IN-SITU HIGH TEMPERATURE X-RAY ANALYSIS OF A SUPERMARTENSITIC STAINLESS STEEL

摘要

The microstructural evolution of a variant of a Super Martensitic Stainless Steel was investigated using in-situ high temperature X-ray diffraction (HT-XRD). The tempering of this alloy is required for adjustment of strength and toughness, and such treatment is performed at intercritical temperatures. The stability of austenite formed during this treatment depends on a number of factors, such as the local chemical composition, temperature and soaking time. After cooling, some amount of this reversed austenite may transform into untempered martensite while other part stay retained. To achieve better properties, it is essential to know the evolution and the relationship between these microstructures during tempering. Thus, in present work the formation of reversed austenite was analyzed by means of HT-XRD at different temperatures and times. Specimens were also characterized using scanning electron microscopy (SEM). It was observed that there is a critical tempering temperature in which reverted austenite tends to stabilize and remain untransformed during cooling.