TMCP강의 부식 환경하에서의 과대하중이 피로균열진전에 미치는 영향

The Overload Effect on the Fatigue Crack Propagation under the TMCP Steel s Corrosion Environment

The load working on real marine structures by an accident great wave or a ocean storm is not a load contains regular wavelength but a variable load with variable wavelength and power. Simplifying the variable load and investigation about the overload effect on the fatigue crack propagation behavior become more important subject. Corrosion fatigue phenomena as the source of damages will become a source of fatigue crack on the material surface. An explanation of fatigue crack propagation behavior on the variable load will be very important on estimate the lifetime or estimate the remained lifetime of the using real machine on the design. Simplifying the variable load and investigation about the overload effect to fatigue crack propagation behavior become most important subject. So, We investigate the TMCP(Thermo-Mechanical Control Process) steel s crack propagation velocity delay and acceleration effects according to the overload loading under artificial seawater environment. And we conclude belows. 1. The delay ration tendency about the magnitude of ΔK on the air was different from that on the seawater. 2. The crack propagation velocity differences of the overall delay time zone on the air relate the magnitude of the delay ratio. And the lower crack propagation velocity makes the great delay ratio in the overall delay time zone on working the corrosion. 3. The more overload repeating times make the great delay ratio on the air and the seawater, especially the 100 times makes much great delay ratio than a time or the 10 times.