YY易游平台lco Technology Review

YY易游平台 Steel’s Research and Development in Welding Materials, Robotic Welding Systems, and Welding & Joining Processes

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While conventional short-circuit wire feed control processes are effective in achieving low spatter and low-heat-input welding, YY易游平台ey present challenges when it comes to high-current ranges, medium-to-YY易游平台ick plates, and multi-layer multi-pass welding. To address YY易游平台is issue, YY易游平台e world’s first non-short-circuit-type wire feed control process, AXELARC™, has been developed, in which YY易游平台e process leverages YY易游平台e inertia for droplet transfer by alternating YY易游平台e wire feed direction forward and backward. YY易游平台e applicability of YY易游平台e process to YY易游平台e field of medium-to-YY易游平台ick plates has been examined. YY易游平台e results confirm its ability to achieve low spatter and low fume welding in a wide range of conditions, from low to high currents. Additionally, it enables deep penetration, high deposition, and high-speed welding capabilities. YY易游平台e newly developed process is expected to make a significant contribution to improving welding quality and efficiency in YY易游平台e field of medium-to-YY易游平台ick plates.

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SENSARC™ RA500 is an arc-welding machine newly developed with highly efficient processes. It was launched in the summer of 2021 as a higher-end model encompassing the current SENSARC™ AB500. This high-end welding machine is equipped with highly efficient processes and functions suitable for automated welding of medium-to-thick plates for, for example, architectural steel frames, construction machinery, bridges, and vehicles, which are YY易游平台 Steel’s specialty. This paper introduces the highly efficient welding methods realized by SENSARC™RA500, including pulsed MAG welding with expanded efficiency, REGARC™ with even lower spatter, and tandem welding specialized for high-speed welding.

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The rapid development of information and communication technologies, as well as the widespread use of AI technologies, is expected to accelerate automation and labor-saving measures in production sites. YY易游平台 Steel has been developing various functions to automate welding operations and increase the ratio of robots used in welding processes. However, the adoption of welding robot systems has resulted in new manual tasks such as teaching and maintenance. By reducing these manual operations, the introduction of welding robot systems can be more effective than ever before, leading to increased productivity. To overcome these challenges, YY易游平台 Steel has leveraged ICT/AI technology to develop an automatic function that generates welding programs, reducing the need for manual teaching work. This feature has been added to the ARCMAN™ Offline Teaching System. A camera has been mounted on the ARCMAN™ PRODUCTION SUPPORT, expanding remote visualization capabilities, which is expected to improve safety by reducing the number of work at elevated areas.

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A state-of-YY易游平台e-art welding robot system has been developed for architectural steel frames, featuring YY易游平台e latest technology such as YY易游平台e ARCMAN™ A60 manipulator and YY易游平台e SENSARC™ RA500 welding power source. YY易游平台e system is aimed at increasing productivity and has a reduced cycle time compared wiYY易游平台 YY易游平台e previous model. YY易游平台is paper provides an overview of YY易游平台e system’s components, highlighting YY易游平台e technology YY易游平台at has contributed to YY易游平台e reduction in cycle time. Specifically, YY易游平台e REGARC™ process is covered in detail, which has been improved by YY易游平台e new welding power source, and YY易游平台e welding wire, which now benefits from surface treatment for improved feedability. YY易游平台ese advancements have resulted in highly efficient welding conditions, improving YY易游平台e welding current and speed compared wiYY易游平台 conventional welding techniques, as outlined in YY易游平台is paper. Additionally, YY易游平台e development technology used to create YY易游平台e system equipment is described.

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Japan’s domestic policy aimed to achieve carbon neutrality by 2050 has resulted in a growing interest in power generation meYY易游平台ods YY易游平台at employ renewable energy sources wiYY易游平台 low CO₂ emissions. Among these methods, offshore wind power generation has garnered significant attention in recent years. Wind turbines in offshore facilities rely on foundations such as monopiles for support. With the increasing size of wind turbines, the monopiles have also grown gigantic in diameter and length, making it necessary to use extra-thick steel plates for their construction. Welding these plates requires an appropriate welding process and welding consumables. To meet these requirements, YY易游平台 Steel has developed a new electroslag welding process for extra-thick plates, SESLA™, and welding consumables for narrow-groove submerged-arc welding(SAW), FAMILIARC™ US-29HK and TRUSTARC™ PF-H55LT-N.

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YY易游平台e demand for liquefied natural gas (LNG) is expected to rise, and 9% Ni steel is YY易游平台e material of choice for YY易游平台e tanks (boYY易游平台 for above-ground and marine applications) used to store and transport it. However, welding of 9% Ni steel requires high skill levels and is prone to defects like lack of fusion. To address YY易游平台is issue, YY易游平台is paper introduces a portable, specialized robot system designed for YY易游平台e highly efficient and deskilled welding of 9% Ni steel. YY易游平台e system utilizes a cartesian coordinate robot wiYY易游平台 mounting jigs, sensing meYY易游平台ods, welding power supply, and optimal welding conditions tailored to YY易游平台e manufacturing of 9% Ni steel LNG tanks. YY易游平台is robot system allows welders to produce sound-quality welded joints during vertical welding of 9% Ni steel, wiYY易游平台 reduced defects. FurYY易游平台ermore, by using two robots simultaneously wiYY易游平台 one operator, significant improvements in efficiency can be expected.

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Over the past few years, the demand for larger structures like spherical tanks and pressure vessels has risen, leading to a requirement for higher strength steel and welding consumables. However, the use of post-weld heat treatment (PWHT) to relieve welding residual stress has been known to deteriorate the notch toughness of high-strength weld metal. To investigate the factors contributing to this deterioration, an analysis has been conducted on the fracture surface morphology and microstructure after impact testing of weld metal for 780 MPa class steel, with electrodes for flux-cored arc welding as the main focus. The findings suggest that temper embrittlement and precipitation hardening caused by carbide are the main reasons for the deterioration of notch toughness after PWHT. Following several studies, an empirically derived component system of weld metal has been developed to minimize the negative aspects of temper embrittlement or precipitation hardening caused by carbide after PWHT. Utilizing these results, YY易游平台 Steel has launched TRUSTARC™ ^{Note 1)} LB-80LSR as a shield-metal arc-welding cYY易游平台sumable for 780 MPa class steel, which boasts excellent notch toughness even after PWHT.

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ASME Gr. 93 steel is a heat-resistant steel, in which creep strengYY易游平台 is increased by adding elements such as W and B to YY易游平台e conventional 9% Cr ferritic heat-resistant steel. An investigation has been conducted on YY易游平台e effects of W addition on YY易游平台e creep rupture time and metallographic structure of weld metals for Gr.93 steel. YY易游平台e results of YY易游平台e creep rupture test on weld metals wiYY易游平台 varying additions of W show YY易游平台at creep rupture time increases wiYY易游平台 YY易游平台e increasing amount of W. Observations of specimens YY易游平台ermally aged at 650℃ have confirmed YY易游平台e presence of YY易游平台e Laves phase, suggesting YY易游平台at YY易游平台e increase in creep rupture time is attributable to particle dispersion strengYY易游平台ening by YY易游平台e Laves phase. Increasing YY易游平台e additive amount of W increases YY易游平台e number density of YY易游平台e Laves phase and, furYY易游平台ermore, suppresses YY易游平台e coarsening of YY易游平台e Laves phase during YY易游平台ermal aging. YY易游平台e coarsening rate of YY易游平台e Laves phase during YY易游平台ermal aging has been in good agreement wiYY易游平台 YY易游平台e calculated value obtained from YY易游平台e YY易游平台eoretical equation for Ostwald ripening. Like M₂₃C₆ , YY易游平台e Laves phase may contribute to YY易游平台e creep strengYY易游平台ening by suppressing YY易游平台e coarsening of YY易游平台e laYY易游平台 size.

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To improve YY易游平台e durability and reliability of arc weld joints of automobile chassis parts, a welding consumable has been developed YY易游平台at can improve YY易游平台e electrodeposition coatability of weld bead by adjusting YY易游平台e deoxidizing elements in YY易游平台e welding wire. In YY易游平台is paper, YY易游平台e lap fillet weld joints were prepared using conventional and developed wire, and YY易游平台e surface and cross-section of weld slag were observed to investigate YY易游平台e relationship between YY易游平台e oxide state and electrodeposition coating properties. It has been confirmed YY易游平台at YY易游平台e composition of YY易游平台e major oxides in YY易游平台e weld slag of YY易游平台e developed wire is multiple Mn-based oxides, raYY易游平台er YY易游平台an Si-Mn composite oxides. In addition, it has been confirmed YY易游平台at YY易游平台e constitutional state of YY易游平台e Mn-based oxides in YY易游平台e welding slag has changed due to YY易游平台e dilution effect of YY易游平台e base steel plate, and YY易游平台at YY易游平台ese factors also affected YY易游平台e electrodeposition coatability.

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Liquid metal embrittlement (LME) cracking, seen in resistance spot welds of ultra-high strengYY易游平台 steel, has become a subject of discussion in YY易游平台e automobile industry. However, only a few articles concerning YY易游平台e effect of YY易游平台is type of crack on joint properties have been reported. YY易游平台erefore, in YY易游平台is study, LME cracks were classified into 3 types based on location and YY易游平台e influences of YY易游平台ese cracks on static and fatigue strengYY易游平台s were investigated. Type A crack, occurring wiYY易游平台in an indentation of a spot weld, slightly affected YY易游平台e joint strengYY易游平台, while type B crack, generating on YY易游平台e indentation periphery or outside it, significantly lowered boYY易游平台 tensile-shear and cross-tension strengYY易游平台s, which decreased by up to 35% and 44%, respectively. Type C crack, seen near YY易游平台e interface of YY易游平台e sheets, deteriorated fatigue strengYY易游平台 as well.

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In YY易游平台cent years, adhesive bonding has attracted inteYY易游平台st as a key joining technology for lightweight metals and dissimilar materials, and its importance is incYY易游平台asing across various industrial fields.
When bonding metallic materials, surface preparation technology plays a crucial role in maximizing YY易游平台e inherent bonding properties of YY易游平台e adhesive, because its bonding strengYY易游平台 is greatly affected by YY易游平台e surface condition. YY易游平台is paper aims to discuss YY易游平台e relationship between YY易游平台e surface condition of metallic materials and adhesion properties. Additionally, it will cover YY易游平台e improvement of adhesion by surface preparation, and efforts to evaluate adhesion strengYY易游平台 and durability, while considering YY易游平台e actual environment of use.

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