• Title/Summary/Keyword: welding plate

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Development of Heat Plate on Butt Welding for PE pipes (PE 배관 맞대기 융착을 위한 열판의 개발)

  • Jin, Hyeong-Guk;Kim, Jae-Seong;An, Dae-Hwan;Lee, Bo-Yeong
    • Proceedings of the KWS Conference
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    • 2006.10a
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    • pp.292-294
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    • 2006
  • Many processes have been introduced to join PE pipes, but most of these methods have lots of disadvantages such as costs and lack of reliability, etc. Recently due to the benefits of cost, safety and reliability, the butt welding has been paid much attention to joint PE pipes. In case of butt welding, the heat plate which is used to melt PE pipes is the most critical equipment. In this study, after developing the heat plate of new shape, the PE double wall pipes with misalignments were butt-welded by using the conventional and developed heat plates and comparison of weld-zones and tensile test was performed. As the results of tensile test, weld-zones using developed heat plate have strength of $147.7{\sim}251.0%$ of weld-zones using conventional heat plate.

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Analysis of Correction of Welding Deformation of Stiffened Plate by Heating Using Equivalent Loading Method based on Inherent Strain (고유변형도 기반 등가하중법에 의한 보강판의 가열 교정 해석)

  • 송하철;류현수;장창두
    • Journal of the Society of Naval Architects of Korea
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    • v.41 no.4
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    • pp.85-91
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    • 2004
  • The objective of the present paper is to develop an analysis method for the correction of welding deformation of stiffened plate by line heating. In this paper, the equivalent loading method, based on the inherent strain theory, was used to analyze the heat-straightening of a stiffened plate. Equivalent loads were obtained by integrating the inherent strains which were determined from the highest temperature and the degree of restraint. Finally, the obtained equivalent loads were imposed, as applied loads, on the elastic analysis for the prediction of correction of welding deformation in stiffened plate. The proposed method is expected as a basic study in heat-straightening analysis of welding deformation in large scale block.

The Effects of Welding Conditions on Allowable Heat Input in Repair Weld of In-Service Pipeline

  • Kim, Y.P.;Baek, J.H.;Kim, W.S.;Bang, I.W.;Oh, K.H.
    • International Journal of Korean Welding Society
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    • v.1 no.2
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    • pp.30-35
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    • 2001
  • Nowadays, repair welding on in-service natural gas pipeline is a matter of primary concern of gas company. The main purpose of this study is to investigate the effects of welding conditions on the allowable heat input for crack-free welds and welds without burn-through onto in-service natural gas pipeline. First of all, single pass weld bead on plates of the various thickness was deposited to evaluate the penetration of weld metal, the depth of heat affected zone and the hardness of repair weld under various welding conditions. Also, finite element analysis has been conducted to validate experimental results of bead-on plate welds and to develop appropriate model for repair welding. The welding experiments of bead-on-plate weld confirmed the influence of plate thickness, heat input and welding process on safety. And, the finite element model was demonstrated by comparing experimental results. The agreement between the computed and measured values was shown to be generally good. Therefore, It is possible to predict the safety of repair welding under various welding conditions with experimental results and finite element analysis model.

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Structural Safety of Nozzle Plate using Simulation (시뮬레이션을 이용한 노즐플레이트의 구조안전성)

  • Jung, Jong Yun;Park, Heesung;Kim, Joon-Seob
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.41 no.3
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    • pp.186-193
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    • 2018
  • Modern manufacturing industries is to produce both precise and robust mechanical parts without failure while they are in service. In order to prevent a part failure for its lifetime, a mechanical design for a part should be examined on a basis of mechanical simulation. A nozzle plate, being a key part in steam engines, changes flow directions of steam in a turbine used in power plant. This paper is to the design and test for part safety and durability. Currently, nozzle plates are fabricated by welding nozzles to their plates. Welding causes some defects on the used materials while they are being manufactured. Another major defect is un-even pitches between welded nozzles. Welding causes phase changes because of high melting temperature of metal. This leads to decay on the welding spots, which weakens their structural strength and then, may lead to early damages on mechanical structures. This research proposes assembly-typed nozzle plate without welding. From the beginning, nozzle and plate are designed for insertion-typed assembly. Nozzle head and foot are designed in accordance with the grooves on outer ring and inner ring of a plate to make mating surfaces. Then the nozzle plate should be proved for structural and fatigue safety before they are put in manufacturing. This research adopts commercial softwares for modeling and mechanical simulation. The test result shows that the design with smaller mating area and deeper insertion produces higher safety in terms of structure and durability. From the conclusion, this paper proposes the assembly-typed nozzle plate to replace the welding typed.

Effect of Welding Condition on Tensile Properties of Friction Stir Welded Joints of Al-7075-T651 Plate (용접 조건이 Al-7075-T651의 마찰교반용접부의 인장 특성에 미치는 영향)

  • Kim, C.O.;Kim, S.J.
    • Journal of Power System Engineering
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    • v.15 no.2
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    • pp.61-68
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    • 2011
  • This paper investigates the tensile properties of the friction stir welded joints of Al 7075-T651 aluminum plate according to the welding conditions. A 7075-T651 aluminum alloy plate with a thickness of 6.0 mm was used in this investigation. For the friction stir welding (FSW) process, a tool with shoulder diameter of 20 mm and probe diameter of 9 mm was used. The rotation speed and traverse speed conditions were changed in this study, the other welding conditions are constant. The welding direction was aligned with the material rolling direction, and dimension of the FSW plate were $250{\times}100{\times}6\;mm$. As far as this work is concerned, the optimal FSW conditions are determined as the rotation speed, 600 rpm and traverse speed 0.8 mm/sec or the rotation speed, 800 rpm and traverse speed 0.5 mm/sec.

A study on the transverse shrinkage for the butt joint welding of plate (평판의 맞대기 이음 용접시의 가로수축에 관한 연구)

  • 이우수;왕지석
    • Journal of Welding and Joining
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    • v.5 no.3
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    • pp.46-52
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    • 1987
  • The mechanism of transverse shrinkage for the butt joint weldig of plates is investigated in this paper. It was certified that the compressive plastic strain due to thermal expansion of materials during heating play an important role on the transverse shrinkage. It was also pointed out that the transverse shrinkage has to be treated with the samples of which the shapes are as close to real shapes of welded materials as possible, because the distribution of temperature and relative rigidity of materials during welding have great influence on the transverse shrinkage. The formulas for the calculation of transverse shrinkage were presented and the experiments were carried out in order to verify the formulas. the main results are as follows; 1. For the bead-on-plate welding, the transverse shrinkage in the begining parts of welding is the smallest, the end parts is next and the transverse shrinkage of mid section is the largest. 2. In bead-on-plate welding, the equations presented in this paper concerning transverse shrinkage coincide fairly well with the experimental values generally. 3. Transverse shrinkage increases generally as specific heat input per unit thickness increaes.

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High Current Arc Welding Technology of Aluminum Alloy (알루미늄 합금의 대전류 아크용접 기술)

  • Choi, Young-Bae;Kang, Mun-Jin;Kim, Dong-Cheol;Hwang, In-Sung
    • Journal of Welding and Joining
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    • v.31 no.1
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    • pp.21-25
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    • 2013
  • Aluminum alloy, Al5083-O, is one of candidate materials for the LNG storage tank, because of its excellent weldability, cryogenic characteristics, and corrosion resistance. The good weldability of Al5083-O is very important in LNG storage tank manufacturing. In this study, high current metal inert gas(MIG) welding process was used to get one pass welding of thick plate aluminum alloy. Bead on plate(BOP) welding was performed to evaluate the effect of welding conditions on the height of bead and depth of penetration. The optimum welding conditions were derived to get one pass welding of the thickness of 14.5mm. The mechanical properties of the welded joint were evaluated. The cross-sectional macro test, tensile test, and bending test satisfied the class rule.