고온 구조물의 한계응력강도 결정을 위한 크리프 일-시간 관계식의 유용성

Abstract

In order to determine creep stress intensity limit of high-temperature components, the usefulness of the creep work and time equation, defined as Wc t ^p = B (where Wc = σ E is the total. creep work done during creep, and p and B are constants), was investigated using the experimental data. For this purpose, the creep tests for generating 1.0% strain for commercial type 316 stainless steel were conducted with different stresses; 160 MPa, 150 MPa, 145 MPa, 140 MPa and 135 MPa at 593°C. The plots of log Wc-­ log t showed a good linear relation up to 10^5 hr, and the results of the creep work-time relation for p, B and stress intensity values showed good agreement to those of isochronous stress-strain curves (ISSC) presented in ASME BPY NH. The relation can be simply obtained with only several short-term I % strain data without lSSC which can be obtained by long-term creep data. Particularly, this relation is useful in estimating stress intensity limit for new and emerging class of high-temperature creeping materials.