Abstract
Creep strength enhanced ferritic (CSEF) steels – Grades 23, 24, 91, and 92 – have been widely
implemented in the fossil fired industry for over two decades. The stress corrosion cracking
(SCC) behavior of these materials with respect to mainstay Cr-Mo steels (such as Grades 11, 12
and 22) has not been properly assessed, particularly in consideration of recent reported issues of
SCC in CSEF steels. This report details the results of Jones test exposures of a wide range of
materials (Grades 11, 22, 23, 24, and 92), material conditions (as-received, “improper” heat
treatments, normalized, weldments) and environments (salt fog; tube cleaning environments
including decreasing, scale removal, and passivation; and high temperature water) to compare
the susceptibility to cracking of these steels. In the as-received (normalized and tempered)
condition, none of these materials are susceptible to SCC in the environments examined.
However, in the hardened condition, certain combinations of environment and alloy reveal
substantial SCC susceptibility.