A Study on HAZ Softening Characteristics of Fiber Laser Weldment for High-Strength Steel

Park, Min-Ho; Kim, Ill-Soo; Lee, Jong-Pyo; Jin, Byeong-Ju; Kim, Do-Hyeong; Kim, In-Ju; Kim, Ji-Sun

doi:2015.33.6.27

J Weld Join > Volume 33(6); 2015 > Article

Research Paper

Journal of Welding and Joining 2015;33(6):27-35.
DOI: https://doi.org/10.5781/JWJ.2015.33.6.27 Published online December 31, 2015.

A Study on HAZ Softening Characteristics of Fiber Laser Weldment for High-Strength Steel

Min-Ho Park^*, Ill-Soo Kim^*, Jong-Pyo Lee^*, Byeong-Ju Jin^*, Do-Hyeong Kim^*, In-Ju Kim^**, Ji-Sun Kim^**

Correspondence: Ill-Soo Kim,
Email: ilsookim@mokpo.ac.kr

Abstract

Laser welding sector in the automotive industry has been widely recognized as one of the most importantbonding processes, such as parts welding. Efforts to improve productivity and weld quality have been progressing steadily. In addition, laser welding is suitable for welding process that can produce high-quality welds suitable for flexible production and small quantity batch productions. In order to ensure the rigidity of the material, high strength material are applied to more than 1 GPa class body parts and automotive bumper beams. However, not only the situation is that the trend of domestic research, but also development is based on product molding considering freedom of shape where reinforcement is applied to meet the safety regulations and high-speed crash performance, despite the use of high strength materials. The tendency for heat-affected zone (HAZ) softening phenomenon common in areas of laser welded high tensile steel welding confirmed the occurrence of weld softening effect according to the process parameters. Based on this, range of process parameters could be selected for ensuring weld quality.

Key Words: Fiber laser weld, High-strength steel, Heat affected zone, Softening effect, Penetration aspect