1992 Volume 41 Issue 4 Pages 224-230
Effects of variations of temperature and stress on stress corrosion cracking (SCC) of JIS STPT 42 carbon steel were investigated in high temperature water. SCC tests were conducted on small tubular specimens under individual or combined variations of water temperature and stress with a triangular wave form. The bi-axial stresses were applied to the tubular specimens by combining the external, axial load and internal pressure with testing water. Tubular specimens were axially loaded in the range of 98 to 392MPa in water containing 8ppm oxygen under variation of temperatures of room temperature to 523K. The results obtained are summarized as follows. (1) SCC susceptibilities were remarkably accelerated by combined variations of temperature and stress. (2) SCC failures occurred in circumferential direction of tube inner surface. Cracks initiated from corrosion pits and propagated transgranularly. (3) Crack propagation could be detected by an acoustic emission technique. The crack propagation rates estimated in this study were in the range of 4.0×10-10 to 1.58×10-9m/s and generally lower than those for sensitized Type 304 stainless steel.
