고 Cr강 용접부의 온도에 따른 피로 특성

There are strong environmental and economic pressures to increase the thermal efficiency of fossil fuel power stations and this has led to a steady increase in steam temperatures and pressures resulting in worldwide plans for ultra super-critical power plants. For examplem, order to improve the thermal efficiency of power plant, there has been a strong drive to develop heat resistant steels with excellent creep, high temperature fatigue and thermal fatigue resistant properties as well as superior oxidation and corrosion resistant properties. In this study, the test material was P122 alloy which has been developed for ultra super-critical power plant. To measure fatigue crack growth at three different microstructures (Base metal, HAZ and Weld metal) regions. Tests were performed with compact tension specimens at 600~700℃ with the loading frequency of 20Hz.