Abstract

Ductile to Brittle Transition Temperature (DBTT) is an important parameter that can be estimated using the Small Punch Test (SPT) utilized in material assessment in industrial structures without significant destruction. This study applies the SPT method to determine DBTT in austenitic/martensitic stainless steel from a gas pipe system that worked for around 20 years at low temperatures and is prone to material degradation due to hydrogen effects and aging. SPTs were conducted at temperatures from -196 to 50 degrees on specimens extracted from the most damage-prone areas on the inner side of the gas pipe. Fracture energies were measured by calculating the area under force-displacement curves obtained SPT. The small punch transition temperature was determined at the middle zone of the upper and lower shelves, being -40 degrees. It was clear from the fracture area and surface using SEM investigations that the material ductile fracture alters to brittle by temperature decrease

Keywords:Fracture mechanics; Ductile to brittle transition temperature (DBTT); Small punch test; Stainless steel; Gas pipe