Journal of Mechanical Science and Technology

The Korean Society of Mechanical Engineers (대한기계학회)
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An Evaluation of Cast Stainless Steel (CF8M) Fracture Toughness Caused by Thermal Aging at 43$0^{\circ}C$

  • Kwon, Jae-Do (Department of Mechanical Engineering, Yeungam University) ;
  • Ihn, Jae-Hyuj (Department of Mechanical Engineering, Yeungam University) ;
  • Park, Joong-Cheul (Department of Mechanical Engineering, Yeungam University) ;
  • Park, Sung-Jong (Department of Mechanical Engineering, Yeungam University)
  • Published : 2002.07.01
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Abstract

Cast stainless steel may experience embrittlement when it is exposed approximately to 300$\^{C}$ for a long period. In the present investigation, the three classes of the thermally-aged CF8M specimen were prepared using an artificially-accelerated aging method. After the specimens were held for 300, 1800 and 3600hrs. at 430$\^{C}$, respectively, the specimens were quenched in water which is at room temperature. Load versus load line displacement curves and J-R curves were obtained using the unloading compliance method. talc values were obtained using the ASTM E813-87 and ASTM E 813-81 methods. In addition to these methods, talc values were obtained using the SZW (stretch zone width) method described in JSME S 001-1981. The results of the unloading compliance method are J$\_$Q/=543.9kJ/㎡ for virgin materials. The values of J$\_$IC/ for the degraded materials at 300, 1800 and 3600hrs. are obtained 369.25kJ/㎡, 311.02kJ/㎡, 276.7kJ/㎡, respectively. The results obtained by the SZW method are compared with those obtained by the unloading compliance method. Both results are quite similar. Through the elastic-plastic fracture toughness test, it is found that the value of loc is decreased with an increase of the aging time.

Keywords

References

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