THE STRAIN FOR STRESS-CORROSION CRACK INITIATION IN TYPE-316 STAINLESS-STEEL IN HIGH-TEMPERATURE WATER

Tapered cylindrical tensile specimens subjected to slow strain rate testing were used to evaluate the crack initiation strain for both annealed and sensitized type 316 stainless steel in 5 ppm chloride containing water in the temperature range 150-300-degrees-C. For annealed material, the strain needed to initiate cracks was less at 200 and 250-degrees-C than at lower or higher temperatures and varied significantly with the applied potential. In contrast for the sensitized material the crack initiation strains were relatively small and relatively insensitive to temperature. The experimental details for the tapered specimen test procedure, the accuracy of the method and the variation of the strain rate along the gauge length are discussed.