| 摘要 |
<p>PURPOSE: A hot-rolled coil and a manufacturing method thereof are provided to improve strength by the upmost generation of precipitate during a maintaining time or an air-cooling time after primary cooling and to stabilize a material by starting a coiling process after sufficiently cooling. CONSTITUTION: A method for manufacturing a hot-rolled coil includes the following steps of: hot-rolling a slab plate at a finish delivery temperature of 810-870°C; primarily cooling the slab plate at a temperature of (A1 transformation point + A2 transformation point)/2±10°C and maintaining or air-cooling the slab for 5 to 7 seconds; and coiling the slab plate after secondarily cooling at a temperature of the A1 transformation point or less. [Reference numerals] (AA) Start; (BB) End; (S110) Hot rolling; (S120) First cooling/maintaining ((A1+A3)/2±10°C); (S130) Second cooling/winding (blew AI)</p> |
