Effect of bypass cold wire spatial position on process stability and elemental transfer in submerged arc welding for in situ alloying

Submerged arc welding (SAW) slag is an industrial waste, generated in large quantities. Its disposal leads to the wastage of non-renewable resources and contributes to environmental degradation. Developing a hardfacing flux from waste-submerged arc welding slag marks a significant advancement in sustainability and industrial efficiency. By repurposing this byproduct, the approach not only tackles the issue of waste management but also conserves non-renewable resources and reduces costs. The resulting hardfacing layers were rigorously tested for chemical, mechanical, and metallurgical properties. The chemical composition of these hardfacings met the DIN 8555 specifications, and they successfully passed the side bend test, demonstrating a robust bond between the hardfaced layer and the base metal. Performance evaluations showed a 63.22% improvement in wear resistance, with a reduced coefficient of friction (0.251 compared to 0.293 for the base material), and a 220% increase in hardness. The hardfaced layers exhibited a defect-free, fine-grained microstructure. With recycling costs at merely 33% of virgin flux, this technology offers a cost-effective and environmentally sustainable alternative for hardfacing applications.

Due to the shielding effect of fluxes, investigations into element transfer during submerged arc welding are often restricted by and/or limited to compositional analysis of the weld metal (WM). Therefore, meaningful discussions about specific locations where responsible reactions occur, such as the arc-containing droplet zone and arc-free slag-metal zone, are often nebulous. To counter such challenges, designed droplet collection trials were conducted over a water-cooling system. By examining the contribution of droplets to element transfer in the WM, the locations and possible pathways facilitating salient element transfer behaviors were elucidated. The results indicated that the transfer levels of Si, Mn, and Ti from the flux into the droplet were, on average, 0.016 wt-%, 0.079 wt-%, and 0.004 wt-% higher, respectively, than levels into the WM, suggesting that element transfer occurred primarily in the droplet zone. The transfer level of O from fluxes into droplets was, on average, 0.022 wt-% lower than that to the WM, indicating that beyond the droplet zone, alternative sources contributed to the increase in O content within the WM. The findings provide a theoretical foundation for precisely manipulating WM compositions and potentially optimizing the entire welding process to a new level.

Finite Element Modeling and Validation of Submerged Arc Welding for Repairing 136RE Heavy Rails

A clean and sustainable environment is essential for all living beings, yet large-scale industrialization often compromises this balance. Boilers and pressure vessels, critical to many industries, produce significant waste and residues, raising serious environmental concerns. This study explores the development of submerged arc welding (SAW) flux by transforming industrial waste materials, specifically boiler fly ash and sugarcane bagasse ash, into a high-performance, cost-effective welding solution. The resulting flux not only reduces reliance on virgin mineral resources but also addresses waste management challenges. Comprehensive evaluations, including chemical composition analysis, mechanical property testing, and microstructural and fractographic analysis using FESEM, confirmed the flux’s adherence to ASME SFA 5.17 standards. Welds produced with the developed flux exhibited superior performance, with higher ultimate tensile strength (548.49 MPa) and impact toughness (133.33 J) compared to commercially available flux, alongside stable arc characteristics and a high-quality weld bead surface. Moreover, the developed flux offered a 64% cost savings over commercial alternatives, demonstrating both economic and environmental benefits. This research enhances welding efficiency and mechanical reliability while promoting sustainability through innovative waste repurposing.

A modification of the submerged arc welding technology is proposed, aimed at obtaining a medium-entropy alloy characterized by a reduced tendency to form cold cracks and high quality of the deposited metal. Microstructure analysis, evaluation of the microhardness distribution over the section of the deposited layer, and identification of nonmetallic inclusions are performed.

This study investigates the influence of Cr2O3-bearing fluxes on the transfer behavior of O and Cr during the submerged arc welding process. A series of fluxes with varying Cr2O3 content are prepared and applied in submerged arc welding. A cross-zone model is developed to separately evaluate the transfer of O and Cr in both droplet and weld pool zones. The results reveal significant O enrichment in the droplet zone due to the decomposition of Cr2O3 under arc heating, followed by deoxidation in the weld pool. Cr transfer is found to be inhibited by the high oxygen potential in the droplets and further affected by evaporation loss. A comparison of predicted ΔCr values shows that the gas–slag–metal equilibrium model overestimates Cr transfer level, while the cross-zone model provides predictions more consistent with experimental results. This study highlights the critical role of Cr2O3 in regulating transfer behaviors O and Cr and provides valuable insights for flux design aimed at achieving precise compositional control and improved weld quality in welding applications.

Hot cracking is one of the most serious welding defects that can significantly reduce the strength of structures, and it is important to prevent hot cracking. In the Japanese shipbuilding industry, one-sided submerged arc welding with multiple electrodes is used to improve the production efficiency of welding large steel plate joints, and it has been reported that hot cracking may occur at the end of the weld. In this study, a new “parallel heating method” is proposed to prevent hot cracking by using the thermal expansion caused by additional heating applied in parallel with the welding torch. In the analysis of bead-on-plate welding, the proposed method reduced high-temperature strain not only at the steady state but also at the beginning and end of the weld. It was confirmed that the effect of reducing high-temperature strain varies depending on the position of the additional torch, and that there is an appropriate heating position. In the analysis of multi-electrode single-sided submerged arc welding, the proposed method has little effect on the weld penetration shape. It was also confirmed that the proposed method has a significant reduction effect on high-temperature strain generated by localized opening deformation, demonstrating the usefulness of the proposed method.

The article discusses modern welding methods in automotive engineering, in particular technologies such as arc welding(MMA, MIG/MAG, TIG), submerged arc welding, electroslag welding and plasma welding. An analysis of their technicalcharacteristics, advantages and disadvantages, as well as the specifics of their application in the context of requirements forquality, reliability and economic efficiency of joints is carried out. It has been determined that the choice of the optimal weldingtechnology depends on the material, design and purpose of the parts, and the introduction of innovative methods contributes toimproving the quality and competitiveness of automotive products.

In this study, X70M PSL 2 (API 5L) steel used in oil pipelines was welded by submerged arc welding method. Weld seam and HAZ were characterized by optical microscopy, scanning electron microscopy (SEM), tensile test, hardness test and Charpy impact test methods. As a result of the optical inspection, it was observed that no welding defects had occurred within the structure. The weld zone, base metal, and HAZ are distinct, and columnar grain growth has occurred in the weld metal. In the SEM study, it was observed that the base material consists of ferrite grains (angular ferrite, polygonal ferrite), the HAZ consists of coarser grains, and the weld metal consists of fine columnar ferrite. As a result of the tensile test, it was determined that the tensile strength of the base material is approximately 648 MPa, while the tensile strength of the welded joint is approximately 695 MPa. The obtained results indicate that the fracture in the welded joint occurred in the base material. The highest average hardness value was measured as 229 HV in the weld metal. In contrast, the average hardness values in the base material and HAZ are 218 HV and 221 HV, respectively. The average impact energy value obtained in the base material is 428 J. The lowest impact energy was obtained in the weld metal. The average impact energy value obtained in the weld metal is approximately 94 J. As one moves from the weld metal towards the base material, the increase in impact energy is remarkable.

In this study, two types of submerged arc welding (SAW) wires were prepared—one without cerium (Ce) and another containing 0.14 wt.% Ce. Deposition experiments were carried out on corrosion-resistant crude oil storage tank steel plates using a multi-layer, multi-pass welding process. Through a combination of microstructural characterization techniques, including optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM), along with mechanical property testing, a systematic investigation was conducted to evaluate the influence of Ce on the weld metal microstructure and its impact toughness at −20 °C. The results reveal that Ce introduced via the welding wire into the weld seam refines and disperses inclusions, leading to the formation of composite inclusions primarily composed of Ce2O3, Ce2O2S, and CeS. These Ce-enriched inclusions serve as heterogeneous nucleation sites, increasing the area fraction of acicular ferrite (AF) within the weld columnar grain region from 52% to 83%, and within the heat-affected zone from 20% to 37%. Correspondingly, the proportions of blocky and polygonal ferrite decrease, while the size of martensite/austenite (M/A) constituents is reduced. The addition of Ce thus diminishes the size of hard phase inclusions and M/A constituents in the weld metal, enhancing the critical fracture stress and increasing the energy required for crack initiation. Meanwhile, the higher proportion of AF elevates the density of high-angle grain boundaries, thereby improving crack propagation resistance. These combined effects raise the −20 °C impact energy of the weld metal from 117 J to 197 J.

Effect of Post-Weld Heat Treatment on the Impact Toughness and Microstructure of 2.25Cr-1Mo-0.25 V High-Strength Steel Submerged Arc Welding Weld Metals

Submerged Arc Welding (SAW) is a widely used welding process in heavy-duty industrial applications. Weld hardness is a critical factor influencing the mechanical properties and performance of welded joints. However, achieving optimal hardness can be challenging due to the complex interplay of process parameters. This research highlights the potential of a modified approach based on the Whale Optimization Algorithm (WOA) as a reliable optimization tool for optimizing hardness settings in a SAW process, thereby contributing to advancements in welding technology and industrial applications. The suggested method introduces several unique features: a dynamic search space adjustment mechanism to adaptively refine the search area, and the incorporation of inertia weights to balance the algorithm’s exploration and exploitation phases. These novel modifications significantly enhance the algorithm’s performance, leading to faster convergence and more precise solutions. The novelty of the proposed method lies in the introduction of a dual-phase adaptive control strategy that adjusts both the search step size and the influence of elite solutions over time. This allows the algorithm to balance global and local searching more effectively. Additionally, a parameter sensitivity feedback loop is incorporated to dynamically refine the influence of each welding parameter based on real-time performance trends, significantly enhancing the robustness and adaptability of the optimization process. To validate the effectiveness of the modified WOA, extensive experiments were conducted on a SAW machine using various welding parameters as input variables and weld hardness as the primary objective function. The modified WOA was compared with the standard WOA and other commonly used optimization algorithms (Particle Swarm Optimization). The results demonstrate that the modified WOA effectively identifies optimal hardness by selecting appropriate parameters, significantly outperforming the other algorithms, resulting in higher weld quality and stronger mechanical properties.

Optimizing Weldability of EH550 Offshore Engineering Steel via TiO2-Assisted Element Transfer During Submerged Arc Welding

Abstract The relationship between local weld geometry and fatigue life has been extensively studied over the past decades, driven by the need to enhance structural integrity and optimize costs throughout a structure’s service life. While numerous studies have explored the influence of weld geometry on fatigue strength, the comparative effect of different welding methods under comparable weld geometry quality remains largely unexplored. Furthermore, the influence of local geometric variations for each welding method has not been systematically evaluated. This study explores a large dataset of laser-scanned butt welds, analyzing key geometric parameters. The dataset is categorized by welding method (laser-hybrid welding, submerged arc welding, and flux core arc welding), and statistical distributions are examined to assess variations in weld geometry and compliance with ISO 5817 quality groups. The characteristic fatigue life for each quality group is estimated. The correlation between geometric factor and fatigue life is evaluated through the residual analysis of stress-life curve linear fitting. According to the findings, different geometry features dominate depending on the welding method. The fracture location is strongly influenced by angular misalignment, while fatigue strength is better explained by quantile-based analysis of local geometry. These results provide a basis for future predictive modeling and quality assessment in welded structures.

Background: Welding processes expose workers to a range of occupational hazards, including chemical pollutants, noise, and non-ionizing radiation, which can compromise health. Effective selection and consistent use of personal protective equipment (PPE), along with engineering and management controls, are essential for mitigating these risks. Objectives: The present study aimed to identify occupational hazards in welding operations and propose strategies to enhance worker safety and health through optimized PPE use and workplace risk management. Methods: Hierarchical task analysis (HTA) was applied to systematically decompose the tasks of argon arc welding (TIG) and submerged arc welding (SAW). Other roles and activities within the workshop were examined to assess potential cross-exposures. Workplace hazards were evaluated using a combined qualitative and quantitative approach, including field observations, interviews with workers and technical experts, and analysis of technical and safety documentation. Environmental measurements included noise, airborne pollutants, and radiation levels. Results: The HTA identified multiple stages in welding processes where workers are exposed to hazards such as metal fumes, hazardous chemicals, noise, non-ionizing radiation, and molten metal spatter. Noise levels frequently exceeded recommended limits, while elevated concentrations of manganese and crystalline silica fumes were detected. Shared workspaces led to secondary exposure to hazards from adjacent tasks. Proper use of PPE, including hearing protection, respiratory masks, flame-resistant clothing, and welding helmets, was shown to effectively mitigate these risks. Conclusions: Welding hazards are cumulative and influenced by both task-specific and environmental factors. Continuous and correct use of PPE, combined with engineering controls and management measures such as task rotation, is critical to protect workers’ health. Ongoing training, supervision, and workplace monitoring are recommended to ensure compliance and reduce occupational risks in welding environments.

Reducing the carbon footprint of the construction sector is a growing priority. This study explores the potential of using submerged arc welding (SAW) slag as a precursor in the development of low-carbon geopolymeric materials for 3D printing. The influence of potassium hydroxide (KOH) molarity, partial replacement of ground granulated blast furnace slag (GGBFS) with SAW slag, and water-to-binder (w/b) ratio was evaluated in terms of fresh and hardened properties. Increasing KOH molarity delayed setting times, with the longest delays at 10 M and 12 M. The highest compressive strength (48.5 MPa at 28 days) was achieved at 8 M; higher molarities led to strength losses due to excessive precursor dissolution and increased porosity. GGBFS replacement increased setting times due to its higher Al2O3 and MgO content, which slowed geopolymerization. The optimized formulation, containing 20% SAW slag and activated with 8 M KOH at a w/b ratio of 0.29, exhibited good workability, extrudability, and shape retention. This mixture also performed best in 3D printing trials, strong layer adhesion and no segregation, although minor edge irregularities were observed. These results suggest that SAW slag is a promising sustainable material showing for 3D-printed geopolymers, with further optimization of printing parameters needed to enhance surface quality.

Effects of Heat Treatment on the Crack Growth Resistance of 420NiMo Hard-Faced Applied on DIN 21CrMoV5-11 Steel Substrate Using Submerged Arc Welding (SAW)

This study investigates the special requirements for longitudinal tensile properties of the weld seam and impact toughness of the welded joint in X65MO-grade longitudinal submerged arc welded (LSAW) pipes, as specified by an international marine engineering project. The feasibility and rationality of the pipe manufacturing process were evaluated experimentally. It was found that matching the yield strength of the weld metal to that of the base metal could induce cracking during guided bending, adversely affecting the comprehensive mechanical properties of the pipe. By optimizing the chemical composition of the base metal, restricting impurity elements in welding consumables, controlling flux basicity, and improving the welding procedure, the embrittlement issue in the mid-thickness region of the weld and heat-affected zone (HAZ) of X65MO Φ711×19.1 mm marine LSAW pipes was resolved. As a result, the weld seam achieved an average Charpy impact energy of 160 J at 0°C with a shear area of 63%, while the HAZ exhibited an average impact energy of 279 J and a shear area of 91%.

Development and performance evaluation of high-value SJ101 submerged arc welding flux from solid waste steel slag