Study on Creep Life Prediction by Initial Strain Method for Friction Welded Joints of Heat Resisting Steels

J. Ocean Eng. Technol. 2001;15(2):46-52.

내열강 마찰용접재의 ISM에 의한 크리프 수명예측에 관한 연구

김헌경,김일석,이연탁,공유식,오세규

부경대학교 대학원 기계공학과,부경대학교 대학원 기계공학과,부경대학교 대학원 기계공학과,부경대학교 기계공학부,부경대학교 기계공학부

Keywords: Heat resisting steels, Friction welding, FRW, Welded joints, Creep life prediction, Larson miller parameter, MLP

핵심용어: 내열강, 마찰용접, 용접재, 크리프 수명예측, 라슨밀러파라미터, 초기연신률법, 음향방출

Abstract

In this paper, the real-time prediction of high temperature creep life was carried out for the friction welded joints of dissimilar heat resisting steels (SUH3-SUH35). various life prediction method such as LMP (Larson_miller Parameter) and ISM (initial strain method) were applied. The creep behaviors of those steels and the welds under static load were examined by ISM combined with LMP at 500, 600 and $700^{circ}C$, and the relationship between these two methods was investigated. A real-time creep lie (tr, hr) prediction equation by initial strain (${varepsilon}_0$, %) under any creep stress ($sigma$, MPa) at any high temperature (T, K) was developed as follows: $t_r={alpha}{varepsilon}_0^{eta}{sigma}^{-1}$ where, ${phi}=16:/n{alpha}=10^{51.412-0.104T+5.375{ imes}10^5T^2}$, $/n{eta}=-83.989+0.180T-9.957{ imes}10^{-5}T^2,{phi}=20:$ ${alpha}=10^{69.910-0.146T+7.744{ imes}10^{-5}T^2$, ${eta}=-51.442+0.105T-5.595{ imes}10^{-5}T^2$ for SUH3-SUH35 friction weld of =16mm and 20mm, respectively.