• Title/Summary/Keyword: 겹치기 용접

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A evaluation on laser lap welding characteristics of Al5J32 alloy for automotive application using Yb:YAG Laser welding (Yb:YAG 레이저를 이용한 자동차용 알루미늄 Al5J32 겹치기 용접부의 Spiking방지 및 용접성 평가)

  • Ahn, Do-Chang;Kim, Cheol-Hee;Kim, Jae-Do
    • Proceedings of the KWS Conference
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    • pp.93-93
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    • 2010
  • 환경 규제 및 배출가스 규제에 의하여 차량 경량화를 위해 점차적으로 Al합금의 차체 및 부품적용 비율이 점차 확대되고 있다. 이에 따라 알루미늄의 레이저 용접 시 출력, 초점거리, 용접 속도 등 공정 변수의 상관관계와 용접 결함 현상에 의한 관심이 집중된 연구가 많이 발표되었으며, 알루미늄 5000계열의 경우 박판 용접 시 기공, 균열 등 과 같은 결함 현상을 방지하기 위하여, Twin spot laser, Laser-TIG hybrid 등과 같은 공법 적용을 제안되었다. 본 연구에서는 Yb:YAG laser welding 시 Mg 함량이 높은 AA5J32을 소재를 이용하여 박판 겹치기 용접 시 Back side spiking 결함 방지를 위한 레이저 빔 출력 파형을 설계하여 실험을 수행하였다. 또한 파형의 특성에 따라 나타나는 겹치기 용접부의 기계적 특성과 기공에 대해 알아 보고자 하였다.

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Weldability of STS316L for LNG Carrier by Fiber Laser (파이버 레이저를 이용한 LNG선용 STS316L의 용접특성)

  • Kim, Jong-Do;Lee, Jae-Beom;Lee, Chang-Je;Song, Moo-Keun;Nam, Gi-Jeong
    • Journal of Advanced Marine Engineering and Technology
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    • v.36 no.8
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    • pp.1061-1068
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    • 2012
  • These days, world wide interest about global warming and environmental pollution and exhausting fossil fuel which have been main energy source in all around the world. So many country have tried to find out the solution by investing new & renewable and clean energy. Therefore LNG have been widely used as a substitution of fossil fuel and clean energy that emits less pollutant like SOx, NOx. Therefore LNG consumption has been quickly raised and LNG carriers have been getting larger for decades. In this study, high power fiber laser was used for welding of stainless steel for LNG carrier to increase its productivity. Used material was STS316L which has low carbon less than 0.03% and its thickness was 8 mm. We carried out bead, lap and butt welding by using the fiber laser which has maximum power up to 5kW. As a result, we could find out that lap and butt joint was possible at welding speed of 2.0m/min and 3.0m/min respectively.

Development of Simplified Finite Element Models for Welded Joints (용접 결합부에 대한 단순화 유한요소 모델 개발)

  • Song, Seong-Il;Ahn, Sung Wook;Kim, Young Geul;Kim, Hyun-Gyu
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.11
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    • pp.1191-1198
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    • 2015
  • In this paper, we develop simplified finite element (FE) models for butt-, lap- and T-welded joints by performing numerical and experimental experiments. Three-point bending tests of butt- and lap-welded specimens are performed to obtain the stiffness of the specimens and the strains at points near the welding beads. Similarly the stiffness and strains of T-welded specimen are measured by applying a point load at the end of the specimen. To develop simplified FE models, we consider the shape parameters of width, thickness and the angle of weld elements in the numerical simulations. The shape parameters of the simplified FE models are determined by building linear regression models for the experimental data sets.

Characteristics of Fiber Laser Lap Welding of Pure Aluminum Multi-thin Plate (순수 알루미늄 다층 박판의 Fiber 레이저 겹치기 용접 특성)

  • Yang, Yun Seok;Park, Eun Kyeong;Lee, Ka Ram;Yoo, Young Tae
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.9
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    • pp.931-942
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    • 2013
  • In this study, we analyzed and compared the ultrasonic welding with the laser welding for the pure aluminium thin plates in a series of secondary lithium-ion batteries which are currently being produced by the ultrasonic welding; and performed the experiment for the purpose of the preceding study to replace the ultrasonic welding method with the laser welding method. As a result, the weld width of ultrasonic welding was 5mm, but that of laser welding was about 1~1.5 mm. As a result of tension test, the tensile strength was high when the pulse duration hour was short at the low peak power, while the high tensile strength was achieved when the pulse duration hour was long at the high peak power. The value of tensile strength was higher in the ultrasonic welding while the laser welding showed a maximum 45% better result as for the welding width.

Pulse GMA weldability of AHSS for Automobile body (자동차 차체용 AHSS 소재에 대한 펄스 GMA 용접성 평가)

  • So, Woo-Ju;Kim, Dong-Cheol;Kang, Mun-Jin;Rhee, Se-Hun
    • Proceedings of the KWS Conference
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    • pp.31-31
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    • 2009
  • 최근 전세계적으로 유가상승 및 환경에 대한 관심이 증대되면서 자동차 업계에서는 차량 경량화를 통한 연비향상에 대한 연구가 활발히 진행되고 있다. 대표적인 기술개발 사례로서 초경량 철강 차체의 개발을 들 수 있다. 이는 고장력강을 적용함으로써 강성을 증대시킴과 동시에 두께감소에 의한 경량화를 이루고자 추진되고 있다. 하지만 고장력강은 자체의 높은 강성을 지니고 있는 반면, 일반 강종에 비해서 스프링백이 크고 용접성도 많이 떨어지는 제약을 안고 있다. 아크 용접법 중 하나인 AC pulse MIG 용접은 DCEP (direct current electrode positive) 와 DCEN (direct current electrode positive) 구간이 주기적으로 반복하는 용접법으로 스패터 발생이 거의 없으며 특히 갭 접합성이 우수하여 자동차 차체 조립공정에 적용되고 있다. 본 연구에서는 자동차 차체용 AHSS 소재의 겹치기 용접 실험을 통해 실제 생산라인에서 용접 이음부에 발생되는 갭에 대해 강건한 용접 공정 조건을 제시하였다. 먼저 고속카메라 촬영을 통해 AC pulse MIG 용접에서 EN ratio 변화에 따른 와이어 용융현상을 분석 하였으며 단면마크로, 인장시험, 인장 파단면 분석을 통해 겹치기 용접에서 0~2mm 사이의 갭 발생에 강건한 용접 조선을 제시하였다.

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The Study on Weldability of Boron Steel and Hot-Stamped Steel by Using Laser Heat Source (III) - Comparison on Laser Weldability of Boron Steel and Hot-Stamped Steel - (레이저 열원을 이용한 보론강 및 핫스탬핑강의 용접특성에 관한 연구 (III) - 보론강 및 핫스탬핑강의 레이저 용접특성 비교 -)

  • Choi, So Young;Kim, Jong Do;Kim, Jong Su
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.1
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    • pp.89-94
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    • 2015
  • This study was conducted to compare the laser weldability of boron steel and hot-stamped steel. In general, boron steel is used in the hot-stamping process. Hot-stamping is a method for simultaneously forming and cooling boron steel in a press die after heating it to the austenitizing temperature. Hot-stamped steel has a strength of 1500 MPa or more. Thus, in this study, the laser weldability of boron steel and thet of hot-stamped steel were investigated and compared. A continuous wave disk laser was used to produce butt and lap joints. In the butt welding, the critical cooling speed at which full penetration was obtained in the hot-stamped steel was lower than that of boron steel. In the lap welding, the joint widths were similar regardless of the welding speed when full penetration was obtained.

The Study on Weldability of Boron Steel and Hot-Stamped Steel by Using Laser Heat Source (II) - Laser Weldability of Hot Stamping Steel with Ultra-High Strength - (레이저 열원을 이용한 보론강 및 핫스탬핑강의 용접특성에 관한 연구 (II) - 초고강도 핫스탬핑강의 레이저 용접특성 -)

  • Kim, Jong Do;Choi, So Young;Park, In Duck
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.12
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    • pp.1373-1377
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    • 2014
  • Hot-stamping is a method of obtaining ultrahigh-strength steel by simultaneously forming and cooling boron steel in a press die after it has been heated at $900^{\circ}C$ or above. After heat treatment, boron steel has a strength of 1500 MPa or more. This material ensures a high level of quality because it overcomes the spring-back phenomenon, which is a problem associated with high-strength steel materials, and the degree of dimensional precision is improved by 90 or more because of the good formability compared with existing types of steel. In this study, the welding characteristics were identified through the butt and lap welding of hot-stamped steel using a disk laser. Full penetration was obtained at a faster speed with butt welding compared to lap welding, and a white band was observed in every specimen.