MXPA99009311A - Delayed cooling system with aislamie granular material - Google Patents

Abstract

The present invention relates to a method for cooling a hot-rolled steel product to a delayed cooling rate, the method comprising: forming the product into a continuous series of rings, depositing the rings on a conveyor at a receiving station and transporting the rings in a non-concentric overlap pattern from the receiving station through a cooling zone to a reforming station where the rings are delivered from the conveyor and assembled in vertical coils, and cover the rings that are transporting through the cooling zone in a layer of granular insulation material

Description

DELAYED COOLING SYSTEM WITH GRANULAR INSULATION MATERIAL * 1. FIELD OF THE INVENTION This invention relates to laminators that produce hot-rolled steel products such as rods, rods and the like, and is related in particular to an improved system and method for cooling said products in delayed cooling regimes. 2. DESCRIPTION OF THE PREVIOUS ICA TECHNIQUE It is known to form hot-rolled steel rods in rings which are deposited on a conveyor and transported through cooling zones where the rod is cooled at controlled regimes in order to achieve desired metallurgical properties. Cooling rates can be accelerated through forced application of a gaseous refrigerant, typically ambient air, or cooling rates can be delayed through the use of insulated covers that line the conveyor. Examples of the above are described in the Patents of E. U., Nos. 3,320, 101 (McLean et al.); 3,930,900 (Wilson); 3,940,961 (Gilvar) and 4,468,262 (Kaneda et al.). A disadvantage of such installations is that the prolonged exposure of the rings to the ambient air and promotes the development of surface oxide, which must be removed afterwards before the product is subjected to further processing, v. g., wire stretching, machining, etc. Also, cooling regimes tend to be non-uniform and somewhat difficult to control. Other attempts at more uniform delayed cooling have included the use of hot water baths and fluidized baths, but these have not proven to be commercially viable.

BRIEF DESCRIPTION OF THE INVENTION The object of the present invention is to overcome the disadvantages associated with the prior art systems described above by embedding the rings that are transported on the conveyor in a granular insulating material. By doing this, the exposure of the ring surfaces to the ambient air is minimized significantly, with a concomitant reduction in the development of surface oxide. Collateral advantages include more uniform cooling, and an ability to more closely control cooling rates, for example by either heating or cooling the granular insulation material before application to the product rings.

BRIEF DESCRIPTION OF THE DIAMETERS These and other objects and advantages will now be described in greater detail with reference to the accompanying drawings, in which: Figure 1 is an illustration of one embodiment of a system according to the present invention; and Figure 2 is an enlarged view of a portion of the system shown in Figure 1; and Figure 3 is an illustration of an alternative system according to the present invention.

DETAILED DESCRIPTION OF PREFERRED MODALITIES With reference initially to Figures 1 and 2, one embodiment of a delayed cooling system according to the present invention is generally represented at 10. A continuous band 12 of steel sheet or other heat-resistant material A suitable portion extends between laminators 14a, 14b, at least one of which is driven by conventional propulsion (not shown) to move the upper band portion from left to right as seen in the drawing. The web is supported at separate locations between the mills 14a, 14b, by rollers typically indicated at 16, which can also be driven. The hot-rolled steel rod is received from a laminator and directed downwards by a spur roller unit 19 and a guide mechanism 20 rolled to a laying head 22 which forms the rod in a continuous series of rings 24. Immediately current above the laying head 22, a feeder mechanism 26 deposits a base layer 28 of a granular insulation material preheated in the strip 12. The insulation material may typically comprise dolomite, silica, sand or the like having a grain or size of particle that fluctuates from approximately 1 to 8 mm.

The rings 24 emerging from the laying head 22 are deposited in a non-concentric overlapping pattern in the base layer 28 of insulation, and are immediately covered by an upper layer 30 of granulated preheated insulation material applied by a second feeder mechanism 32. Typically, the rod rings will be laid on the conveyor at an elevated temperature above about 500 ° C, and the granular insulation will be preheated to ± 100 ° C of that laying temperature, resulting in the rod being cooled in the transporter to a delayed regime in the order of 0.05 to 1 o C / sec. It will be understood, of course, that this is only one of a thousand different delayed cooling processes that can be carried out with the described system. Cooling rates will vary depending on the temperature of the rod that is laid on the conveyor, the temperature and / or type of granular insulation, and other factors, including the optional use of insulating covers or the like to further delay cooling. Under certain conditions, it may be desirable to cool rather than preheat the granular insulation material. At the delivery end of the conveyor, the rings 24 pass on mutually driven rollers 36 before being received in a reformer chamber 38 where they are assembled in vertical cylindrical rolls. The granular insulation material falls between the rollers 36 to a hopper 40. An auger 45 moves the insulation material laterally from the hopper to a bucket conveyor 44 or other similar transport mechanism that serves to recirculate the granular insulating material back to the feeder mechanism 32, and via an auxiliary conveyor 47 to the feeder mechanism 26. Although the granular insulating material will be continuously reheated by the heat given by the rings in the conveyor, some additional reheating may be required, and for this purpose the heaters 46 may be provided along the path of the conveyor 44 and / or below the web 12. The upper end of the reforming chamber 38 is of a known design, as described for example in U.S. Patent Nos. 5,501, 410 (Starvaski) and 5,735,477 (Shore et al.), And includes a nose cone 40 suspended by an iris mechanism 42 which can be oved in and out of the downwire path and insulated pots 44 are movable in roller conveyor segments 46a-46d driven from a standby "A" to a coil-receiving position "B" in the reforming chamber 38 , and from there to a "C" procrastination station. Each pot has an inner core 48 which cooperates with a surrounding insulated wall to define an annular chamber 50. Piston-cylinder units 52 are operable to raise the roller conveyor segment 46b, thereby raising the wave 44 supported therein to place its core 48 in support contact with the nose cone 40. This releases the iris mechanism 42 for retraction, so the rings are allowed to descend over e! cone 40 of nose and to chamber 50 of the underlying pot for collection in a coil. Upon completion of a coil forming operation, the iris mechanism 42 closes and the conveyor segment 46b is lowered, resulting in the nose cone 40 being redeposited in the iris. The filled pot is then changed to the procrastination station C where it is covered by a cover 54. At the same time, another empty pot moves to the position B of receipt of coils and the entire operation is repeated. In an alternative embodiment of the present invention as depicted in Figure 3, the granular insulation material falling between the separate rollers 36 is directed downward to the annular chamber 50 of a pot in the standby station A. The full pot is then changed to the position B of receipt of coils, and its place in the waiting station A is taken by another empty pot (not shown). In this embodiment, the pots are provided with a door mechanism 56 in the bottoms of the annular chambers. During the bobbin forming operation, the pot door mechanism in the receiving position B is opened to control the discharge of granular insulation material downwards through the rollers separated from the conveyor segment 46b on a conveyor belt 58 to return to bucket conveyor 44. The gradually decreasing level of the granular insulation in the chamber 50 of the pot serves as a downward coil support which keeps the top of the accumulating coil at a relatively constant level.

In light of the foregoing, it will be appreciated that the present invention offers a number of significant advantages not available with prior art systems. Of particular importance is the immediate incrustation of the rings 24 emerging from the laying head 22 in the granular insulation material. By doing this, the development of surface rust is minimized significantly, while at the same time making it possible to achieve a more uniform and controllable regime of delayed cooling. At the end of the delayed cooling cycle in the conveyor, the granulated insulation material can either be recovered and recirculated back to its initial application points, or it can supply a continuous support function in the insulated pots that are used in the reforming chamber. It will now be apparent to those skilled in the art that the modalities chosen herein for the purpose of description are amenable to modification by structurally and functionally replacing steps and / or equivalent components. By way of example only, and without limitation, other systems including those that are pneumatically driven may be employed to recirculate the granular insulation material. The length, design and configuration of the conveyor can be modified to meet the requirements of several installations. The insulated covers on the conveyor are optional, as are the heaters that can be used to reheat the granular insulation material in several stages during the delayed cooling, recovery and recirculation cycles.

It is my intention to cover these and all changes and modifications that do not depart from the spirit and scope of the invention as defined by the claims appended hereto.

Claims (23)

1. REVI N DICACIONES
2. 1 . A system for cooling a hot-rolled steel product to a delayed cooling rate, said system comprising: cooling means for forming said product in a continuous series of rings; conveying means for receiving said rings of said cooling means in a receiving station and for transporting said rings in a non-concentric overlap pattern of said receiving station through a cooling zone to a reforming station in which said rings they are delivered from said conveying means and assembled in vertical coils; and insulating means to cover the rings that are transported through said cooling zone with granular insulation material. The system as claimed in claim 1 wherein said isolating means includes first feeder means for depositing a first layer of said granular insulating material in said conveying means at a location upstream of said reforming station, said first layer thereby underlining the rings that are received from said cooling means, and second feeder means for depositing a second layer of granular insulation material on thereby, received rings at a location downstream from said reforming station.
3. 3. The system as claimed in claim 1 fer comprising means for separating said granular insulation material from said rings prior to delivery of said rings from said conveying means.
4. The system as claimed in claim 3 fer comprising means for recovering the granular insulation material thereby separated, and return means for recirculating the granular insulation material thus recovered back to said insulation means.
5. The system as claimed in claim 4 fer comprising means for reheating the granular insulation material that is recirculated back to said insulation means.
6. The system as claimed in claim 3 fer comprising insulated pots for containing said vertical spools, and second conveying means for transporting said pots from a waiting station to said reforming station where said pots receive and contain said rings in the form of of coil, and from shower reforming station to a holding station where said rings continue to cool to a delayed regime in said pots.
7. The system as claimed in claim 6 fer comprising means for filling the pots in said holding station with the granular insulation material which is separated from said rings.
8. 8. The system as claimed in claim 7 fer comprising means for removing the granular insulation material from said pots in said reforming station, said removal being at a controlled rate with respect to the rate at which said pots are receiving rings from said half conveyor.
9. The system as claimed in claim 8 fer comprising recovery means for recovering the granular insulation material thus removed, and for recirculating the granular insulation material thus recovered back to said insulating medium.
10. The system as claimed in claim 9 fer comprising means for reheating the granular insulation material which is recirculated back to said insulating medium. 1.
11. A method for cooling a hot-rolled steel product to a delayed cooling rate, said method comprising: forming the product into a continuous series of rings; depositing said rings on a conveyor in a receiving station and transporting said rings in a non-concentric overlap pattern of said receiving station through a cooling zone to a reforming station where the rings are delivered from the conveyor and assembled in vertical coils; and cover the rings that are transported through said cooling zone with granular insulation material.
12. The method as claimed in claim 1 wherein a first layer of said granular insulation material is deposited on said conveyor at a location upstream of said receiving station, thereby underlying the rings that are deposited at said conveyor, and wherein a second layer of said granular insulation material is deposited on said conveyor at a current location below said receiving station, whereby said are embedded in said granular insulation material.
13. The method as claimed in claim 1, further comprising the step of separating said granular insulation material from said rings at a location upstream of said receiving station.
14. The method as claimed in claim 13 further comprising the step of recovering and recirculating the granular insulation material thereby separated for reuse to cover the rings that are transported through said cooling zone.
15. 15. The method as claimed in claim 14 further comprising the step of reheating the granular insulation material that is recirculated.
16. 16. The system as claimed in claim 13 further comprising the step of containing the vertical coils that are formed in said receiving station in insulated pots.
17. 17. The method as claimed in claim 16 wherein before being placed in said receiving station, said pots are filled with the granular insulation material thus separated, and said granular insulation material is then gradually removed from said pots in said receiving station, the withdrawal regime of said granular insulation material being related to the regime to which said pots receive rings from said conveyor.
18. 18. The method as claimed in claim 17 further comprising the step of recovering the granular insulation material thereby separated for recirculation and reuse to cover the rings that are conveyed through said cooling zone.
19. 19. The method as claimed in claim 18 further comprising the step of reheating the granular insulation material that is recirculated.
20. The method as claimed in claim 1 wherein said rings are deposited on said conveyor at a laying temperature above about 500 ° C.
21. The method of claim 20 wherein before covering said rings, said granular insulation material is preheated to a temperature of ± 100 ° C of said laying temperature.
22. 22. The method of claim 21 wherein said rings are cooled to a delayed rate of the order of 0.05 to 1o C / sec.
23. 23. The method of claim 1 wherein said granular isolation material is selected from the group consisting essentially of dolomite, sand, silica and the like.