The objective of the laboratory experiments described in this paper was to examine how exposure to a
combination of H2S and CO2 would impact on environmental cracking, hydrogen charging and loss of
ductility of CRAs and Alloy 718 immersed in calcium bromide brines and high density buffered
potassium/cesium formate brines at 40°C (104°F) and 160°C (320°F).
The test results indicate that modified 13Cr-2Mo is susceptible to environmental cracking at 160°C
(320°F) in high-density brines contaminated with a mixture of CO2 and H2S. In calcium bromide brine
the cracking occurred both at high (160°C / 320°F) and low (40°C / 104°F) temperatures. In the
buffered formate brine, cracks were observed on cross-sections at high temperature only.