Study on the Corrosion Fatigue Crack Propagation Behavior of Steel Used for Frame of Vehicles in Marine Environment

J. Ocean Eng. Technol. 1992;6(2):76-84.

해양환경중에서 자동차 프레임용 강재의 부식피로균열전파거동에 관한 연구

이상열,임종문,이종악

포항전문대학교 자동차과,포항전문대학교 자동차과,부산수산대학교 기계공학과

Keywords: Corrosion Fatigue, Aspect ratio, Stress intensity factor range, Accelerative factor, Potential of electrode, Less noble potential

핵심용어: 부식피로, 형상비, 응력확대계수병위, 가속계수, 전극전위, 비전위

Abstract

In this study, corrosion fatigue test of SAPH45 steel was performed by the use of plane behavior of base metal (BM) and heat affected zone (HAZ) of SAPH45. The main results obtained are as follows: 1) The more aspect ratio (b/t) of corner crack decreases, the more aspect ratio (b/a) takes greatly effect by corrosion. 2) The correlation between the stress intensity factor range ($Delta$k) and crack growth rate (da/dN) for weldment in seawater is given by Paris rule as follow: da/dN=C($Delta$K) super(m). Where m is constant, and the value is 3.82-3.84. 3) The accelerative factor ($alpha$) of BM and HAZ under seawater is about 1.1-1.9, and ($alpha$) of HAZ increases more and more under the low $Delta$K region. 4) HAZ is more susceptible to corrowion than BM because of potential of electrode (E sub(c)) of HAZ becomes more less noble potential than that of BM.