Behavior to a cyclic fracture of an ASTM 316 stainless steel

Abstract

The study of the fractography of a material is extremely important, because through it is possible to reach conclusions that indicate the reason and the conditions by which a material may break. Austenitic stainless steels, when subjected to uniaxial loads, with low deformation rates, until rupture, have a ductile fracture macroscope aspect, however, a detailed analysis by techniques such as scanning electron microscopy (SEM) can show fragile fracture regions, which can occur due to the phase transformation that austenitic steels present when subjected to plastic deformation (TRIP effect) or by hardened austenite. This work aims to evaluate the fracture aspect of a 316 stainless steel, subjected to low frequency uniaxial cyclic loading for comparative purposes with the fracture aspect of the same fractured material in a tensile test, verifying how the type of loading changes can affect the fracture morphology of the material. The results indicate that both types of loading have ductile fractures, but with different morphologies, that is, cup and cone type for traction and 45° rupture for the cyclic test. This difference indicates that the crack is nucleated in different regions for each load, and may also indicate that they are dependent on the amount of material hardened and transformed during each test.