13th International Conference on Fracture June 16–21, 2013, Beijing, China rolling and recrystallization [10]. The average grain size was found to be similar in all samples: 10 μm for the warm-rolled samples and 12 μm for the cold- and hot-rolled samples. Pearlite: 10%; G.S.: 11 μm SampleHRA SampleHRB Pearlite: 15%; G.S.: 11 μm Pearlite: 12%; G.S.: 11 μm SampleWRB Pearlite: 14%; G.S.: 13 μm SampleWRA Figure 1. Optical micrographs of some of the investigated samples (G.S.: grain size). After cathodic hydrogen charging, the cold- and hot-rolled samples developed HIC, with cracks growing following intergranular and transgranular paths as shown in Fig. 2. In a remarkable contrast, no HIC damage was observed in any of the warm-rolled samples. It is important to stress that, given that cathodic hydrogen charging introduces more diffusible hydrogen into the steel than the standard HIC test (NACE TM0284-96, [11]), the present results are expected to be similar to those obtained had the latter method been used. (a) (b) Figure 2. SEM micrograph of typical HIC-damaged regions in samples CRA (a) and HRA (b). Figure 3 shows the position of several {111}ND, {112}ND, and {001}ND orientations and fibers in the {200} and {222} pole figures, as well as the position of the α (<011>RD) and γ ({111}ND) texture fibers in the ϕ2 = 45 deg. section of the ODF in Euler space. For the group of HIC-free (warm-rolled) samples, whose pole figures and O is far from nt [8]. sed xture, DFs are shown in Fig. 4, the crystallographic texture crystalline sample, with a low random (phon) texture compo that of a random poly ne Ba on what is shown in Fig. 3, one realizes that sample WRA has a well-developed fiber te which is very close to {111}ND. Similarly, sample WRB shows a strong {111}ND fiber, together with a much less noticeable, yet present, {001}ND fiber. TD 200 RD TD 222 RD (112)[1-10] (112)[1-31] (001)[1-10] (001)[0-10] (111)[1-10] (111)[1-21] (112)[131] (a) (b) Figure 3. Position of ideal orientations and texture fibers typical of rolled and recrystallized bcc steels. (a) Pole figures. (b) ODF in Euler space (ϕ2 = 45 deg. section). -3-
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