*3.3. Q&P Experiments, Steel B*

Figures 8 and 9 show the results of the XRD measurements and tensile tests for Steel B similar to Figures 6 and 7. The behavior of Steel B differs from Steel A. Instead of a steady reduction in austenite fraction, there is an initially high amount (12 vol %) at *QT* = 300 ◦C followed by an appreciable drop at *QT* = 275 ◦C to a nearly stable austenite fraction (7–8 vol %) irrespective of further reduction in *QT* temperature down to 200 ◦C, Figure 8a. The corresponding average carbon content in retained austenite decreased from about 1.2% to 1% with an increase in *QT* from 200 to 300 ◦C, Figure 8b.

**Figure 8.** (**a**) The retained austenite fraction of Steel B with respect to initial quench temperature *QT*. (**b**) The carbon content of the retained austenite with respect to *QT*. Specimens annealed at 850 ◦C, quenched to *QT* and partitioned at 450 ◦C for 100 s.

**Figure 9.** (**a**) The measured 0.5% proof strength and *Rm* values for Steel B with respect to *QT*. (**b**) The uniform elongation *Ag* and total elongation *A* for Steel B with respect to *QT*. Specimens annealed at 850 ◦C, quenched to *QT* and partitioned at 450 ◦C for 100 s.

Figure 9 shows the results of the tensile property characterization of the Steel B specimens. Interestingly, there is a significant drop in yield strength beyond the *QT* > 250 ◦C. The low yield strength at *QT* = 300 ◦C is, however, accompanied by a high *Rm* of 1250 MPa, even though the *Ag* and total elongation *A* seem somewhat insensitive to the *QT*.
