Transactions of the Korean Society of Mechanical Engineers A (대한기계학회논문집A)

The Korean Society of Mechanical Engineers (대한기계학회)
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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 (Dept. of Marine Engineering, Graduate School, Korea Maritime and Ocean Univ.) ;
  • Kim, Jong Do (Division of Marine Engineering, Korea Maritime and Ocean Univ.) ;
  • Kim, Jong Su (Automotive Parts Technology Support Center, Korea Institute of Machinery & Materials)
  • 최소영 (한국해양대학교 대학원 기관공학과) ;
  • 김종도 (한국해양대학교 기관공학부) ;
  • 김종수 (한국기계연구원 부산자동차부품기술센터)
  • Received : 2014.10.09
  • Accepted : 2014.11.03
  • Published : 2015.01.01
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Abstract

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.

본 연구의 목적은 열처리 전 후의 보론강 레이저 용접성을 비교하는 것이다. 일반적으로 보론강이 핫스탬핑 공정에 사용되고 있으며, 핫스탬핑 공정은 강판을 오스테나이트 온도까지 가열한 후 성형과 동시에 냉각하는 방법이다. 열처리후 보론강은 1500 MPa 이상의 고강도를 가진다. 따라서 본 연구에서는 보론강 및 핫스탬핑강의 레이저 용접성을 조사한 후 비교하였다. CW 디스크 레이저를 이용하여 레이저 출력 및 용접속도를 변화시켜가며 맞대기 및 겹치기 용접을 실시하였다. 맞대기 용접 결과, 핫스탬핑강에서 완전 용입을 얻을 수 있는 임계냉각속도가 보론강보다 낮았으며, 겹치기 용접결과 완전 관통이 일어난 용접 조건에서는 접합부 폭은 용접속도와 관계없이 거의 유사하였다.

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References

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