Structural transformations in steel 1Kh15N5AM2 during heating and cooling

1. With heating of steel 1Kh15N5AM2 at high temperature the austenite is transformed into δ ferrite, which begins at 1200° in the EAM steel and at 1250° in the ESR steel. 2. In the EAM steel the grains of δ ferrite are rounded, while in the ESR steel the δ ferrite forms prisms or platelets. This is due to the preexisting δ ferrite nuclei in the EAM steel. Because of the high homogeneity of the ESR steel, δ ferrite is formed in the crystallographic planes of austenite. 3. The transformation of austenite into martensite during cooling to room temperature after heating to 1300° occurs in the same temperature range for steels melted by both procedures although the amount of martensite is somewhat higher in the ESR steel. Evidently this is due to the larger volume of metal with an even concentration of alloying elements in the axes of the dendrites in the ESR steel. 4. The combined use of high-temperature and color metallography makes it possible to follow the reactions involved in the transformation of δ ferrite into austenite and then into martensite during colling.