| abstract |
The invention relates to a method for manufacturing a high-strength structural steel and to a high-strength structural steel product. The method comprises a providing step for providing a steel slab, a heating step ( 1 ) for heating said steel slab to 950 to 1300 C, a temperature equalizing step ( 2 ) for equalizing the temperature of the steel slab, a hot rolling step including a hot rolling stage of type I ( 5 ) for hot rolling the steel slab in the no-recrystallization temperature range below the recrystallization stop temperature (RST) but above the ferrite formation temperature A3, a quenching step ( 6 ) for quenching said hot-rolled steel at cooling rate of at least 20 C/s to a quenching-stop temperature (QT) between Ms and M f temperatures, a partitioning treatment step ( 7, 9 ) for partitioning said hot-rolled steel in order to transfer carbon from martensite to austenite, and a cooling step ( 8 ) for cooling said hot-rolled steel to room temperature. |