Claims
- 1. In the hot rolling of metal slabs to strip thickness on a hot strip mill including an in-line roughing train, a reversing mill stand having a coiling furnace on both an upstream side and a downstream side thereof and a finishing train having a synchronized speed cone associated therewith, the steps comprising:
- A. passing a heated slab into and through the roughing mill to form a transfer bar;
- B. passing said transfer bar back and forth through the reversing mill stand and in and out of said coiling furnaces in initial reducing passes to form a workpiece, said reversing mill stand being operated independent of said speed cone; and
- C. passing said workpiece from said upstream coiling furnace through said reversing mill stand in a final reducing pass and into the finishing train at a speed consonant with said speed cone.
- 2. The method of claim 1 wherein said initial reducing passes are carried out at speeds substantially greater than the final reducing pass.
- 3. In the hot rolling of metal slabs to strip thickness, the steps comprising:
- A. passing a heated metal slab into and through a roughing mill and reducing the said slab to a transfer bar on the order of one to three inches in thickness;
- B. passing said transfer bar immediately to and between the work rolls of a reversing finishing mill stand and reducing it in thickness;
- C. passing the workpiece immediately into a heated furnace on the downstream side of said reversing finishing mill stand and coiling it in said furnace;
- D. discharging the workpiece from said downstream heated furnace and passing it back through and further reducing the workpiece in said reversing finishing mill stand;
- E. immediately passing the workpiece into and coiling it in the heated furnace on the upstream side of said mill stand;
- F. thereafter uncoiling and discharging the workpiece from said upstream coiling furnace and passing it between the work rolls of said reversing finishing mill stand and further reducing it therein, the rolling speed on said pass being consonant with the speed cone on subsequent passes through continuous finishing stands and the rolling speeds on the two preceding passes on the reversing mill stand being higher than the speed on the third pass and unrelated to the aforesaid speed cone;
- G. immediately thereafter passing said workpiece successively through and reducing it further in a plurality of continuous finishing stands; and
- H. thereafter cooling the strip and coiling it on a finish coiler.
- 4. The rolling method set forth in claim 3 and in which the initial slab weight passed to the roughing mill was sufficient to provide a finished coil having a specific weight on the order of 500 pounds per inch of width or more.
- 5. The rolling method defined in claim 3 and in which the slab initially fed to the roughing mill was on the order of nine to twelve inches in thickness and is reduced on the roughing mill to a thickness of on the order of one to three inches.
- 6. The rolling method as defined in claim 5 and in which the finished gauge of the strip is on the order of 0.050 inch to 0.080 inch and the specific weight of the coil is on the order of 500 pounds per inch of width or greater.
- 7. In the hot rolling of metal slabs to strip thickness and in coils having a specific weight on the order of 500 pounds per inch of width or greater, the steps comprising:
- A. passing a heated metal slab into and through a roughing mill and reducing the slab to a transfer bar;
- B. passing said transfer bar immediately to and between the work rolls of a reversing finishing mill stand and reducing it in thickness;
- C. passing the workpiece immediately into a heated furnace on the downstream side of said reversing finishing mill stand and coiling it in said furnace;
- D. discharging the workpiece from said downstream heated furnace and passing it back through and further reducing it in said reversing finishing mill stand;
- E. immediately passing the workpiece into and coiling it in a heated furnace on the upstream side of said reversing mill stand;
- F. thereafter uncoiling and discharging the workpiece from the upstream coiling furnace and passing it between the work rolls of said reversing finishing mill stand and further reducing it therein, the rolling speed on said third pass being consonant with the speed cone on subsequent passes through continuous finishing stands;
- G. immediately thereafter passing the workpiece successively through and reducing it further in a plurality of continuous finishing stands; and
- H. thereafter cooling the formed strip and coiling it on a finish coiler.
- 8. In the rolling method defined in claim 7, maintaining the temperature profile of the workpiece entering the continuous stand such that between the front end thereof and the rear end the temperature differential is at all times less than 100.degree..
- 9. The rolling method of claim 7 and in which the temperature profile of the finished strip has a temperature drop of on the order of 100.degree. or less from one end to the other.
CROSS REFERENCES TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. Pat. No. 4,308,739, issued Jan. 5, 1982, and entitled "Method For Modernizing A Hot Strip Mill". U.S. Pat. No. 4,308,739 is hereby incorporated by reference into this application and made a part hereof.
US Referenced Citations (2)
Foreign Referenced Citations (1)
Number |
Date |
Country |
918005 |
Feb 1963 |
GBX |
Continuation in Parts (1)
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Number |
Date |
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Parent |
115611 |
Jan 1980 |
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