• Proceedings of the KWS Conference
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• 2002.10a
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• pp.101-106
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• 2002

Requirements to fabrication processes for arc welding of highly loaded thick-walled joint and problems of research and development in term s of the tendency for the modern aircraft structure development are outlined. A justified, choice of the development line of the new promising welding processes for solution of these problems is presented. A complex of new welding processes and technologies for making highly reliable joints with different thickness (up to 120 mm and more) and length of weld (up to 0.1 m; 0.1-0.5 m and more than 0.5 m) has bee developed. It is shown that the possibility to control the heat flow distribution over the groove surface of the welded joints provides for improved reliability. The new welding processes are equipment are effectively used in serial production of the Mykoyan md Sukhoi supersonic aircrafts as well as in AN-124 Ruslan and AN-225 Mriya wide body aircrafts.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.1-14
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• 2002

There is a continuous development of the most common welding processes like MMA, MIG/MAG, PAW and SAW. At the same time there is a conversion from stick electrodes to solid and cored wires with an increased productivity as a result. In parallel with these changes new processes are introduced and implemented. The number of Friction Stir Welding installations is starting to grow fast Hybrid laser welding has probably made a technical break through. The Magnetic Pulse Welding process is taking off. The different mechanical joining methods; clinching and self-piercing riveting; must not be forgotten. Structural adhesive is another method to consider.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.169-175
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• 2002

World demand for natural gas has generated the need for many new land transmission pipelines to be installed in the next decade or so. Although mechanized gas metal arc welding is well developed, there are opportunities for cost savings by using alternative welding processes. Hybrid Nd:YAG laser - gas metal arc welding enables fibre optic delivery of the laser energy to a robotic welding head to be combined with the addition of extra energy and a consumable to produce good quality, deep penetration welds in a single pass. The present paper describes initial procedure development to optimize the laser and gas metal arc welding parameters for making joints in pipeline steel. Satisfactory joint quality was obtained and it is intended to develop the process to prototype field trials.

• Proceedings of the KWS Conference
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• 2005.06a
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• pp.82-84
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• 2005

Among the advanced welding processes which are superior to conventional process, Electron beam welding and Narrow-gap TIG welding are most prospective in being applicable for the heavy industry field. With STS316LN, which is high strengthened austenitic stainless steel, the characteristic evaluation for these welding processes was carried out through the mechnical tests and property analyses. For the tensile strength EBW is better while in reverse for the yield strength. In Narrow-gap TIG the distribution of hardness values has some deviation according to the thickness direction while EBW has a tendency of a litter high hardness values in weld metal. After EB welding brings the reduction of nitrogen content, in TIG welding weld metal depends on the contents of welding material. Both processes have almost austenitic structure, but weld metal of EBW is also shown terrific structure

• Nuclear Engineering and Technology
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• v.33 no.2
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• pp.175-183
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• 2001

Various welding processes are now available for end cap closure of nuclear fuel element such as TG(Tungsten Inert Gas) welding, magnetic resistance welding and laser welding. Even though the resistance and TIG welding processes are widely used for manufacturing commercial fuel elements, they can not be recommended for the remote seal welding of a fuel element at a hot cell facility due to the complexity of electrode alignment, difficulity in the replacement of parts in the remote manner and a large heat input for a thin sheath. Therefore, the Nd:YAG laser system using optical fiber transmission was selected for Zircaloy-4 end cap welding inside hot cell. The laser welding apparatus was developed using a pulsed Nd:YAG laser of 500 watt average power with optical fiber transmission. The weldability of laser welding was satisfactory with respect to the microstructures and mechanical properties comparing with TIG and resistance welding. The optimum operation processes of laser welding and the optical fiber transmission system for hot cell operation in a remote manner have been developed The effects of irradiation on the properties of the laser apparatus were also being studied.

• Journal of Welding and Joining
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• v.32 no.1
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• pp.53-60
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• 2014

The automatic arc welding is generally accepted as the preferred joining technique and commonly chosen for assembly of large metal structures such as in areas of automotive, aircraft and shipbuilding due to its joint strength, reliability, and low cost compared to other joint processes. Recently, several mathematical models have been developed and studied for control and monitoring welding quality, productivity, microstructure and weld properties in arc welding processes. This study indicates the prediction of process parameters for the expected welding quality with accordance to the adaptive GTA welding process. Furthermore, the mathematical models is also develop to aid the selection of an optimal welding process as the generation of process controls to predict the bead geometry as a function output parameters in the GTA welding process. The developed models through this study showed comparatively excellent predicted results, and will extend to other welding processes to integrate an optimized system for the robotic welding process.

• Proceedings of the KWS Conference
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• 1999.10a
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• pp.43-46
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• 1999

It has been suggested that the motivation for automation of welding processes ncludes the replacement and extension of the functions of human operators. Among these types of the welding automation, SAW(Submerged Arc Welding) was prevalently used, because it is highly suited to a wide range of application, especially for the high speed welding. A Significant portion of the total manufacturing time for a pipe fabrication process is spent on the welding following primary machining and fit-up processes. To achieve the reliable weld bead appearance, the automatic seam tracking and adaptive control to fill the groove are urgently needed. This paper proposed the mechanical functions of multi-torches welding system, flux supply and recovery system in conjunction with the complex air pulsing method and various types of methodologies. It was shown that the multi-torches welding system revealed the high welding qualities for the circular and rectangular pipes. In conclusion, the multi-torches welding system developed will contribute the advanced welding technology, welding automation and increment of the market in these areas.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.3
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• pp.184-190
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• 2012

Objectives: This study aimed to characterize the nanoparticles produced by welding and grinding processes. Methods: The number concentrations of particles were mapped to determine the distribution of welding fumes in a workplace atmosphere using a hand-held condensation particle counter. An electrical low-pressure impactor was used for measuring the number concentration and particle size distribution. Results: High number concentrations were found around arc cutting and welding (grinding) processes. In the worker's breathing zone, the mean number concentration was 655,000 particles/cm3 and the count median diameter (CMD) was 84 nm with several multi peak distributions (~20, 70, 300 nm). However, at a distance of 3 m from the welding position, the number concentration decreased to 153,000 particles/cm3 with a 70 nm single peak size distribution. During a grinding process, peaks with high concentrations of nanoparticles were temporarily observed. The mean number concentration was 1,520,000 particles/cm3, and the CMD was 30 nm. Nanoparticles (<100 nm) made up 58% and 92% of the aerosols produced by welding and grinding processes, respectively.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.34 no.1
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• pp.90-96
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• 2011

The shock absorber base assembly is one of the parts in the shock absorber equipment that controls the vehicle movement. It absorbs the shock and vibration to guarantee riding stability and comfort. It demands strength, reliability and strict airtightness of the welded section because the shock absorber base assembly is a container which resists pressure and needs durability by being filled with gas and oil. However, the current engineering needs a lot of production time, has a high cost and shows a low production rate. These problem due to the eight production processes, four of which are spot welding, reinforcement welding like metal active welding (MAG), prior process of the base assembly cap and tube for precision and pressing. We will analyze the manufacturing processes of the base assembly and suggest an improved manufacturing method that uses frictional welding. The results will show that the new method of the frictional welding is better than the previous welding technique. Through the use of this concept of frictional welding, the welding conjunction will be strengthened, measurements will be more precise, and the cost and the number of processes will be reduced.

• Journal of Welding and Joining
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• v.34 no.5
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• pp.41-46
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• 2016

Welding is an absolutely essential component of industries such as the automotive industry, the construction industry and even the aviation industry. Although it is a widespread technology it is still characterized by lots of uncertainties. This still requires well experienced and highly skilled workforce to design and perform safe welding processes. The early knowledge of distortion and residual stresses is almost an issue which is influenced mainly by the welding parameters and the fixture design. But more and more engineers want to know as well final properties of the assembled components. With the beginning of the computer age in the 1970s and 1980s last century, the numerical prediction of manufacturing processes using FEM was gradually getting better and has established itself in the industry since the 1990s as a standard tool. Unlike in metal casting and forming industry, however, the everyday use of FEM- simulation tools for welding processes eked out a shadowy existence for a long time. This paper will give a short classification of welding simulation types and a structured overview on the technical questions. Selected case studies and the benefits achieved through simulations with the software Simufact welding are discussed. Finally an outlook on future developments will be given.