Tensile and fracture properties of circumferentially notched tensile specimens of stainless steel weldments

الملخص EN

The tensile and fracture properties of different types of austenitic stainless steel weldments were determined using round notched tensile specimens.

These included 304L, 316L and 6%Mo super austenitic stainless steels and their weld metals.

The triaxial state of stress, the plastic constraint and the plane strain conditions developed ahead of the notch root make notched specimens eligible for the evaluation of fracture toughness.

This was achieved through the testing procedure: J-evaluation on tensile test (JETT) using circumferentially notched round bar specimens.

The JETT index was taken as a measure of the relevant elastic-plastic fracture toughness of the tested materials.

In the case of austenitic stainless steels being too ductile at room temperature the resulted JETT were of relatively higher values than the fracture toughness values determined from the standard fracture mechanics test methods.

This could be related to the difference in the stress state ahead of the sharp crack of the standard fracture mechanics specimen and that of the blunt notch of the tensile specimen.

The results showed that the 6% Mo weld metal ranked highest while the 316L weld metal ranked lowest regarding JETT fracture toughness values.

The deformation mechanisms pertinent to austenitic stainless steels (generation of stacking faults and formation of strain induced martensite) were employed for the interpretation of the experimental results.