To provide a method for manufacturing a high-strength steel sheet superior in a strength-ductility balance.
The method for manufacturing the high-strength steel sheet superior in workability includes: a primary annealing step of holding a steel sheet having a predetermined chemical component at a temperature of the Ac3 point or higher for 10 seconds or longer, cooling the held steel to the Ms point or lower at a cooling rate of 10°C/second or more, holding the cooled steel at 150°C or higher and lower than 250°C for 30-700 seconds, and cooling the held steel to room temperature; and a secondary annealing step of subsequently holding the cooled steel at a temperature of the Ac1 to the Ac3 point for 10-200 seconds, cooling the held steel to 300-500°C at a cooling rate of 10°C/second or more, holding the cooled steel at 300-500°C for 10-500 seconds and cooling the held steel to room temperature.
MIURA MASAAKI
| JP2008007854A | 2008-01-17 | |||
| JP2004218025A | 2004-08-05 |
Tadashi Sugakawa
Hiroaki Ito
Hisahiko Ueki
Akemi Takeoka