Patent ID: 11897014
Assignee: POSCO CO., LTD
Field: Materials, metallurgy (Chemistry)
Classification: CPC B  C | IPC B  C

Claim 0:
1. A method of manufacturing a hot-press formed member, the method comprising:
aluminum-plating a surface of a base steel sheet and coiling the steel sheet, thereby obtaining an aluminum-plated steel sheet;
annealing the aluminum-plated steel sheet, thereby obtaining an aluminum-iron alloy-plated steel sheet; and
hot-press forming the aluminum-iron alloy plated steel sheet,
wherein an aluminum plating amount is 30-200 g/m2 based on a single side surface of the steel sheet,
wherein a cooling rate to 250° C. is less than 20° C./sec after the aluminum plating,
wherein coiling tension is 0.5-5 kg/mm2 during the coiling,
wherein the annealing is performed in a batch annealing furnace in a heating temperature range of 550-750° C. for 30 minutes-50 hours,
wherein, when the heating is performed from room temperature to the heating temperature during the annealing, an average temperature increase rate is 10-100° C./h, and an average temperature increase rate in a 400-500° C. range is 1-15° C./h,
wherein a difference between an atmosphere temperature in the batch annealing furnace and a temperature of the steel sheet is determined to be 5-80° C., and
wherein a heat treatment is performed in a temperature range of Ac3-950° C. during the hot-press forming, the heating is performed at a temperature increase rate of 3-18° C./s to a temperature range from 200° C. to Ac3-950° C., and a heat treatment is performed for 1-15 minutes as a total heating time, where the total heating time is defined as the heating time including both the heating time in the temperature increase range and the heating time in the temperature range of Ac3-950° C., and hot-press forming is performed.