Effects of texture on fatigue crack propagation of low-carbon steel

Plane bending fatigue tests were carried out on several kinds of hot-rolled low-carbon steel sheets with texture to clarify the effects of texture on fatigue crack propagation. The crack growth rate of each material was determined uniquely by a term sigma(a)(n)l, where sigma(a) is nominal stress amplitude, l is the crack length, and n is a material constant. The n exhibited different values according to the materials, whereas there is not so much difference in the sigma(B) of each material. The different n in such materials may result from the difference in texture. Moreover, the value of n tended to decrease with an increase in r value, plastic anisotropy ratio. The analysis based on the small-crack growth law, dl/dN = C-3(sigma(a)/sigma(B))(n)l, in which the effect of a material property was considered, suggested that the effect of texture on the value of C-3 is negligible. The reciprocal of C-3 represents the resistance to small crack propagation in each material.