Effect of Machining Conditions on Residual Stress Corrosion Cracking of 316L SS
Surface generation using conventional machining processes shows a residual stress distribution which mainly depends on the process parameters. This distribution affects the mechanical stability of the layers affected by the process. Particularly, when a specific level of the residual stresses is reached, a stress corrosion cracking (SCC) of the 316L austenitic stainless steel occurs in the MgCl2 (40%) solution at 142°C. Results obtained in this investigation have shown that the non-cracking residual stress threshold value depends not only on the couple workspace material / environment, but on the surface generation process also. Indeed while, a threshold SCC value of +380 MPa was measured in the case of surfaces generated using the turning process, a value of +280 MPa only was evaluated for the ground surfaces. This difference was discussed on the basis of the relation between the mechanism of crack initiation under SCC and the electrochemical reactivity of the generated surfaces using a specific process. Hence, one can conclude that the residual stress heterogeneity at the surface as well as in the under layer and the finished surface reactivity explain the morphology of the generated cracks by SCC and the sense of the non-cracking threshold must be revised.
Sabine Denis, Takao Hanabusa, Bob Baoping He, Eric Mittemeijer, JunMa Nan, Ismail Cevdet Noyan, Berthold Scholtes, Keisuke Tanaka, KeWei Xu
C. Braham et al., "Effect of Machining Conditions on Residual Stress Corrosion Cracking of 316L SS", Materials Science Forum, Vols. 490-491, pp. 305-310, 2005