In the absence of definitive data, mechanistic and modeling approaches to describe environmental cracking in
high temperature water are forced to depend too strongly on speculative hypotheses. Because data often exhibit a
scatter of about a factor of 1000, the last two decades have focused on improved and critical experiments, and
identifying the common threads across many materials and environments. The present data provide excellent
insight into many issues, and good insights into others. They also identie new / emerging issues in the broad area
of environmental cracking, e.g., related to dWda, reloading effects, and fracture toughness and tearing resistance.
Environmental cracking depends on many interdependent variables, and the only comprehensive way of
tackling this problem is to identifv the underlying processes that control SCC. This paper discusses the processes
that must be understood and modeled, and the challenges in expanding the predictions to emerging phenomena.
Key words: stress corrosion cracking, crack growth rates, prediction, mechanisms, emerging issues, high
temperature water, water chemistry, stainless steel, Ni alloys, corrosion potential, stress intensity factor.