화력 발전용 고압 로터강의 정하중 및 변동하중하의 고온 크립 균열전파 특성에 관한 연구

다국어 초록 (Multilingual Abstract)

The crack length measurements by electrical potential(EP) method for 1% Cr-Mo-V and 12%Cr steel of 0.5T-CT specimen were performed at 500℃, 600℃ and 700℃, and an applicability of stress intensity factor(K<SUB>I</SUB>), net section stress(σ<SUB>net</SUB>), C<SUP>*</SUP>-integral and C<SUB>t</SUB> parameter was studied to measure creep crack growth rate(da/dt) with side groove and without side groove under static and cyclic loading condition. The experimental result could be summarized as follows :<br/>
1) Crack measurement by EP method was available and coincided with the Johnson's analytical equation.<br/>
2) da/dt by K<SUB>I</SUB> and σ<SUB>net</SUB> was not adequate because of the wide scatter band according to load and temperature, but C<SUP>*</SUP>-integral, except for transition region, was adequate.<br/>
3) C<SUB>t</SUB> parameter showed the best fitted line through total creep region without relating with both temperature and load condition.<br/>
4) Under the cyclic loading condition, C<SUB>t</SUB> parameter was proper to estimate da/dt.<br/>
And it was shown that da/dt for 1% Cr-Mo-V steel under the static condition(R=1) was 1.16 times faster than the case under cyclic loading(R=0), and for 12% Cr steel, 1.43 times.