• Title/Summary/Keyword: Welding Material

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A Study on Fatigue Strength of Austenitic Stainless Steel for Centrifuge (원심분리기용 오스테나이트계 스테인리스강의 피로강도에 관한 연구)

  • Lee, Mee-Hae;Kim, Yong-Soo;Park, Joon-Woo
    • Journal of the Korean Society of Safety
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    • v.23 no.3
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    • pp.12-16
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    • 2008
  • For industrial centrifuges, the state of their welding areas, even with a naked-eye observation, offers potential safety problems such as inconsistent bead formation. STS304, which is used mainly in centrifuges, is made of metal alloys with chrome and nickel as the main ingredients, offering excellent corrosion resistance, thermal resistance, and high strength, and thus allowing it to be used for diverse purposes. This paper conducted tensile and fatigue tests of STS304 to improve the safety of centrifuges. In the findings, for the static behavior of the STS304 material, welded specimens increased their yield and tensile strength compared with the base test specimens, but decreased their elongation ratio. Also, the data dispersion phenomenon of welded specimens remarkably increased.

Analysis of Residual Stress Relaxation in Welded Joints due to External Loads (외부하중에 의한 용접 체결부의 잔류응력 이완 특성 해석에 관한 연구)

  • Jang, Chang-Doo;Song, Ha-Cheol;Jo, Young-Chun
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2003.10a
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    • pp.167-170
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    • 2003
  • Thermal elastic-plastic analysis was performed to assess the initial residual stress distribution of welded joints considering temperature dependent material properties. The test model was the idealized boxing fillet specimen, frequently appeared in the joints of longitudinal and transverse members of ship structure. Residual stress relaxations due to external loads were analyzed by subsequent elastic-plastic analysis considering loading and unloading steps, and the characteristics of residual stress relaxations were discussed with the levels of external loads. Additionally, to define the fatigue life of crack initiation and propagation, the S-N data for each crack length were appraised.

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Multi-objective Optimum Structural Design of Marine Structure Considering the Productivity

  • Lee, Joo-Sung;Han, Jeong-Hoon
    • Journal of Ocean Engineering and Technology
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    • v.23 no.3
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    • pp.1-5
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    • 2009
  • It is necessary to develop an efficient optimization technique to optimize engineering structures that have given design spaces, discrete design values, and several design goals. In this study, an optimum algorithm based on the genetic algorithm was applied to the multi-object problem to obtain an optimum solution that simultaneously minimizes the structural weight and construction cost of panel blocks in ship structures. The cost model was used in this study, which includes the cost of adjusting the weld-induced deformation and applying the deformation control methods, in addition to the cost of the material and the welding cost usually included in the normal cost model. By using the proposed cost model, more realistic optimum design results can be expected.

Integrity Assessment of Stationary Blade Ring for Nuclear Power Plant (원자력 발전소용 블레이드링 건전성 평가)

  • Park, Jung-Yong;Chung, Yong-Keun;Park, Jong-Jin;Kang, Yong-Ho
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.85-89
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    • 2004
  • The inner side between HP stationary blades in #1 turbine of Nuclear Power Plant A is damaged by the FAC(flow assisted corrosion) which is exposed to moisture. For many years the inner side is repaired by welding the damaged part, however, FAC continues to deteriorate the original material of the welded blade ring. In this study, we have two stages to verify the integrity of stationary blade ring in nuclear power plant A. In the stage I, replication of blade ring is performed to survey the microstructure of blade ring. In the stage II, the stress analysis of blade ring is performed to verify the structural safety of blade ring. Throughout the two stages analysis of blade ring, the stationary blade ring had remained undamaged.

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Automated Production System for Manufacturing the Doctor Blades of Laser Printers (레이저프린터용 닥터 블레이드 생산 자동화)

  • Jun, Sung-Hoon;Lee, Eung-Ki
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.4
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    • pp.633-638
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    • 2012
  • The doctor blade is a core part of a laser printer and directly influences the printing quality. The main specifications for doctor blades ate for them to be precise and durable. It is necessary to study an automatic production system for doctor blades in order to obtain high-efficient manufacturing processes. In this paper, the technology and the design of the automatic production line has for manufacturing doctor blades has been researched. The automated manufacturing process consists of five steps, which are the supplying of raw material, shearing, bending, bracket supplying, and the laser-spot welding process. The proposed automatic manufacturing system allowed for faster and more reliable production of doctor blades.

Optimal Design of Metallic Sandwich Plates with Inner Dimpled Shell Subjected to 3-Point Bending (굽힘 하중을 받는 딤플형 금속 샌드위치판재의 최적설계)

  • Seong D.Y.;Jung C.G.;Yoon S.J.;Yang D.Y.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.702-705
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    • 2005
  • Metallic sandwich plates with Inner dimpled shell subjected to 3-point bending have been analyzed and then optimized for minimum weight. Inner dimpled shells can be easily fabricated by press or roll with high quality precision and bonded with same material skin sheets by resistance welding or adhesive bonding process. Optimized shape of inner dimple is a hemispherical shell to minimize weight without failure, including face yielding, face buckling and inner dimple buckling. It is demonstrated that bending stiffness of sandwich plate is 2 or 3 times than solid plates with same strength

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Development of Intelligent Filler Wire Feeding Device for Improvement of Weld quality (용접부 품질향상을 위한 지능형 용접 와이어 공급 장치 개발)

  • Lee J.S.;Sohn Y.I.;Park K.Y.;Lee K.D.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.950-955
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    • 2005
  • This paper describes an intelligent filler wire feeding device which can control 3- dimensional seam tracking and the filler wire speed by measuring the gap position and the joint gap width in laser welding. By means of visual sensor controlled filling the missing material into the joint gap and 3 dimensional seam tracking, lineup errors from manufacturing tolerances and the repeatability of lineup jigs and weld robot can be balanced and at an even seam quality which avoids weld defects. In this paper, we assessed weld quality in 2mm sheets of A16061 which had various gap width by using the intelligent filler wire feeding device.

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Analysis of Aticulated Robot Manipulator to Reduce Body's Weight (경량화를 위한 수직 다관절로봇 매니퓰레이터의 해석)

  • 최원홍;김태기;이의훈;최만수
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1993.10a
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    • pp.575-581
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    • 1993
  • This paper deals with analysis of articulated robot manipulator used for Arc welding and Material handling. Compared with present robot of which weight holding capacity is 6kg, this robot shows wider and symmetric working range for it's serial type mechanism. The link length is determined to have widest working range by using optimal simulation. To reduce body's weight, small AC servo motor is adopted and driving peak torque exerted at each joint is reduced by using dynamic analysis. So it is possible to reduce body's weight by 40% compared with the same class's robot and get wider working range. And by adopting modular design concept, each axis is designed to be changed easily for user's special need and repair.

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Hot Metal Extru-Bending Process for the Aluminum Curved Tube Product (알루미늄 중공 곡관제품의 열간 압출굽힘가공)

  • 박대윤;진인태
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.05a
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    • pp.359-362
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    • 2003
  • The bending phenomenon has been known to be occurred by the different of velocity at the die exit. The difference of velocity at the die exit section can be obtained by the different velocity of billets through the multi-hole container and by the cohesion of billet inside the porthole die chamber. The bending phenomenon can be controlled by the different hole diameter. The experiments using aluminium material for the curved tube product had been done. The results of the experiment show that the curved tube product can be formed by the extru-bending process without the defects such as the distortion of section and the thickness change of the wall of tube and the folding and wrinkling. It is known that the welding and extruding of each billet has done simultaneously although the curved tube is extruded with four billets.

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Forming Characteristics of Laser Welded Tailored Blanks I : Tensile Deformation Characteristics. (레이저 용접 테일러드 블랭크의 기본 성형특성 I : 인장변형 특성)

  • Park, Gi-Cheol;Han, Su-Sik;Kim, Gwang-Seon;Gwon, O-Jun
    • Transactions of Materials Processing
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    • v.7 no.1
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    • pp.23-35
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    • 1998
  • In order to analyze the tensile deformation characteristics of laser welded tailored blanks. laser welded blanks of different thikness and strength combinations were prepared and tensile tests were done. The tensile elongation along the direction perpendicular to weld line of laser welded blanks was reduced as increasing the deformation restraining force (strength X thicknes) ratio between two welded sheets and fracture occurred at weaker side of base sheets if void ration of welded sheets and fracture occurred at weaker side of base sheets if void ratio of weld section was less than 45% The tensile elongation along weld line reached above 90% of the elongation of base material if welding was done perfectly. Total elongation along the direction perpendicular to weld line was able to be predicted by force equilibrium and power law behavior of base sheets and it was related with the deformation of stronger sheet and formability of weaker side.

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