A Study on the Welding Characteristics of Hastelloy C-276 using a Continuous Wave Nd:YAG Laser

Na, Gee-Dae; Yoo, Young-Tae; Shin, Ho-Jun; Oh, Yong-Seok

Journal of KWJS 2008;26(5):49-59.
Published online November 12, 2008.

연속파형 Nd:YAG 레이저를 이용한 Hastelloy C-276의 용접특성에 관한 연구

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A Study on the Welding Characteristics of Hastelloy C-276 using a Continuous Wave Nd:YAG Laser

Gee-Dae Na, Young-Tae Yoo, Ho-Jun Shin, Yong-Seok Oh

Abstract

Hastelloy C-276, corrosion resistant alloy at high temperature, is used in chemical plant and power generation industry. In this study, process parameter of laser welding for welding property in Hastelloy C-276 using a continuous wave Nd:YAG laser was studied. As the result of experiment, laser welding did not show segregation or crack at heat affected zone compared to conventional GTWA welding. The melting zone showed cell dendritic structure along with welding line. In addition, planer front solidification is occurred from welding structure, and it was progressed to cellular solidification. Optimal process parameter for butt welding was 1.2kW and 2.0 m/min for laser power and welding speed, respectively. While heat input, output density, tensile stress, and longitudinal strain was 441.98×103 J/㎝2, 29.553×103 W/㎝2, 768 ㎫, and 0.689, respectively. Lap welding of the same material showed greater discrepancy in tensile property during 1 line and 2 line welding. For 1 line welding, tensile stress was about 320 MPa, and 2 line showed slightly larger tensile stress. However, strain was decreased by 20%. From this result, lap welding of the same material, Hastelloy C-276, with 2 line welding is considered to be more effective process than 1 line welding with consideration of mechanical property.

Key Words: CW Nd:YAG laser, Hastelloy C-276, Bead profile, Lap welding, Microstructure