&chi; Phase (Fe<SUB>2</SUB>C) in Tempering Carbon Steels

The Silicon Effect in the Tempering of Martensite in Steels

High-silicon steels have long been known to possess exceptional resistance to tempering, but the reasons for this effect were unknown. We report here a study of the third stage of tempering of these steels, in which cementite is formed. In a 0.75 wt% C 1.4 wt% Si alloy steel, tempered for 1 hour at 380°C, it is found that silicon atoms are rejected from the growing cementite into the ferrite ma...

A new nanoscale metastable iron phase in carbon steels

Metastable ω phase is common in body-centred cubic (bcc) metals and alloys, including high-alloying steels. Recent theoretical calculations also suggest that the ω structure may act as an intermediate phase for face-centred cubic (fcc)-to-bcc transformation. Thus far, the role of the ω phase played in fcc-bcc martensitic transformation in carbon steels has not been reported. In previous investi...

Comments About the Strengthening Mechanisms in Commercial Microalloyed Steels and Reaction Kinetics on Tempering in Low-Alloy Steels

Some phase transformations in steels

About 70% of all the steel compositions that are currently used have been developed within the last 10 years. Novel iron alloys are being conceived, manufactured, and marketed with a regularity which has confounded many prophecies. Phase transformation theory has contributed to the successful development of steels. This overview will begin therefore with a discussion of the atomic mechanism by ...

High Temperature Behavior of Dual Phase Steels

Dual phase steels with different martensite volume fraction and morphology were tensile tested at a temperature range of 25 to 5500C. Stress-strain curves of all steels showed serration flow at temperatures of 250 and 3500C, and smooth flow at the other temperatures. Both yield and ultimate tensile strengths increased with increasing testing temperature up to about 450<sup...