of the magnetic field. Manual arc welding with direct current involving a non-melting electrode in argon is characterized by a moderate level of magnetic field in workplace. During manual arc welding with coated electrodes, the exceeded level of the magnetic field is observed only on the electrode cable itself. It is shown that the spectral composition of the magnetic field signal is determined mainly by the welding technique itself, the peculiarities of arc combustion, and the nature of the transfer of electrode metal in the arc gap, as well as the initial parameters of the power supplies of the welding arc

Effect of Mechanical Shock Treatment on Microstructure and Corrosion Properties of Manual Argon Arc Welding Joints of 2205 Duplex Stainless Steel.

Pneumatic chipping hammer and ultrasonic impact peening were used to relieve the welding residual stress of 2205 duplex stainless steel by manual argon arc welding, and the influences of these mechanical shock treatment technologies on the residual stress, microstructure, and corro-sion resistance of the welding seam were studied. Results showed that after pneumatic chipping hammer or ultrasonic impact peening, a small amount of plastic deformation occurred in the welded joint of 2205 duplex stainless steel, which led to an increase in the dislocation density in the microstructure. Meanwhile, the stress state of the welded joint changed from the residual tensile stress to the residual compressive stress. The maximum residual compressive stress could reach −579 MPa. The combined action of the two effectively improved the corrosion resistance of the welded joint. Among them, the best overall effect was the ultrasonic impact peening tech-nology.

Development of a simulation model of the manual gas tungsten arc welding process and visualization of the welder’s skill

Development of a simulation model of the manual gas tungsten arc welding process and visualization of the welder’s skill

The Effect of Quenchants on the Mechanical Properties of Scrap Carbon Steel on Welded Joints by Manual Metal Arc Welding Process

The Effect of Quenchants on the Mechanical Properties of Scrap Carbon Steel on Welded Joints by Manual Metal Arc Welding Process

Comparative analysis on occupational hazards of three welding operations

Objective: To explore the occupational hazards caused by three kinds of welding operations, and to provide data support for individual protection. Methods: In October 2020, the welding fumes, metal elements and welding arc generated by three welding operations of argon gas shielded welding (JS80 welding wire) , manual welding (ZS60A welding rod) and carbon dioxide shielded welding (907A flux cored wire) were collected and measured in the welding laboratory. The samples were analyze and compare in the laboratory, and the differences of the occupational hazard factors of the three welding operations were judged. Results: The concentration of welding fume produced by carbon dioxide shielded welding, manual welding (ZS60A electrode) , and argon gas shielded welding (JS80 welding wires) were 6.80 mg/m(3), 6.17 mg/m(3), and 3.13 mg/m(3), respectively. The effective irradiance of the welding arc outside the welding mask from high to low is manual welding (ZS60A electrode) , carbon dioxide shielded welding (907A flux-cored welding wire) , and argon shielded welding (JS80 welding wire) , respectively 1 010.7, 740.9, 589.5 μW/cm(2). The long-wave ultraviolet UVA intensity generated by argon shielded welding (JS80 welding wire) is the largest, which is 1 500 μW/cm(2). The content of Mn in the three welding operations is the highest, and JS80 welding wire has the highest Mn content of 128493.2 mg/kg. 907A flux cored wire has the highest Ti content, which is 24355.5mg/kg. The electrode ZS60A has the highest Cu content, which is 24422.12 mg/kg. Conclusion: The intensity of occupational hazards is different in the three kinds of welding operations, so the methods of personal protective equipment, field exposure assessment and health monitoring should be more targeted.

Realization of Control System of Automatic Welding Machine for Air Conditioning Flange Based on CANopen

The principle of automatic welding machine (AWM) for air conditioning flange is introduced. The architecture of the control system of AWM realizes the multi spindle linkage control. The communication between PLC and servo driver is built based on CANopen protocol, and the communication between PLC and touch screen is set up based on Modbus RTU protocol. To meet the welding machine spindle coordination control requirements, the PLC program is designed by Delta ISPsoft programming software, and simplified by the application of sequential function chart (SFC) and function block. The human machine interaction (HMI) is developed by Xinjie Touchwin. Linear interpolation algorithm (LIA) is used to prevent the welding defects on the air conditioning flange corner thus it improves the welding quality and realizes the straight path of welding torch from the original to starting welding point and from the end welding point to the original simultaneously. The AWM for air conditioning flange can replace the manual welding and has a broad application prospect in many areas.

Technogenic resources of ferrous metallurgy and their complex processing in the conditions of JSC Uzmetkombinat

The article deals with the involvement of accumulated and formed technogenic formations in the form of steel-making slag and dust-like waste from ferrosilicon production into processing, in order to obtain additional valuable components from industrial waste. To isolate them, various methods of hydraulic classifi cation, jigging, enrichment have been investigated, and gravitational enrichment on a concentration table is recognized as the most optimal. The possibilities of using technogenic waste of aspiration dust from the production of ferroalloys – microsilica containing at least 85% amorphous silica in its composition – can be used for the production of sodium silicate binder (liquid glass) by the autoclave method. The resulting material can be used as an import-substituting raw material in the production technology of manual arc welding electrodes.

The effect of corrosion on the hysteresis properties of welded steel

ABSTRACT To study the effect of corrosion on the mechanical properties of welded steel hysteresis, a cyclic load test was performed on corroded welded steel. Accordingly, a generalised hysteretic mechanical model of welded steel with the corrosion degree as a variable was established. Taking a D36 steel plate fabricated via manual arc welding as the research object, specimens were prepared using the accelerated electrochemical corrosion method. Mechanical performance experiments under tension, compression, and multiple cyclic loading systems were conducted on specimens, the hysteretic mechanical properties of welded steel were mostly concerned. On that base, a generalised hysteretic material model for welded-corroded steel which consists of a skeleton curve, an unloading curve and a reloading curve is proposed. All the parameters used to describe these curves are related to the degree of corrosion, determined by the regression on the test data. The accuracy and effectiveness of the model were verified experimentally.

Catastrophic Impact Loading Resilience of Welded Joints of High Strength Steel of Refineries' Piping Systems.

Refineries piping installation systems are designed, fabricated, and operated to assure very high levels of quality and structural integrity, to provide very high resilience to catastrophic events like earthquakes, explosions, or fires, which could induce catastrophic damage of piping systems due to collapse of nearby structures as towers, bridges, poles, walkways, vessels, etc. To evaluate the catastrophic impact loading resilience to failure of MMA (Manual Metal Arc Welding), GMA (Gas Metal Arc Welding), SSA (Self-shielded Arc Welding), and LASER+GMA of modern API 5L X80 pipes butt welded joints used for piping installation systems of refineries, the new, original technique of the quantitative and qualitative evaluation of impact loading resilience of butt welded joints of pipes was developed. The high-quality butt welded joints were impact loaded by the freely dropping 3000 kg mass hammer of the die forging hammer apparatus. The impact loading energy needed to exceed the yield strength of the extreme zone of welded joints and to induce catastrophic fracture of butt welded joints of API 5L X80 pipes was calculated using FEM (Finite Element Method) modeling of the impact loading process of tested butt welded joints of pipes. Results of the FEM modeling of impact loading technique of butt welded joints of piping systems indicate that it is a useful tool to provide valuable data for experimental impact loading tests of welded joints of pipes, decreasing the time and cost of the experiments. The developed impact loading technique of butt welded joints of pipes to simulate the catastrophic events in refinery piping systems and evaluate the resilience of the butt welded joints of pipes to catastrophic failure proved to be very efficient and accurate. Experiments of impact loading indicated that all specimens of butt welded joints API 5L X80 steel pipes are resilient to failure (cracks) in the extreme stressed/strained areas, above yield and tensile strength of the weld metals, no cracks or tears appeared in the extreme stressed/strained areas of the edges of the pipes, proving the very high quality of API 5L X80 steel pipes.

Control of Welding Speed and Current in Machine–Human Cooperative Welding Processes

In intelligent manufacturing processes, the dependence of the weld quality on the welder’s skills in manual welding should be minimized. To better control the welding quality, a machine–human cooperative control system was designed in this study, and a skills learning experiment was conducted to correlate the relationship between welding speed and welding current. The obtained skills were then transferred to the control system to control the human welder to achieve the desired welding speed. In addition, to adjust the welding current to control the welding power, the desired full penetration welds were finally obtained. In the present study, full penetration welds with different welding speeds were obtained in a 304 stainless steel pipe having a wall thickness of 2.03 mm and an outside diameter of 113.5 mm using the machine–human cooperative welding process. The back fusion width was 2.3 to 5.5 mm, which met the quality requirements of the weld. This study provides a research direction for effectively solving the problem of the shortage of welders and for helping unskilled welders to produce quality welds, and lays the foundation for developing the next generation of machine–human cooperative intelligent welding system.

An interactive extended reality-based tutorial system for fundamental manual metal arc welding training

An interactive extended reality-based tutorial system for fundamental manual metal arc welding training

Identification of defective weld and quality monitoring in manual metal arc welding process using surface level image features

The current research work is the demonstration of the development of a monitoring methodology for the identification of defective weld using surface-level features. A novel grey level-based indicator has been proposed in this research work that has the potential to identify defective welds. The proposed methodology has been validated with a well-established 2D wavelet transform framework to prove the capacity of the proposed methodology. In comparison to the wavelet transform the proposed methodology has been found to be more successful and computationally efficient with less a priori knowledge and limited pre-processing steps making it more effective. In this framework extracted image features along with the process parameters are used as the input to the support vector machine-based regression model for the prediction of the ultimate tensile strength of the welds. It is observed that the model yields an average absolute percentage error of 2.83% compared to the model developed only with process parameters that yield an error of 5.09%. The improvement in the prediction capability of the model leads to the impression that the proposed methodology is effective. The methodology can be used in human free automation system for monitoring of manual metal arc welding process.

Gas tungsten arc process optimization and assessment for robotized position welding of austenitic stainless steel edge joints

Gas tungsten arc welding (GTAW) is a common joining method for austenitic stainless steel sheets. Edge joint is frequently used configuration when the aim is to produce weldments e.g., between the tube sheets and the tubes and to other hollow structures needing tight sealing welds and sound joints. In those applications all positions for welding is usually needed. Robotized welding is utilized, when manual welding is not possible, e.g., in maintenance for nuclear power applications. In automatic welding a strict control of location of arc and welding parameters are extremely important. In this work the aim was to find suitable welding parameters, as pulse parameters, welding speed and shielding gas composition and study their effects on weld joint penetration and weld quality in different welding positions. In addition, the inaccuracy in the alignment of the arc and its effects was tested in different cases. It was found that it was possible to find the optimal parameters in different positions, flat (PA), overhead (PE), and vertical-up position (PF). However, the vertical-down position (PG) was giving a lower joint penetration in the cases which allow sound welds. Therefore, it was considered that the fabrication of the circumferential joint was best done in two steps to avoid the PG position, which ensures that a sound weld with the set 2.6 mm penetration requirement is achieved over the entire circumference. The use of a shielding gas mixture containing argon and 2% hydrogen showed significant advantages over the other three shielding gas compositions tested, which was observed as deeper penetration of the welds.