A Study on the Characteristics of Fatigue Crack Growth of A516 Steel for Pressure Vessel at Low Temperatures

J. Ocean Eng. Technol. 1999;13(3):108-113.

Park, Kyung-Dong;Ro, Tae-Young;Kim, Young-Dae;Kim, Hyung-Ja;Son, Jae-Yun;

압력용기용 A516강의 저온피로크랙전파특성에 관한 연구

박경동;노태영;김영대;김형자;손재윤;

부경대학교 공과대학 기계 ${cdot}$자동차공학부;부경대학교 공과대학 기계${cdot}$자동차공학부;부경대학교 공과대학 기계${cdot}$자동차공학부;부경대학교 공과대학 기계${cdot}$자동차공학부;부경대학교 대학원;

Keywords: Crack Propagation, Fatigue, Low Temperature, Crack Closure, Stress Ratio

핵심용어: 크랙전파, 피로, 저온, 크랙개폐, 응력비

Abstract

In this study, CT specimens were prepared from ASTM A516 Gr. 65 which was used for pressure vessel plates for moderate and lower temperature service. Fatigue crack growth test was carried out in the environment of low temperature of $10^{circ}C, -10^{circ}C, -30${circ}C;and;-50^{circ}C$ and in the range of stress ratio of R=0.05 and 0.3 by means of opening mode displacement. Based on these test results, the characteristics from temperature and stress ration were shown as follows. 1) As the stress ratio, R increased da/dN and ${Delta}K$ of 2nd stage gradually decreased. And as R decreased, the effect of temperature became greater and greater. 2) As the temperature descended, da/dN decreased on a certain ${Delta}K$, and ${Delta}K$ did in a same da/dN. And the stress ratio, R exerted greater influence at the lower temperature. 3) The fatigue crack growth constant, m increased at $10^{circ}C$ and $-10^{circ}C$, snd decreased at $-30^{circ}C$ and $-50^{circ}C$ following the increment of stress ratio R. And m increased along with the reduction of temperature greatly decreased at $-30^{circ}C$ to come close to two(2).