Study on the Mechanism of Strengthening and Toughening Effect
of Titanium Addition on HSLA Steel
مطالعهی مکانیزم استحکامبخشی و اثر چقرمهسازی افزودن تیتانیم روی فولاد HSLA
ABSTRACT
Based on the determination of load variation against deflection by means of Instrumented Charpy Impact testing, the impact energy distribution of the High Strength Low Alloy (HSLA) steel containing Nb, Ni and Ti for pressure vessels at low temperature has been quantitatively studied. The total impact energy Et could be divided into two parts, Ei and Ep. Ei is related to the base strength of the material in terms of the grain size and alloy addition, which is also found to be less influenced by the holding time of normalization process at 910℃. Whereas, Ep of Ni-Nb-Ti HSLA steel is strongly linked to the period of holding time. Thermodynamic kinetic investigation was carried out to study the strengthening mechanism with metallurgical microstructure analysis.