• Title/Summary/Keyword: Butt weld

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Effect of Distance and Restraint Degree between Fillet and Butt Weldment on Residual Stress Redistribution at each Weldment (필릿과 맞대기 용접부 간의 간격 및 구속도에 따른 잔류응력 재분포 특성에 관한 연구)

  • Jin, Hyung-Kook;Lee, Dong-Ju;Shin, Sang-Beom
    • Journal of Welding and Joining
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    • v.28 no.3
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    • pp.59-64
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    • 2010
  • The purpose of this study is to identify the principal factor controlling transverse residual stress at the weldment for joining unit hull blocks. In order to do it, the comprehensive FE analyses were carried out to evaluate the effect of distance between fillet and butt weldments, stiffener span and in-plane restraint degree on the amount and distribution of transverse residual stress in way of the weldments between unit hull blocks. In accordance with FEA results, principal factor controlling the amount of transverse residual stress at the weldments was identified as in-plane restraint degree of butt weldment for unit blocks. The effect of other variables on the transverse residual stress was very small relatively.

Design of Specimen for Weld Residual Stress Simulation (용접 잔류응력 모사를 위한 시편 설계)

  • Kim, Jin-Weon;Park, Jong-Sun;Lee, Kyung-Soo
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.67-72
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    • 2008
  • The objective of this study is to design a laboratory specimen for simulating residual stress of circumferential butt welding of pipe. Specimen type and method for residual stress generation were proposed based on the review of prior studies and parametric finite element simulation. To prove the proposed specimen type and loading method, the residual stress was generated using the designed specimen by applying proposed method and was measured. The measured residual stress using X-ray diffraction reasonably agreed with the results of finite element simulation considered in the specimen design. Comparison of residual strains measured at several locations of specimen and given by finite element simulation also showed good agreement. Therefore, it is indicated that the designed specimen can reasonably simulate the residual stress of circumferential butt welding of pipe.

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A Study on the Corner Crack Propagation by Plane Bending Fatigue in Butt Welded Joints of Steel (平面굽힘 疲勞荷重 에 의한 鋼熔接部 의 모서리균열 傳파特性)

  • 김영식;조상명
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.6 no.3
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    • pp.232-238
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    • 1982
  • The behavior of corner crack propagation by unidirectional plane bending fatigue was investigated in the butt welded joints of SS41 and SM50 steel plates including an edge through-thickness notch. The properties of fatigue crack propagation were inspected in the weld metal, heat-affected zone, and base metal of the welded joints. Main results obtained are as follows; (1) When a plate with an edge through-thickness notch is loaded by plane bending fatigue in indirection, the 2 variant corner cracks on the upper and lower edge of the plate are initiated and propagated respectively from the notch. (2) In case of a specimen containing a corner crack, it is more reasonable to estimate the crack propagation rate by area of fracture surface than by crack surface length. (3) The rate of fatigue crack propagation becomes faster in the following order; weld metal, heat-affected zone, and base metal. (4) The specimen including reinforcement shape is rapidly failed throughout bond due to effect of its shape when the repeated load exceeds a certain cycle.

Effect of Process Parameters on Laser Weldability of AZ31 Magnesium Alloy (AZ31 마그네슘합금의 레이저 용접성에 미치는 공정변수의 영향)

  • Kim, Jong-Do;Kil, Byung-Lea;Lee, Jung-han
    • Journal of Advanced Marine Engineering and Technology
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    • v.32 no.4
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    • pp.570-577
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    • 2008
  • Magnesium alloys are potentially useful as structural materials due to higher strength/weight ratio, heat conductivity and recyclability compared to other alloys. These alloys have attracted the interest of modern manufacturing such as the automobile, computer, communication and consumer electronic appliances industries. Hence welding techniques are required to be developed for these applications. Laser are known to be an excellent tool for them. This paper presents the laser weldability of AZ31 magnesium alloy with CW Nd:YAG laser. The low viscosity and surface tension of the melt pool make magnesium more difficult to weld than steel. As a result of this study, optimal process parameters could be obtained without weld defects. Also it was certain that cutting methods had influence on butt weldability.

Design of a Laboratory Specimen for Simulation of Weld Residual Stress (용접 잔류음력 모사를 위한 시편 설계)

  • Kim, Jin-Weon;Park, Jong-Sun;Lee, Kyoung-Soo
    • Journal of the Korean Society of Safety
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    • v.24 no.1
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    • pp.7-13
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    • 2009
  • The objective of this study is to design a laboratory specimen for simulating residual stress of circumferential butt welding between pipes. Specimen type and method to generate residual stress were proposed based on the review of prior studies and parametric finite element analysis. To prove the proposed specimen type and loading method, the residual stress was generated using the designed specimen by applying proposed method and was measured. The measured residual stress using X-ray diffraction reasonably agreed with the results of finite element analysis considered in the specimen design. Comparison of residual strains measured at several locations on the specimen and given by finite element simulation also showed good agreement. Therefore, it is indicated that the designed specimen in this study can reasonably simulate the axial residual stress of a circumferential butt welding of pipe.

Study on Residual Stress Redistribution by Changing of Distance and Restraint degree between Fillet and Butt weldment (필렛 및 맞대기 용접부의 간격 및 구속도에 따른 잔류응력 재분포 특성에 관한 연구)

  • Jin, Hyung-Kook;Lee, Dong-Ju;Shin, Sang-Beom
    • Proceedings of the KWS Conference
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    • 2009.11a
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    • pp.94-94
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    • 2009
  • The purpose of this study is to identify the principal factor controlling transverse residual stress at the weldment for joining unit hull blocks. In order to do it, the comprehensive FE analyses were carried out to evaluate the effect of distance between fillet and butt weldments, in-plane and out-of-plane restraint degree on the amount and distribution of transverse residual stress in way of the weldments between unit hull blocks. In accordance with FEA results, principal factor controlling the amount of transverse residual stress at the weldments was identified as in-plane restraint degree of butt weldment for unit blocks. The effect of other variables on the transverse residual stress was very small relatively. Based on the results, it can be concluded that the proper distance between fillet weldment for stiffener and butt weldment for joining unit blocks should be determined in consideration of in-plane restraint intensity of butt weldments.

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An Investigation of Welding Variables on Resistance Upset Welding for End Capping of HWR Fuel Elements (중수로 핵연료 봉단마개의 저항업셋 용접을 위한 용접변수)

  • 이정원;박춘호;고진현;정성훈;정문규
    • Journal of Welding and Joining
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    • v.7 no.2
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    • pp.60-69
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    • 1989
  • The present study was aimed at investigating the effect of welding parameters such as welding current, electrode force(or squeeze force) and parts cleaning on the sound weld, and establishing the most reliable weld conditions for HWP(Heavy Water Reactor) fuel end capping with the resistance upset butt welding. Major results obtained are as follows. 1. The amount of sound weld was increased with increasing weld current(5.0-11KA) because the activated diffusion with increasing heat generation played an important role in eliminating the porosity and weld line in the weld interface. 2. It was found that weld current was not significantly influenced by the electrode force although the increase of it caused a slight increase of weld current and upset deformation. 3. Acetone rinsing before drying for the Zircaloy-4 end cap cleaning produced the reliable sound weld because it would remove the remaining solvent and surface films, and provided the uniform contact between the end cap and the tube. 4. The optimum welding conditions for fuel end capping by a resistance upset hytt welding are obtained as follows. weld current: 10-11KA, electrode force: 62-90KPa parts cleaning: vapor degreasing.rarw.water, acetone rinsing.rarw.drying.

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