• Title/Summary/Keyword: Contact Welding

검색결과 219건 처리시간 0.026초

Nickel dust-induced occupational contact dermatitis by welding and grinding work in shipyard workers: a report of nine cases

  • Daehwan Kim;A Ram Kim;Hanjun Kim;Sunghee Lee;Byeonghak Seo;Ho Seok Suh;Chang Sun Sim;Heun Lee;Cheolin Yoo
    • Annals of Occupational and Environmental Medicine
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    • 제34권
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    • pp.7.1-7.10
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    • 2022
  • Background: Occupational skin diseases are skin conditions that occur or worsen in relation to work and known to be the second most common type of occupational disease affecting individuals in the United States. In Korea, epidemiological reports related to occupational skin diseases are rare. But, no cases of occupational contact dermatitis caused by welding and grinding work have been reported previously. Case presentation: Nine male workers working in the production department for liquefied natural gas (LNG) ships in Ulsan complained of erythematous papules/patches and itching in various areas of the body after welding and grinding work. The work environment monitoring report revealed that the amount of nickel dust exceeded the time weighted average (TWA) and poor local ventilation status. Based on the symptoms and the overall results of surveys, several tests, and work environment monitoring report, the 2 workers who had positive patch-test reactions to nickel were diagnosed with nickel dust-induced allergic contact dermatitis. The other 7 workers were diagnosed that there was a high probability that they had nickel dust-induced irritant contact dermatitis. The 2 workers who had nickel dust-induced allergic contact dermatitis were recommended to switch their jobs. Conclusions: Nickel is one of the most common cause of allergic contact dermatitis. In this case, the dust was assumed to be created by welding work with a high nickel content new welding rod and subsequent grinding work, and the concentration of this dust exceeded the time weighted average. Thus, it is thought that the nickel dust may have caused contact dermatitis through continuous contact with the workers' exposed skin in a poorly ventilated space. Currently, several domestic shipbuilding companies are manufacturing LNG tankers using a new construction method. Consequently, it is highly likely that similar cases will occur in the future, which makes this case report meaningful.

GMA용접 동안 콘택트팁 마모가 용접품질에 미치는 영향 (Effect of welding quality to wear of Contact Tips for GMA Welding)

  • 김남훈;김희진;유회수
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2004년도 춘계 학술발표대회 개요집
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    • pp.188-190
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    • 2004
  • 가스메탈아크용접(gas metal arc welding, 이하 'GMA용접' 이라고 함)은 용가재로서 소모전극 와이어를 일정한 속도로 용융지에 공급하면서 와이어 선단과 모재 사이에서 전기적 아크가 발생되도록 하는 용접법이다. (중략)

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곡 블록 용접변형 해석법에 관한 연구 - 해석법 정립 및 실 블록 적용 (Study on Analysis Method for Welding Deformation of curved Block - Development of Analysis and Application of real Block)

  • 이명수;장경복;양진혁;강성수
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2006년도 춘계 학술대회 개요집
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    • pp.77-79
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    • 2006
  • To achieve high productivity of assembly hull blocks, it is important to predict welding deformations accurately and to apply these data to the production planning. In the deformation analysis of hull block, simplified methods (elastic analysis) such as inherent method, equivalent loading method and local & global approach are usually used instead of thermal-elastic-plastic analysis because of calculating time and cost. To be much more practical, these simplified methods should consider gravity effect of plate and contact condition between the plate and the positioning jig. In this research, using finite element method, practical predicting method for the welding deformation of the curved hull blocks with considering welding sequence, gravity effect and contact condition is proposed.

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곡 블록 용접변형 해석법에 관한 연구 - 시험편 테스트 및 검증 (Study on Analysis Method for Welding Deformation of curved Block - Specimen test and Verification)

  • 이명수;장경복;박중구;양진혁;강성수
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2005년도 추계학술발표대회 개요집
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    • pp.17-19
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    • 2005
  • To achieve high productivity of assembly hull blocks, it is important to predict welding deformations accurately and to apply these data to the production planning. In the deformation analysis of hull block, simplified methods (elastic analysis) such as inherent method, equivalent loading method and local & global approach are usually used instead of thermal-elastic-plastic analysis because of calculating time and cost. To be much more practical, these simplified methods should consider gravity effect of plate and contact condition between the plate and the positioning jig. In this research, using finite element method, practical predicting method for the welding deformation of the curved hull blocks with considering welding sequence, gravity effect and contact condition is proposed.

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스텐레스 철도차량 외판 압흔 깊이 감소를 위한 스폿용접용 전극팁 개발 (Development of electrode tips for spot welding to reduce indentation of car body surface of stainless rolling stocks)

  • 서승일
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2002년도 춘계학술대회 논문집
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    • pp.386-391
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    • 2002
  • Stainless rolling stocks are usually fabricated by spot welding process without painting. Indentation on the surface of the car body after spot welding injures the beauty of the stainless rolling stocks. In this study, electrode tips to reduce the indentation are developed and applied to the actual spot welding works. The developed tips are composed of head, nut hole far cooling water, body and resistance material. They provide large surface contact area with the base materials during spot welding and enhance the current density by necking. Experimental results using the developed tips show that small indentation and sufficient tensile shear strength is produced due to large contact area and enhanced current density.

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