MANUFACTURING METHODS AND APPARATUS FOR TARGETED COOLING IN HOT METAL ROLLING

• US 20140260483A1
• Filed: 03/07/2014
• Published: 09/18/2014
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Novelis Incorporated (Hindalco Industries Limited)
• Original Assignee: Novelis Incorporated (Hindalco Industries Limited)
• Inventors: Januszkiewicz, Krzysztof Ryszard, Stanistreet, Timothy Francis
• Granted Patent: US 9,180,506 B2
• Time in Patent Office: Days
• US Class Current: 72/201
• CPC Class Codes: B21B 1/26 by hot-rolling , e.g. Steckel hot mill
• CPC Class Codes: B21B 2003/001 Aluminium or its alloys
• CPC Class Codes: B21B 2027/103 cooling externally
• CPC Class Codes: B21B 27/10 externally
• CPC Class Codes: B21B 37/74 Temperature control, e.g. by cooling or heating the rolls or the product B21B37/32, B21B37/44 take precedence
• CPC Class Codes: B21B 45/0203 Cooling
• CPC Class Codes: B21B 45/0206 Coolants
• CPC Class Codes: B21B 45/0218 for strips, sheets, or plates B21B45/023, B21B45/0233 take precedence
• CPC Class Codes: B21B 45/0293 Recovering coolants
• CPC Class Codes: Y02P 70/10 Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working

Abstract

A rolling mill apparatus and methods of hot rolling with targeted cooling. In one aspect, a mill having multiple roller stacks includes a cooling system that directs the bulk coolant flow to a heat exchanger having first and second heat exchangers in parallel. The first heat exchanger is adapted to cool the heated coolant to a first temperature for use in a first coolant stream discharged through a first set of nozzles during rolling, while the second heat exchanger is adapted to cool heated coolant to a lower temperature for use in a second coolant stream at a second temperature lower than the first for discharge through a second set of nozzles downstream to facilitate rolling or coiling of the rolled metal.

Claims

1. A sheet metal rolling apparatus for rolling a sheet metal, said apparatus comprising:

a first roll stand and a second roll stand positioned in series in a conveyance direction along which the sheet metal is conveyed, wherein each of the first and second roll stands includes a pair of rolls through which the sheet metal is rolled;

a first set of cooling nozzles adapted to discharge a cooling fluid to an entry surface of rolls of the first rolling stand, the first set comprising one or more cooling nozzles;

a second set of cooling nozzles adapted to discharge the cooling fluid to the exit surfaces of the work rolls of the first roll stand, the second set comprising one or more cooling nozzles;

a heat exchanger system that cools the cooling fluid heated by the work rolls after discharge from the first and second set of cooling nozzles sufficiently for subsequent discharge through the first and second set of cooling nozzles, wherein the heat exchanger system comprises;

a first heat exchanger configured to transfer heat from the heated cooling fluid to cool the cooling fluid to a first temperature; and

a second heat exchanger configured to transfer heat from the heated cooling fluid to cool the cooling fluid to a second temperature lower than first temperature; and

a piping system through which the cooling fluid collected after discharge is transported to the heat exchanger system and the first and second set of cooling nozzles, the piping system being configured such that cooling fluid exiting the first heat exchanger is discharged by the first set of cooling nozzles and cooling fluid exiting the second heat exchanger is discharged by the second set of cooling nozzles.

2. The sheet metal rolling apparatus of claim 1, wherein the rolling mill comprises one or more additional roll stands and wherein cooling the sheet metal comprises discharging the cooling fluid at the second temperature between any two of the roll stands or between all the stands as desired.

3. The sheet metal rolling apparatus of claim 1, wherein the first and second heat exchangers are configured such that a temperature of the cooling fluid discharged from the second set of cooling nozzles is about 5 to 15 degrees Celsius lower than the first temperature.

4. The sheet metal rolling apparatus of claim 1, wherein the first and second heat exchangers are positioned in parallel along a flow path of the cooling fluid through the piping system.

5. The sheet metal rolling apparatus of claim 1, wherein the piping system is configured such that a larger portion of the discharged cooling fluid passes through the first heat exchanger than the second heat exchanger.

6. The sheet metal rolling apparatus of claim 1, wherein the piping system is configured such that about 5 to 20% of the discharged cooling fluid passes through the second heat exchanger.

7. The sheet metal rolling apparatus of claim 1, wherein each of the first and second heat exchangers comprises one or more heat exchangers.

8. The sheet metal rolling apparatus of claim 5, wherein the piping system is configured such that a first portion of the discharged fluid collected is directed through the first heat exchanger and a section portion of the discharged fluid collected is directed through the second heat exchanger.

9. The sheet metal rolling apparatus of claim 8, wherein the piping system is configured such that:

the first heat exchanger is fluidly coupled with the second set of cooling nozzles through one or more valves, and/or

the second heat exchanger is fluidly coupled with the second set of cooling nozzles through one or more valves.

10. The sheet metal rolling apparatus of claim 9, wherein the one or more valves configured to allow the second coolant flow to a selected set of nozzles, wherein the selected set of nozzles comprises a top cooling set of nozzles.

11. The sheet metal rolling apparatus of claim 1, wherein a number of sets of cooling nozzles is between 1 and a total number of roll stands of the mill minus 1.

12. The sheet metal rolling apparatus of claim 1, wherein three sets of cooling nozzles are directed to a top roll surface of each stand.

13. The sheet metal rolling apparatus of claim 1, wherein the first and second sets of nozzles are used in addition to a standard set of cooling and lubrication nozzles discharging coolant to an entry side of the top or bottom roll surface of each roll stand.

14. A method of sheet metal rolling, said method comprising:

rolling a sheet metal between a pair of rolls of each of a first roll stand and a second roll stand of a rolling mill, the roll stands positioned in series along a conveyance path of the sheet metal;

cooling the sheet metal downstream of the first roll stand and upstream of the second roll stand by discharging a cooling fluid at a first temperature from a first set of cooling nozzles during rolling;

cooling the sheet metal downstream of the second roll stand by discharging the cooling fluid at a second temperature from a second set of cooling nozzles during rolling, wherein the second temperature is lower than the first temperature;

collecting the cooling fluid discharged from the first and second set of cooling nozzles, the cooling fluid having been heated by the sheet metal during rolling;

cooling a first portion of the collected cooling fluid in a first heat exchanger to the first temperature by pumping the cooling fluid therethrough;

cooling a second portion of the collected cooling fluid in a second heat exchanger to the second temperature by pumping the cooling fluid therethrough; and

pumping the cooling fluid cooled in the first heat exchanger to the first set of cooling nozzles concurrent with the pumping the cooling fluid cooled in the second heat exchanger to the second set of cooling nozzles.

15. The method of claim 14, wherein the rolling mill comprises one or more additional roll stands and wherein cooling the sheet metal comprises discharging the cooling fluid at the second temperature between any two of the roll stands or between all the stands as desired.

16. The method of claim 14, wherein the second temperature is about 5 to 15 degrees Celsius lower than the first temperature.

17. The method of claim 14, wherein the piping system is configured such that the second portion is about 5 to 20% of the collected discharged cooling fluid.

18. The method of claim 14, wherein the cooling fluid is discharged from the first set of nozzles at the first temperature and the cooling fluid at the second temperature is discharged from the second set of nozzles at the second temperature concurrently during a pass of the sheet metal.

19. The method of claim 14, wherein a number of sets of cooling nozzles is between 1 and a total number of roll stands of the mill minus 1.

20. The method of claim 14, wherein the first and second sets of nozzles are used in addition to a standard set of cooling and lubrication nozzles discharging coolant to an entry side of the top or bottom roll surface of each roll stand.