Apparatus For Continuously Quenching A Heated Metal Plate

Abstract

An apparatus for continuously quenching a heated metal plate moving and restrained in a plane. A pair of quench headers are positioned above and below the plate each having a slot through which quench fluid is directed at an angle in the direction of plate movement. Beyond the impingement of the quench fluid on the plate are a pair of sral grooved rollers positioned and spaced apart engaging the top and bottom surfaces of the metal plate.

Parent Case Text

This application is a continuation-in-part of my copending application Ser. No. 182,724 filed Sept. 22, 1971 for which I am claiming the benefit of the filing date.

This invention relates to an apparatus for continuously quenching a heated metal plate moving and restrained in a plane.

More particularly, this invention pertains to apparatus in which a pair of slotted quench headers direct quench fluid at an angle in the direction of movement of the plate which is subsequently restrained by a pair of spiraled grooved rollers engaging the plate on the top and bottom surfaces.

This invention represents an improvement over the structure shown in my U.S. Pat. No. 3,420,083 (issued Jan. 7, 1969). That patent discloses the use of grooved rolls whereas my present invention teaches replacing those grooved rolls with spiral grooved rolls having sloped walls forming the grooves. These rolls are used to restrain the plate during the quenching operation. In using the type of invention disclosed in my U.S. Pat. No. 3,420,083, large quantities of water are delivered to the plate surface at a high velocity. At the point of initial impingement, the angle must be such as to assure the prevention of any water being driven back along the plate surface in a direction opposite to that of the plate advance. In working with such quantities of water and pressures there is an accumulation of fluid on the top surface of the plate, especially wide plate and the only route of escape is at the edge of the plate. While the use of grooved rolls shown in my U.S. Pat. No. 3,420,083 makes it possible for water to pass further down the plate away from the area of initial impingement, it does nothing to accelerate the movement of the water to the edge of the plate. Furthermore, with straight or annular grooves there is at the lines of contact, an interruption of the quenching fluid along the plate surface following initial impingement. This could create a condition whereby beyond those lines of interruption, the subsurface heat of the plate raises the surface of the steel above a temperature which will temper the steel at the surface causing a loss of hardness and related properties. The steel gives evidence of being tempered by having a typical bluish coloration. Though the grooved roll shown in U.S. Pat. NO. 98 3,420,083 has only a limited contact with the plate surface, this contact between roll and plate does stop the quench water at the line of contact so that there is no quench water in contact with the plate thereafter until water from adjoining areas can flow into the dry areas. The result may be stripes of soft steel on the plate surface which is surface steel that has been tempered by the subsurface heat. To overcome these problems I have designed a spiral grooved roller with sloped wall grooves. The roller is spiraled from the center toward each end of the roll. Water striking the walls of the grooves will then be deflected toward the plate areas downstream to the lines of interruption thereby bringing quench water quickly back into those areas where the flow of water was interrupted by the intermittant contact of the spiraled roll with the plate. This is of great importance on the undersurface of the plate since the flow due to gravity will not bring the water back into the areas which are dry due to the interruption of the quench fluid by the spiraled roll contacting the plate. There is an additional component of water directed toward the plate surface as a result of the walls of the grooves on the rolls being sloped. It is understood that these spiraled grooves will convey plate accurately in the direction of rotation so long as the plate rolls between the spiraled rolls and does not slip in relation to the spiraled rolls.

Practical considerations in the past required an initial quench water velocity of 150 feet per second to produce a perpendicular velocity component of 30 ft./sec. at impingement with the metal plate. This required water pressure at release of around 150 p.s.i. The principal problem encountered in using the means directing quench fluid in the equipment shown in U.S. Pat. No. 3,420,083 was that it was necessary to release the water to atmosphere about 8 inches from the plate surface. Following its release the wter swept around a curved deflector to direct it correctly to the required point of impingement to effect the creation of a uniform curtain of water. Obviously during the time the water traveled from point of release to point of impingement a considerable decrease in velocity occurred due to an unavoidable angle of water divergence, entrainment of air and friction with the deflector. Such a decrease in velocity and widening of the band of impingement considerably reduces the severity of the resulting quench.

In present practices to avoid surface tempering, the plate is moved at a relatively slow speed to allow time to elapse before the point of water interruption. This results in plate warping between the points of restraint before and after impingement of the quench fluid and cooling of the plate to such a degree that the warpage is fixed. Spiral grooved rolls permits higher plate speeds through the quench with a considerable improvement in plate flatness. Actual maximum speeds were originally 30 to 40 feet per minute for the thinnest plate. The speed was then increased to 60 feet per minute with the use of annular grooves. When using spiral grooved rolls, the speed is no longer limited by the occurrence of surface tempering caused by the interruption of flow of quench fluid along the plate. Therefore, plate 3/16 inch thick can be passed through the quench at speeds over 250 feet per minute. New techniques in quenching use the heat remaining in the plate after rolling. Such an operation requires higher plate speeds through the quench. The one problem is that heavy plate takes less time to roll and more time to quench. The solution is to quench at higher plate speed which is made possible by the spiral grooved roll.

The invention of the new header makes it possible to release the water at a point about 2 inches from the point of impingement. No deflector is required to change individual jets to a curtain because the fluid is in the form of a curtain at the point of release. As a result it is possible to produce a nearrow band of impingement fluid with a high perpendicular velocity component with only about 40 p.s.i. water pressure at the point of release. This effects a sharper and more effective band of impingement with very substantially reduced requirements for volume and pressure of quench water. This means a considerable saving of money in water supply facilities with comparable savings in power requirements for average size plate quenches.

I provide an apparatus for continuously quenching a heated metal plate moving and restrained in a plane, the improvement comprising means applying a curtain of quench fluid which impinges the top and bottom surfaces of the metal plate; the fluid is applied in the direction of movement of the metal plate; and a pair of spiral grooved rollers positioned and spaced apart to engage the top and bottom surfaces of the metal plate, the rollers are positioned subsequent to the impingement of the quench fluid in the direction of movement of the metal plate.

I preferably provide that the spiral grooved rollers are formed by sloped walls and the spiral going from the center to each end of the roll.

I preferably provide that the means applying a curtain of quench fluid comprises a pair of corresponding headers positioned above and below the travel of the metal plate, each header formed by a gate member converging with a rigid back member to form a longitudinal slit across the path of the plate travel, the slit oriented to face the plate at an angle in the same direction of travel of the metal plate, the gate member is adjustable to vary the opening of the slit and means supplying quench fluid to each header.

Other objects, purposes and advantages of the invention will become apparent as the following description of a present preferred method of practicing the invention proceeds.

Description

In the accompanying drawings I have illustrated a present preferred method of practicing the invention in which:

FIG. 1 is a longitudinal sectional view of the quench apparatus;

FIG. 2 is an isometric portion of the quench apparatus including the quench headers 18 and 20 with a pair of spiraled grooved rolls and a subsequent pair of quench spray pipes showing a plate traveling between the pairs of headers and rolls;

FIG. 3 is an elevational view of a spiraled grooved roll;

FIG. 4 is a cross sectional view of the roll shown in FIg. 3 and taken on the line IV--IV of FIG. 3;

FIG. 5 is an enlarged fragmentary view of one of the quench headers;

FIG. 6 is an elevational view of another embodiment of a spiraled grooved roll which can be used instead of the spiral grooved roll shown in FIG. 3;

FIG. 7 is another embodiment of an enlarged fragmentary view of a quench header which can be used instead of the header shown in FIGS. 2 and 5; and

FIG. 8 is an elevational view of another embodiment of the threaded rod and nut at the gate of the header shown in FIG. 7.

Referring to FIG. 1, the apparatus comprises a plurality of upper and lower entry cylindrical rolls 10, 12, 14 and 16 which restrain the plate 30 in a plane at the entry end 26 of the apparatus. Adjacent to rolls 12 and 16 are top and bottom quench headers 18 and 20 which produce high velocity quench curtains (sheets of liquid) 62 and 64 respectively which impinge the metal plate 30 on top and bottom surfaces of the plate. Positioned beyond quench headers 18 and 20 in point of travel of the plate 30 are spiraled grooved rolls 22 and 24 engaging the top and bottom of the plate 30 followed by quench spray pipes 32 and 34 which supply quench fluid on the plate 30 and toward rolls 22, 24, 36 and 38. Positioned beyond quench spray pipes 32 and 34 are additional spiraled grooved rolls 36 and 38 which engage the top and bottom of the plate 30. Positioned beyond those rolls are quench spray pipes 40 and 42 and additional spiraled grooved rolls 44 and 46.

As plate 30 leaves a furnace it enters into the entry end of the apparatus described where it is restrained in a plane by the entry rollers and the spiraled grooved rollers until it leaves at the exit end of the apparatus. The main headers 48, 50, 52 and 54 supply quench headers 18 and 20 and quench spray pipes 32, 34, 40 and 42 with quench fluid. The quench spray popes 32, 34, 40 and 42 have a plurality of openings (or nozzles) to release the quench fluid. Beams 58 support the spiraled grooved rolls 22, 24, 36, 38, 44 and 46. Frames 60 and 61 support the support beams 58 and rolls 10, 12, 14 and 16 as well as headers 18 and 20 and the quench spray pipes 32, 34, 40 and 42. The upper rolls have a load 56 exerting a downward force which is transmitted to the plate 30. All of the cylindrical rolls and the grooved rolls 10, 12, 14, 16, 22, 24, 36, 38, 44 and 46 are driven at the same speed by means of a sprocket and chain motor drive shown in my earlier U.S. Pat. No. 3,423,254. Rolls 10, 12, 22, 36 and 44 rotate in the opposite direction from rolls 14, 16, 24, 38 and 46. Each of the rolls are journaled and supported by bearings as shown in my U.S. Pat. No. 3,423,254. The upper frame 60 is pre-positioned until the top cylindrical rolls 10 are positioned to restrain the metal plate 30 as it enters the apparatus after leaving a furnace. The metal plate 30 then passes between rolls 12, 16, 22, 24, 36, 38, 44 and 46. Quench fluid 62 and 64 in the form of a continuous high velocity curtain impinges the metal plate 30 which sets the cooling temperature of the metal plate 30. The high velocity quench curtains impinge the plate 30 on top and bottom surfaces at an angle between 10.degree. and 40.degree. which prevents the quench fluid from reaching a part of the work 30 which has not advanced to the point of impingement.

FIG. 2 shows a more detailed isometric view of the headers 18 and 20 which provide the initial quench curtains 62 and 64 with the use of the spiraled grooved rolls 22, 24, 36 and 38 with additional quenching spray pipes 32 and 34. All of the spiraled grooved rolls 22, 24, 36, 38, 44 and 46 are identical. Rolls 44 and 46 are not shown in FIG. 2. The spiraled grooved roll 22 (also shown in FIGS. 3 and 4) shows a plurality of spiraled rib-like walls 74 disposed in parallel spaced relation, the walls extending from the center 76 in opposite directions outwardly to each end 78 and 80 (shown also in FIG. 3). The spiraled walls are tapered symmetrically in thickness, that is the side surfaces 82 and 84 slope inwardly as the wall approaches the outer surface of the roll 22 (shown in FIG. 4). The use of the spirally grooved roll 22 with the spiraled walls 74 directed from the center 76 toward each end 78 and 80 accelerates the movement of the quench fluid to the edge of the plate 30. Quench fluid is also deflected toward the plate areas downstream in the line of travel of the plate to the points of interruption thereby bringing quench liquid quickly into those areas where the flow of quench fluid was interrupted by the intermittent contact of the spirally grooved roll. The sloped sides of the walls provide an additional component of quench fluid directed toward the plate surface.

FIGS. 2 and 5 show detailed isometric views of the headers 18 and 20. The header 18 is coupled to the main header 48 by the conduit coupling 86 shown in FIG. 5. Headers 18 and 20 are identical except they are reversed in position and are positioned directly above and below and facing each other allowing the plate to pass between them. Header 18 has a gate member 88 which converges with a rigid back member 90 to form a longitudinal slit 92 across the path of the plate 30 travel. The slit 92 is oriented to face the plate 30 at an angle in the same direction of the travel of the metal plate 30. Gate member 88 is adjustable to vary the opening of the longitudinal slit 92 by loosening bolts 94 and 96 which are inserted through oversized holes. The gate member 88 can be moved upwardly or downwardly to vary the slit opening 92. A hinge member 98 couples the gate member 88 and can be swung open after bolt 94 is removed for ease of cleaning obstructions from the slot and replacemnt of gate member 88.

After the initial line of impingement 100 on plate 30 (FIG. 2) is formed by quench curtains 62 and 64, quench spray pipes 32, 34, 40 and 42 provide quench fluid on the plate 30 toward each of the spiraled grooved rolls that the particular quench spray pipe straddles.

The initial quench fluid in the form of quench curtains 62 and 64 impinge the metal plate 30 at a high velocity which sets the cooling temperature of the plate 30. The quench fluid then travels between the spiraled grooved rolls 22, 24, 36, 38, 44 and 46 and follows the metal plate 30 which is restrained by the rolls. The additional quench fluid from quench spray pipes 32, 34, 40 and 42 maintains the cool temperature reached at the initial impingement point 100 (FIG. 2) on the plate 30 surface.

The spiral grooved rolls 22, 24 shown in FIGS. 2 and 3 are expensive to make and machine. To provide a spiral grooved roll at a reduced cost the spiral grooved roll generally shown as 102 in FIG. 6 was developed. It comprises a shaft 104 on which are mounted a plurality of discrete cylindrical spiral segments 106 and 108. The segments 106 have their spiral grooves oriented in reverse direction of the cylindrical spiral groove segments 108. The segments are divided in their orientation at the center 110 of the shaft 104. The use of the segments gives the advantage of being able to use segments which can be cut on machines for cutting worms or they can be cut on a suitable gear cutting machine. By using segments made from gear cutting machines the cost of producing the spiral groove rolls is greatly reduced.

FIG. 7 shows another embodiment of a header 112. The purpose of the header 112 is to provide an adjustable opening to quickly and easily flush out accumulated obstructions. The header 112 comprises a U-shaped, rigid back member 114 and a gate 116 which is pivotally connected at 118 by means of a hinge 120 on one end of the gate member 116 and a corresponding end of the U-shaped rigid back member 114. The other end of the gate member 116 opposite the pivot 118 converges with the U-shaped rigid back member 114 to form a longitudinal slit 122 across the path of the plate travel. The slit is oriented to face the plate at an angle in the same direction of travel of the metal plate. To open the gate member 116 a rod 124 extends through both the gate member 116 and U-shaped rigid back member 114. It is threaded at each end and has corresponding nuts 126 and 128. Rubber gaskets 130 and 132 hold leakage through gate and the rigid U-shaped back member to a minimum. In order to move the gate 116 away from the rigid backup member 114 about pivot 118 and thereby open the slot 122, nut 128 is rotated. This enables one to flush out any accumlated obstructions. For a very long header, there would be a plurality of rods 124 with corresponding nuts 128 and each of the nuts would be coupled to an output shaft of a small worm gear reducer. The reducers would all be in a line and would have their inward shafts all coupled together in series. In this manner all the adjusting nuts could be turned simultaneously and uniformly by rotating the coupled input shafts either manually or by a suitable powered unit. The slot 122 would then be opened or closed through its full length for flushing or for adjustment of the slot width.

FIG. 8 shows a resilient biasing means 134 between the gate member 116 and the nut 128 on the rod 124.

Claims

I claim:

1. Apparatus for continuously quenching a heated metal plate moving and restrained in a plane, the improvement comprising:

a. header means for impinging a continuous curtain of quench fluid on the top and bottom surfaces of the metal plate, the curtain of quench fluid being applied in the direction of movement of and at an acute angle with respect to the metal plate; and

b. a pair of parallel spirally grooved rollers positioned and spaced apart to engage the top and bottom surfaces of the metal plate, the rollers being positioned downstream with respect to the line of impingement of the quench fluid in the direction of movement of the metal plate, and effective to distribute the quenching fluid uniformly and evenly over top and bottom surfaces of the moving plate as it moves past said rollers.

2. Apparatus as recited in claim 1 wherein the spirally grooved rollers have grooves formed by tapered rib walls which slope inwardly as the height of the walls approaches the outer surface of the roller.

3. Apparatus as recited in claim 1 wherein each of said header means is formed by a hinged gate member releasably fixed in a converging position with respect to a rigid back member to form therewith a longitudinal slit across the path of the plate travel, the slit being oriented to direct the curtain of quench fluid in the direction of travel of the metal plate and at an angle of 10.degree. to 40.degree. thereto, the gate member being adjustable in length to vary the width of the opening of the slit, and conduit means supplying pressurized quench fluid to each of said header means.

4. Apparatus as recited in claim 1 wherein each of the spirally grooved rollers comprises a shaft and a plurality of discrete spirally grooved cylindrical segments which are mounted in spaced relation along said shaft, the segments to one side of the longitudinal center of each roller having grooves spiraled in one direction and those on the opposite side of the longitudinal center of the roller having grooves spiraled in the opposite direction.

5. Apparatus as recited in claim 1 wherein each of said header means is formed by a gate member having a pivot connection at one end to a rigid back member and converging with the rigid back member at an end opposite the pivot connection to form with the back member a longitudinal slit across the path of the plate travel, the slit being oriented to direct the curtain of quench fluid in the direction of travel of the metal plate, and means for holding the gate in a fixed position and for moving it pivotally toward and away from the rigid back member to vary the width of the opening of the slit to enable accumulated obstructions therein to be flushed out by pressurized fluid supplied to the header means.

6. Apparatus as recited in claim 2 wherein the tapered rib walls of the spirally grooved rollers extend in opposite directions from the center of the roller toward each end, the oppositely extending sections of said tapered rib walls meeting in end-to-end abutting relation at the center of the roller.

7. Apparatus as recited in claim 5 wherein the rigid back member is U-shaped in cross-section and wherein the means for moving the gate member pivotally toward and away from the rigid U-shaped back member comprises a rod connecting the rigid U-shaped back member and the gate member, the rod extending through an opening in the gate member and having threads on the end of which a corresponding nut is screwed which when turned in one direction allows the gate member to be pivoted away from the U-shaped back member by the pressurized fluid within the header means and which when turned in the opposite direction moves the gate member toward the U-shaped back member.

8. Apparatus as recited in claim 7 wherein a resilient biasing means is inserted on the rod between the gate member and the nut for yieldingly holding the gate member in position against the force of pressurized fluid within the header means.

9. Apparatus as recited in claim 1 wherein each of said header means is formed by a hinged gate member releasably fixed in a converging position with respect to a rigid back member to form therewith a longitudinal slit acorss the path of the plate travel, the slit being oriented to direct the curtain of quench fluid in the direction of travel of the metal plate and at an angle of 10.degree. to 40.degree. thereto, and conduit means supplying pressurized quench fluid to each of said header means.