Reverse Transformation Mechanism of Martensite to Austenite in 00Cr15Ni7Mo2WCu2 Super Martensitic Stainless Steel

The reverse transformation mechanism of martensite to austenite in 00Cr15Ni7Mo2WCu2 super martensitic stainless steel has been studied. The experimental results indicated that the volume fraction of reversed austenite in 00Cr15Ni7Mo2WCu2 super martensitic stainless steel increased first and then decreased with increasing tempering temperature over a range of 550-750 degrees C after quenching at 1050 degrees C. The reversed austenite formed along the martensite lath boundaries. When the tempering temperature was below 700 degrees C, the reversed austenite grew with a Ni-enrichment; when the temperature was above 700 degrees C, the reversed austenite re-dissolved and transformed to martensite and a part of the reversed austenite divided the original wider martensitic laths into a number of thinner ones. The basic mechanism for formation of the reversed austenite is diffusion in 00Cr15Ni7Mo2WCu2 super martensitic stainless steel.