EFFECT OF IN-SITU VIBRATION ON THE PROPERTIES OF A-GRADE STEEL SMA WELDMENT

  • Park, Tae-Dong (Hyundai Industrial Research Institute, Hyundai Heavy Industries Co. Ltd,) ;
  • Kim, Ha-Geun (Hyundai Industrial Research Institute, Hyundai Heavy Industries Co. Ltd,) ;
  • Youn, Joong-Geun (Hyundai Industrial Research Institute, Hyundai Heavy Industries Co. Ltd,)
  • Published : 2002.10.01

Abstract

Effect of in-situ vibration on the properties of A-grade steel SMA weldment has been investigated. Welding was performed on the steel fixed at the experimental jig under the mechanical vibration of a given frequency. The applied frequency varied from 39 to 43.5 Hz (harmonic frequency). For weldments formed under the vibration with a sub-harmonic frequency, both the columnar width of the weld metal and the prior austenite grain size of the HAZ near the fusion line clearly decreased. This indicates that the vibration increase the cooling rate after welding. Vibration effect was also found at the weld metal formed at the center region of the weldment. The weld metal showed liner microstructure both in columnar zone and in equiaxed zone with thinner grain boundary ferrite. However mechanical properties of the weld metal did not exactly follow the microstructural changes developed under the vibration. The weld metal formed under the vibration revealed higher yield and tensile strength but lower ductility and impact toughness, compared with the conventional weld metal.

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