PSI - Issue 16

Jesús Toribio / Procedia Structural Integrity 16 (2019) 281–286

284

Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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4. Anisotropic fracture behaviour and deflected (polygonal) crack paths in cold drawn pearlitic steels

As described by Toribio (2004), transversely pre-cracked rods were subjected to monotonic tensile loading up to fracture. Fig. 5 shows the propagation profile for a hot rolled bar (not cold drawn at all) and for a heavily drawn pearlitic steel (commercial prestressing steel wire whose markedly oriented microstructure is shown in Fig. 4).

Fig. 5. Crack paths (propagation profiles) produced by axial fracture in inert (air) environment in steels with 0 (a) and 6 (b) cold-drawing steps; f: fatigue crack growth; I: mode I propagation; II: mixed mode propagation (propagation step in heavily drawn steels); F: final fracture.

Toribio and Ovejero (2001a) studied the hydrogen assisted cracking (HAC) behaviour in cold drawn pearlitic steels. Fig. 6 summarizes the results regarding crack paths (propagation profiles), where a progressively anisotropic HAC behaviour (with increasing crack deflection) is observed.

Fig. 6. Crack paths (propagation profiles) produced by hydrogen assisted cracking (HAC) in steels with 0 (a), 3 (b) and 6 (c) cold-drawing steps; f: fatigue crack growth; I: mode I propagation; II: mixed mode propagation (propagation step in heavily drawn steels); F: final fracture.

Toribio and Ovejero (2001b) studied the localized anodic dissolution (LAD) behaviour in cold drawn pearlitic steels. Fig. 7 summarizes the results regarding crack paths (propagation profiles), where a progressively anisotropic LAD behaviour (with increasing crack deflection) is observed.

Fig. 7. Crack paths (propagation profiles) produced by localized anodic dissolution (LAD) in steels with 0 (a), 3 (b) and 6 (c) cold-drawing steps; f: fatigue crack growth; I: mode I propagation; II: mixed mode propagation (propagation step in heavily drawn steels); F: final fracture.