Temper Resistance of Pressure Hull Steel Microalloyed with Niobium, Titanium, andVanadium

摘要

The role of microalloying additions (0.001-0.03 wt-%) to the quenched andtempered steel ASTM A517 F has been examined. Steels with different levels of the microalloying elements were prepared and assessed via transmission electron microscopy and hardness loss during tempering. The extent of precipitation of the microalloys was also calculated using published expressions for the solubility of carbonitride phases. it was found that titanium is precipitated at high temperature and does not affect the temper resistance of the steel. However, vanadium remains in solution at the austenitising temperature and has a significant effect on hardness loss during tempering. When niobium is also added, there is some precipitation in austenite with the titanium but the temper resistance is further increased.