Casting strip

• US 6,698,498 B1
• Filed: 10/24/2001
• Issued: 03/02/2004
• Est. Priority Date: 04/08/1999
• Status: Expired due to Term

• Current Assignee: Nucor Corporation
• Original Assignee: Castrip LLC
• Inventors: Ziegelaar, John Albert, Kato, Heiji
• Primary Examiner(s): Elve, M. Alexandra
• Assistant Examiner(s): MCHENRY, KEVIN L
• Application Number:
  US09/958,187
• Time in Patent Office: 860 Days
• Field of Search: 164/480, 164/428, 164/460, 164/417, 164/477, 164/476, 164/451, 164/452, 164/454, 164/150.1, 164/413, 295/277
• US Class Current: 164/477
• CPC Class Codes: B22D 11/0622 formed by two casting wheels
• CPC Class Codes: B22D 11/0694 for peeling-off or removing the cast product
• CPC Class Codes: B22D 11/126 for cutting

Abstract

Twin roll caster produces cast steel strip that passes in a transit path through pinch roll stand and optional hot rolling mill and runout table to a coiling station which has a pair of switchable coilers. A strip shear located in advance of the coiling station is operable to sever strip into discrete lengths which can be diverted by setting deflectors to allow the severed lengths to pass across a runout table to a scrap bin. The strip may be thus severed and diverted to scrap on development of strip defects or malfunctioning of equipment without stopping continuous casting and the strip redirected to the coiling station when the problem is rectified.

Claims

1. A method of continuously casting and handling metal strip, comprising:

supporting a casting pool of molten metal on one or more chilled casting surfaces;

moving the casting surface or surfaces to produce a solidified strip moving away from the casting pool;

guiding the solidified strip along a transit path which takes it away from the casting pool to a coiling station;

coiling the strip onto a coiler at the coiling station;

operating a strip shearing so as to sever the strip in advance of the coiling station into discrete lengths;

diverting the severed lengths of strip from the coiling station to a scrap station; and

halting the operation of the strip shearing so as to reinstate delivery of continuous strip to the coiling station and directing the reinstated continuous strip to a second coiler at the coiling station.

2. A method as claimed in claim 1, wherein a scrap bin is located at the scrap station to receive the severed lengths of strip.

3. A method as claimed in claim 2, wherein the operation of the strip shearer and diversion of the severed lengths of strip to the scrap station is initiated in response to observation or detection of defects in the strip.

4. A method as claimed in claim 3, comprising the steps of inspecting the strip for defects as it passes in said transit path by means of strip defect detector located along that path and initiating operation of the strip shearer in response to an indication from the defect detector of defects in the strip.

5. A method as claimed in claim 4, wherein the defect detector is operated to detect variations in thickness of the strip.

6. A method as claimed in claim 5, wherein the defect detector comprises an X-ray gauge.

7. A method as claimed in claim 4, wherein the defect detector is operated to detect surface defects in the strip.

8. A method as claimed in claim 4, wherein the strip proceeding along said transit path passes through a cooling station and the strip is examined by the defect detector upstream and downstream of the cooling station.

9. A method as claimed in claim 8, wherein the strip is examined upstream of the cooling station for thickness defects and is examined downstream of the cooling station for surface defects.

10. A method as claimed in claim 2, wherein the operation of the strip shearer and diversion of the severed lengths of strip to the scrap station is initiated in response to malfunctioning of equipment employed in the casting or handling of the strip.

11. A method as claimed in claim 1, wherein the operation of the strip shearer and diversion of the severed lengths of strip to the scrap station is initiated in response to observation or detection of defects in the strip.

12. A method as claimed in claim 11, comprising the steps of inspecting the strip for defects as it passes in said transit path by means of a strip defect detector located along that path and initiating operation of the strip shearer in response to an indication from the defect detector of defects in the strip.

13. A method as claimed in claim 12, wherein the defect detector is operated to detect variations in thickness of the strip.

14. A method as claimed in claim 13, wherein the defect detector comprises an X-ray gauge.

15. A method as claimed in claim 12, wherein the defect detector is operated to detect surface defects in the strip.

16. A method as claimed in claim 12, wherein the strip proceeding along said transit path passes through a cooling station and the strip is examined by the defect detector upstream and downstream of the cooling station.

17. A method as claimed in claim 16, wherein the strip is examined upstream of the cooling station for thickness defects and is examined downstream of the cooling station for surface defects.

18. A method as claimed in claim 1, wherein the operation of the strip shearer and diversion of the severed lengths of strip to the scrap station is initiated in response to malfunctioning of equipment employed in the casting or handling of the strip.

19. A method as claimed in claim 1, wherein the casting pool of molten metal is maintained by flow of molten metal from a tundish supplied alternatively by each of a plurality of ladles brought to a pouring position by a rotating turret.

20. An apparatus for continuously casting and handling metal strip comprising:

a pair of generally horizontal chilled casting rolls forming a nip between them;

a metal delivery system to deliver molten metal into the nip between the casting rolls to form a casting pool of molten metal supported on the rolls;

a rotator to rotate the casting rolls in mutually opposite directions whereby to produce a cast strip delivered downwardly from the nip;

a strip guide to guide the strip delivered downwardly from the nip through a transit path which takes it away from the nip;

a coiling station to receive the strip from said transit path and provided with a pair of coilers and a strip deflector apparatus operable alternatively to direct the strip to one or other of the coilers;

a strip shearer downstream of the strip guide operable repeatedly to sever the strip in advance of the coiling station to chop the continuously delivered strip into a multiplicity of discrete strip lengths; and

a strip diverter to divert the multiplicity of discrete strip lengths so as to bypass both coilers at the coiling station and deliver them to a scrap station.

21. An apparatus as claimed in claim 20, wherein a scrap bin is located at the scrap station to receive the severed lengths of strip.

22. An apparatus as claimed in claim 21, wherein there is a pair of strip deflectors at the coiling station operable alternatively to divert the strip to one or other of the coilers.

23. An apparatus as claimed in claim 20, wherein the strip deflector apparatus comprises a pair of strip deflectors at the coiling station operable alternatively to divert the strip to one or other of the coilers.

24. An apparatus as claimed in claim 23, wherein the strip diverter comprises a runout table to guide the severed strip lengths to the scrap station when the deflectors are inoperative to deflect strip to either coiler.

25. An apparatus as claimed in claim 20, and further including a strip defect detector disposed along said transit path in advance of the coiling station and operable to detect defects in the strip.

26. An apparatus as claimed in claim 25, wherein there is an operative connection between the defect detector and the shearer such that the shearer is operable in response to an indication from the defect detector of defects in the strip.

27. An apparatus as claimed in claim 25, wherein the defect detector is operable to detect variations in thickness of the strip.

28. An apparatus as claimed in claim 27, wherein the defect detector comprises an X-ray gauge.

29. An apparatus as claimed in claim 25, wherein the defect detector is operable to detect surface defects in the strip.