Method for manufacturing a high-strength structural steel and a high-strength structural steel product

摘要

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 Mf 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.

主权项

1. A method for manufacturing a high-strength structural steel comprising the following:
a providing step for providing a steel slab, a heating step for heating said steel slab to a temperature in the range 950 to 1300° C., a temperature equalizing step for equalizing the temperature of the steel slab, a hot rolling step including a hot rolling stage of type I for hot rolling said steel slab in the no-recrystallization temperature range below the recrystallization stop temperature (RST) but above the ferrite formation temperature A3, a quenching step for quenching the hot-rolled steel at cooling rate of at least 20° C./s to a quenching-stop temperature (QT), which quenching-stop temperature (QT) is between Ms and Mf temperatures, a partitioning treatment step for partitioning the hot-rolled steel in order to transfer carbon from martensite to austenite, and a cooling step for cooling the hot-rolled steel to room temperature by forced or natural cooling.