The effect on the impact properties of type 304 stainless steel

The relationship between the degree of sensitization and the corrosion resistance of austenitic stainless steel has been reported since long time, however this relationship does not account for all the experimental results reported on the literature. The present work was developed in order to establish the effect of time and temperature in the degree of sensitization in stainless steel type 304 at short treatment times (up to 6 hrs.) in the range of 450-850oC. The maximum amount of degree of sensitization was found at 650oC and the mechanical properties were in direct relationship to the amount of carbides at the grain boundary. For lower temperatures an abnormal mechanical behavior was found, and it is explained by means of precipitation kinetics which induces the intragranular carbide formation. Diffusion phenomena observed in higher temperature were attributed to deterioration of mechanical properties. (Author)