Shielded Metal Arc Welding Research Articles

Modeling of physicochemical and thermophysical characteristics of SrO-CaO-Al2O3-CaF2-based shielded metal arc welding coating

This study investigates electrode coatings designed for use in nuclear power plant weld joints, particularly their electrical, thermophysical and physicochemical properties. The Al2O3-CaF2-CaO-SrO-based shielded metal arc welding electrodes were developed using the extreme vertices design technique. The coating composition's structure and phases were analyzed using X-ray diffraction, while Fourier transform infrared spectroscopy analysis was used to identify the types of bonds present. Advanced characterization methods were utilized to assess the coating formulations’ physicochemical, thermophysical and structural aspects. Thermal properties, including specific heat, thermal diffusivity and conductivity, were evaluated using a hot disk apparatus, while thermogravimetric analysis was employed to determine the enthalpy change and thermal stability of the flux coating. The electrical properties of the flux coatings were examined using a precision LCR instrument. Statistical analysis was employed to create regression models for each coating property to investigate the influence of mineral constituents on the flux coating properties. Regression analysis is a statistical method used to establish a relationship between mineral interactions. In flux composition selection, it can help determine the physical significance of each factor and its relationship with the coating's performance. The results indicate that the mineral constituents’ individual elements, binary and tertiary interactions, significantly impact the flux composition's physicochemical, electrical and thermophysical properties.

Quenched and Tempered Steels Welded Structures: Modified Gas Metal Arc Welding-Pulse vs. Shielded Metal Arc Welding

Quench and tempered (Q&T) steels are widely used for a diverse range of applications, particularly in the mining and defence industry, where wear and unconventional loading are common. Furthermore, they are particularly prone to hydrogen assisted cold cracking (HACC), imposing a more careful selection of consumables and requiring a comparably higher welder skill level to fabricate defect-free structures. Therefore, the cost of fabrication of welded structures is higher when the more preferred welding technique of shielded metal arc welding, SMAW, is employed. The introduction of the modified pulsed arc mode of depositions, a variation to pulsed arc deposition, has improved the productivity rates and can be utilised by welders with a greater skill variations. In this study, full-strength butt welds of Q&T steel (AS/NZS 3597 Grade 700), with the thickness of 20 mm, are fabricated under a high level of restraint using both conventional SMAW and modified pulse gas metal welding (GMAW-P). The study investigated the economic feasibility of the two deposition modes and the propensity to cracking for the welded joints under high restraint conditions. Utilising the modified GMAW-P resulted in 63% and 88% reduction in the ‘Arc-On’ time and the total normalised fabrication time, respectively. However, strict controls must be implemented, due to the increased propensity to lack of fusion-type defects, to optimise the welding procedure and mediate for such defects if GMAW-P is to provide a techno-economically beneficial alternative to conventional SMAW when welding Q&T steels.

Pembuatan Lift Barang Untuk Rumah Dua Lantai

Limited land availability is a major obstacle to occupancy in Indonesia. In addition, residential owners who have constraints on physical limitations will have difficulty going up and down stairs by carrying loads. Based on these problems, the manufacture of a goods elevator with a carried out for a two-story house. The process of making a goods elevator starts from the process of re-design, preparation of materials tools and manufacturing process. Manufacturing processes in the manufacture of elevators include cutting, welding and pouring processes. Furthermore, the manufacturing process is divided into three parts, namely the manufacture of the main frame, the manufacture of cages and the place of electrical hoist as a drive pulley. The results of the elevator have dimensions of 6 meters in length of 0.8 meters and a width of 0.8 meters, while the cage has a height dimension of 1.5 meters long 0.74 meters and a width of 0.74 meters. The main frame construction uses the UNP 65×40×4 profile and the L 40×40×2 profile which is connected through part of the SMAW welding process and bolt nut connection. While in the cage using hollow profile baja 30×30×2, UNP 65×35×4 and wire mesh wire. Tempat electrical hoist uses UNP 85×45×5 profile and L 70×70×5 profile. The drive system in the elevator uses a 1200 kg PA electrical hoist with a single-phase 1800 watt electric power specification with a voltage of 220 V.

Effect of buttering on the wear behavior of the SMA welded hardfacing layer in a low-carbon steel

Abstract In this study, the effect of the buttering layer (18.5% Cr + 9% Ni) and the chemical composition of the hardfacing filler materials on the microstructure and wear behavior of the structural steel (S355JR) was investigated. The chromium-based hardfacing alloys deposited by shielded metal arc welding (SMAW) have also been investigated to establish the relationship between microstructures and wear properties. The microstructure of hardfacing deposits has been examined by using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. A linear reciprocating abrasive wear test experiment was conducted on the hardfacing deposits using an Al2O3 ball under constant wear test conditions. The experimental results show that the microstructure of hardfacing deposits consists of martensitic matrix and complex (M7C3) carbides. In addition, the increased chromium concentration of filler materials leads to an increase in the volume fraction of the primary carbides in the matrix of hardfacing deposits. The buttering layer caused the formation of diluted hardfacing deposits. Also, it significantly reduced the hardness and wear rate of hardfacing deposits. Fe14-Fe14 hardfacing deposit has exhibited the best wear properties with a low coefficient of friction.

Analisis Dampak Perubahan Arus Pengelasan Terhadap Kekuatan Sambungan Las Pada Material Stainless Steel 316

In a situation of increasing urbanization in the capital, the demand for decent and quality housing is also increasing rapidly. This increase was in line with increasing market demand for specific construction products such as railings, doors and windows which are of good quality. The research method and data collection will start from nine pairs of 316 stainless steel plates which will be welded using SMAW welding. Welding on stainless steel plates will be carried out with varying welding currents of 60 A, 70 A and 80 A. Each of these welding currents will be carried out on three stainless steel plates. The results showed that the use of a higher variation of welding current in the welding process resulted in a higher strength of the welded joint. The elastic modulus can decrease due to several factors such as the presence of microscopic cracks, changes in crystal structure, or changes in the bonds between atoms or molecules of the material. The strength of welded joints in stainless steel 316 material can also be affected by other factors besides variations in welding current. Parameters such as mains voltage, welding time and type of electrode also contribute to the strength of the welded joint.

Cyclic plasticity and ULCF behavior of steel butt-joints considering different welding methods

In order to reveal the influence of welding method on the cyclic plasticity and ultra-low cycle fatigue (ULCF) behavior of low-alloy butt-joints, three different welding methods, namely, shielded metal arc welding (SMAW), gas metal arc welding (GMAW), and submerged arc welding (SAW), were considered. Dog-bone flat-plate specimens with the welds were cut off from the plates for cyclic tests. The load-carrying capacity, energy dissipation property, and ULCF performance of the specimens were discussed. According to the experimental results, GMAW and SAW lead to the highest and lowest peak loads, respectively. The various welding methods have a slight influence on the equivalent viscos damping (EVD) coefficient of the specimens. Compared with those of the base metal (BM) specimen, ductility of the welded specimens is degraded by 34.62–61.54%, yield strength is deteriorated by 2.86–13.20%, ULCF life is decreased by 71.33%-92.31%. Metallurgical and scanning electron microscope (SEM) analysis were further conducted to reveal the mechanism behind the significantly compromised ULCF behavior of the welded specimens. In-depth numerical analysis was also conducted to reproduce the experimental processes. In the finite element (FE) analysis, inverse calibration technique was applied to determine the Voce-Chaboche (VC) combined hardening constitutive model parameters, and then cyclic void growth model (CVGM) was adopted for fracture simulation.

THE EFFECT OF VARIATION OF ELECTRIC CURRENT IN FLASH BUTT WELDING FOR CONNECTING THE RESULTS OF THE WIRE DRAWING PROCESS USING AISI 1080 MATERIAL ON TENSILE STRENGTH AND MICRO STRUCTURE

This study aims to determine the effect of variations in electric current in SMAW welding on tensile strength and microstructure. One of the factors that affect the strength of a material is the mechanical strength of the material properties. if the material is welded, it can affect the tensile strength and structure of the material. This research uses AISI 1080 steel material with a diameter of 1.24mm which contains C = 0.083%, Si = 0.21%, Mn = 0.5%, P = 0.008%, S = 0.007%, Cu = 0.03%, Cr = 0.03%, Ni = 0.02%, B = 0.013%, Alt = 0.025%, As = 0.06%, N = 0.0038%, and O = 0.1%. Specimens were welded with varying electric currents at intervals of 25mA, starting from 700mA, 725mA, 750mA, 775mA, and 800mA using the splicing method. The tensile strength results from flash butt welding with a current of 700mA were 853.6N/mm², at a current of 725mA it was 867.7N/mm², at a current of 750mA it was 847.4N/mm², at a current of 775mA it was 881.8mA, and at a current of 800mA it was 805.3mA.

ANALYSIS OF THE INFLUENCE OF BACKHAND AND FOREHAND WELDING DIRECTIONS ON MECHANICAL PROPERTIES USING THE SMAW METHOD

Abstract
 The use of metal materials to support human life continues to grow along with the rapid development of science and technology. This greatly influences the technology to process it into a ready-to-use product. Among the production techniques used to make a product is the welding process. Welding is a method of joining that is widely used in steel building construction and machine construction. Another connection method used on metal joints is bolts and rivets. Welding technology, besides being able to be used to join and cut metal, can also be used to fill holes in castings, make hard coatings on tools, thicken worn parts, and other kinds of repairs.
 AISI 1037 is a carbon steel with a carbon content of around 0.37%, which is classified as Medium Carbon Steel. The tensile strength of AISI 1037 is 650 MPa with a yield stress of 350 MPa. A test has been carried out on AISI 1037 with the welding method, where the welding method used is the 1G and 1 F welding process. With this method compared to the mechanical properties of the welding results, the seam used is seam V with an E 6013 electrode with a diameter of 2.6mm. The welding process refers to the AWS D1.1 standard with the SMAW welding type with a plate thickness of 5mm.

Investigation of welding of dissimilar high thickness SA106 Gr.C carbon steel and SA335P12 alloy steel to eradicate the failure in boiler components fabricated through SAW and SMAW processes

This study reports the effect of Shielded metal arc welding (SMAW) and Submerged arc welding (SAW) processes used to fabricate high-thickness end cover plates by welding of dissimilar materials SA 335 P12 steel pipes and ASTM A 106 grade C carbon steel. The study emphasizes the structure-property relation of the welded joints made by two different techniques using macrostructure and microstructural examination with optical and electron microscopy and hardness evaluation. The joints were subjected to magnetic particle non-destructive testing and the SAW joint was found to be defect-free. Microstructural examination revealed acicular ferrite microstructure on the SAW joint but bainite and martensite microstructure on the SMAW joint. After heat treatment hardness values disclosed the dissolution of the hard phases. The joints fabricated with SAW demonstrated high ductility with an increase in elongation of 23% and 37.5%, during the bend test and the tensile test respectively. Higher thickness welding of dissimilar joints by SAW is prefereed over SMAW joints, as it requires fewer weld passes and produce superior weld quality without any defects.

Sualtında Birleştirilen AH36 Gemi Sacının Mikro Yapı ve Mekanik Özelliklerinin İncelenmesi

Bu çalışmada, örtülü elektrot ark kaynağı yöntemi ile yerli E6013 rutil elektrotlar (GeKaTec UW E6013) kullanılarak gemi imalat sektöründe; gemilerin gövdesinde ve tankların yapımında yaygın olarak kullanılan AH36 çelik plakaları su altında alın alına birleştirilmiştir. Kaynak işlemleri gerçek deniz ortamında 4 metrelik bir derinlikte uzman sanayi dalgıçları tarafından gerçekleştirilmiştir. Plakalar ilk olarak AWS D3.6 standardının gerekliliklerine uygun olarak tahribatsız muayene testlerine tabi tutulmuştur. Daha sonra su altında birleştirilen kaynaklı plakaların mekanik özelliklerini belirlemek amacıyla sertlik, çentik darbe, eğme ve çekme testleri uygulanmış olup, sonuçlar kaynak bölgesinde meydana gelen mikro yapısal dönüşümlerle birlikte yorumlanmıştır.

Hot Tensile Properties of SMA Welded Similar and Dissimilar Joint of P91 and SS304 Grade Steels

P91 martensitic and SS304 austenitic stainless steel is identified as the steels for use in high temperature areas of ultra-super critical boilers. The boiler piping involves similar and dissimilar weld joints of P91 and SS304 grade steels. The welded joints are exposed to high temperature in service and it is therefore required to evaluate the high temperature behaviour of such joints. Hot tensile test is a short-term high temperature test which is a useful tool to study the high temperature behaviour of the welds. In this investigation, shielded metal arc welded (SMAW) similar joints of P91/P91 martensitic steel, SS304/SS304 austenitic steels joined using matching weld metal and dissimilar joints of P91/SS304 welded using Inconel weld metal are subjected to hot tensile test at temperatures of 550 deg C, 600 deg C and 650 deg C. The stress-strain behaviour of the weld joints at elevated temperature was studied.

Wideband, Wearable, Printed Monopole Antenna System for Integration into an Electromagnetic Radiation Evaluation Device

This paper describes the design steps carried out to prove the concept of a wideband monopole antenna system to be used in a wearable device conceived for the evaluation of electromagnetic field radiation. Such a device is envisaged to be integrated into protective vests worn by professional users in their working space environment as part of intelligent multi-risk protection. Initially, the main characteristics of a simple straight monopole are reviewed to serve as a reference. A modified octagonal monopole antenna element is introduced, and a two dual-linearly polarized configuration of such monopoles is designed, fabricated, and tested to be used in the frequency range of 0.7-3.5 GHz. The expected radiation characteristics (input reflection coefficient and isolation between vertically and horizontally polarized ports) are confirmed experimentally. The effects of a thick lossy foam substrate layer used to mitigate the presence of the metal shield, employed in the vest lining as a Faraday cage protection, are analyzed both by simulation and experimentally. Finally, electromagnetic simulations are carried out to confirm that a system of five dual-linearly polarized monopole elements located in the chest, shoulders, back, and helmet of the user can provide an adequate estimation of the incident electromagnetic field radiation.

Development of an Artificial Intelligence-Based System for Predicting Weld Bead Geometry

The prediction of the weld bead geometry parameters is an important aspect of welding processes due to it is related to the strength of the welded joint. This research focuses on using statistical design techniques and a deep learning neural network to predict the weld bead shape parameters of shielded metal arc welding (SMAW), metal inert gas (MIG), and tungsten inert gas (TIG) welding processes. With the statistical design techniques, experiments were carried out to obtain the data for generating the regression models. Establishing mathematical models that shows the relationship between welding process parameters and weld bead size is significant for practical applications. The mathematical model enables the determination of the weld bead size when setting specific welding process parameters. In this research, experimental research results were obtained to build mathematical models showing the relationship between welding process parameters and weld bead geometries for SMAW, MIG, and TIG welding processes. The research results serve as the basis for establishing predictive systems or optimizing welding process parameters. With deep learning neural network techniques, we developed an artificial intelligence-based system for predicting complicated relations between the welding process parameters and the weld bead size. Both a regression model and the deep learning model result in a good correlation between the welding process parameters and the weld bead geometry.

Coupling effect of thermal aging and pre-strain on fracture behavior of SMAW welded joints

A repairing process is commonly needed to correct installation slope and geometrical deviation of nuclear power piping, but the resulting pre-strain has obvious degradation impacts on the long-term operation of surge pipeline, especially for the shielded metal arc welding (SMAW) joints. In this paper, to investigate the embrittlement induced by thermal aging and pre-strain, the SMAW welded joints with the base metal Z2CND18-12N2 and welded metal ER316L were subjected to different pre-strain (0%, 8%, 12% and 15%) and the accelerated thermal aging from 0 h to 13000 h at 400 ℃. Then, the Charpy impact test and compact tension fracture test were conducted to determine fracture properties of the SMAW welded joints. Results showed that both thermal aging and pre-strain can significantly reduce the fracture properties of SMAW welded joints. The impact absorbed energy reached stable after thermal aging 500 h, but it has been decreasing with the pre-strain varying from 0% to 15%. Moreover, it is shown that for pre-strained SMAW welded joints, with the increase of thermal aging duration, the absorbed energy first recovers, and then decreases until stable. Compared with pre-strain, the influence of thermal aging is dominant. Finally, combined with microscopic analysis, the comprehensive effects of thermal aging and pre-strain on the embrittlement mechanism of SMAW welded joints were discussed.

Finite element analysis results visualization of manual metal arc welding using an interactive mixed reality-based user interface

Welding is extensively used in manufacturing industries for various applications. However, residual stress is induced due to the non-uniform temperature distribution on the weld plates during the welding process, which significantly affects the fatigue strength. In addition, the non-uniform expansion and contraction of the weld and surrounding base metal cause structural distortion. The distortion affects final product quality and results in lower productivity. Therefore, the structural analysis of the welded component is significantly important. In this work, a mixed reality (MR)-based user interface was developed to overlay the finite element analysis (FEA) results on the real weld plates in real time for manual metal arc welding (MMAW). Since the numerical simulation using FEA requires a large number of computational resources, a gradient boosted regression tree (GBRT) model was trained to predict the residual stress and deformation results. Furthermore, a lookup table and a trilinear interpolation method were used to render the results based on users' input data using Microsoft HoloLens 2 in real time. The developed interactive MR-based user interface can help welders quickly predict and control the residual stress and welding distortion before the real welding process and help novices learn the relationship between the welding parameters and the induced residual stress and deformation.

Study on the Novel High Manganese Austenitic Steel Welded Joints by Arc Welding for Cryogenic Applications of LNG Tanks

The novel high-Mn austenitic steel is becoming a promising steel for cryogenic applications of LNG tanks. The welded joints take a critical role in cryogenic service for storage tanks. In this work, we developed well-matched high-Mn welding consumables and prepared the welded joints by shielded metal arc welding (SMAW), submerged arc welding (SAW) and gas tungsten arc welding (GTAW). The detailed welding parameters were proposed first, then the welding quality, mechanical properties, and microstructure were investigated. The results show that good welding quality, excellent mechanical properties, and stable levels of mechanical properties were obtained for high-Mn steel welded joints using similar welding consumables, the solid core of electrodes, and solid welding wires. Notably, the lowest cryogenic absorbed energy was found at 5 mm away from the fusion line rather than at the fusion line. The hardness of the welded joints was detected to be less than 280 HV due to the whole austenitic microstructure.

Applying the column generation method to the intensity modulated high dose rate brachytherapy inverse planning problem

Objective. Intensity modulated high dose rate brachytherapy (IMBT) is a rapidly developing application of brachytherapy where anisotropic dose distributions can be produced at each source dwell position. This technique is made possible by placing rotating metallic shields inside brachytherapy needles or catheters. By dynamically directing the radiation towards the tumours and away from the healthy tissues, a more conformal dose distribution can be obtained. The resulting treatment planning involves optimizing dwell position and shield angle (DPSA). The aim of this study was to investigate the column generation method for IMBT treatment plan optimization. Approach. A column generation optimization algorithm was developed to optimize the dwell times and shield angles. A retrospective study was performed on 10 prostate cases using RapidBrachyMCTPS. At every iteration, the plan was optimized with the chosen DPSA which would best improve the cost function that was added to the plan. The optimization process was stopped when the remaining DPSAs would not add value to the plan to limit the plan complexity. Main results. The average number of DPSAs and voxels were 2270 and 7997, respectively. The column generation approach yielded near-optimal treatment plans by using only 11% of available DPSAs on average in ten prostate cases. The coverage and organs at risk constraints passed in all ten cases. Significance. The column generation method produced high-quality deliverable prostate IMBT plans. The treatment plan quality reached a plateau, where adding more DPSAs had a minimal effect on dose volume histogram parameters. The iterative nature of the column generation method allows early termination of the treatment plan creation process as soon as the dosimetric indices from dose volume histogram satisfy the clinical requirements or if their values stabilize.

A Comparative Study on Microstructural Characterization of Thick High Strength Low Alloy Steel Weld by Arc Welding and Laser Welding

Welding and the behavior of the weldments are important, since welding of high strength low alloy (HSLA) steels is a conventional method for manufacturing industrial parts. This work conducts a comparative investigation of microstructural characteristics and mechanical properties for joints of 16-mm-thick HSLA Q890 steel produced by multi-layer multi-pass shielded metal arc welding (SMAW) with filler wire and single-layer autogenous laser beam welding (LBW). The mechanical properties of the welded joints were assessed in terms of tensile and impact using butt joints. The results show that tensile failure occurred in the base metal during the tensile tests for most of the trials. The ultimate tensile strength and percent elongation of the LBW welded joint (973.5 MPa and 10%) are higher than those of the SMAW joint (951 MPa and 2.9%) due to the filler filling process of the SMAW process. The Charpy impact energy of the weld metal (16.4 J and 15.1 J) is lower than that of the heat-affected zone (18.5 J and 19.5 J) in the LBW joint and the SMAW joint.

Investigations on wetting and structural behavior using CaF2-SiO2-CaO-22.5%TiO2 SMAW electrode coating for AUSC applications

This study investigates the structural behavior and high-temperature wettability of a CaF2-SiO2-CaO-22.5%TiO2 shielded metal arc welding electrode coating for advanced ultra-supercritical power plant applications. The wettability parameters were measured, including contact angle, spread area, adhesion energy, and surface tension. Extreme vertices mixture design approaches were used to develop 13 different electrode coatings. To determine the contact angle at solid/liquid interface, circular pellets were made from powder samples and heated inside the furnace at 1125°C at a constant heating rate. Young's and Boni's equations are used to calculate the surface tension value for 13 coated samples using the calculated contact angle. Adhesion energy for 13 coated samples is calculated using Dupre's equation. Phases and structural behavior of coating samples were measured by Fourier transform infrared spectroscopy and X-ray diffraction. The developed regression model estimates the impact of primary ingredients and their interaction on the calculated wettability characteristics. CaF2.SiO2, CaO.SiO2, and CaO.CaF2 binary mixture is the more favorable and substantially impacts contact angle, whereas ternary interactions of CaO.SiO2.CaF2 shows an opposite effect on contact angle. Coating numbers 2 and 10 give better wetting behavior and spread area due to the low value of contact angles. Individual ingredient shows an increasing effect on surface tension and adhesion energy. Ternary component of CaO.CaF2.SiO2 is favorable and shows an increasing impact on adhesion energy.

Electrical conductivity measurements in piston cylinder press: metal shielding in the assembly design and implications

Electrical conductivity measurements in piston cylinder press: metal shielding in the assembly design and implications