Welding in the World最新文献

Directed energy deposition-arc with metals (DED-ARC/M) is gaining popularity in aerospace applications due to its cost-reduction potential and shorter lead times. A notable example of expensive products manufactured traditionally is pressure tanks with oval shapes. These parts are roughly machined from bulk material and then reduced to their final thickness. By employing DED-ARC technology, material waste and CNC machining time can be minimized, leading to a significant reduction in overall part costs. This paper focuses on the design of experiments (DoE) for optimizing welding parameters to manufacture a pressure tank for aerospace applications using 17–4 PH stainless steel. To meet the high-quality and lightweight requirements of aerospace applications, it is crucial to set the welding parameters correctly. The presented DoE consists of three stages. Initially, a number of single beads with distinct parameters are deposited for a layer height of 2–3 mm. Through geometric macro inspection, most of the single-bead parameters are eliminated. Using the remaining parameter sets, flat walls are manufactured, and the specimens are taken from these walls to assess their mechanical properties. Finally, the parameter sets that yield the highest mechanical quality are employed in the additive manufacturing of the pressure tank for aerospace applications.

Wire-arc directed energy deposition (WA-DED) is the subject of extensive research in metal additive manufacturing (AM). This study investigates the influence of ultrasonic vibration (UV) on the material properties of deposited ER2209 duplex stainless steel filler wire and evaluates the effects of UV treatment on walls fabricated both with and without weaving. The results demonstrate the effectiveness of a specially developed UV table prototype, showing clear impacts on grain size and ferrite content in the deposited samples. UV treatment reduces the primary ferrite grain width and enhances phase distribution homogeneity, potentially influencing the ferrite-to-austenite transformation during successive reheating cycles. Although the effects on surface morphology and hardness were minimal, significant microstructural changes occurred within the deposited material. UV-induced grain refinement modifies the austenite content, revealing a beneficial interaction between vibration and phase evolution. The UV table design provides a valuable foundation for reproducibility; nevertheless, further optimization of the setup is required to improve performance and support its integration into advanced industrial applications.

The successful application of thick-section electron beam (EB) welding in 2205 duplex stainless steel (DSS) materials will be evaluated in this paper. This work focuses on the joining of safety critical components (traditionally produced from wrought plate) with the aim to optimise the manufacturing method and reduce material waste. Here, TWI will present the objectives of the program, challenges of the work including the developments and improvements observed. In particular will be discussion of the phase balance and material performance of the weld solidification product and heat-affected zone. EB welding of these materials has traditionally led to an undesirable phase balance due to the rapid cooling rates produced by the low heat input process. However, this paper will show methods of achieving suitable phase balances whilst using the EB process. Both weld and heat-affected zone (HAZ) ferrite levels of between 40 ≤ F% ≤ 70 were achieved in 20 mm and 60 mm DSS. This was achieved whilst having no observed negative effect on the other tested material properties where hardness, transverse tensile and Charpy V notch tests were conducted. Transverse tensile tests showed an ultimate tensile strength and elongation that were comparable to the parent material. Hardness testing showed that there was no significant change in hardness in the HAZ and weld metal compared to parent metal. Charpy V notch tests showed that all tested samples had an absorbed energy of ≥ 124 J with all samples remaining unbroken (partially fractured). A compelling case will be presented for the application of EB welding for the joining of safety critical DSS components.

In addition to the unique weld seam properties, friction stir welding (FSW) includes specific challenges such as comparatively high static and dynamic forces and torque during welding. In the literature review to date, the design of the tools is mostly based on empirical values, which can result in over- and undermatching. The aim of this study is to systematically analyze the dynamic tool damage and the respective failure mechanisms in relation to the tool dimensions and process temperature, accounting for weld seam length and quality. The determination of partial tool damage enables classification of the maximum tolerable tool life, considering the impact of process temperatures on permissible stresses of FSW tools made of H13 steel. The results indicate that dynamic stresses can be significantly affected by rotational speed and welding speed. Linear damage accumulation was used to predict the maximum tolerable tool life by summing up partial damage over time, which has never been used in the context of friction stir welding on the basis of experimental measurement data. For this purpose, forces and torques were converted into stresses on the probe and initially compared with analytically determined S–N curves for the main stresses during welding. Although the resulting weld seam lengths currently indicate a clear overestimation of the tool life, they allow for an estimation of the tool damage depending on the used probe diameter and welding speed. Particularly when a rotational speed of 2500 min⁻¹ is considered, an eleven times overestimation of tool life results for the 5 mm probe and eight times for the 6 mm probe. The most favorable outcomes were observed when the 5 mm probe was operated at 4000 min⁻¹, with an estimated tool life of 238 m and an experimental result of 213 ± 35 m, as an exact determination of the tool life was possible in this instance. A sensitivity analysis with regard to the recording frequency demonstrates a strong dependence on the pre-processing of the measurement data. For instance, adjusting the recording frequency and using a Butterworth low-pass filter enhances the prediction by approximately 47% (6 mm probe at 2500 min⁻¹). The incorporation of experimentally determined S–N curves could further enhance the precision of the prediction in the course of further investigations. The experiments were carried out with a force-controlled robotized welding setup from Grenzebach Maschinenbau GmbH in which AA 6060 T66 sheets with a thickness of 5 mm were joined.

The analysis in this study is centered on the butt laser welding of 2.5-mm-thick sheets of 6063-T6 and 6082-T6 aluminum alloys. This type of joint is common in new energy vehicle bodies. It helps to reduce weight and combines the strength and toughness of both alloys. This investigation applies numerical simulation to examine the effects of laser heat input on the behavior of the molten pool’s flow. A rise in heat input is associated with a decrease in the molten pool’s stability. This phenomenon is evidenced by the retrograde and ascending movement of the liquid metal within the pool. The formation of columnar crystals is observed in the weld metal zone (WMZ) adjacent to the fusion line (FL) on both sides, while equiaxed crystals are primarily found at the heart of the WMZ. With increased heat input, the weld joint’s micro-hardness, ultimate tensile strength, and elongation undergo an initial increase and are followed by a decrease. The side of 6063-T6, characterized by a lower initial hardness, undergoes rapid solidification near the FL, leading to the formation of fine non-equilibrium grains. Due to their small size and high defect density, the mechanical strength is reduced, which is the site of fracture. Recommended for publication by Commission IV—Power Beam Processes.

This article provides a comprehensive overview of current practices in real-time monitoring of friction stir welding, focusing on sensor-based methodologies employed to enhance product quality and process control in this advanced joining technique. As the industrial sector moves toward Industry 4.0, the integration of sophisticated monitoring systems is essential for efficient data exchange and sustainable growth. The review discusses various critical aspects of FSW, including process parameters, while highlighting the applicability of sensors such as temperature, force, torque, acoustic emission, and imaging technologies. The study categorizes the existing sensor approaches into single-sensor and multi-sensor methodologies. The article also identifies research gaps in online defect monitoring, emphasizing the need to explore further monitoring techniques, cloud computing, and sensor fusion to facilitate the wider adoption of real-time monitoring solutions in industrial FSW applications. Through this analysis, the article aims to contribute to improving the efficiency and reliability of FSW, thereby broadening its applicability in industries like automotive and aerospace.

Laser-directed energy deposition (L-DED) demonstrates high reliability in repairing titanium alloy components, validated through fatigue assessments of Ti60 heterogeneous structures containing base material (BM) and deposited zone (DZ). The present L-DED process achieves robust metallurgical bonding with near-isotropic DZ microstructures, yielding minimal strength mismatch and comparable fatigue lives between BM and DZ. Deposited material can be near defect-free as confirmed via X-ray computed tomography. A cyclic plasticity model, calibrated using wrought material data, simulates interfacial multi-axial stresses and strain localization. Critical plane-based models predict fatigue lives effectively, demonstrating the applicability of conventional assessment frameworks in medium- to high-cycle fatigue regime. DZ shows better defect tolerance than the BM, with its higher fatigue limit based on Murakami’s empirical model. Stress triaxiality near the interface accelerates low-cycle fatigue damage, yet no interfacial failures occur, highlighting the process’s mechanical robustness. These findings validate the L-DED process in balancing defect control and performance, providing a reliable methodology for aerospace component repair.

In response to the crisis of global climate change, various national and industrial efforts to reduce greenhouse gas emissions continue to be implemented. In particular, the aviation, automotive, and material industries are striving to reduce CO₂ emissions by utilizing magnesium alloys to achieve product weight reduction. Magnesium alloy, as a representative lightweight non-ferrous metal, has been observed in other studies to exhibit excellent properties, such as high specific strength, electromagnetic shielding ability, and vibration and impact absorption. However, due to the inherent material properties of magnesium alloys, challenges arise when welding is conducted. This is in contrast to other metals such as iron-based alloys. Therefore, various studies are still being conducted to address and improve these issues. In this study, bead-on-plate experiments using fiber laser welding on magnesium alloys were conducted to determine the appropriate butt welding conditions. Based on the derived conditions, butt welding was performed, followed by an analysis of the mechanical behavior and microstructure to investigate the characteristics. The results of this study identified a correlation between the characteristics of magnesium alloys and their mechanical behavior during fiber laser welding, suggesting that the findings could serve as fundamental data for future industrial applications.

This study investigates the impact of laser overlap welding parameters on the mechanical and microstructural properties of dissimilar joints between AISI 1018 low-carbon steel and stainless steel 301LN. A series of experiments were conducted varying laser power, travel speed, and oscillation amplitude to determine optimal welding conditions. Tensile tests revealed that the welds exhibited significantly different strengths and displacements, with the optimal parameters achieving a maximum load of 39.6 kN and a displacement of 9.3 mm. Macrostructural analysis indicated that higher oscillation amplitudes resulted in broader but shallower welds, whereas lower amplitudes achieved deeper penetration. Microstructural examination showed varied phase formations, including martensite and bainite, influenced by the diffusion of alloying elements such as chromium and nickel. The formation of chromium carbides significantly enhanced the hardness of the fusion zone, with microhardness values reaching up to 470 HV at moderate penetration. Fractographic analysis of tensile-tested samples highlighted different fracture mechanisms, with optimal welds fracturing in the base material rather than the weld interface, indicating superior joint strength. This study provides critical insights into optimizing laser overlap welding parameters to enhance the mechanical performance and structural integrity of dissimilar metal joints, contributing to improved industrial welding practices.