Effects of Mn and Heat-input on the Mechanical Properties of EGW Welds

일렉트로 가스 용접부의 기계적 성질에 미치는 Mn 및 입열량의 영향

  • Kim, Nam In (Technical Research Institute, Hanjin Heavy Industries & Construction Co., Ltd.) ;
  • Jeong, Sang Hoon (Technical Research Institute, Hanjin Heavy Industries & Construction Co., Ltd.) ;
  • Lee, Jeong Soo (Technical Research Institute, Hanjin Heavy Industries & Construction Co., Ltd.) ;
  • Kang, Sung Won (Department of Naval Architecture & Ocean Engineering, Pusan National University) ;
  • Kim, Myung Hyun (Department of Naval Architecture & Ocean Engineering, Pusan National University)
  • 김남인 (한진중공업 기술연구소) ;
  • 정상훈 (한진중공업 기술연구소) ;
  • 이정수 (한진중공업 기술연구소) ;
  • 강성원 (부산대학교 조선해양공학과) ;
  • 김명현 (부산대학교 조선해양공학과)
  • Received : 2008.09.02
  • Published : 2009.03.25

Abstract

This paper is concerned with effects of Mn and heat-input on the mechanical properties of EGW welds. Four different kinds of welding consumables were fabricated by varying Mn contents such as 1.3, 1.5, 1.7, 2.0%Mn and each consumable was welded for EGW on four heat-input conditions between 190 and 340 KJ/Cm. Mn contents were decreased as heat-input increases and alloy elements (C, Si, Ti, B, Al) to deoxidize easily also revealed similar tendency to Mn. Their microstructure, Charpy impact property and strength were investigated, and it is found that Charpy impact property and strength exhibit a strong dependence on change of microstructure by Mn contents and heat-input. The increase of Mn contents or the decrease of heat-input made the microstructure fine and increase volume fraction of acicular ferrite, thereby leading to the great improvement of Charpy impact property and strength. In case of single EGW, optimum Mn contents are over 1.7% for the toughness and strength.