The influence of long term use of inhibitors in hydrochloric acid pickling baths on hydrogen induced stress corrosion cracking

摘要

The influence of commercially available inhibitors on the absorption of hydrogen by steel (St 52, StE 460, StE 690, 42CrMo4) in 15% hydrochloric acid was studied. The pickling bath aged continuously due to the chemical reaction with oxidized steel sheets. The H{sup}+- and inhibitor concentration decreased with time. The influence of this ageing process on hydrogen-induced stress corrosion cracking was tested by in-Situ tensile tests in the bath solution. With increasing ageing of the bath, the reduction in fracture area was reduced and approached the values measured for non-inhibited acid baths. Furthermore hydrogen permeation was investigated. Permeation current densities rose with increasing ageing of the pickling solution.