HYDROGEN FATIGUE RESISTANT FERRITIC STEEL AND MANUFACTURING METHOD THEREOF

摘要

Provided are a ferrite steel having tensile characteristics and fatigue characteristics sufficient to withstand application in a hydrogen environment, and a method for manufacturing the same. One or more elements selected from V (vanadium), Ti (titanium), and Nb (niobium) are added and at least a carbide of one or more of the elements selected from V, Ti, and Nb is included in the composition along with ferrite crystal grains so that the drawing and fatigue crack propagation rates of the ferrite steel in a hydrogen environment are improved. The effects of the invention were confirmed when the ferrite crystal grains were fine grains having a grain size of 1 µm or smaller, when they were coarse grains having a grain size of several µm to 20 µm, and when they were coarse grains having a grain size of several µm to 60 µm.