Iurkevych R. Resistance to corrosion and stress corrosion cracking in hydrogen sulfide-containing environments of ferritic-austenitic and ferritic-pearlitic steels used for gas extraction equipment

The object of our research is corrosive stress cracking of the low-alloying and corrosion resistance steels which used in gas extraction equipment and them the welded connections. The aim of the research was to establish the mechanism of sulfide stress cracking of ferritic-austenitic steels and their welded connections; choose a high-efficiency domestic inhibitor for sulfide corrosion and hydrogen induced cracking protection of ferritic-pearlitic steels. Gravimetry, polarization method, corrosive-mechanical tests, metallography and x-ray spectrometry method were used. Results - the mechanism of sulfide stress cracking of ferritic-austenitic steels is established. It was revealed that in hydrogen sulfide-containing media the weldments of both non-heat treated similar and dissimilar are resistant to stress corrosion cracking under constant strain condition at all stress levels till yield point of the base material. An original method was developed and a laboratory autoclave was patented for studying corrosion rate of materials in mineral water solution containing aggressive gases. The technological regulation has been published and utilized for the application of the Naftokhim-8 inhibitor in the Lokachynsky gas field for protection of equipment.