发明名称 |
Method for manufacturing a precipitation-hardening cold-rolled steel sheet having excellent yield ratios |
摘要 |
A method for manufacturing a precipitation hardening cold-rolled steel sheet with an excellent yield ratio. The method may include the steps of hot rolling a steel slab with finish rolling at a temperature of Ar3 transformation point or more to form a hot-rolled steel sheet, coiling the hot-rolled steel sheet at a temperature of 550-600 ° C., cold rolling the hot-rolled steel sheet at a reduction ratio of 50% or more; and recovery-recrystallization annealing the cold-rolled steel sheet at a line speed of 150-200 mpm and at a temperature of 780-820° C. in a continuous annealing furnace. The recovery-recrystallization annealing may provide a recrystallization ratio of 65-75%. The steel slab includes, by weight %: C: 0.07-0.10%, Mn: 1.41-1.70%, P: 0.05-0.07%, S: 0.005% or less, N: 0.005% or less, acid-soluble Al: 0.10-0.15%, Nb: 0.06-0.09%, B: 0.0008-0.0012%, Sb: 0.02-0.06%, and the balance comprising Fe and other unavoidable impurities. |
申请公布号 |
US8864922(B2) |
申请公布日期 |
2014.10.21 |
申请号 |
US201313782987 |
申请日期 |
2013.03.01 |
申请人 |
POSCO |
发明人 |
Han Sang-Ho |
分类号 |
C21D8/02;C21D6/02;C22C38/60;C22C38/00;C22C38/12;C22C38/04;C22C38/06 |
主分类号 |
C21D8/02 |
代理机构 |
McDermott Will & Emery LLP |
代理人 |
McDermott Will & Emery LLP |
主权项 |
1. A method for manufacturing a precipitation-hardening cold-rolled steel sheet, comprising:
hot rolling a steel slab with finish rolling at a temperature of Ar3 transformation point or more to form a hot-rolled steel sheet, the steel slab comprising, by weight %: C: 0.07-0.10%, Mn: 1.41-1.70%, P: 0.05-0.07%, S: 0.005% or less, N: 0.005% or less, acid-soluble Al: 0.10-0.15%, Nb: 0.06-0.09%, B: 0.0008-0.0012%, Sb: 0.02-0.06%, and the balance comprising Fe and other unavoidable impurities; cold rolling the hot-rolled steel sheet at a reduction ratio of 50% or more; and recovery-recrystallization annealing the cold-rolled steel sheet at a line speed of 150-200 mpm and at a temperature of 780-820° C. in a continuous annealing furnace, wherein a yield ratio of the cold-rolled steel sheet is 85% or more. |
地址 |
Pohang KR |