Microstructure of 13Cr super martensitic stainless steel

Microstructure of 13Cr super martensitic stainless steels after different heat treatments was studied by means of TEM and XRD.The results show that the microstructure of the steels after quenching is lath martensite matrix.The prior austenite grain size is from 16.8 μm to 56.88 μm for the steels quenched at 800-1100 ℃.The prior austenite grain size and the size of martensite lath bundle increase with the raising of quenching temperature.When the steels are tempered at 650 ℃ after quenching at different temperatures,the microstructure is fine tempered martensite retaining the morphology of quenched martensite.Reversed austenites with strip and diamond shape is observed along the boundary of prior austenite and lath boundaries of martensite in the steels quenched at 1050 ℃ and then tempered at different temperatures.When the samples are tempered at temperature lower than 650 ℃,the volume fraction of reversed austenite is increased with the increase of tempering temperature and time.