Hydrogen and chloride induced stress corrosion cracking of high strength steel wires

Research output: ThesisDoctoral Thesis

Abstract

Wires offer numerous applications and can be easily hardened using drawing processes. However, to confirm the extent of guaranteed strength and resistance to stress corrosion cracking, further research is required. This study investigates the resistance of ferritic¿pearlitic and austenitic steel wires to hydrogen embrittlement and stress corrosion cracking. The critical hydrogen content and locations of hydrogen in ferritic¿pearlitic steels were determined using numerical and analytical methods, and the activation energies in the material were determined using thermal desorption spectroscopy. Slow strain rate tests and microstructure analysis were used to determine the resistance of austenitic steel wires to hydrogen and chloride ions. At higher degrees of deformation, ferritic¿pearlitic wires exhibit stronger hydrogen trapping in deep traps (dislocations and voids in the cementite phase) and, in combination with a fibre effect, improved hydrogen resistance. Austenitic steel wires absorb significantly more hydrogen, but they can also store significantly more hydrogen in the lattice without embrittlement. However, as cold deformation increases, no irreversible hydrogen trapping occurs, resulting in a sharp decrease in resistance at degrees of deformation greater than 50 %. In chloride-containing media, the hot-rolled material demonstrated the best resistance; this resistance decreases drastically at low degrees of deformation and improves slightly with increasing degrees of deformation owing the occurrence of twinning up to approximately 50 % cold deformation. Furthermore, extremely high residual stresses cause a rapid decrease in resistance.

Details

Translated title of the contributionWasserstoff- und Chlorid induzierte Spannungsrisskorrosion von hochfesten Drähten
Original languageEnglish
QualificationDr.mont.
Awarding Institution
Supervisors/Advisors
DOIs
Publication statusPublished - 2023