• 제목/요약/키워드: Repair Welding

검색결과 158건 처리시간 0.018초

Experimental evaluation of fatigue strength for small diameter socket welded joints under vibration loading condition

  • Oh, Chang-Young;Lee, Jun-Ho;Kim, Dong-Woo;Lee, Sang-Hoon
    • Nuclear Engineering and Technology
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    • 제53권11호
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    • pp.3837-3851
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    • 2021
  • To investigate how the fabrication and repair of socket welded joints could be used to enhance fatigue resistance under vibration condition, experimental test data of installation conditions that potentially influence fatigue strength were analyzed with the S-N curve. It was found that the decreasing fatigue strength of stainless steel socket welded joints was attributed to the effect of high heat input of welding process. The effect of welding method, slip-on gap and radial-gap conditions on fatigue strength was insignificant. The test data of repair technique application, 2 × 1 leg length and of socket weld overlay, clearly showed higher fatigue strength but there was a limitation for higher stress region because of the weld toe crack.

수중용접봉으로 용접한 누수 배관 용접부위의 부식 특성 평가 (Evaluation of Corrosion Characteristics on Welding Part of Leakage Water Pipe by Underwater Welding Electrode)

  • 김진경;문경만
    • 한국마린엔지니어링학회:학술대회논문집
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    • 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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    • pp.93-94
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    • 2006
  • The repair welding of small leakage parts on the water pipeline in engine room is often and important factor in standby and emergency condition in a ship. So, the purpose of this study is to evaluate the corrosion characteristics of welding part of leakage water pipe in case of some underwater welding electrodes. The corrosion current density between welding metal and base metal was considerably different according to used underwater welding electrodes. In case of DC welding, its corrosion characteristics was better than that of AC welding.

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Mathematical Models for Optimal Bead Geometry for GMA Welding Process

  • Park, C.E.;Li, C.S.;Kim, I.S.
    • International Journal of Korean Welding Society
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    • 제3권1호
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    • pp.8-16
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    • 2003
  • A major concern in Gas Metal Arc (GMA) welding process is the determination of welding process variables such as wire diameter, gas flow rate, welding speed, arc current and welding voltage and their effects on the desired weld bead dimensions and shape. To successfully accomplish this objective, 81 welded samples from mild steel AS 1204 flats adopting the bead-on-plate technique were employed in the experiment. The experimental results were used to develop a mathematical model to predict the magnitude of bead geometry as follows; weld bead width, weld bead height, weld bead penetration depth, weld penetration shape factor, weld reinforcement shape factor, weld bead total area, weld bead penetration area, weld bead reinforcement area, weld bead dilution, length of weld bead penetration boundary and length of weld bead reinforcement boundary, and to establish the relationships between weld process parameters and bead geomery. Multiple regression analysis was employed for investigating and modeling the GMA process and significance test techniques were applied for the interpretation of the experimental data.

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클래드강 맞대기 용접부의 후열처리 유지시간에 따른 델타 페라이트 거동 (δ-Ferrite Behavior of Butt Weld Zone in Clad Steel Plates Depended on Holding Time of PWHT)

  • 박재원;이철구
    • Journal of Welding and Joining
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    • 제32권2호
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    • pp.29-36
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    • 2014
  • Recently, in order to enhance the function and usefulness of products, cladding of dissimilar materials that maximizes the performance of the material is being widely used in all areas of industry as an important process. Clad steel plate, produced by cladding stainless steel plate, an anticorrosive material, on carbon steel plate, is being used to produce pressure vessels. Stainless steel plate has good corrosion resistance, and carbon steel plate has good rigidity and strength; clad steel can satisfy all of these qualities at once. This study aims to find the ${\delta}$-ferrite behavior, mechanical properties, structure change, integrity and reliability of clad steel weld on hot rolled steel plates. For this purpose, multi-layer welding, repair welding and post weld heat treatment were implemented according to welding procedure specifications (WPS). In order to observe the mechanical properties and toughness of clad steel weld zone, post weld heat treatment was carried out according to ASME Sec. VIII Div.1 UW-40 procedure for post weld heat treatment. With heat treatment at $625^{\circ}C$, the hold time was used as the process variable, increased by intervals that were doubled each time, from 80 to 1,280 min. The structure of weld part was typical cast structure; localized primary austenite areas appeared near central vermicular ferrite and fusion line. The heat affected zone showed rough austenite structure created by the weld heat input. Due to annealing effects of heat treatment, the mechanical properties (tensile strength, hardness, impact value) of the heat affected area tended to decrease. From the results of this study, it is possible to conclude the integrity of clad steel welds is not affected much in field welding, repair welding, multi-layer welding, post weld heat treatment, etc.

주철 보수용접부의 잔류응력 분포에 관한 연구 (A study on Residual Stress Distribution of a Repair Weldment of Casting)

  • 김현수;배상득;박윤기
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2003년도 추계학술발표대회 개요집
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    • pp.207-209
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    • 2003
  • In FE analysis for residual stress of a casting, contact force between mould and casting material and gravity force must be considered for exact simulation. Preheating of a repair weldment had a little effects on the reduction of residual stress. However, preheating with hammer peening had a great deal of effects on the reduction of residual stress. A method for estimation of fatigue life for a repair weldment has been established.

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