The Effect of Sensitizing Temperatures for Stress Corrosion Cracking of Austenitic Stainless Steel in Magnesium Chloride Solution

摘要

The change of the mechanism for Stress Corrosion Cracking (SCC) on 304 austenitic stainless steel was investigated in 42 wt% magnesium chloride solution at 106 0C by using a constant load method. The solutionannealed specimens were applied under constant load of 30.5 Kg/mm2 and 40 Kg/mm2. The nonsolution annealed specimens were applied under constant load of 20 Kg/mm2 and 25 Kg/mm2. All experiments were carried out under an open circuit condition. The most of fracture mode on nonannealed type 304 at various sensitizing temperature (6000C, 7000C, 8000C) is intergranular. All fracture mode in annealed type 304 at various sensitizing temperature is trangranular. The deformation can be easy to move by growing grains in annealed type 304 so that it can be predicted by decreasing Vickers hardness value. In nonannealed type 304, the deformation can be sustained because of the small size of grains. The role of ? martensite mechanism in nonannealed type 304 significantly contribute to the forming of fracture in MgCl2 solution at 1060C especially in grain boundaries. In annealed type 304, mechanism of fracture can be related to deformation through slip plane in grains.