Process of producing a hot coil and a production system of producing the same
AssigneeKyoei Steel Ltd.
InventorsKoichi Takashima, Yoshimichi Okita
Life of this patent
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Abstract
A hot coil with high quality and low cost is produced by rolling a billet continuously prepared with a 70 to 120 mm middle thickness continuous casting mechanism, a billet conveying table, a heating mechanism, a high draft rough rolling mill, a finishing rolling mill, and a down coiler, which components are all disposed closely together along a straight line. The center surface temperature of the billet and a peripheral velocity of the roll of the high draft rough rolling mill are controlled within a predetermined range to provide for continuous rolling through the system.
Claims12
A hot coil manufacturing process carried out with a hot coil production system comprising a middle-thickness continuous billet casting unit, a heating unit, a high-draft roughing mill, a finishing mill and a coiler, all disposed along a straight line, wherein a billet is continuously rolled between the heating unit and the coiler, and wherein the process comprises:
- operating the continuous billet casting unit to produce a billet having a thickness of 70 to 120 mm;
- transferring the billet produced by the continuous billet casting unit from the continuous billet casting unit to the heating unit such that the time elapsed from the start of casting in the continuous billet casting unit to the arrival of the billet at the heating unit is approximately proportional to the thickness of the billet, with the time being under 10 minutes for a billet having a thickness of 70 mm and the time being under 15 minutes for a billet having a thickness of 120 mm;
- controlling the heating unit so that the surface temperature at a center of the billet is 950.degree. to 1150.degree. C. after being heated in the heating unit;
- operating the roughing mill such that a first roll thereof has a peripheral speed of 5 m/min to 20 m/min;
- and
- controlling the hot coil manufacturing process such that the temperature of the billet after being heated by the heating unit until completion of its passage through the finishing mill is maintained higher than the transformation temperature of steel.
A hot coil production system comprising:
- a production line including a middle-thickness continuous billet casting unit for casting a billet, a billet heating unit, a high-draft roughing mill, a finishing mill and a coiler, all disposed along a straight line;
- wherein said high-draft roughing mill and said finishing mill are mounted proximate one another along said straight line with no heater unit being interposed therebetween;
- wherein a guide member is provided for guiding the billet into said finishing mill;
- and
- wherein a support roll is provided for supporting the billet as it is guided into said finishing mill.
Dependencies are inferred from the claim text.