Effects of Distributions of Constituent Phases on Mechanical Properties of C–Si–Mn Dual-phase Steel

Two kinds of ferrite were produced due to slow cooling after intercritical annealing, one being intercritically-annealed (αa phase), and the other transformed (αc phase). The effects distributions αa αc phases on mechanical properties a Fe–0.17C–1.5Si–1.7Mn dual-phase steel examined experimentally at room temperature. types annealing (IA) conducted control distribution. IA temperature time are Ta = 800°C (1073 K) ta 0.5 h (1.8 ks), respectively, for first type, 740°C (1013 4 (14.4 second one. For both IA, was slowly cooled 400°C (673 rate 10°C/s, followed by water quenching. While total volume fraction fα is close 0.68–0.69 800 1013 K), combination each α phase different K). fαa fαc 0.33 0.36 0.68 0 respectively. ultimate tensile strength su about 970 MPa independent values. Thus, effect between phases. In contrast, uniform strain eu local el increase with increasing phase. Such in attributed larger values hardening dσ/dε large region. Misfit stored boundary causes dσ/dε. On hand, suppression void formation deduces el. Acceleration dynamic recovery adjacent martensite (M phase) decrease hardness M can suppress formation. Consequently, contributes improvement steel.