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Influence of titanium content and grain size on hydrogen cracking behaviour of hot‐rolled steels
Author(s) -
Valentini Renzo,
Solina Adriano,
Cramer Christian
Publication year - 1994
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.199400937
Subject(s) - titanium , metallurgy , materials science , hydrogen , grain size , grain boundary , cracking , composite material , microstructure , chemistry , organic chemistry
Hydrogen induced cracking was investigated for hot‐rolled titanium steels. Aim of the present work was to observe the influence of titanium content and grain size on the cracking behaviour. Three titanium steels (0.12‐0.30 % Ti; O.0057‐0.0480 % C) and one non‐titanium steel (0.0056 % C) were used for the investigation. Various grain sizes were generated by heat treatment at 950, 1050 and 1150 °C; furnace cooling was applied. The specimens were electrolytically charged with hydrogen at various current densities. It was found that cracks are generated at low charging current densities for the investigated steels. The titanium steels showed better performance than the non‐titanium steel. It was shown that the charging current density does not correspond to the hydrogen concentration in a steel; the hydrogen concentration in steel B was 3.8 ppm at 1 mA/cm 2 , in steel D it was found to be 15.5 ppm at 0.5 mA/cm 2 . The total hydrogen concentration was found to be influenced by content of precipitates and grain size. It was shown that the percentage of cracked grain boundary area increases with increasing grain size. This increase is linear for the non‐titanium steel whilst for the titanium steels a plateau was observed at a grain size diameter of 50 μm.