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비파괴 계장화 압입시험을 이용한 저항 점용접부 물성 평가

Evaluation of Mechanical Properties by Using Instrumented Indentation Testing for Resistance Spot Welds

  • 최철영 (부산대학교 재료공학부) ;
  • 김준기 (한국생산기술연구원 용접접합그룹) ;
  • 홍재근 (재료연구소 특수합금연구그룹) ;
  • 염종택 (재료연구소 특수합금연구그룹) ;
  • 박영도 (동의대학교 신소재공학과)
  • Choi, Chul-Young (School of Materials Science and Engineering, Pusan National University) ;
  • Kim, Jun-Ki (Advanced Welding & Joining Technology Center Korea Institute of Industrial Technology) ;
  • Hong, Jae-Keun (Structural Material Division, Korea Institute of Materials Science) ;
  • Yeom, Jong-Taek (Structural Material Division, Korea Institute of Materials Science) ;
  • Park, Yeong-Do (Department of Advanced Material Engineering, Dong-eui University)
  • 투고 : 2011.01.25
  • 심사 : 2011.02.18
  • 발행 : 2011.02.28

초록

Nondestructive instrumented indentation test is the method to evaluate the mechanical properties by analyzing load - displacement curve when forming indentation on the surface of the specimen within hundreds of micro-indentation depth. Resistance spot welded samples are known to difficult to measure the local mechanical properties due to the combination of microstructural changes with heat input. Particularly, more difficulties arise to evaluate local mechanical properties of resistance spot welds because of having narrow HAZ, as well as dramatic changed in microstructure and hardness properties across the welds. In this study, evaluation of the local mechanical properties of resistance spot welds was carried out using the characterization of Instrumented Indentation testing. Resistance spot welding were performed for 590MPa DP (Dual Phase) steels and 780MPa TRIP (Transformation Induced Plasticity) steels following ISO 18278-2 condition. Mechanical properties of base metal using tensile test and Instrumented Indentation test showed similar results. Also it is possible to measure local mechanical properties of the center of fusion zone, edge of fusion zone, HAZ and base metal regions by using instrumented indentation test. Therefore, measurement of local mechanical properties using instrumented indentation test is efficient, reliable and relatively simple technique to evaluate the tensile strength, yield strength and hardening exponent.

키워드

참고문헌

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