Mechanical and thermal induced phase transformations in superduplex stainless steel

The aim of this work is to study the microstructural changes in SAF 2507 type superduplex stainless steel due to heat treatments and mechanical fatigue process. Specimens were heat treated in the 400-1360 °C temperature range for 1 and 5 hours respectively. An other series of specimens were periodically loaded by using a fatigue testing machine. The microstuctural changes were investigated by using a complex micromagnetic measuring system which includes a Barkhausen noise measuring and a magnetic harmonic analysing system. The RMS value of the Barkhausen noise, the distortion factor (k), and magnetic coercivity values were measured. The microstuctural changes were investigated by metallography using scanning electron microscope